CMP Journal 2026-10-30
Statistics
Nature Physics: 4
Physical Review Letters: 5
arXiv: 178
Nature Physics
Thermodynamic demonstration of tetracriticality and multicomponent superconductivity in UTe2
Original Paper | Superconducting properties and materials | 2026-10-29 20:00 EDT
Sahas Kamat, Jared Dans, Shanta Saha, Artem D. Kokovin, Johnpierre Paglione, Jörg Schmalian, B. J. Ramshaw
The candidate topological superconductor UTe2 exhibits a complex phase diagram with multiple superconducting states, and the nature of their coexistence is not yet resolved. In particular, the apparent observation of two intersecting second-order phase boundaries at a triple point in the pressure-temperature phase diagram is thermodynamically forbidden. This suggests either a hidden phase transition or a fundamental misunderstanding of the superconductivity in this material. Here we observe an additional phase boundary that is characterized by an upward jump in the sound velocity. This is direct thermodynamic evidence for a phase transition in which superconducting order is lost on cooling. Our results establish a tetracritical point beyond which the ambient and pressure-induced superconducting order parameters form a multicomponent state. We use the measured phase diagram to demonstrate that strong competition between the two superconducting order parameters drives the loss of order when cooling, and leads to phase locking that suppresses superconducting fluctuations. These findings provide the definitive magnetic field-pressure-temperature phase diagram of UTe2 and establish a thermodynamic foundation for multicomponent superconductivity.
Superconducting properties and materials, Phase transitions and critical phenomena
Multiparticle quantum walks in a dipole-conserving Bose-Hubbard model
Original Paper | Ultracold gases | 2026-10-29 20:00 EDT
Sooshin Kim, Byungmin Kang, Perrin Segura, Yanfei Li, Ethan Lake, Brice Bakkali-Hassani, Markus Greiner
A strong potential gradient can localize individual particles in a crystal or optical lattice by making ordinary hopping energetically costly. Interactions can nevertheless enable correlated hopping processes that preserve the system’s centre of mass or, equivalently, its dipole moment. This constraint gives rise to fractonic behaviour, in which isolated excitations are immobile but their bound states can move. Here we realize individual mobile bound states of fractons in a dipole-conserving Bose-Hubbard model and observe their coherent quantum dynamics. Starting from a one-dimensional chain of ultracold bosonic atoms in an optical lattice, we use site-resolved optical potentials to deterministically generate localized dipole and antidipole excitations, which represent mobile bound states of a hole and a doublon. We track their individual quantum walks and characterize their strongly interacting scattering dynamics. Our study provides a bottom-up investigation of a Hamiltonian with kinetic constraints and offers an approach to exploring low-energy phases of fractonic matter.
Ultracold gases, Quantum simulation
Automated inverse design of metainterfaces with tailored friction laws
Original Paper | Surfaces, interfaces and thin films | 2026-10-29 20:00 EDT
Li Fu, Djibril Gabriel Kashala, Davy Dalmas, Julien Scheibert
Providing dry solid contacts with on-demand macroscale frictional behaviour remains a formidable challenge in tribology, haptics and robotics. It has been shown that metainterfaces created from surfaces with engineered asperity-based topographies can achieve such friction control. However, only a few types of friction behaviour were demonstrated because suitable topographies were identified on the basis of human intuition. Here we introduce a numerical-optimization-based inverse design framework to automatically discover new metainterfaces that satisfy specified friction laws–relationships between friction and the normal force. To illustrate the framework’s versatility, we first expand the range of achievable friction coefficients for a given pair of materials. We next unlock friction laws showing power-law variation of frictional force with normal force, with exponents ranging between 2/3 and 1.35. We then achieve bilinear variation when the range of normal force is divided into segments, including cases for a smaller slope in the second segment than in the first. We validate relevant cases experimentally. Our automated framework enables systematic exploration of large parameter spaces, not limited to topography but potentially incorporating the individual asperities’ bulk material or surface physicochemistry. It offers design solutions for different friction laws and provides insights into the relationship between local interfacial properties and macroscopic friction.
Surfaces, interfaces and thin films, Design, synthesis and processing
Motors use biased diffusion to shepherd diffusible proteins on microtubules
Original Paper | Motility | 2026-10-29 20:00 EDT
Leila Farhadi, Shane A. Fiorenza, Sithara Wijeratne, Konstantinos Nakos, Yang Yue, Morgan L. Pimm, Jakia Jannat Keya, Kristen J. Verhey, Radhika Subramanian, Meredith D. Betterton
Far-from-equilibrium mixtures of active and passive molecules self-organize, but the principles remain unclear. Microtubules are cytoskeletal polymers composed of 13 protofilaments bound by mixtures of actively moving motors and passively diffusing microtubule-associated proteins (MAPs). They can serve as a model system for self-organization on a multi-lane lattice. Here we show that motors can shepherd diffusive MAPs along the lattice by rectifying Brownian motion into net directional drift without motor-MAP binding. Our model reveals that biased movement increases when fewer protofilaments are accessible or when lateral diffusion between protofilaments is limited, and identifies local dimensionality and diffusion as key parameters governing spatial patterning. In particular, shepherding depends on the total number of motors bound to the microtubules, and not on the individual motor processivity. We experimentally recapitulate micrometre-scale shepherding with a kinesin-1 motor (K401) and a diffusive MAP (PRC1), which show no detectable binding. These findings suggest shepherding is an emergent mechanism by which ensembles of motors generate micrometre-scale spatial patterning and transport of MAPs without direct binding interactions.
Motility, Biological physics
Physical Review Letters
Reduced Gravitational Wave Signal Reopens the Ultralight Primordial Black Hole Window
Article | Cosmology, Astrophysics, and Gravitation | 2026-10-29 06:00 EDT
Yann Gouttenoire, Nicholas Leister, and Pedro Schwaller
The hot big bang may have emerged from evaporation of primordial black holes (PBHs) lighter than . Standard monochromatic treatments predict nearly simultaneous evaporation, abrupt reheating, and a large poltergeist scalar-induced gravitational wave signal. We confront this expectation with th…
Phys. Rev. Lett. 137, 181002 (2026)
Cosmology, Astrophysics, and Gravitation
Odd-Even Parity of Nonlinear Hall Effects in Bilayer Graphene
Article | Condensed Matter and Materials | 2026-10-29 06:00 EDT
Zitian Pan, Jiaheng Li, Jin Cao, Xuejin Zhang, Jundong Zhu, Yu Hong, Zhiheng Huang, Jingwei Dong, Dongxia Shi, Kenji Watanabe, Takashi Taniguchi, Wei Yang, Cong Xiao, Shengyuan A. Yang, Hongming Weng, Luojun Du, and Guangyu Zhang
Experiments reveal a potentially useful odd-even dichotomy in the nonlinear Hall response of bilayer graphene.
Phys. Rev. Lett. 137, 186302 (2026)
Condensed Matter and Materials
Quantum Monte Carlo Studies of U(1) Lattice Gauge Models of Kondo Breakdown
Article | Condensed Matter and Materials | 2026-10-29 06:00 EDT
Gaopei Pan and Fakher F. Assaad
In the local-moment regime, heavy fermions are most economically described by a compact U(1) gauge theory. Motivated by this perspective, we study a minimal compact U(1) lattice gauge model describing a spin chain coupled to two-dimensional Dirac conduction electrons. The spin chain is described by …
Phys. Rev. Lett. 137, 186503 (2026)
Condensed Matter and Materials
Consistent Time Reversal and Reliable and Accurate Inference in the Presence of Memory
Article | Statistical Physics; Classical, Nonlinear, and Complex Systems | 2026-10-29 06:00 EDT
Tassilo Schwarz, Anatoly B. Kolomeisky, and Aljaž Godec
Thermodynamic inference from coarse observations remains a key challenge. Memory, in particular correlations between consecutively observed mesostates, blur signatures of irreversibility and must be accounted for in defining physical time reversal, which remains an open problem. We derive an experim…
Phys. Rev. Lett. 137, 187401 (2026)
Statistical Physics; Classical, Nonlinear, and Complex Systems
Curvature Potential Formulation for Thin Elastic Sheets
Article | Polymers, Chemical Physics, Soft Matter, and Biological Physics | 2026-10-29 06:00 EDT
Yael Cohen, Animesh Pandey, Yafei Zhang, Cy Maor, and Michael Moshe
Thin sheets, from graphene to biological membranes, exhibit wrinkling, folding, and thermal deformations driven by geometric nonlinearities. They are treated using weakly nonlinear theories such as the Föppl-von Kármán equations, whose reliance on small slopes and a single-valued height field exclud…
Phys. Rev. Lett. 137, 188201 (2026)
Polymers, Chemical Physics, Soft Matter, and Biological Physics
arXiv
Tuning La0.7Sr0.3MnO3 magnetic anisotropy via interfacial coupling in homometallic trilayers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Nunzia Coppola, Giovanni Vinai, Alksandr Yu Petrov, Chiara Sacco, Hafiz Sami Ur Rehman, Sofia Scarnicci, Lucia Capogna, Cinzia Di Giorgio, Carmela Aruta, Luigi Maritato, Alice Galdi
In this work we explore the complex magnetic behaviour of SrMnO3/La0.7Sr0.3MnO3/SrMnO3 trilayers combining magneto-optic Kerr effect (MOKE) and magneto-resistance measurements. The interplay of structural and orbital reconstruction and the competition of ferromagnetism/antiferromagnetism at the interfaces is responsible of a variety of complex magnetic properties, highlighting the use of heterostructures as an effective strategy to tune and control magnetic behaviour. We demonstrate the possibility to tune the magnetic properties of a ferromagnetic La0.7Sr0.3MnO3 (LSMO) layer, embedded in two homometallic antiferromagnetic layers (SrMnO3, SMO), by properly varying the role of interfaces using two different LSMO thickness values. Spin reorientation of the LSMO magnetic easy axis away from its room temperature orientation was observed below 125 K, due to the predominance of exchange interaction at the interface over the substrate-induced magnetic anisotropy, in agreement with established models for homometallic manganite heterostructures. The competition of super-exchange and exchange interactions at the interface results in a highly frustrated interfacial spin glass state, resulting in 20-fold enhancement of the coercive field and exchange bias. The modification of the magnetocrystalline anisotropy driven by the interfacial effects leads to a change in the anisotropic magneto-resistance response of the system, which dominates the low temperature behaviour.
Materials Science (cond-mat.mtrl-sci)
21 pages, 10 figures. Supplementary: 2 pages, 1 figure
A $B_{1g}$ phonon unlocks $d$-wave superconductivity in the repulsive Hubbard model
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-30 20:00 EDT
Wen O. Wang, Tianshu Li, Xiaoyue Ma, Rong Zhang, Lei Zhang, Shruti Agarwal, Benjamin Cohen-Stead, Emily Z. Zhang, Brian Moritz, Steven Johnston, Zhi-Xun Shen, Thomas P. Devereaux
Using numerically exact finite-temperature quantum Monte Carlo, we demonstrate that a $ B_{1g}$ phonon coupled to the doped $ t$ -$ t’$ repulsive Hubbard model produces genuine $ d$ -wave superconductivity at a substantial transition temperature, in excess of either interaction alone. The observed trends suggest that stronger Hubbard repulsion may cooperate with the phonon to further raise the pairing scale. The enhancement persists at stronger repulsion within the accessible window, limited by the fermion sign problem, and follows a common trend across phonon frequencies $ \Omega$ when organized by a retardation scale $ 2\pi T/\Omega$ . We also find a well-defined superconducting dome in doping, echoing a characteristic feature of correlated superconductors. Our results identify the $ B_{1g}$ phonon as a plausible microscopic ingredient for robust $ d$ -wave superconductivity in the Hubbard model and suggest a concrete, physically motivated route toward materials with higher superconducting transition temperatures.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
49 pages, 18 figures (main text: 20 pages, 4 figures; Supplementary Materials: 29 pages, 14 figures)
Approaching Landauer’s limit in a single superconducting vortex memory bit
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-30 20:00 EDT
Nofar Fridman, Itai Keren, Avia Noah, Yishay Zur, Martin E. Huber, Nadav Katz, Roland Willa, Hadar Steinberg, Yonathan Anahory
This work investigates the energy required to manipulate a memory bit using a superconducting vortex confined in a nanoscale double-well pinning potential. In the experiments, various double-well systems subjected to sinusoidal forces is explored, and the effects of both driving force and frequency is analyzed. Results reveal characteristic stochastic resonance behavior for weak drives and adiabatic manipulation at strong, low-frequency drives. Although our experimental method requires a steady sinusoidal drive incompatible with Landauer’s erasure protocol, our numerical analysis demonstrates that the work required for such bit manipulation (erasure) is within an order of magnitude of Landauer’s limit ($ k_B T \ln 2$ ) at 4.2 K. These findings open possibilities for creating highly efficient memory elements that could be integrated with cryogenic quantum circuits or function as topological quantum computing qubits; thereby contributing to memory devices with lower energy consumption and mitigating the escalating global energy demand in the computing industry.
Statistical Mechanics (cond-mat.stat-mech), Superconductivity (cond-mat.supr-con)
Main text: 13 pages, 6 figures. Supplementary information: 15 pages, 10 figures
Fridman, N., et al. (2026). Approaching Landauer’s limit in a single superconducting vortex memory bit. Nature Communications
Meta-Altermagnetism and Enhanced Spin-Splitting
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-30 20:00 EDT
Altermagnets are collinear magnets with zero net magnetization and spin-split electronic bands. Here, we explore whether altermagnetism can exhibit a discontinuous jump, a phenomenon we refer to as meta-altermagnetism. We show that meta-altermagnetism can emerge in 2D systems when magnetic-order-induced band reconstruction drives spin-split van Hove singularities (vHSs) across the Fermi level. Using mean-field theory for an extended $ t$ -$ J$ model on a two-sublattice square lattice including anisotropic hopping integral, we find that a first-order meta-altermagnetic transition produces an intermediate altermagnetic regime with reduced staggered magnetization but strongly enhanced magnetic octupole and time-reversal-odd spin-splitter conductivity. We further show that the first-order transition line terminates at a quantum critical endpoint, giving rise to a rich phase diagram as the chemical potential and anisotropic hopping strength are varied. Our results identify the spin split vHSs as a route to enhancing spin-splitter effect for spintronic applications.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
10 pages, 5 figures
MoireKP: An Automated Workflow for Symmetry-Constrained Moiré Continuum Models
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Yan Zhang, Hanqi Pi, Wangqian Miao, Zhong Fang, Hongming Weng, Xi Dai, B. Andrei Bernevig, Quansheng Wu
First-principles Hamiltonians contain the electronic information needed to study moiré materials, but their size makes subsequent calculations costly. We present MoireKP, an automated workflow for constructing compact continuum models from localized-orbital ab initio Hamiltonians. The workflow constructs a valley-resolved truncated atomic-plane-wave (TAPW) Hamiltonian, selects a low-energy basis, and projects the crystal-symmetry operations into this basis. These representations determine the symmetry-allowed Hamiltonian terms, whose coefficients are obtained by projecting the low-energy effective Hamiltonian onto the corresponding operator basis. The model dimension, localized reference states, and harmonic cutoff can be selected automatically or specified by the user. This Hamiltonian-based construction retains wave-function information within the selected low-energy subspace. We apply the workflow to AA-stacked twisted bilayer MoTe$ _2$ , AB-stacked twisted bilayer ZrS$ _2$ , and A–AB twisted trilayer MoTe$ _2$ , covering K, M, and $ \Gamma$ valleys. All models reproduce TAPW band energies within 3.0 meV in the target windows along high-symmetry $ k$ paths.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Computational Physics (physics.comp-ph)
32 pages, 10 figures, 5 tables, including appendices. Code: this https URL
Field theory of competing phases in the interacting Kitaev chain
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-30 20:00 EDT
Pradip Kattel, Thierry Giamarchi
We study the interacting Kitaev chain with nearest-neighbor interactions and finite chemical potential using a combination of bosonization and density-matrix renormalization-group calculations. Focusing away from special exactly solvable lattice limits, we develop a continuum field-theoretic description of the generic finite-density interacting regime, where doping nonperturbatively modifies the competition between superconducting pairing and commensurate charge ordering. We show that the phase diagram consists of an intermediate incommensurate Luttinger liquid between the topological superconducting and commensurate charge-density-wave Mott phases, as well as a trivial band-insulating regime at large chemical potential. The commensurate–incommensurate and incommensurate–topological-superconducting phase boundaries are governed by Pokrovsky–Talapov and Berezinskii–Kosterlitz–Thouless criticality, respectively. We analyze the interacting topological superconducting regime and its boundary excitations. At the semiclassical level, and explicitly in the free-fermion boundary theory, the topological phase supports exponentially localized Majorana edge modes at interfaces between topological and trivial regions. We also construct a dual continuum fermionic representation in which this topological bulk sector is described instead by conventional symmetry breaking. This gives a continuum version of the SPT–SSB correspondence between different fermionic representations. Overall, our results provide an analytical description of one-dimensional interacting topological superconductors, from the competition between topology and commensurability and the resulting quantum criticality to the dual symmetry-breaking description of the topological phase.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
5 figures, 19 pages
Long-Range Toric Code: Finite-Temperature Topological Order in Two Dimensions
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-30 20:00 EDT
Jacopo Gliozzi, Taylor L. Hughes, Kyung-Su Kim
We introduce two-dimensional toric code models with additional long-range loop interactions. Our models preserve the topologically ordered ground states of the ordinary toric code, while confining anyons at zero temperature. For sufficiently long-ranged interactions, we argue that this confinement persists at finite temperatures, strongly constraining anyon mobility and giving rise to finite-temperature topological order. This topological phase acts as a self-correcting quantum memory and exhibits long-range entanglement. For shorter-ranged interactions, signatures of topological order survive only up to an exponentially large length scale at finite temperature, yielding a partially self-correcting quantum memory.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
12+6 pages, 9+3 figures
Spin Space Symmetry Without Spin Space Groups
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-30 20:00 EDT
Spin space groups provide a complete symmetry classification of magnetic structures in the non-relativistic limit and have become an increasingly useful language for organizing magnetic phases and their physical properties. Each spin space group with a given parent space group is specified, up to spin-only symmetries, by a real representation of that space group acting in spin space. We argue that working directly with this representation not only avoids the construction and identification of the group, but also organizes and simplifies the resulting symmetry constraints on allowed responses. Determining the presence or absence of magnetic compensation, piezomagnetism, spin and charge transport, the Edelstein effect, and momentum-space spin textures becomes an ordinary problem in the representation theory of space groups. The resulting conditions reduce to overlaps between the three exterior powers of the defining representation and multipole representations of the point group. Several physically distinct responses then reduce to the same condition on the defining representation. For example, a $ p$ -wave spin texture and the time-even Edelstein effect are allowed under the same condition, as are piezomagnetism and a $ d$ -wave spin texture in compensated order. The wave-vector content of the exterior powers gives a further hierarchy of selection rules: depending on the relevant power, a uniform response requires one, two, or three ordering wave vectors to sum to a reciprocal lattice vector. These rules can exclude many responses before point-group symmetry is considered. We illustrate the approach with examples drawn from a wide variety of materials hosting collinear, coplanar and non-coplanar magnetic order. Finally, we discuss extensions of these results to magnetic space groups, connections to Landau theories of collinear order, and the characterization of odd-parity magnets.
Strongly Correlated Electrons (cond-mat.str-el)
31 pages, 12 figures; Web tool: this https URL
Evidence for a charged vortex lattice in an exciton superfluid
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-30 20:00 EDT
Ryan L. Lee, Jungwoo Lee, Viliam Vaňo, Bo Zou, Cheng-Li Chiu, Kenji Watanabe, Takashi Taniguchi, Allan MacDonald, Ali Yazdani
Lattices of quantized vortices are a defining property of rotating superfluids and of type-II superconductors in magnetic fields. Realizing an analogous vortex lattice in an exciton superfluid-formed from bound electron-hole pairs-has remained challenging because excitons are electrically neutral. Building on previous theoretical studies of the low-energy excitations in an exciton superfluid, recent theory has predicted that in a strong magnetic field, a weakly charged exciton superfluid can stabilize a vortex-antivortex lattice arising from the mutual repulsion of fractionally charged vortex cores. Here we report evidence for this predicted vortex lattice in a bilayer exciton condensate by imaging its charged vortices with the scanning tunnelling microscope. The condensate forms between Landau levels of two graphene layers separated by a thin hexagonal boron nitride barrier in a perpendicular magnetic field. We find that the vortex lattice periodicity scales with the total excess charge and is insensitive to its distribution between the two layers, in quantitative agreement with theoretical predictions. Our observations provide evidence for phase coherence in an exciton superfluid system.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Parity-Resolved Many-Body Kinetics of a Topological Qubit under Nonequilibrium Phonon Pulses
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-30 20:00 EDT
Phonon bursts from ionizing radiation cause correlated errors in superconducting quantum processors. We study prescribed nonequilibrium phonon pulses in a Majorana qubit formed by two $ 2,\mu\mathrm{m}$ proximitized nanowires. Combining the lattice Lutchyn–Oreg model, microscopic electron–phonon coupling, and parity-resolved many-body dynamics, we track excitation, relaxation, and logical coherence. Without quasiparticle escape, recombination restores the initial Majorana occupations in about 130 ns, while phonons exchanged during excitation and recovery can retain logical-state information, leaving permanent coherence loss. For mirror-symmetric wires, the fractional coherence loss per wire is 0.75–1.0 times the excitation probability averaged over the two logical states, even at zero Majorana splitting; breaking mirror symmetry can suppress dephasing at small splitting. Factorized Boltzmann kinetics neglects quasiparticle correlations and overestimates residual parity flips. At equal deposited energy density, phonon spectra yield different excitation probabilities and coherence losses. Comparisons with Kitaev chains matched to the wire’s gap and Majorana decay length reveal that low electron density suppresses excitation by energetic phonons, whereas hard-wall boundaries in a high-density control increase excitation efficiency by a factor of $ 5\times10^4$ relative to the wire for pulses centered at 1 meV. Magnetic-field and chemical-potential tuning yield different phonon sensitivities at the same bulk gap through changes in spin and electron–hole structure. Including hybrid states’ semiconductor weights reduces near-threshold excitation rates fourfold when the tunnel coupling equals the parent superconducting gap. Our framework connects phonon spectra to leakage, poisoning, and coherence loss to guide Majorana-device design.
Superconductivity (cond-mat.supr-con), Quantum Physics (quant-ph)
Geometry-controlled active transport in smectic textures
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-30 20:00 EDT
Yhony M. Arce, William G. C. Oropesa, Alef R. Siqueira, Hartmut Löwen, André P. Vieira, Danilo B. Liarte
Self-propelled particles moving through structured anisotropic media such as smectic liquid crystals exhibit transport properties that differ qualitatively from those in isotropic environments. Here we introduce a minimal model of an active Brownian particle whose propulsion axis is coupled to the layer-normal field of a smectic liquid crystal. Using numerical simulations complemented by approximate analytical calculations, we investigate the dynamics of an active particle in three representative two-dimensional smectic microstructures: a uniform planar texture, an isolated toroidal focal conic domain, and a periodic array of toroidal focal conic domains. For the planar and isolated focal-conic geometries, we characterize the crossover from short-time superdiffusion to long-time normal diffusion. In periodic focal-conic arrays, however, transport is controlled by two distinct persistence mechanisms whose relative importance depends on the Péclet number ($ \mathrm{Pe}$ ) and the coupling strength $ \varepsilon$ between the particle orientation and the smectic layer-normal field. At small $ \varepsilon$ , long-time diffusion is governed by the intrinsic persistence time of the active Brownian dynamics. At large $ \varepsilon$ , repeated scattering by smectic defects generates an emergent persistence time that dominates the transport. These results demonstrate that the competition between the intrinsic persistence of active motion and the mean free time between encounters with smectic defects provides a simple physical mechanism for the emergence of nontrivial diffusive behavior in structured anisotropic media.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
11 pages, 7 figures (5 pdf and 2 png)
GæniceN: a minimal model to relax magnetization states self-consistently in general artificial spin ices
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
H. Braun, E. Freeman, G. Alatteili, E. Iacocca
Artificial spin ices are geometric arrangement of nanomagnets that exhibit reconfigurable magnetization states and GHz dynamics. Their investigation in the GHz regime is challenging because of the existence of multiple modes and the impact of magnetization deviations at the edges of the nanomagnets. A minimal model to capture such dynamics require three macrospins per nanomagnet, an approach that was implemented for generic artificial spin ices in the tool Gaenice. Here, we use the Gaenice framework to realize a relaxation method to stabilize magnetization states self-consistently, called GaeniceN. We implement the dissipative component of the Landau-Lifshitz equation in an iterative approach to efficiently converge to the relaxed state. As an example, we find our approach to correctly predict the transition between phases in a pyramid ASI subject to a low-magnitude external field by computing the system’s average energy. Because they are rooted on the same framework, GaeniceN produces the initial condition needed for Gaenice to compute dynamics such as ferromagnetic resonance or band structures. Combined, these tools will be able to aid in the design of artificial spin ices with applications in magnonics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Planar energetics do not determine twin persistence in nanocrystalline aluminium
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Yue Wu, Yuan Tian, Haoyu Wan, Deng Pan, Mingwei Chen
Planar energetics are the standard descriptors of twinnability in face-centred cubic metals and the usual validation targets for interatomic potentials. Here we show that they do not determine whether deformation twins persist in nanocrystalline aluminium. Two machine-learned potentials reproducing the same zero-load slip curves and closely spaced layered energy surfaces predict, from a common separated-fault precursor under identical loading, retained twin coverage of 64% and 14%. The divergence traces to forces within distorted partial cores acting along the trailing translation that would remove an outer fault. Planar energetics do set the margin: an outer fault more than halves the incremental barrier for middle-plane shear, yet twin completion and fault removal remain separated by only 10–21 mJ m\textsuperscript{-2}. Whether an assembled twin persists is decided instead by the orientation of local traction relative to the full-slip bisector and by the arrival order of partial-slip fronts from the grain-boundary network.
Materials Science (cond-mat.mtrl-sci)
Anomalous Hall Conductivity as an Intrinsic Property of a Tight-Binding Graph
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
E. S. Andriyakhina, G. Lemut, P. W. Brouwer
In a ballistic system, the anomalous dc Hall response generically depends on microscopic details, including the geometric embedding of the orbitals and the precise implementation of the measurement. Here, we consider the question under what circumstances the anomalous Hall conductivity can be regarded as an intrinsic property of a system. We show that the full dc Hall response $ \sigma_{xy}^{\rm H}$ becomes embedding-independent in the presence of relaxation by impurity scattering, although the individual (intrinsic) band and (extrinsic) side-jump and anomalous-distribution contributions to the Hall conductivity separately remain embedding-dependent. We further derive a symmetry criterion for when the band term itself becomes embedding-independent, but argue that this alone neither identifies it with the full Hall conductivity $ \sigma_{xy}^{\rm H}$ , nor makes it a reliable approximation for $ \sigma_{xy}^{\rm H}$ . More broadly, our results establish embedding dependence as a diagnostic of whether a response coefficient represents a stationary intrinsic property of a material or retains sensitivity to measurement protocol.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Few-Electron Partitioning in the Fractional Quantum Hall Regime
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
T. Jonckheere, J. Rech, B. Grémaud
Motivated by few-electron partitioning experiments [Shaju et al., Nature 642, 928 (2025)], we study the partition statistics of $ N$ -electron states at a fractional quantum Hall point contact. At the solvable point $ g=1/2$ , we obtain nonperturbative current and noise formulas for arbitrary drives, while for Lorentzian pulses (Levitons) the full counting statistics reduces to an $ N\times N$ determinant. We show that the charge is transferred solely in units of $ e$ , and that symmetrized cumulants for $ N=2,3,4$ reveal strong antibunching and higher-order correlations, observable in a $ (\nu_1,\nu_2)=(1,1/3)$ junction.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Analytical framework for interpreting thermoreflectance measurements of nanoline gratings under finite spot illumination
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Abhishek Pathak (1), Seungwon Park (1), Shubham Deshmukh (1), Alan J. H. McGaughey (1), Jonathan A. Malen (1) ((1) Department of Mechanical Engineering, Carnegie Mellon University)
A frequency-domain thermoreflectance (FDTR)-based technique is presented to measure the effective thermal properties of a material stack whose surface is patterned with metallic nanoline gratings that are heated and probed by lasers. An analytical heat diffusion model is derived for predicting the FDTR phase response that incorporates a finite laser spot radius with a Gaussian intensity profile for the pump and probe lasers, as well as the dimensions of the nanoline grating. The model is validated by comparing with measurements of Au nanoline gratings, with widths ranging from 100 to 1000 nm, fabricated on a-SiO$ _2$ and $ c$ -sapphire substrates. Due to the short phonon mean free paths (MFPs) in these substrates, thermal transport remains in the diffusive regime for the whole range of nanoline widths. The model and the measurement show excellent agreement across different laser spot radii and nanoline widths, with a bulk thermal conductivity value of $ c$ -sapphire and the thermal boundary conductances at the Au-Cr/a-SiO$ _2$ and Au-Cr/$ c$ -sapphire interfaces comparable to our prior measurements and the literature. The validated model will serve as a robust baseline for extending this method to measure effective thermal conductivity as a function of the heater size. This approach is particularly relevant for materials where non-diffusive thermal transport regimes enable probing phonon MFP dependent contributions to the thermal conductivity.
Materials Science (cond-mat.mtrl-sci)
Electronic-morphological decoupling in mixed-dimensional halide perovskite heterostructures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Mahmoud Samadpour, Alireza Fathi Beiraghvandi, Kazem Meraji, Tristan Sachsenweger Ballantyne, Fuxiang Ji, Mahdi Mohammadi, Nasim Kabir, Wolfgang Tress
Surface morphology is widely considered an indicator of thin-film quality, with smoother films generally expected to exhibit more uniform optoelectronic properties. Here, we demonstrate that substantial surface evolution does not necessarily lead to increased electronic heterogeneity in mixed-dimensional perovskite heterostructures. We investigate how low-dimensional Ruddlesden-Popper capping layers derived from the sterically hindered 5-tert-butyl-phenanthridinium cation affect the spatial distributions of photoluminescence (PL) characteristics and quasi-Fermi level splitting (QFLS) in 3D perovskites. By combining statistical atomic force microscopy (AFM) analysis with confocal, spatially resolved PL spectroscopy, we correlate surface topography with microscale optoelectronic properties.
Although capping increases surface roughness and height asymmetry, it does not increase electronic inhomogeneity. Instead, the heterostructures exhibit enhanced PL, reduced non-radiative recombination, and improved spatial uniformity of radiative QFLS compared with pristine 3D films. Under accelerated aging, this contrast becomes more pronounced: pristine films develop substantial spatial fluctuations in emission and QFLS, whereas capped heterostructures largely preserve their optoelectronic homogeneity. These findings indicate that the low-dimensional capping layer suppresses aging-induced optoelectronic disorder, demonstrating that electronic uniformity can be maintained despite morphological irregularity. This decoupling provides a design principle for developing durable, high-performance perovskite photovoltaics.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
23 pages, 14 figures
Finite-step statistical mechanics of scale-invariant learning: spectral equations of state and curvature transport
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-30 20:00 EDT
Stationary learning admits an ideal-gas description under restrictive noise assumptions. In neural networks whose gradient noise departs from these assumptions, however, an entropy-scaling relation resembling a Maxwell relation remains approximately valid. We ask which thermodynamic-looking relations follow from scale symmetry rather than equilibrium, and how departures from the ideal-gas description can be quantified, for discrete stochastic gradient dynamics with memory. An exact rescaling of trajectories explains the entropy relation without assuming thermal equilibrium. Within a local harmonic approximation, self-adjusting weight norms yield a spectral equation of state whose virial coefficients are set by moments of the curvature spectrum, and coupled parameter groups can sustain stationary probability currents. Our central result beyond this approximation is an exact curvature-transport identity. Together with a finite-step loss balance, it decomposes corrections to the harmonic fluctuation relation into measurable curvature changes, finite-step remainders, gradient-memory correlations and finite-window drift terms. A related displacement-weighted curvature change provides a diagnostic of the arrow of time; its mean and second moment give a lower bound on the relative entropy between forward and reversed state pairs. We also calculate the activation-boundary contribution to curvature for rectified teacher-student networks with Gaussian inputs. Tests in sphere models, teacher-student networks and convolutional networks on CIFAR-10 and CIFAR-100 support the transport description and identify limits of the harmonic and cubic-remainder approximations. These results separate symmetry-based relations from equilibrium assumptions and provide quantitative diagnostics of nonideal fluctuations in learning dynamics.
Statistical Mechanics (cond-mat.stat-mech), Disordered Systems and Neural Networks (cond-mat.dis-nn), Machine Learning (cs.LG)
45 pages, 6 figures, 9 tables
From a Lifshitz Transition to Spin-Density-Wave Order: Sr$_2$RuO$_4$ under Uniaxial Strain
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-30 20:00 EDT
Evgeny A. Stepanov, Sophie Beck, Maria Chatzieleftheriou, Antoine Georges
In recent years, the effects of uniaxial strain on Sr$ _2$ RuO$ _4$ have been extensively investigated, revealing a pronounced enhancement of the superconducting critical temperature accompanied by experimental indications of an emergent magnetically ordered state. In this Letter, we study the impact of strain on the spectral and magnetic properties of this material within an advanced many-body theoretical framework. We find that strain induces an anisotropic Lifshitz transition, which enhances the electron scattering rate along the elongation axis while simultaneously promoting coherent Fermi-liquid behavior in the perpendicular direction, in close agreement with experimental observations. Taking into account this anisotropic behavior allows us to capture the magnetic instability leading to a finite-temperature ordered state at large strain values. Our analysis further reveals that the magnetic response is dominated by two competing wave vectors associated with distinct nesting vectors: one within the $ \gamma$ sheet and the other between the $ \alpha$ and $ \beta$ sheets of the Fermi surface. Both wave vectors can stabilize magnetic order, with their competition depending sensitively on the coherence of the respective Fermi surface sheets.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Coherent control and high purity single-photon emission from telecom quantum dots on metamorphic InGaAs
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
Beatrice Costa, Bianca Scaparra, Hubert Riedl, Gregor Koblmüller, Eugenio Zallo, Jonathan J. Finley, Lukas Hanschke, Kai Müller
Semiconductor quantum dots emitting in the telecommunication O- and C-bands are promising candidates as single-photon sources for fiber-based quantum communication. In this work, we show how coherent quasi-resonant and phonon-assisted excitation help reveal the intrinsic optical properties of InAs quantum dots embedded in relaxed InGaAs matrices on top of metamorphic InGaAs layers for achieving emission in the telecom bands. By systematically comparing excitation schemes, we separate excitation-induced effects from intrinsic emitter properties. This allows us to observe linewidths as narrow as 21 $ \mu$ eV, the disappearance of slow decay channels, and single-photon purity reaching second-order autocorrelation values in the order of $ 10^{-2}$ . Photoluminescence excitation reveals higher excited states, enabling coherent control of trion transitions and the observation of Rabi-like oscillations in both telecom bands. These results confirm the promising potential of these quantum dots for applications in quantum technologies.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
Thermal laser evaporation of superconducting Nb films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Yifei Yan, David S. Catherall, Finley B. Donachie, Dorsa Najafipanah, Austin J. Minnich
Thermal laser evaporation (TLE) is an emerging physical vapor deposition (PVD) technique that uses continuous-wave lasers to evaporate even the most refractory elements. The deposition and characterization of superconducting refractory elements are of interest to assess the quality of films deposited by TLE. Here, we report the deposition of niobium (Nb) on c-plane sapphire using a home-built TLE system equipped with a 1070 nm continuous-wave fiber laser. A deposition rate of 0.19 Å/s was achieved with 533 W of laser power focused to a diameter of approximately 500 $ \mu$ m on a Nb target. A film with a thickness of $ 22.47 \pm 0.05$ nm and a root-mean-square (RMS) roughness of $ 0.23 \pm 0.02$ nm exhibited a room-temperature resistivity of $ 21.60 \pm 0.05$ $ \mu\Omega\mathrm{cm}$ and a residual-resistivity ratio (RRR) of 5.71. The superconducting transition temperature, $ T_\mathrm{c}$ , of the film was measured as 9.24 K, only 10 mK below the bulk value, with a transition width of 29 mK. Among films deposited without substrate heating, the electrical and superconducting properties of the present films meet or exceed those deposited by other techniques. This work contributes to the emerging consensus regarding TLE as a versatile PVD method for refractory elements and compounds.
Materials Science (cond-mat.mtrl-sci)
Emergent higher-order optical nonlinearity in self-assembled polar supertextures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Daniel A. Bustamante Lopez, Deepankar Sri Gyan, Xiaojiang Li, Vladimir A. Stoica, Sujit Das, Peter Meisenheimer, Akash Surampalli, Mohit Tanwani, Xianghan Xu, Aiden Ross, Long-Qing Chen, Sang-Wook Cheong, Lane W. Martin, Ramamoorthy Ramesh, Venkatraman Gopalan, Wanzheng Hu
Giant optical nonlinearities enable advanced materials control and bridge exotic light-matter phenomena to next-generation photonics. However, materials exhibiting strong higher-order optical nonlinearity beyond the second order are typically rare. Here, we report the discovery of a giant and ultrafast second-harmonic generation (SHG) in self-assembled polar skyrmions under mid-infrared excitations. The transient SHG intensity exhibits a distinctive power dependence originating from higher-order nonlinearity. More generally, we show that large higher-order nonlinearity emerges across diverse domain structures in polar superlattices. Phase-field simulations demonstrate a strong and periodic local permittivity variation within each polar texture at equilibrium, and further confirm the fast polarization oscillation in polar skyrmions with mid-infrared excitations. This intense local permittivity modulation can satisfy epsilon-near-zero conditions, unlocking dramatically enhanced nonlinear optical responses without photonic engineering. Consequently, the self-assembled polar topologies with strong inherent optical nonlinearity could establish a platform for quantum information processing and high-speed optical communications.
Materials Science (cond-mat.mtrl-sci)
ACS Nano (2026)
Incoherent dark excitons extend Floquet-like physics across time and momentum
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
Xing Zhu, Jacques Hawecker, Enrico Perfetto, Vivek Pareek, David R. Bacon, Harley Suchiang, Nanami Tomoda, Amrita Mitra, Takumi Fukuda, Sebastien Roux, Ouri Karni, Jack Featherstone, Kenji Watanabe, Takashi Taniguchi, Michael K. L. Man, Julien Madéo, Felipe H. da Jornada, Gianluca Stefanucci, Keshav M. Dani
Floquet phenomena - where a coherent, time-periodic drive hybridizes the conduction band with energy-replicated copies of the valence band - have been demonstrated with intense optical fields and, more recently, other bosonic excitations. However, within mean-field approximations and the current understanding of Floquet phenomena, these effects survive only for the coherence time of the drive, limiting practical use and current demonstrations to the sub-picosecond regime. Here, consistent with recent theoretical predictions beyond the mean-field picture, using time- and angle-resolved photoemission spectroscopy in WSe$ _2$ /MoS$ _2$ heterostructures, we show that incoherent, dense populations of dark interlayer excitons hybridize the conduction band with energy-replicated copies of the valence band, mimicking Floquet-like phenomena - now persisting for nearly a nanosecond. With increasing interlayer exciton density, the valence band and its replica evolve from an inverted-parabolic to a Mexican-hat dispersion, a signature of the predicted non-zero static coupling that hybridizes the bands and scales linearly with the exciton density. By tuning twist angle, we further show that dark excitons with net momentum create replicas that hybridize with bands offset not just in energy but also in momentum, providing another powerful degree of freedom beyond conventional Floquet engineering. These results establish a robust, long-lived route to engineering electronic states, beyond a coherent, zero-momentum drive.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
17 pages, 8 figures
Level ordering in the linear $E \otimes e$ dynamic Jahn-Teller model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-30 20:00 EDT
The ground level of the linear $ E\otimes e$ dynamic Jahn-Teller model has long been believed to be the doublet with vibronic angular momentum $ j = \pm\tfrac12$ . We prove that, for arbitrary coupling strength, the $ n$ th level $ E_{nj}$ in the subspace of fixed $ j$ strictly increases with $ |j|$ for every $ n$ , $ E_{n,1/2} < E_{n,3/2} < E_{n,5/2} < \cdots$ ; in particular, the ground level is always the $ j = \pm\tfrac12$ doublet. The proof uses only a unitary transformation that lowers $ j$ by one, combined with the variational principle. We also give an explicit lower bound on the gap $ E_{0,j+1} - E_{0j}$ .
Strongly Correlated Electrons (cond-mat.str-el)
6 pages, 1 figure
Crystoria: A Large-Scale Crystal Dataset Linking Thermodynamic and Dynamical Stability for Materials AI
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Ke-Xin Pang, Ze-Feng Gao, Yan Gao, Zhong-Yi Lu
Large-scale crystal databases have transformed materials discovery by making millions of structures and thermodynamic properties accessible to materials informatics. Yet dynamical stability remains sparsely characterized at a comparable scale because its evaluation is substantially more computationally demanding than conventional structure and energy calculations. This mismatch creates a critical gap between the rapidly expanding crystal-structure space and the physical information available for materials research and machine learning. Here we introduce Crystoria, a large-scale crystal dataset designed to bring dynamical stability to the scale of modern materials data. We construct Crystoria by systematically curating low-energy and metastable inorganic crystals, standardizing their structural identities, and combining machine-learning-accelerated structural relaxation with phonon-based dynamical screening. The resulting dataset contains 2,649,640 crystal structures, spanning 89 elements, 219 of the 230 space groups, and primitive cells containing 1-48 atoms. Among them, 1,793,353 structures (67.68%) are classified as dynamically stable, revealing substantial variation in dynamical stability across chemical and crystallographic space. By bringing dynamical stability to the scale of millions of crystal structures, Crystoria provides a physically grounded foundation for materials artificial intelligence (AI) and enables systematic exploration of the dynamical crystal landscape.
Materials Science (cond-mat.mtrl-sci)
9 pages, 3 figures, 1 table; 6 pages of Supplementary Information with 4 supplementary figures included
Influences of $N_2$ flow rate on the superconducting properties and dimensionality of epitaxial TiN thin films
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-30 20:00 EDT
Shilong Chen, Yuchuan Liu, Yihui Sun, Xiaoni Wang, Wei Peng, Yu Wu, Gang Mu, Zhirong Lin
TiN thin films have received great attention in the field of superconducting quantum computing due to their low loss characteristics derived from stable chemical and thermal properties, as well as excellent electrical conductivity. In this study, TiN thin films with a thickness of 35 nm were epitaxially grown on MgO substrates using the DC reactive magnetron sputtering technique. The crystal structure, film thickness, and surface morphology of the thin films were characterized. The films exhibit a very flat surface with a root mean square roughness of only a few tenths of a nanometer. The influences of nitrogen ($ N_2$ ) flow rate on the surface morphology, superconducting transition temperature ($ T_c$ ), residual resistivity ratio (RRR), normal-state resistivity ($ \rho_n$ ), upper critical field, and superconducting dimensionality were investigated systematically. The experimental results show that the TiN film deposited with a $ N_2$ flow rate of 1.5 sccm exhibits optimal performance, including the highest $ T_c$ (4.93 K), the largest RRR, the lowest $ \rho_n$ , and the lowest slope of the out-of-film upper critical field near Tc. Moreover, it is found that the background vacuum inside the growth chamber has a significant impact on the superconducting properties of TiN films, and the degradation of vacuum degree can lead to the decrease of $ T_c$ . The upper critical field reveals a significant anisotropic feature. Importantly, the in-film upper critical field data demonstrates that the optimization of sample quality leads to deviation from two-dimensional superconducting behavior, which provides a new perspective on the influencing factors of superconducting dimensionality beyond the thickness of films. The present results provide useful references for a comprehensive understanding of the relationship between growth parameters and the superconducting properties of thin films.
Superconductivity (cond-mat.supr-con)
14 pages, 6 figures, 4 tables
Acta Phys. Sin., 2026, 75(11): 110703
Charge Filling-Dependent Valley Polarization and its Dynamics Driven by Correlated Interlayer Exciton States in WSe2/WS2 Heterobilayer
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
Zhiwei Li, Haonan Wang, Yubei Xiang, Wataru Idehara, Hailin Liu, Shinichiro Matano, Kenji Watanabe, Takashi Taniguchi, Kazunari Matsuda
Moiré heterostructures of transition metal dichalcogenides provide an emerging platform for studying the strongly correlated electronic and excitonic states. The valley degree of freedom and its dynamics in the strongly correlated electronic and excitonic states in the moiré system are crucial for fundamental understanding and applications of valleytronics. Although the strongly correlated states in moiré systems have been extensively investigated, their impact on valley degrees of freedom and its dynamics remains unexplored. Here, we study the charge filling-dependent valley relaxation dynamics of interlayer excitons (IXs) in WSe2/WS2 moiré heterobilayer system. The evolution of moiré IXs dynamics across the Mott transition is elucidated by combining time-resolved optical spectroscopy with Monte Carlo simulation. Our results show that the radiative decay and recombination rate of IXs are enhanced at the integer filling factors n (=-1). Moreover, the valley relaxation rate of IXs at n=$ \pm$ 1 is significantly decreased. The resulting reduction in wavefunction overlap and phonon scattering process suppresses the nonradiative recombination and intervalley scattering of IXs. These anomalous behaviors are attributed to the modification of IXs recombination pathways and enhance excitonic coherence due to the localization of introduced charge carriers at integer filling of moiré site. Our results explore exciton and valley dynamics as sensitive probes of strongly correlated states in moiré systems and highlight possible ways to control excitonic coherence and valleytronic properties in two-dimensional quantum materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Finite-Temperature Magnetism and Longitudinal Spin Transport in Compensated Half-Metal Ferrimagnets with Near-Zero Magnetization
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Jiahao Shentu, Jie Li, Jianting Dong, Meng Zhu, Chen Wang, Qing Zhang, Yizhuo Song, Wenqi Sun, Jia Zhang
Fully compensated ferrimagnets, characterized by nearly vanishing magnetic moments at zero temperature, perfect spin-polarized electronic structures, and ultrafast spin dynamics, represent a highly promising materials platform for next-generation spintronic devices. By minimizing stray magnetic fields and reducing switching currents, FCFs enable a viable path toward high-speed, low-power spintronic devices. In this work, we present a systematic investigation of the electronic structure, finite-temperature magnetism, and spin-dependent transport properties of the Heusler-type fully compensated half-metallic ferrimagnet Mn3Al in magnetic tunnel junctions. We demonstrate that Mn3Al is a half-metallic FCF with 100% spin polarization and fully compensated magnetization at 0 K. Combining density functional theory with Monte Carlo simulations, we characterize its finite-temperature magnetic properties and show that Mn3Al exhibits a net magnetization below 11.6 emu/cc at 300 K, confirming the robustness of its nearly compensated ferrimagnetic order at room temperature. Furthermore, we predict that the Mn3Al/MgO/Mn3Al MTJ yields a giant tunneling magnetoresistance effect at 0 K, which remains as high as 232% at 300 K. Our results establish Mn3Al and related half-metallic FCFs as excellent candidates for magnetoresistance-based spintronic applications.
Materials Science (cond-mat.mtrl-sci)
18 pages, 5 figures, 1 table
The Flexoelectric Twist: Persistence of Heavy Fermion Picture in Small-Angle Twisted Bilayer Graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
Qirong Yao, Ka Cheuk Fan, Tianyu Qiao, Hao Shi, Xi Dai, Berthold Jäck
Twisted bilayer graphene (TBG) near the first magic angle ($ \theta\approx1.05^{\circ}$ ) hosts flat bands that provide a fertile ground for exploring strongly correlated and topological phases. At smaller twist angles ($ \theta<1^{\circ}$ ), attice relaxation profoundly alters the moiré landscape. The extent to which moiré lattice reconstruction at different length scales affects the electronic structure through electro-mechanical coupling remains unresolved. Here, using scanning tunneling microscopy on small-angle TBG devices ($ \theta\approx0.3-0.7^{\circ}$ ), we observe a pronounced $ dI/dV$ peak at the AA site of the moiré lattice on top of a spectrum that is asymmetric about the charge neutrality point, lattice reconstruction over moiré lattice length scales, as well as a dilation of the atomic lattice at the AA sites. We demonstrate at a phenomenological level that the inclusion of moiré lattice reconstruction supports compact localized heavy fermion $ f-$ states localized at AA sites. The additional inclusion of atomic lattice dilation enerates a strong flexo-electric response that explicitly breaks particle-hole symmetry, pushing compact, localized $ f$ -states at the AA sites down in energy. Consequently, these heavy fermion states energetically coexist with itinerant $ c$ -electrons at the AB/BA sites. Our spatially resolved spectroscopic measurements quantitatively visualize this coexistence, confirming the persistence of the heavy fermion model in the small-angle regime $ \theta<1^{\circ}$ . Our findings provide microscopic insights into how flexo-electricity affects the low-energy electronic structure of small-angle TBG. More broadly, our study establishes small-angle TBG as a new class of moiré materials to explore the interacting Kondo lattice problem with high tunability of the $ f-$ occupation and $ c-$ density through twist-angle and electrostatic back gates, respectively.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
First-Principles Identification of Higher-Order Configurational Energy Terms and Their Magnetic-State Dependence in Lithium-Rich Oxyfluorides: From QUBO to HUBO
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
In this work, we use spin-polarized density functional theory (DFT) to identify substantial third-order, nonadditive configurational energy contributions in lithium-rich oxyfluorides that quadratic unconstrained binary optimization (QUBO) models cannot represent. We test the extension from QUBO to higher-order unconstrained binary optimization (HUBO) in two disordered-rocksalt cathode materials, Li$ _2$ MnO$ _2$ F (LMOF) and Li$ _2$ Mn$ _{0.5}$ Ti$ _{0.5}$ O$ _2$ F (LMTiOF), using composition-preserving DFT energy maps. Using fixed-geometry energy maps, we show that cubic HUBO captures nonadditive contributions absent from QUBO models and substantially reduces fitting errors in both materials. Direct DFT energy differences confirm third-order nonadditivity, while comparisons of magnetic initializations reveal a strong dependence of the LMTiOF contribution on the converged electronic state. These results support the inclusion of higher-order terms when modeling configurational energetics and highlight the need to account for magnetic-state dependence in constructing DFT energy maps. The extracted terms describe effective couplings among composition-preserving exchange variables, rather than uniquely identified microscopic three-atom interactions.
Materials Science (cond-mat.mtrl-sci)
Time evolution in the multi-component dynamical Keldysh models
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
We construct a time evolution operator for a dynamical quantum models with a multi-component random Gaussian field characterized by a long correlation time. We analyze three paradigmatic cases: non-Abelian $ SU(2)$ symmetry class for the three-component Gaussian noise and Abelian symmetry classes $ U(1)$ and $ Z_2$ for the two- and one-component noises correspondingly. Starting with a limiting case of the infinite correlation time (Keldysh model) we shown that statistics of the two-component random field with a non-zero mean is described by the Rice distribution. We derived and solved the system of coupled linear differential equations for the exact diagonal and off-diagonal single-particle Green’s functions. We showed how the finite time correlation in Keldysh models are accounted by a continuous fractions method.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Disordered Systems and Neural Networks (cond-mat.dis-nn), Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
7 pages, 1 figure
Structural Determination vs Stochastic Events: Relaxation Dynamics in a Supercooled Liquid
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-30 20:00 EDT
Shivam Mahajan, Peter Harrowell, Massimo Pica Ciamarra
Structural relaxation in supercooled liquids is influenced by the initial configuration, yet its microscopic evolution exhibits substantial variability. Here, we investigate the interplay between structural constraints and dynamical stochasticity by examining fluctuations of relaxation dynamics across and within isoconfigurational ensembles. We show that fluctuations among trajectories originating from the same configuration constitute a substantial fraction of the total dynamical fluctuations over a broad range of temperatures. At the collective level, the distribution of relaxation times is well described by a stochastic model involving a sequence of effective relaxation events, whose number decreases upon cooling. At the microscopic level, dynamical fluctuations exhibit spatial correlations that grow upon cooling, revealing a spatial organization of relaxation even when the initial configuration is fixed. Remarkably, the characteristic length associated with these fluctuations closely follows the length scale inferred from the stochastic first-passage model, establishing a connection between the spatial organization of dynamical fluctuations and the temporal statistics of collective relaxation. Together, these results suggest that structural relaxation is governed by an interplay between configuration-dependent constraints and stochastic dynamical events: the initial structure influences when and where relaxation occurs, without uniquely determining its microscopic realization.
Soft Condensed Matter (cond-mat.soft)
29 pages, 13 figures
Strain-overlap and surface-confinement engineering in AlScN/YIG magnetoacoustic devices
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
Kevin Künstle, Kaya Gauch, Agnė Žukauskaitė, Stephan Barth, Mathias Weiler
We establish AlScN/YIG/GGG as an integrated piezoelectric-magnetic heterostructure for electrically generating surface acoustic waves (SAWs) and coupling them to spin waves in monocrystalline YIG. Combining electrical transmission measurements of interdigital-transducer delay lines with finite-element simulations, we identify the excited modes as Rayleigh-type SAWs whose surface confinement varies strongly with AlScN thickness. The resulting changes in the strain field within YIG directly modify the magnetoelastic coupling. Using the simulated complex strain components and an effective-driving-field model, we calculate the relative SAW attenuation for several AlScN thicknesses and wavelengths. The calculations qualitatively reproduce the measurements: at all investigated wavelengths, thinner AlScN layers yield stronger relative attenuation. Experimentally, the attenuation approaches 70dB/mm for a 54.5nm-thick AlScN layer at a wavelength of 1.2$ \mu$ m. However, the strongest relative attenuation does not maximize the detectable signal. Instead, the absolute field-induced transmission change peaks at an AlScN thickness of approximately 100nm, with the precise optimum depending on the acoustic wavelength. These results identify the AlScN thickness as a key design parameter for balancing magnetoelastic attenuation and pure SAW transmission in AlScN/YIG devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Direct real-space imaging of sign-reversal superconducting state by scanning Josephson tunneling
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-30 20:00 EDT
Tianheng Wei, Yanzhao Liu, Wei Ren, Zhen Liang, Ziqiang Wang, Jian Wang
Phase-sensitive experiments based on Josephson tunneling have been considered as a pivotal method to determine the pairing symmetry in high-temperature (high-Tc) cuprate superconductors. However, in iron-based superconductors, traditional phase-sensitive experiments face setbacks because of the complexity of pairing symmetry in multiband systems. Here, using scanning Josephson tunneling microscopy (SJTM), we report the half-unit-cell periodic Josephson tunneling modulations in monolayer high-Tc Fe(Te,Se) film epitaxially grown on SrTiO3(001). The Josephson tunneling almost vanishes along the lines connecting next-nearest-neighbor Fe atoms under an s-wave superconducting tip. Combined with single-particle tunneling spectra showing the full superconducting gap, our experimental results are consistent with the sign-reversal nodeless d-wave pairing symmetry. Our findings provide sub-unit-cell scale superconducting phase information for understanding the mechanism of high-Tc superconductivity. We anticipate our work as a starting point for atomically resolved Josephson interference experiments using SJTM in various unconventional superconductors.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Layer-Parity Control of the Superconducting Diode Effect in Monolayer NbSe$_2$
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-30 20:00 EDT
Yusuf Wicaksono, Toshikaze Kariyado
The superconducting diode effect is often associated with finite-momentum pairing, although model studies indicate that rectification reflects the asymmetry of the free energy about its minimum rather than the equilibrium pair momentum itself. Using a Wannier-based, self-consistent finite-$ \mathbf Q$ Bogoliubov-de Gennes approach with a Fermi-surface-adaptive quadrature that converges the critical currents, we show that the layer parity and orientation of magnetic proximity select the diode response of monolayer NbSe$ 2$ . For in-plane exchange, the equilibrium pair momentum $ \mathbf Q{\rm eq}$ and the diode efficiency are both linear in the layer-odd exchange contrast: parallel proximity on the two Se sublayers is reciprocal, and antiparallel proximity doubles the response. An out-of-plane component separates the two observables. It leaves $ \mathbf Q_{\rm eq}$ nearly unchanged but, through pair breaking, suppresses the efficiency by more than an order of magnitude and, at low temperature, reverses it. Purely out-of-plane exchange, for which $ C_3$ symmetry forbids a helical term, keeps $ \mathbf Q_{\rm eq}=0$ yet produces a trigonal diode effect, controlled by the layer-even exchange and larger than the in-plane one above $ 0.65$ ~meV at low temperature. Magnetic layer parity thus selects between a helical and a trigonal diode channel. The trigonal channel is an intrinsic, symmetry-allowed contribution to the field-free rectification reported in NbSe$ _2$ /CrBr$ _3$ and predicts that two-sided out-of-plane proximity cancels it when antiparallel and, at the same exchange per layer, enhances it about fourfold when parallel, in the computed range.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Coherent Electronic Lensing in Proximitized Graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
Ivan Villani, Samuele Fracassi, Niccolò Traverso Ziani, Maura Sassetti, Matteo Carrega, Vaidotas Mišeikis, Camilla Coletti, Fabio Beltram, Kenji Watanabe, Takashi Taniguchi, Sergio Pezzini, Stefan Heun
Spatially resolved control of coherent electron transport offers a route to understanding and engineering interference phenomena in hybrid superconducting devices. Here, we use Scanning Gate Microscopy (SGM) to investigate Fabry-Pérot (FP) interference in the n-p-n cavity of a ballistic graphene Josephson junction. Spatial maps of the superconducting switching current and normal-state conductance reveal circular interference fringes arising from two distinct effects of the SGM tip potential. A global shift of the Fermi wave vector modulates the FP resonances of the cavity, while a local perturbation produces additional oscillations that persist at fixed Fermi wave vector as the tip bias is varied. An analytical model identifies the origin of this local response with coherent electron lensing, in which the tip modifies the phase accumulated along interfering trajectories. The measured fringe patterns in the switching current indicate that this mechanism affects superconducting transport, consistent with tip-induced shifts of the resonance conditions for Andreev bound states. These results establish SGM as a tunable local lens for controlling interference in superconducting ballistic graphene devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con), Quantum Physics (quant-ph)
Strain-Induced BCC-to-FCC Transformation in Tungsten Uncovered by Molecular Dynamics Simulations with Machine Learning Potentials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Qiu-Hong Hu, YueYue Wang, Xinyi Leng, Hezhu Shao, Luru Dai
Polymorphic transformations occur in a minority of metals. Tungsten is not one of them. This observation does not rule out its intrinsic phase transition possibility, but may be due to inaccessible thermodynamic and mechanical conditions in conventional experiments. Herein, we investigate the body centered cubic (BCC) to face centered cubic (FCC) transformation in tungsten via a rigorously validated machine learning potential (MLP) molecular dynamics (MD) approach. Our simulations demonstrate that strain induced BCC to FCC transformation indeed occurs in tungsten. The FCC phase exceeds 20 at.% at low temperature and in the presence of dislocations. In the perfect crystal moderate temperatures favor phase transformation kinetics. Structural analysis confirms the transformation following the Bain and Nishiyama Wassermann orientation relationship. These results establish the viability of strain induced polymorphic transformation in tungsten and provide a critical guideline for the experimental production of duplex tungsten with enhanced ductility addressing a longstanding challenge in tungsten material engineering for high-temperature structural applications.
Materials Science (cond-mat.mtrl-sci)
10 pages, 7 figures. accepted by PRX Intelligence, Received 5 October 2026
Two-Dimensional Magnetic Materials from Ferromagnetism to Altermagnetism: Fabrication, Symmetry, Evidence, and Device Readiness
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Guojian Zhao, Ziang Meng, Li Liu, Zhiyuan Duan, Jingyu Li, Sixu Jiang, Xiaoyang Tan, Shiheng Bu, Chen Liang, Xiaoning Wang, Peixin Qin, Zhiqi Liu
Atomically thin magnets are governed by composition, thickness, stacking, strain, defects, substrates, ferroic order, and interfaces. This Review organizes two-dimensional (2D) magnetism using net magnetization and momentum-space spin splitting or spin-polarization patterns as primary coordinates, supplemented by sublattice structure and the symmetry relations between opposite-spin sublattices. Ferromagnets generally carry a net moment; ferrimagnets can be fully compensated. Conventional antiferromagnets may retain spin-degenerate bands, while altermagnets permit nonrelativistic alternating spin splitting under dimension-specific symmetry constraints. M1-M4 reporting classes introduced here distinguish layer-resolved atomically thin forms, non-layer-resolved thin flakes or films, bulk benchmarks, and theoretical candidates or design routes; the evidence category and ordering-temperature provenance are reported independently. Current experimental support for altermagnetism comes mainly from M2 thin-film and M3 bulk benchmarks, leaving a fully verified atomically thin M1 altermagnetic phase as an open experimental goal. Most proposed monolayer and few-layer systems therefore fall within M4, and contested cases clarify the measurements needed for phase assignment. Device readiness is compared qualitatively using operating temperature, readout, switching, domain control, stability, scalability, interface sensitivity, and integration difficulty. Reliable phase assignment and device assessment require complementary measurements from the same material form under matched conditions, ideally on the same specimen or in situ.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph)
73 pages, 14 figures, 7 tables. Review published at Advanced Functional Materials
Far Tails of the Positional Distribution in random walk: A Saddle-Point Approach
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-30 20:00 EDT
Chen Zhou, YuDa Cheng, Yangji Li, Jing Xu, Wanli Wang
Rare events and large-deviation theory have attracted considerable interest in the study of random walks. Here, we investigate the rare events of the positional distribution of continuous-time random walks under ordinary and equilibrium initial conditions using the saddle point method. We show that the far-tail behavior is sensitive to the expansion of the waiting-time distribution near its minimum value. For a general power-series expansion near the minimum waiting time, the positional distribution exhibits an approximately exponential decay in its far tails. In contrast, when the waiting-time distribution has a cutoff at its minimum value, the positional distribution exhibits an unexpected Gaussian decay, in contrast to the far-tail behavior of the renewal-count distribution. We further find that the most likely number of renewals required to reach a given position, as well as the associated rate functions, is insensitive to the initial conditions, whereas the far tails of the positional distribution retain a dependence on the initial conditions. Our results provide new insights into the rare-event statistics and large deviations of random walks.
Statistical Mechanics (cond-mat.stat-mech)
Ordered patches cap the stability of disordered frameworks
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Structural disorder can stabilize frameworks against pressure-induced failure, yet the ordered regions it contains limit this gain. We show that, in rigid-jointed frames under hydrostatic pressure, an ensemble containing arbitrarily large patches of a crystal at positive density, whose centres carry a scaled crystal prestress, cannot stay linearly stable once those patches are stressed beyond the crystal’s threshold for localizable instabilities. A homogeneous loss of positive definiteness while all Bloch modes, including the acoustic limit, remain stable cannot localize, leaving a window for stabilization. Extending an acoustic criterion to prestress, we show for all point groups that such a window requires a strain that keeps the crystal’s symmetry. Unless the patches are shielded from stress, disorder cannot protect a crystal against a failure that breaks its symmetry, and protects a cubic crystal at most against volume collapse. In two-dimensional Truchet frames, planted ordered domains bring the threshold within 1% of the bound, and correlations short of long-range order localize failure on ordered clusters. Across 876 slender-strut nets, 798 fail first by a localizable instability; the other 78 have a median window of 7.6%. Stability gained through disorder is capped by the localizable instabilities of the local order it permits.
Materials Science (cond-mat.mtrl-sci), Disordered Systems and Neural Networks (cond-mat.dis-nn)
24 pages, 6 figures; Supplementary Information (72 pages) included. Code and data: this https URL (Zenodo DOI https://doi.org/10.5281/zenodo.23682287)
Extraordinary stiffening and reciprocal control in a DNA condensate/actin composite
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-30 20:00 EDT
Sam Wilken, Austin Hopkins, Kyu Hwan Choi, John Berezney, Matthew E. Helgeson, M. Cristina Marchetti, Sho Takatori, Zvonimir Dogic, Omar A. Saleh
Soft composites, materials consisting of inclusions within a polymeric matrix, offer a broad design space with diverse mechanical properties. Composite stiffness is normally set by the volume fraction of filler, and classical theory predicts at most ~25% stiffening when inclusions occupy 10% of the volume. Here we introduce a composite of phase-separated DNA droplets that occupy <10% of an entangled actin network, yet stiffen it 25-fold, reversibly. Microscopy reveals that actin penetrates the DNA droplets, leading network elasticity to determine their size; thus the system exhibits reciprocal control between matrix and droplet properties. We attribute the extraordinary stiffening to entrainment of actin by the droplets, which enlarges the effective inclusions until their contact network dominates the mechanics. This shows that liquid-liquid phase separation can control not only local compositions, but also mechanics, achieving exceptional stiffening at modest filler fractions through local geometries that constrain the matrix beyond the inclusions themselves.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci), Biological Physics (physics.bio-ph)
Reciprocal transverse Seebeck and Peltier effects in MoSi2
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Aina Sakamoto, Shoya Ohsumi, Shogo Yoshida, Ryuji Okazaki, Yoshiki J. Sato
Transverse thermoelectric conversion, in which charge and heat currents are interconverted in orthogonal directions, has recently attracted increasing attention as an alternative to conventional longitudinal thermoelectric conversion. Although transverse Seebeck effect has been investigated in various materials, its reciprocal process, transverse Peltier effect, remains much less explored, and direct comparison of the two effects in the same homogeneous material is still limited. Here, we experimentally investigate both transverse Seebeck and Peltier effects in a single crystal of MoSi2, an axis-dependent conduction polarity material in which the sign of the Seebeck coefficient varies depending on the crystallographic axis. Multi-terminal voltage measurement determines the direction of the induced internal electric field and establishes the transverse Seebeck response. We also directly visualize the transverse temperature modulation consistent with the corresponding transverse Peltier effect by using lock-in thermography under an applied ac current. These results establish reciprocal transverse thermoelectric conversion in a homogeneous nonmagnetic single crystal without engineered interfaces.
Materials Science (cond-mat.mtrl-sci)
6 pages, 4 figures. Accepted for publication in Appl. Phys. Lett
Tan’s Contact for Trapped Spin-Orbit-Coupled Fermi Gases at Finite Temperature
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-10-30 20:00 EDT
Tianhao Wu, Yuanbang Wei, Rui Tian, Dongdong Pu, Beizhi Chen, Qihang Ying, Hongyan Shi, Yue Zhang, Shuai Li, Bo Liu
Tan’s contact, bridging microscopic features of many-body quantum systems to two-body contact interactions, is pivotal in the description of quantum gases. However, past studies of Tan’s contact of the spin-orbit coupled Fermi gases have been exclusively discussed at zero temperature. The thermal effects on that, which cannot be neglected in most experimental conditions, has not been explored so far. Here, through a path integral Monte Carlo (PIMC) study, we show that thermal effects fundamentally alter the scaling relation between spin-orbit coupling (SOC) and Tan’s contact. The linear scaling of Tan’s contact with respect to the strength of SOC found at zero temperature is drastically undermined by the thermal effects. And a new mechanism based on the competition between the mean occupancy and the energy-reweighted occupancy of the opposite spin fermion pairs within the interaction range has been unveiled, which radically changes the above linear scaling to a non-monotonic dependence. Our work should be useful for future experiments to explore the preternatural thermal effects on Tan’s contact of the strongly interacting spin-orbit-coupled Fermi gas.
Quantum Gases (cond-mat.quant-gas), Atomic Physics (physics.atom-ph), Quantum Physics (quant-ph)
5 pages, 3 figures
Giant piezomagnetic response driven by spin reorientation in the topological Kagome magnet TbMn6Sn6
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Hanyang Qian, Wen Sun, Juntao Huo, Guowei Li
Achieving a large strain response to a small magnetic-field variation remains a challenge in magnetomechanical materials, particularly in topological systems where the coupling between spin reconstruction and lattice deformation remains unclear. Here, we report an anomalous magnetostrictive response associated with field-induced spin reorientation in the topological Kagome magnet TbMn6Sn6. Below its spin-reorientation temperature of 310 K, an in-plane magnetic field induces an abrupt increase in magnetostriction, which exceeds 120 ppm at 240 K. This transition produces a giant differential piezomagnetic coefficient of approximately 5000 ppm T-1, far exceeding the values reported for other topological magnetic materials and commercial FeGa alloys, and placing TbMn6Sn6 among the most field-sensitive magnetostrictive materials. The field position of this peak agrees with the anomalies in magnetization and magnetotransport, demonstrating that the large differential response is tied to field-induced spin reorientation. Thermal expansion also changes across the spin-reorientation boundary. Raman measurements reveal corresponding anomalies in phonon energy and linewidth, indicating that the reorientation modifies the lattice dynamics. The combined results support a mechanism in which competing magnetic anisotropies of the Tb and Mn sublattices, coupled through Tb-Mn exchange, create magnetic configurations with different equilibrium strains. This finding establishes spin reorientation as a route to giant piezomagnetic responses in topological magnets and provides a basis for magnetomechanical sensing and switching near room temperature.
Materials Science (cond-mat.mtrl-sci)
13 pages, 4 figures
Swimming versus Screening: How Activity Reshapes the Ionic Cloud of a Charged Particle
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-30 20:00 EDT
Tanmoy Chakraborty, Tomer Markovich, Ram M. Adar
A major question in active matter is how interactions between particles are modified by activity. Here, we address this question for Coulomb interactions by considering a charged swimmer immersed in an electrolyte. A static charge is screened by an ionic cloud that decays over the Debye length $ \lambda_D$ . We show that the persistent motion of the swimmer can qualitatively modify the steady-state ionic charge-density profile. At low activity, the swimmer appears effectively quasistatic to the ions, and conventional Debye-Hückel screening is recovered. At higher activity, the ballistic-to-diffusive dynamics of the swimmer are reflected in distinct spatial regimes. A power-law decay is followed by a stretched-exponential decay at intermediate distances. At sufficiently large distances, exponential screening is restored, but with an increased screening length, $ \lambda>\lambda_D$ , revealing activity-induced underscreening. Thus, active motion modifies both the spatial form and the range of electrostatic screening. Our results motivate the study of active electrolytes composed of positively and negatively charged swimmers.
Statistical Mechanics (cond-mat.stat-mech), Soft Condensed Matter (cond-mat.soft)
Nonreciprocal Floquet tunneling dynamics of spin-orbit-coupled bosonic atoms in a non-Hermitian double-well potential
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-10-30 20:00 EDT
Limei Ju, Yingying Zhang, Jilei Liang, Shoukang Chang, Zunlue Zhu, Lu Qin, Wuming Liu, Xingdong Zhao
The stable tunneling dynamics in non-Hermitian quantum systems is one of the fundamental issues in the study of quantum transport. Nonreciprocal coupling, as another crucial manifestation of non-Hermiticity, exerts significant regulatory effects on the stability of quantum devices and on spin tunneling dynamics. Here we place spin-orbit-coupled bosonic atoms in a double-well potential with gain and loss, and investigate the effect of nonreciprocal coupling on the system dynamics. Through an analytical analysis of the Floquet states and the quasi-energy spectrum under periodic driving, we obtain the PT-symmetry phase diagram of the system. We further explore the synergistic regulation mechanism of several factors—including the strength of nonreciprocal coupling, the non-Hermitian strength arising from gain-loss, and the periodic driving—on stable spin-flip tunneling. The results show that precise manipulation of nonreciprocity and gain-loss can substantially enlarge the stable parameter region. In nonreciprocal systems with balanced gain and loss, the continuity or discreteness of the stable parameter region is determined by the parity of the driving-frequency ratio $ \Omega/\omega$ , and the spin-flip tunneling can be precisely controlled through the parameters $ \lambda$ and $ 2\varepsilon/\omega$ . For the unbalanced gain-loss scenario, the equilibrium conditions for achieving stable spin-flip tunneling under different parities of $ \Omega/\omega$ are further provided. These findings offer a new theoretical approach for realizing robust spin-flip tunneling, provide guiding significance for the study of quantum-state transport in non-Hermitian ultracold atomic systems, and also serve as a reference for the experimental design of novel spin-based quantum devices.
Quantum Gases (cond-mat.quant-gas), Optics (physics.optics)
13 pages, 7 figures
High-Performance Nuclear Demagnetization Refrigerator Reaching 50 $μ$K
New Submission | Other Condensed Matter (cond-mat.other) | 2026-10-30 20:00 EDT
Zhengchao Liu, Junyang Song, Bingbing Tong, Hiroki Ikegami
Research in the deep sub-mK regime around 0.1 mK may open new opportunities in condensed matter physics in light of recent rapid progress in quantum technologies and quantum materials. Here, we report the design and performance of a nuclear demagnetization system that provides efficient access to the deep sub-mK regime for a wide range of experiments, using a standard wet dilution refrigerator with a medium-sized copper nuclear stage. We show that the temperature measured by a Pt NMR thermometer reaches 50 $ \mu$ K and that the refrigerator can maintain 100 $ \mu$ K for more than ten days. Remarkably, even with only 12 hours of precooling, the refrigerator cools into the deep sub-mK regime and can maintain 100 $ \mu$ K for more than three days, providing sufficient time for sample measurements. Numerical analyses indicate that the copper nuclear-spin system is cooled to about 18 $ \mu$ K, whereas a local heat leak to the thermometer limits the thermometer temperature to about 50 $ \mu$ K. These features establish the system as a practical platform for efficient experiments in the deep sub-mK regime.
Other Condensed Matter (cond-mat.other)
35 pages, 8 figures
Topology of Wannierizable Insulators
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
We study the freedom in choosing Wannier centers and the associated symmetry representations in noninteracting Wannierizable insulators. We compare Wyckoff deformations of atomic configurations with symmetry-preserving adiabatic deformations of occupied states, both with and without adding common occupied atomic orbitals. Explicit examples show that stable Wyckoff equivalence and adiabatic equivalence at fixed filling do not imply each other. In spinless $ Fm’m’m’$ , an Euler class distinguishes stably Wyckoff-equivalent configurations. In spinless $ P\overline1’$ , adiabatically equivalent configurations remain distinct under stable Wyckoff deformations. We also classify when stable Wyckoff and stable adiabatic equivalence coincide. They agree in two or fewer dimensions and in three-dimensional spinful systems. For three-dimensional spinless systems, Chern insulator pumps give additional equivalences in 134 magnetic space groups. These groups preserve spacetime orientation and have a point whose site-symmetry group contains $ 222$ , $ \overline1’$ , or $ \overline4’$ .
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
20 pages, two figures
Uniaxial strain tuning of functional properties in antiferroelectric PbZrO3 membrane capacitors
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Umair Saeed, Huazhang Zhang, David Pesquera, Fernando Gómez-Ortiz, Jessica Padilla- Pantoja, Jose Santiso, Philippe Ghosez, Gustau Catalan
Lead zirconate (PbZrO3, PZO) is a prototypical antiferroelectric (AFE) system promising for applications such as energy storage and neuromorphic computing. However, in conventional thin-film architectures, its functional potential is often limited by substrate clamping. Although emerging freestanding membrane techniques offer an approach to release this clamping and enable dynamic strain engineering, a systematic understanding of how external strain modulates the switching between AFE and ferroelectric (FE) states is missing. In this study, we investigate the uniaxial strain effects on PZO membrane capacitors transferred onto flexible substrates via a gold-bonding method. We demonstrate that in-plane dynamic strain modulates the AFE-FE switching and functional properties. Corroborated by atomistic simulations, we reveal that the strain-dependent evolution arises from the superposition of the intrinsic strain dependence of specific domain orientation variants and extrinsic strain-induced redistribution of the relative population of different domain variants. These findings provide a predictive understanding of uniaxial strain tuning of AFE-FE switching in PZO, and pave the way for exploiting the functional potential of freestanding antiferroelectric membranes.
Materials Science (cond-mat.mtrl-sci)
Manuscript and supplementary, 4 figures
Amorphous selenium-alloyed TeOx thin-film solar cells
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Zhaoheng Ling, Linqu Luo, Chrysa Aivalioti, Temur Maksudov, Mengxi Zhang, Theodoulos Kalogerakis, Lazaros Panagiotidis, Elefterios Lidorikis, Spyros Doukas, Nikolaos Kalfagiannis, Epameinondas Tziortzios, Leonidas Tsetseris, Huihui Zhu, Ao Liu, Yong-Young Noh, Martin Heeney, Shadi Fatayer, Thomas D. Anthopoulos
Tellurium dioxide (TeO$ _2$ ) is a wide-bandgap oxide with attractive processing versatility and emerging p-type semiconducting behaviour, making it a promising material system for optoelectronic and photovoltaic applications. However, TeO$ _2$ -derived thin films prepared by scalable manufacturing processes, such as vacuum sublimation, can contain residual metallic Te$ ^0$ species that introduce trap states, limit hole transport, and promote carrier recombination. Here, we demonstrate a selenium alloying strategy to control the defect chemistry of vacuum-sublimed TeO$ _x$ films. TeO$ _2$ :Se powder mixtures (90:10wt%) were thermally evaporated and subsequently annealed in air at 225$ ^\circ$ C for up to 9h, yielding amorphous TeO$ _x$ :Se films with an optical bandgap of 0.98eV under optimised conditions. Structural, chemical, optical, and electrical analyses show that prolonged annealing promotes Se redistribution, suppresses residual Te$ ^0$ to approximately 0.4%, reduces the film’s surface roughness, and shifts the valence-band edge. To evaluate the potential of TeO$ _x$ :Se for photovoltaic applications, we fabricated thin-film solar cells with an ITO/ZnO/TeO$ _x$ :Se/MoO$ _x$ /Ag architecture. Devices based on an 80nm TeO$ _x$ :Se active layer annealed for 9h exhibit optimal performance, with broadband photocurrent generation from 300 to 1000nm, yielding an open-circuit voltage of 0.50V, a short-circuit current density of 8.50mAcm$ ^{-2}$ , a fill factor of 0.44, and a maximum power conversion efficiency of approximately 1.87%. These results establish selenium-alloyed TeO$ _x$ as a viable oxide-derived absorber for thin-film photovoltaics and highlight chemical-state control as an effective route for improving photovoltaic performance.
Materials Science (cond-mat.mtrl-sci)
n/a
Information-Theoretic Reliability–Safety Bounds and Finite-Alignment Dynamics in AI Knowledge Distillation
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-30 20:00 EDT
Miao-Miao Yi, Zhen-Yu Cai, Y -M. Du, C. P. Sun
The reliability and safety of artificial intelligence (AI), together with their transfer and evolution through knowledge distillation, have attracted growing attention. We establish an information-theoretic bound on the reliability–safety trade-off and characterize the dynamics of this trade-off under knowledge distillation. We first prove a universal trade-off inequality that is independent of the specific model form. Its boundary is determined solely by a single parameter Kh, which quantifies the hidden layer’s ability to distinguish benign from hazardous inputs. We then develop a canonical Boltzmann-machine model of AI response behavior and derive two exact relations between reliability and safety. The trade-off curve is determined by the hazard discrimination capacity K, while the overall answer tendency controls the operating point along the curve. These relations agree well with existing experimental data. In knowledge distillation, we find that teacher responses induce a renormalization of the student model’s trade-off parameters. We further use a renormalization-group approach to study multigenerational distillation, deriving exact recursion relations and the associated renormalization-group-like flows for two representative direct intergenerational distillation protocols at arbitrary teacher–student alignment strength. These flows reveal fixed-point structures, long-term dynamics, and critical behavior, yielding testable predictions for the critical transition between capability loss and stable transmission.
Statistical Mechanics (cond-mat.stat-mech), Artificial Intelligence (cs.AI)
Finite-time minimum-work protocols for underdamped traps driven by active forces
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-30 20:00 EDT
Kangcan Yao, Ruicheng Bao, Zhonghuai Hou
Active systems provide non-equilibrium energy that can, in principle, be harvested using control protocols, making the optimization and reliability of work extraction a fundamental problem in microscopic thermodynamics. Yet how inertia and activity jointly modify the optimal work extraction protocol, the maximum extractable work its fluctuations, and implementability of protocols remains unclear. Here, we design minimum-work protocols, which maximize work extraction whenever extraction is possible, for an underdamped active particle in a translated harmonic trap. Remarkably, both the minimum mean work and its fluctuations are independent of mass, although inertia modifies the protocol. The results are then applied to an underdamped active Ornstein-Uhlenbeck particle (AOUP), designing an explicit work-extraction criterion and revealing extracted work’s dependence on rotational noise and initial conditions. We further show that inertia strongly affects the difficulty of implementing the optimal protocol, producing a transition-like change between underdamped and overdamped optimal protocols. These findings uncover work extraction mechanisms at the microscale and guide the design of reliable energy-harvesting microscopic devices and robots.
Statistical Mechanics (cond-mat.stat-mech)
The effects of hydrodynamic interactions on the swimming velocity and stability of a swarm of microswimmers
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-30 20:00 EDT
Andrés Córdoba, Jay D. Schieber
The dynamics and stability of a swarm of microswimmers is examined here using a thermodynamically compliant microswimmer model. The theory presented here is a mean-field model in which the swarm is considered to be a uniform solution of swimmers that are moving, on average, in the same direction. The hydrodynamic interaction between swimmers is modeled accurately assuming a crystalline arrangement to the swarm. A swimmer in the swarm can swim up to twelve times faster than when alone in an infinite sea, when the volume fraction of swimmers in the swarm is about 0.14. Moreover we have also studied the stability of the swarm around a uniform crystalline arrangement by calculating the hydrodynamic torques generated by the swarm as a function of the volume fraction of swimmers. The predictions presented here agree with recent multiparticle simulations that have shown that hydrodynamic torques have a stabilizing effect in swarms of pullers while swarms of pushers are generally destabilized by hydrodynamic interactions. The thermodynamically admissible coupling between the swimmer’s motion and fuel consumption allows us to study the full dynamics instead of artificially constrained steady-states only. By accounting for fuel consumption and high order hydrodynamic interactions we are able to examine the swarm’s stability as function of fuel concentration and the volume fraction of swimmers. We find that at high concentrations of fuel, swarms of pullers are stabilized by hydrodynamic torques for volume fractions of swimmers as low as 0.02 but at lower volume fractions Brownian forces make the swarm unstable.
Soft Condensed Matter (cond-mat.soft)
Phys. Fluids 35, 111901 (2023)
Symmetries and Propagation of Surface Plasmon Polaritons in Axion Electrodynamics
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
Surface plasmon polaritons at the interface between a conductor governed by axion electrodynamics and an ordinary dielectric are studied using a general phenomenological model, in which the macroscopic response is described by an axial vector $ \mathbf{G} $ , responsible for the anomalous Hall effect, and a pseudoscalar $ W $ , accounting for the chiral magnetic effect. We extend the analysis of the chiral magnetic effect in the planar geometry, address its role in the cylindrical one and, in both geometries, discuss the case in which the two effects coexist. We find an upper bound on $ W $ , a nonreciprocity requiring both effects and the absence of freely propagating modes, depending on the orientation of $ \mathbf{G} $ , for the planar interface, and, for the cylindrical one, a novel coupling between the linear and orbital angular momenta of the modes, which already arises from the chiral magnetic effect alone and persists when the anomalous Hall effect is also present. The exact eigenmodes of the axion medium are derived, and the symmetries and propagation features of the surface modes are made explicit by analytical and asymptotic evaluation of the dispersion relations.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Gravitational anomaly spectroscopy of a Kitaev spin liquid
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-30 20:00 EDT
The chiral central charge $ c$ measures the gravitational anomaly of a two-dimensional topological phase. It fixes the heat current carried along the edge. So far, it has been accessed through thermal transport, where phonons complicate the signal, or through wave-function probes that need a pure ground state. Here we show that $ c$ is a spectroscopic quantity of the edge. A weak modulation of the edge couplings that travel along the edge is absorbed according to the Virasoro algebra. Normalized by the response to a static change of the same couplings, the absorbed weights obey $ D_n=2n\langle L_0\rangle+\frac{c}{12}(n^3-n)$ , so that $ \mathcal{C}\equiv2D_2-4D_1=c$ in any state of the ideal edge theory, thermal or not. The central charge thus appears in transition weights, although it cancels from excitation gaps. The ratio of line weights with and without a vison in the bulk, $ \Lambda=4h_\sigma/c$ , needs no calibration and fixes the conformal spin $ h_\sigma$ of the non-Abelian Ising anyon. For the Kitaev honeycomb spin liquid we find $ \mathcal{C}=0.49999$ and $ h_\sigma=0.06250$ on 7168 spins. Calibrating with the shift of the measured line itself gives $ c$ within about $ 1%$ on 96 spins and within $ 1%$ under $ 20%$ random coupling errors. Interacting edge Majoranas in a fixed flux sector, treated with DMRG, keep $ \mathcal{C}$ within $ 1.5%$ while the edge velocity changes by $ \pm13%$ . An exact simulation of a quantum-processor protocol, including the native Floquet circuit, returns $ c$ within $ 3.5%$ on 96 to 600 spins.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
10 pages 5 figures
Large connectivity expansion of Ising Spin Glasses on random graphs
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-10-30 20:00 EDT
Luca Maria Del Bono, Flavio Nicoletti, Federico Ricci-Tersenghi
We compute a high-connectivity analytical expansion for Ising spin glasses on sparse random graphs. We expand the cavity equations around the fully-connected mean-field limit, focusing on the critical behavior of the system: our approach allows us to compute the de Almeida-Thouless line of mean-field finitely-connected systems in the temperature $ T$ –magnetic field $ H$ plane, by means of closed analytical equations. The exact cavity solution of such systems can only be obtained by solving numerically iterative equations, so our approach brings a notable computational advantage. On the theoretical side, we are able to identify three sources of corrections to the fully-connected mean-field solution: i) the non-Gaussianity of the cavity fields, ii) the statistical correlation between the cavity fields and their fluctuations, and iii) the corrections to the cavity filter functions. These corrections are treated using two different expansions: a non-uniform expansion, where we expand all three contributions around the mean-field solution, and a uniform expansion, where we only expand the statistics but leave the cavity filters untouched. The former allows for a direct comparison with the Sherrington-Kirkpatrick model but fails at low temperatures, as a consequence of the de Almeida-Thouless line diverging in the zero-temperature limit. On the other hand, the uniform expansion describes with good accuracy the critical behavior of the system. We also extend these results to the $ T = 0$ limit.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech)
20 pages, 6 figures
Mixed-State Topological Transition and Emergent Fractionalized Supersymmetry in the Non-Abelian Kitaev Spin Liquid
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-30 20:00 EDT
Zhou-Quan Wan, Hong Yao, Shao-Kai Jian
We study a mixed-state topological transition in the non-Abelian Kitaev spin liquid driven by a bond-dephasing channel. In the vectorized picture, bond dephasing maps onto interactions between two time-reversed fractionalized Majorana systems coupled to gapped $ \mathbb Z_2$ gauge fields, enabling sign-problem-free Monte Carlo simulations. We show that increasing dephasing condenses an inter-copy fermion pair, converting $ {\rm Ising}\boxtimes\overline{\rm{Ising}}$ to toric-code order in the Choi state and yielding intrinsically mixed-state topological order upon unfolding. More interestingly, at a temporal interface between topological and trivial Kitaev states, a Chern-number mismatch enforces a gapless Majorana mode. Dephasing then drives a mixed-state topological transition at which the gapless mode develops emergent $ \mathcal N=1$ supersymmetry. Our Monte Carlo simulations yield $ \nu=1.27(3)$ and $ \eta_b\simeq\eta_f\simeq0.40$ , consistent with the exact supersymmetric values $ 5/4$ and $ 2/5$ . The supersymmetric partners are fractionalized and appear physically as distinct gauge-invariant spin strings, providing concrete observables for future experiments.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
4.3 pages + supplemental material, 3 figures
A Luminescent Organic Triradical as an Optically Addressable Qudit
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Kueyoung E. Kim, Avik Bhanja, Alistair Inglis, William K. Myers, Sam L. Bayliss, Richard H. Friend, Petri Murto
Luminescent molecular trityl radicals provide options for optically-addressable electron spins and are promising for quantum sensing. Here, we present a luminescent triradical comprising three trityl groups covalently attached to a central phenyl ring. We find two distinct photoluminescence bands at 633 nm and 690 nm with different temporal evolutions, which we attribute to excited quartet and doublet states respectively. The ground state quartet is 1 meV (11.5K) lower in energy than the doublet, resulting in near-equal population of doublets and quartets at room temperature. We demonstrate optically initialized spin polarization, coherent control of the ground state quartet, and optical readout. Potential for optical quantum sensing is shown via optically detected magnetic resonance at room temperature and magneto-photoluminescence up to 3% at 5 mT. This material is a candidate optically addressable molecular qudit, providing opportunities to leverage larger state spaces than qubit systems.
Materials Science (cond-mat.mtrl-sci)
24 pages, 7 figures
Multiscale evaluation of the elastic response of polycrystalline NiAl using molecular statics, EBSD-based finite element and analytical homogenization methods
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Szymon Nosewicz, Marcin Maździarz, Paweł Hołobut, Witold Chromiński, Katarzyna Kowalczyk-Gajewska, Grzegorz Jurczak
The presented work proposes a multiscale framework for the numerical and analytical determination of the elastic constants of the intermetallic nickel aluminide (NiAl) at the microscopic scale. Molecular dynamics (MD) calculations have been employed to evaluate the stiffness tensors of a single NiAl monocrystalline body with cubic Pm$ \bar{3}$ m symmetry. The atomistic results were transferred to the upper scale as an input to micromechanical models. Here, finite element modeling (FEM) and analytical homogenization methods were used to simulate the elastic behavior of polycrystalline NiAl, with special attention to grain anisotropy and its morphology. The microstructural features of the heterogeneous body were evaluated experimentally using electron backscatter diffraction (EBSD) and subsequently used to generate a 3D polycrystalline geometric model that preserves realistic distributions of grain orientations and grain sizes. The reconstructed NiAl polycrystal was subjected to uniaxial tensile test simulations using FEM to evaluate the effective Young’s modulus ($ E$ ) and Poisson’s ratio ($ \nu$ ). The numerical results were confronted with the experimental values of $ E$ and~$ \nu$ . With these model assumptions, a very good agreement between numerical and experimental results was achieved. Finally, the experimental results were compared with classical analytical estimates. Among the analytical approaches, the Hashin-Shtrikman upper bound and self-consistent approximation reproduced the experimental Young’s modulus with minor deviations.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
30 pages, 10 figures
Transverse momentum transport and collective-mode localization in dipolar tube arrays
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-10-30 20:00 EDT
Camilla Polvara, Nishchhal Verma, Sarang Gopalakrishnan, Vadim Oganesyan
We study transverse transport of longitudinal momentum in an array of one-dimensional Bose gases coupled by dipolar interactions without particle tunneling. Within zero-temperature Bogoliubov theory, we characterize this transport using the inter-tube momentum correlator and its squared magnitude, termed amplitude and intensity. In a uniform array, pairs of Bogoliubov quasiparticles propagate ballistically across the tubes, while their dephasing produces a $ t^{-3}$ decay of the long-wavelength amplitude. Tube-to-tube density imbalance acts as quenched disorder and localizes the transverse collective modes. At fixed longitudinal momentum, this arrests the growth of the intensity profile, whose time-averaged spatial decay measures the localization length. Equal-time correlations are much less sensitive to disorder and primarily reflect the interaction range: in the uniform array they decay with tube separation as $ r^{-7}$ for dipolar coupling, compared with exponential decay for nearest-neighbor coupling. Finally, sufficiently strong inter-tube repulsion destabilizes the longitudinally uniform state toward density modulations staggered between neighboring tubes, at a threshold independent of density imbalance.
Quantum Gases (cond-mat.quant-gas)
20 pages, 14 figures
Spectrum of the steady-state distribution function of disordered Lindbladian fermions at large channel number
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
Maksim Parfenov, Igor Burmistrov
Free fermions coupled to particle gain and loss relax to a Gaussian steady state, in which every natural orbital has its own occupation. We find the distribution of these occupations $ \varrho_{\rm st}$ for a random Hamiltonian coupled to many random gain and loss channels. Each orbital is filled and emptied at its own rates, and the Hamiltonian, moving particles across the levels during their lifetime, averages the differences between the orbitals. We show that this averaging is incomplete: the spread of the occupations decreases only as the inverse square root of the number of channels per level. At large system size the distribution depends on the grain Hamiltonian only through its density of states $ \nu(E)$ . The spread is bounded by the baths alone: even Hamiltonians with unbounded, heavy-tailed spectra cannot widen it beyond this bound. The spread suppresses the particle-number fluctuations below their binomial value.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech)
Autonomous Quantum Measurement with Agentic AI
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Eunbi Rha, Abhijatmedhi Chotrattanapituk, Mouyang Cheng, Chung-tao Chou, Shenyong Ye, Ashley S. Dale, Long Ju, Luqiao Liu, Mingda Li
Quantum materials exhibit diverse electronic and functional phenomena, but their characterization requires extensive experimental expertise, iterative decision-making and accumulated laboratory knowledge that is difficult to document and transfer. Here we introduce Quantum Agent (QUANTA), an agentic artificial intelligence (AI) framework for autonomous quantum-materials characterization. Using a widely adopted Physical Property Measurement System (PPMS) as an experimental platform, QUANTA combines retrieval augmentation using scientific literature, experimental protocols and prior measurements with specialized agents for experimental planning, troubleshooting, and data interpretation. A separate deterministic control layer validates instrument actions. Guided by incoming data, QUANTA evaluates measurement quality, revises experimental plans and selects subsequent measurements. We demonstrate these capabilities through transport measurements of the topological Weyl semimetal TaP, as well as investigations of nonlinear responses in magnetic material Co2MnGa. These results establish QUANTA as a generalizable framework for evidence-driven, safeguarded and closed-loop quantum-materials characterization.
Materials Science (cond-mat.mtrl-sci), Artificial Intelligence (cs.AI)
Effect of the surface on the energy levels in PbS and PbSe nanocrystals
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
O. Lundgren, A. V. Rodina, Al.L. Efros
The structure of the electron and hole quantum confinement levels in spherical PbS and PbSe nanocrystals (NCs) is studied within the framework of a four-band effective-mass model. This level structure was initially calculated within the Kang–Wise model, which employs the standard boundary condition of vanishing carrier wave functions at the NC surface. This model, however, does not allow one to account for the effect of the NC surface on the level structure. Here, the effect of the NC surface is modeled using general boundary conditions (GBCs) imposed on the envelope wave functions at the surface. We show that the surface properties modify the size dependence of the electron and hole confinement levels and lead to an additional spin–orbit splitting of the $ 1P_{h,e}$ levels. Using the GBCs, we are able to quantitatively describe the size dependence of the lowest optical transitions in bare PbS and PbSe NCs and explain the differences between the absorption spectra of bare and Cl-passivated PbS NCs
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
33 pages, 6 figures, Submitted to Physical Review B
Learning Between the Lines: Interaction Interpolation in a Multi Element Machine Learning Interatomic Potential
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Ademola Soyemi, Kipton Barros, Timothy C. Germann, Benjamin T. Nebgen, Brenden W. Hamilton
The continuous development of machine learning inter-atomic potentials (MLIAPs)has greatly accelerated materials research in recent years. However, the need to con- struct custom MLIAPs for each unique problem remains a bottleneck which raises the question of the transferability of MLIAPs. While foundation MLIAPs can achieve transferability due to the broad coverage of chemical space represented in their training sets, their size and computational cost limits their routine use. We address this gap by developing a lightweight general-purpose MLIAP for metal alloys spanning twelve elements (Al, Sc, Ti, V, Cu, Zn, Zr, Nb, Mo, Hf, Ta, W). Here, we utilize a step-wise active learning (AL) approach to develop a compact yet diverse dataset and model that generalizes well by interpolating from previously seen interactions. The resulting potentials transfer effectively to unseen, higher body-order alloys systems, requiring only unary and binary training data to capture ternary and quaternary systems. The model also transfers well to new elements via an alchemical extrapolation within the network, requiring only unary data for the new element and its alloys. These findings suggest that MLIAPs trained on targeted, diversity-driven datasets provide transferability at a relatively low computational cost, offering a practical path toward general-purpose, resource-efficient MLIAPs for materials modeling.
Materials Science (cond-mat.mtrl-sci)
Thermodynamic cost of locally maintaining a steady state
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-30 20:00 EDT
The Gibbs states of local Hamiltonians have short-range conditional correlations. To maintain a steady state with long-range conditional correlations, one might expect that a stochastic process must ``pay’’ either in nonlocal moves or entropy production. Surprisingly, we find strictly local Gaussian processes that obey detailed balance and have unique steady states with arbitrarily long-range conditional correlations. We show that such processes must still produce entropy, if implemented using a local quadratic Hamiltonian coupled locally to equilibrium, rapidly relaxing baths. We lower-bound this entropy production in terms of the steady state’s conditional mutual information (CMI); if the CMI decays exponentially with distance, the associated length-scale is called the Markov length $ \xi$ . The entropy production per site per relaxation time obeys $ \hat\sigma \ge c \xi^2$ for large $ \xi$ , and with $ c$ an implementation-dependent constant. We also bound the tradeoff between coupling range and entropy production. We contrast these Gaussian processes with jump processes on discrete state spaces, for which, under certain irreducibility assumptions, steady states with long-range CMI are only possible if detailed balance is violated. We conjecture (and present evidence) that rapidly mixing local jump processes cannot stabilize steady states with long-range CMI.
Statistical Mechanics (cond-mat.stat-mech)
21 pages, 2 figures, comments welcome
Collective sliding relaxor ferroelectricity across thousand-layer van der Waals superstructures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Nianze Shang, Cuiju Yu, Yucai Lin, Juan C. Arias-Muñoz, Jiajie Qi, Quanlin Guo, MD Gius Uddin, Youqiang Huang, Tuomas Pajunpää, Christopher P. Edwards, Rodolfo E. Canet-Albiach, Faisal Ahmed, Andreas C. Liapis, Yaoqiang Zhou, Zhibin Zhang, Hao Hong, Qing Dai, Andrea Alù, José L. Lado, Kaihui Liu, Zhipei Sun
Relaxor ferroelectrics are among the most important electromechanical materials owing to their exceptionally large electrostrictive responses. However, conventional relaxor behavior is generally associated with chemical complexity and structural disorder, where local compositional fluctuations generate polar nanoregions, making the microscopic origin of this behavior difficult to control and engineer. Here we report sliding relaxor ferroelectricity (S-RFE), a previously unknown relaxor state in which engineered stacking-phase heterogeneity enables cooperative interlayer sliding to generate collective relaxor behavior. Through stacking-phase engineering in rhombohedral boron nitride, we create sliding domains that act as structural analogues of polar nanoregions and cooperatively align under an electric field through interlayer sliding. This collective state produces reversible electromechanical deformation of up to approximately $ -1.6%$ with negligible hysteresis in approximately 300-nm-thick crystals, corresponding to approximately 1000 atomic layers. The resulting electrostriction coefficient ($ Q_{33}$ of approximately $ 1200,\mathrm{m}^{4}\mathrm{C}^{-2}$ ) exceeds those of most crystalline electrostrictors by orders of magnitude. Unlike conventional relaxors, whose electromechanical response is often suppressed by dipolar freezing at low temperatures, S-RFE remains active down to 1.6 K and maintains giant electromechanical functionality. Our results establish sliding relaxor ferroelectricity as a new route to relaxor behavior and reveal how atomic-scale interlayer motion can be amplified into collective mesoscale functionality across approximately one thousand layers, providing a materials-by-design platform for electromechanical, photonic, and quantum technologies based on van der Waals materials.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph), Optics (physics.optics)
20 pages, 5 figures
Development and application of a machine learning potential for diamond surfaces and their sliding interfaces with silicon nitride and silica: effect of passivation, orientation and load
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Enrico Pedretti, Maria Clelia Righi
Friction and wear of diamond are controlled by its surface chemistry, which determines whether covalent bonds form across the sliding interface. First-principles simulations have explored the role of surface orientation and passivation, but are limited to a few hundred atoms and tens of picoseconds. To bridge this gap, we develop a reactive machine learning interatomic potential for the C/H/N/O/Si chemical space, covering diamond, silicon nitride, silicon oxide, their surfaces, interfaces, and environmental molecules. The potential is trained on a large dataset of diverse structures and is tested on multiple physical properties, including ab initio reaction barriers on diamond surfaces, and structural/mechanical properties of amorphous Si$ _3$ N$ _4$ and SiO$ _2$ . We then simulate sliding of diamond-Si$ _3$ N$ _4$ interfaces with four surface orientations, clean and H/OH-passivated terminations, and normal loads from 0.1 to 23 GPa. We identify two different regimes: one where sliding is localized at the interface, and shear stress is proportional to the interfacial bond density, and another where shear is distributed inside the softer material, and adhesion due to full interfacial bonding dominates. These results show how passivation, surface orientation and load together determine interfacial bonding and friction, with implications for the environmental sensitivity of diamond wear. More broadly, the potential enables reactive simulations of diamond, silicon nitride and silica with near-ab initio accuracy at length and time scales beyond first-principles methods, providing a useful tool for future studies of wear at plowing asperities, chemical-mechanical polishing, and properties of amorphous ceramic films.
Materials Science (cond-mat.mtrl-sci)
14 pages, 5 figures
Comment on “Is there a density-gradient expansion for the electronic exchange energy?”
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Mario Benites, Angel Rosado, Efstratios Manousakis
Perdew et al. [arXiv:2610.07201 (2026)] dispute our finding [Phys. Rev. B 113, 115136 (2026)] that the separate exchange ($ b_x$ ) and correlation ($ b_c$ ) contributions to the $ q^2$ coefficient of the long-wavelength proper polarization function depend on the infrared regularization of the Coulomb interaction, although their sum $ b_{xc}=b_x+b_c$ does not. We question their claim that the conventional exchange coefficient is uniquely determined. In Qian’s [J. Math. Phys. 56, 111901 (2015)] derivation, which Perdew et al. cite in support of their claim of a unique exchange-gradient coefficient, an integral of the form $ \int_{-a}^{b}dx/x$ crosses a singularity and does not exist as an ordinary improper integral. Its finite Cauchy principal value (which is a particular way of regularizing the integral) is obtained only by excluding equal intervals on the two sides of the singularity; unequal exclusions give different answers. Independently, Sham’s calculation with the screened interaction $ e^{-\lambda_0 r}/r$ gives an exchange-gradient coefficient different from the bare-Coulomb calculations of Svendsen–von Barth [Int. J. Quantum Chem. 56, 351 (1995)] and Engel–Vosko [Phys. Rev. B 42, 4940 (1990)]. The discrepancy remains when $ \lambda_0>0$ is so small that $ 1/\lambda_0$ is comparable to the size of the observable universe, making the two interactions experimentally indistinguishable on laboratory scales. Why should the exactly unscreened result be preferred, even if its calculation is accepted as valid? Our calculation shows that the ambiguity of the separate contributions cancels in the combined, regulator-independent coefficient $ b_{xc}$ .
Materials Science (cond-mat.mtrl-sci)
5 pages. Comment on arXiv:2610.07201
Separating the Density Wave Phase from Zero-Resistance Superconductivity in La$_4$Ni$3$O${10}$
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-30 20:00 EDT
P. Puphal, A. Suthar, B. Wehinger, V. Sundaramurthy, T. Priessnitz, M. Knauft, P. Sosa-Lizama, Y.-M. Wu, M. Hepting, J. Nuss, M. Isobe, P. A. van Aken, Y. E. Suyolcu, B. Keimer, H. Takagi, P. Reiss
Identifying the key ingredients for superconductivity under pressure in the Ruddlesden-Popper nickelates remains a formidable challenge, due to a complex interplay between structural variations, oxygen content and location, electronically ordered phases, and the need for high pressures to reach the superconducting phase. To disentangle these complex inter-dependencies, here we study a series of clean single crystals of trilayer La$ _4$ Ni$ _3$ O$ _{10}$ . We discover that enhanced biaxial, compressive pressures induce a zero-resistance state at a 60% lower pressure compared to previous reports. At the same time, we completely separate the low-pressure density wave phase from superconductivity, effectively ruling out that soft, quantum critical fluctuations of the density wave order parameter act as the pairing glue in this system. Our results establish biaxial, in-plane pressures as a powerful tool for promoting superconductivity in nickelates, unifying the required pressure scales for superconductivity in different Ruddlesden-Popper structures, and providing a connection to the recently discovered thin film samples.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
Coexistence of superconductivity and magnetic order in BaFe$_2$S$_3$: evidence for orbital-selective delocalization
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-30 20:00 EDT
Y. Oubaid, N. S. Dhami, P. Fertey, C. V. Colin, C. Ritter, A. Forget, D. Bounoua, J.-P. Rueff, M. Verseils, P. Foury-Leylekian, V. Balédent
Understanding how superconductivity emerges from correlated electronic states is a central challenge in condensed matter physics. The quasi-one-dimensional spin-ladder compound \bfs\ serves as a unique platform to study this interplay, as it lacks the two-dimensional square lattice characteristic of most iron-based superconductors. Here, we combine high-pressure x-ray and neutron diffraction, x-ray emission spectroscopy, and electrical transport to map its structural, magnetic, and electronic evolution into the superconducting regime. We \revised{observe} a striking pressure-induced decoupling: while the long-range stripe-type antiferromagnetic order remains remarkably robust under pressure up to the onset of superconductivity, the local iron magnetic moment is suppressed by nearly 80%. This dichotomy \revised{points to an orbital-selective mechanism}, where specific Fe $ 3d$ electrons remain localized to sustain magnetism while others delocalize to form the itinerant and superconducting state. \revised{Superconductivity emerges while long-range magnetic order is still present, revealing that the two coexist in \bfs, which we attribute to} the selective response of multiorbital electronic degrees of freedom.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
Magnetism in a homometallic square-planar Cu$({\mathrm{II})}$$_4$Cu$({\mathrm{II})}$ metallacrown
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-30 20:00 EDT
Luca Bischof, Ariyan Tavakoli, Sascha Pietruska, Lena Spillecke, Ina Heckelmann, Changhyun Koo, Luca M. Carrella, Eva Rentschler, Hans Christian Schneider, Rüdiger Klingeler
The well-established homometallic metallacrown Cu(II)[12-MC$ _\text{Cu(II)N(Shi)}$ -4]$ ^{2-}$ , comprising four square-planarly arranged Cu(II) ions surrounding a slightly off-plane central Cu(II) ion, provides an excellent platform for investigating magnetism in exchange-coupled Cu(II) clusters both by experimental and ab initio numerical methods. In the present work, sterically bulky substituents are introduced into the salicylhydroxamate ligand to obtain a modified derivative, Cu$ ({\mathrm{II})}$ [12-MC$ _\text{Cu$ ({\mathrm{II})}$ N(L)}$ -4]$ ^{2-}$ (Cu$ 4$ Cu), thereby effectively suppressing intermolecular magnetic interactions and enabling a detailed investigation of its intrinsic ground-state spin structure and exchange interactions. Static magnetization reveals competing antiferromagnetic exchange interactions of $ J_1=-8.1(2)$ THz ($ -33.5(8)$ meV) between the central and the peripheral sites and $ J_2=-4.40(12)$ THz ($ -18.2(5)$ meV) between neighboring sites on the ring of the metallacrown, which are corroborated by ab initio broken symmetry-based density functional theory (DFT). These couplings yield an $ S=1/2$ ground state for Cu$ 4$ Cu at low temperatures, for which X-band and high-frequency/high-field electron paramagnetic resonance (EPR) precisely determine the $ g$ -factors $ g_x = 2.028$ , $ g_y = 2.056$ , and $ g_z = 2.222$ close to axial anisotropy and in agreement with our DFT results. The ground-state spin-configuration is characterized by $ d{xy}$ -character of the unoccupied states. Furthermore, our magnetization data evidence thermal transitions across a doublet-to-quartet gap of $ \Delta{1/2\rightarrow3/2} = 4.8(4)$ THz which is also indicated by the emergence of an excited-state EPR signal.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Spectral theory of large data with power-law latent features
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-10-30 20:00 EDT
Power-law eigenvalue spectra of covariance matrices estimated from data appear in diverse domains ranging from neural populations to proteins. We introduce a generative latent feature model for such data, optionally corrupted by measurement noise, and develop its spectral theory. We derive closed leading-order self-consistent equations for the Stieltjes transform of the covariance matrix from which the bulk eigenvalue density is obtained and provide a variational principle for the self-consistent equations. We also compute the positions and fluctuations of isolated top eigenvalues. The theory is validated in known algebraic limits and tested against simulations.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech), Data Analysis, Statistics and Probability (physics.data-an)
19 pages, 7 figures
Nonreciprocity Propels Nematic Defects
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-30 20:00 EDT
Nonreciprocal interactions are a generic source of nonequilibrium dynamics, yet their consequences for nematic topological defects remain unexplored. We introduce a nonreciprocal nematic model on a two-dimensional hexagonal lattice and formulate a continuum theory containing a nematic nonreciprocal torque. In the deterministic limit, simulations and symmetry analysis show that this torque drives +1/2 defects to self-propel along their polar axes. Nonreciprocity modifies the splitting pathway of integer +1 defects. These results identify a symmetry-resolved route from nonreciprocity to nematic defect transport and topological reorganization, distinct from active-stress-driven motion.
Soft Condensed Matter (cond-mat.soft)
Response of Hydrogels and Microgels to Nanoparticle Crowding
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-30 20:00 EDT
Internal degrees of freedom of cross-linked polymer networks enable compressible hydrogels and microgels to swell or deswell by absorbing or expelling solvent in response to environmental changes. Macromolecules in solution can influence the swelling response by acting as crowding agents, with practical relevance for drug delivery and biosensing. We extend the Flory-Rehner theory of polymer network swelling to incorporate nanoparticle crowders as another implicit species that can perturb a gel through volume exclusion, including the entropic cost of crowder penetration from polymer field theory. Within the free energy landscape of asymmetric ternary mixtures, we numerically solve equilibrium relations equating solvent and crowder chemical potentials inside and outside the gel. Independently, we perform Monte Carlo simulations, including trial moves that allow gels to swell and take up crowders. We investigate how crowder size, solution concentration, cross-link density, and solvent quality influence swelling of polymeric gels, partitioning of crowders between inside and outside, and structural properties of microgel suspensions governed by Hertzian elastic pair interactions. Our results show that nanoparticle crowding promotes deswelling, thereby weakening interparticle correlations, and that, with increasing the concentration of crowders, polymeric gels reach a maximum loading capacity, dependent on crowder size and polymer cross-link density.
Soft Condensed Matter (cond-mat.soft)
16 pages, 17 figures
Mahesh Aryal and Alan R. Denton, J. Chem. Phys. 164, 064904 (2026)
HERA: Assessing an Autonomous Agent for Quantum Device Measurement
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
Zachary W. Gomez, Nathan Bittner, Jordan T. McCourt, Qingrui Cao, Sandesh S. Kalantre, Benjamin H. Alexander, Zhiren Zheng, Kenji Watanabe, Takashi Taniguchi, Aaron Sharpe
Large language model agents have begun to carry out laboratory measurements, but their scientific conclusions are useful only if they hold up under scrutiny. Demonstrating this requires controlled studies because models are stochastic and the context a model is given steers its conclusions. Here we introduce HERA, an autonomous agent designed to carry out cryogenic transport measurements of quantum devices. HERA draws on a knowledge base curated by lab members that holds measurement protocols, software tools, and literature references. We assessed HERA with a blinded trial against an expert on the stacking order of two multilayer graphene devices, an ablation of its knowledge base, and hundreds of offline replays in which models designed the trial’s central measurement without running it. HERA’s conclusions matched the expert’s sealed conclusions on both tested devices. The ablation and the replay studies measured the impact of the knowledge base across different models, showing that with it every model designed better measurements and reasoned more soundly. To test how readily HERA extends to a new problem, we tasked it with finding and characterizing superconductivity in a different material system. This required a few hours of expert time to develop a new experimental protocol, after which HERA did both autonomously. These results show that, with a knowledge base designed for the task, language model agents are capable of sound experimental science.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Artificial Intelligence (cs.AI)
16 pages, 5 figures, plus Supplementary Information (7 figures, 6 tables); data and code at this https URL and this https URL
A rhombic spin-1 interpretation of a room-temperature GaN emitter
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Single defects in GaN show optically detected magnetic resonance at room temperature. In the more abundant class, a minimal $ S=3/2$ model leaves a $ g\approx 4$ line unexplained. For one defect, this line lies near the sum of the two outer lines, consistent with transitions among three shared levels. A rhombic $ S=1$ model reproduces the three line positions with rms errors of 8.1-9.8 MHz. The tested second-order $ S=3/2$ fits containing all three transitions and the published minimal model do not reproduce these positions. A ladder fitted to the strong lines remains viable if the $ g\approx 4$ line is a separate transition near the sum of the outer two. An unresolved frequency-window shift prevents the existing data from establishing the $ S=1$ assignment uniquely. We propose a zero-field sweep that directly tests the isolated $ S=1$ assignment.
Materials Science (cond-mat.mtrl-sci), Quantum Physics (quant-ph)
13 pages, 4 figures; Supplemental Material appended (28 pages, 3 figures). Data and output files: this https URL
The End of Chaos at the Ideal Glass Transition
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-30 20:00 EDT
Zi-Long Wang, Jack F. Douglas, Matteo Baggioli, Zhao-Yan Sun, Wen-Sheng Xu
The ideal glass transition has often been associated with the extrapolated vanishing of configurational entropy $ S_c$ , yet how this thermodynamic criterion is reflected in microscopic dynamics remains unclear. Here, we show that the vanishing of deterministic chaos quantified by the maximum Lyapunov exponent $ \lambda_{\mathrm{max}}$ provides such a dynamical signature. Using molecular dynamics simulations across diverse model glass-forming liquids in two and three dimensions, we show that $ \lambda_{\mathrm{max}}$ follows an approximate scaling $ \lambda_{\mathrm{max}} \propto (T-T_{\lambda})^{1/2}$ and extrapolates to zero at a temperature $ T_{\lambda}$ consistent with the Kauzmann temperature $ T_{\mathrm{K}}$ . Furthermore, we establish the quantitative relation $ \lambda_{\mathrm{max}}^2 \propto T S_c$ , directly linking chaotic dynamics to configurational entropy. By demonstrating that $ \lambda_{\mathrm{max}}^2 \propto \sigma_K^2$ , where $ \sigma_K^2$ is the variance of local potential energy landscape curvature fluctuations, we connect the suppression of chaos directly to landscape geometry. These results provide a unified thermodynamic, dynamical, and geometric framework for glass formation, identifying the ideal glass transition as the endpoint of chaotic exploration of the energy landscape.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
11 pages, 16 figures
Two faces of symmetry match in gear-like coupled rotary motors
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-30 20:00 EDT
Sara Iranbakhsh, David A. Sivak
Rotary molecular motors commonly couple components with different rotational symmetries, but how this gearing controls energy transduction remains unclear. Here we show that symmetry can produce a fundamental tradeoff in coupled stochastic barrierless rotary motors: the gear ratio that maximizes output power under tight coupling is also the ratio that requires the strongest coupling to remain locked. Consequently, weakening the coupling can invert the effect of gearing, transforming a power maximum into a local minimum. At strong driving, both the power-optimal and most slip-susceptible ratios approach symmetry match. Numerical solutions of the Fokker-Planck dynamics for rotors with finite energy barriers reproduce these predictions and reveal how the behavior changes when driving strength is fixed per rotation or per subunit. Motivated by the bacterial flagellar motor, these results identify coupling strength as a key determinant of whether matched rotational symmetries enhance or suppress energy transduction, providing a general design principle for coupled molecular motors.
Statistical Mechanics (cond-mat.stat-mech), Biological Physics (physics.bio-ph)
5 pages, 5 figures (main text)
The Constructive Cavity Method for the Ising Perceptron
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-30 20:00 EDT
Simone Franchini, Francesco Concetti, Giampiero Bardella
We apply the Constructive Cavity Method (CCM) to the Ising perceptron. The process starts from positive soft channels admitting an auxiliary representation $ U(x)=\int_{\mathbb{R}} e^{tx}\rho(\mathrm{d}t),\qquad \rho\ge0, $ with an auxiliary measure having a finite exponential quadratic moment. This rewrites the perceptron as a dense, bipartite Gaussian model with an Ising layer and a continuous auxiliary layer. The CCM blanket geometry then gives two constructive variance profiles, $ Q_\ell$ on the Ising side and $ \Gamma_\ell$ on the auxiliary side. The bipartite shell scale is $ Q_{\ell+1}\Gamma_{\ell+1}-Q_\ell\Gamma_\ell, $ and Gaussian core comparison removes the core contribution $ \Delta Q_\ell\Delta\Gamma_\ell$ under blanket refinement. The scalar cavity functional has three terms, $ \mathcal{A}{\mathrm{perc}}(\nu)=\mathbb{E}\left[\log\langle2\cosh x\rangle\nu+\alpha\log\langle U(s)\rangle_\nu-\log\langle e^y\rangle_\nu\right], $ where $ x$ is the new-spin field, $ s$ is the new-constraint field, and $ y$ is the cavity correction. CCM identifies the constructive cavity variables with the Aizenman–Sims–Starr random overlap structure (ROSt) variables. Parisi’s recursive averaging then gives $ \mathcal{G}{\mathrm{perc}}^{\mathrm{CCM}}(\zeta,Q,\Gamma)=X_0(0)+\alpha Y_0(0)-\frac{1}{2}\sum{\ell=0}^{R}\zeta_\ell\left(Q_{\ell+1}\Gamma_{\ell+1}-Q_\ell\Gamma_\ell\right). $ The replica-symmetric specialization gives Gardner’s formula for the generalized Ising perceptron. Specializing the constraint terminal to the hard channel gives the Krauth–Mézard functional for the binary perceptron.
Statistical Mechanics (cond-mat.stat-mech)
25 pages, no figures
Atomic Charge Chirality from Electric Multipoles
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-30 20:00 EDT
We establish an electric-multipole ($ Q_{lm}$ ) criterion for chirality of local atomic charge distributions. For the 11 crystallographic chiral point groups, we identify representative lowest-rank multipole contents required to distinguish the opposite handednesses. For the axial groups $ C_n$ and $ D_n$ with $ n=2,3,4,6$ , chirality arises from the relative orientation of two azimuthal anisotropies with $ m=n$ , belonging to consecutive ranks $ l=n$ and $ n+1$ . Their coexistence produces a latitude-dependent twist of the $ n$ -fold charge distribution. The polar component, although allowed in $ C_n$ , is distinct from this chiral mechanism and is not required for handedness. The cubic groups $ T$ and $ O$ exhibit distinct realizations, with octahedral chirality first appearing at rank nine. We further show that, within a spinless $ s$ -$ p$ -$ d$ -$ f$ atomic basis, the scalar charge density contains multipoles only up to rank six and therefore cannot encode the handedness of $ C_6$ , $ D_6$ , or $ O$ . These results connect electric-multipole content and atomic orbital degrees of freedom to the microscopic encoding of crystallographic handedness.
Strongly Correlated Electrons (cond-mat.str-el)
6 pages, 1 figure, 1 table
Berry curvature dipole circuit quantum electrodynamics
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
Oles Matsyshyn, Valla Fatemi, Justin C.W. Song
Quantum three-wave mixing is an important resource in superconducting quantum circuits. The traditional implementation uses Josephson junction arrays and is activated by magnetic flux. Here we introduce the Berry curvature dipole (BCD) quantum circuit element, which achieves quantum three-wave mixing without breaking time-reversal symmetry. This quantum three-wave mixing results from the BCD nonlinear Hall effect in noncentrosymmetric quantum materials taken to a dissipationless, quantum coherent few-photon regime. We show how nonlinear Hall materials can be integrated to superconducting microwave circuits to accomplish multiphoton vacuum Rabi splittings and dynamical stabilization of bosonic Schrödinger cat states. Such BCD circuit quantum electrodynamics are a concrete exemplar of a physical resource for quantum information processing enabled by nonlinear response in quantum materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
16 pages, 5 figures
Local Josephson response near nonmagnetic impurities and vortices in a two-orbital $s_{\pm}$ superconductor
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-30 20:00 EDT
We study the local Josephson response near nonmagnetic impurities and vortices in a self-consistent two-orbital $ s_{\pm}$ superconductor. For a local $ s$ -wave tip that couples equally to the two orbitals, anomalous spectral contributions of opposite sign nearly cancel in the clean sample. Nonmagnetic impurities redistribute these contributions and can reverse the local coupling without a corresponding $ \pi$ phase shift of the bond pair fields. Negative coupling appears at off-center sites at weaker impurity potentials than at the impurity site. The impurity-induced change is concentrated at lower quasiparticle energies, while states over a broader energy range contribute to the total clean and impurity couplings. In zero field, the coupling also changes sign as the tip gap is varied, and increasing the tunneling strength can reverse the $ m=1$ sine component of the current without changing the sample state. At the chosen coherence-peak energy, increasing impurity strength mainly changes the relative intensities of existing quasiparticle-interference features. In a self-consistent two-vortex state, the Josephson response develops a spatially varying phase relative to the condensate. The response and condensate share the winding close to each core, while larger loops enclose additional winding of the Josephson response. The local Josephson sign and phase reflect the anomalous spectrum and the tip–sample coupling.
Superconductivity (cond-mat.supr-con)
27 pages, 24 figures
Nodal magnon spin current at an antiferromagnet/altermagnet junction
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
We investigate the thermally driven magnon spin current across a junction between a $ d$ -wave altermagnet (AM) and a ferromagnet (FM) or an antiferromagnet (AFM).
The current consists of a component independent of the interface angle and an angularly dependent component with the $ d$ -wave form.
For a sublattice-symmetric interface, the two junctions behave oppositely under reversal of the altermagnetic domain: in the FM/AM junction the angularly dependent component is odd and cancels on averaging over the domains, whereas in the AFM/AM junction the angularly independent component vanishes by symmetry and the angularly dependent component survives the domain average at a fixed Néel vector of the AFM.
Both follow from a selective tunneling: a pair of spins bonded across the interface transmits magnons when the spins are parallel and not when antiparallel, which makes the AFM/AM junction a magnon valve: the configuration in which the bonded spins are antiparallel blocks the current up to the sublattice admixture of the magnons.
The anisotropic tunneling is detectable as the sign reversal of the current between the interfaces normal to $ [310]$ and $ [130]$ , and the valve reads the Néel vector of the altermagnet relative to that of the antiferromagnet through the magnitude of the current at a fixed interface.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Lone-Pair Stereoactivity Overrides Mass Scaling of Thermal Expansion and Heat Conduction in Non-vander Waals Layered Bismuth Oxychalcogenides
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Linzhen Li, Guangwu Zhang, Ziyan Qian, Wei Jing, Yang Lu, Jiaqi Gu, Kaifeng Huang, Yanguang Zhou, Qiye Zheng
Heavier chalcogens are generally expected to soften isostructural semiconductor lattices, raising thermal expansion and lowering thermal conductivity. Layered bismuth oxychalcogenides, Bi2O2X (X = S, Se, Te), are mixed-anion crystals whose covalent slabs and ionic sheets are bound electrostatically rather than by van der Waals forces and whose Bi3+ 6s^2 lone pairs can become stereochemically active. Despite the rapid development of Bi2O2Se for fin and gate-all-around transistors, its fundamental thermal expansion and heat transport mechanisms remain poorly understood. Here, we show that lone-pair stereoactivity, not chalcogen mass, governs both properties. Path-integral molecular dynamics shows that the volumetric thermal expansion coefficient at 300 K decreases from 8.14 x 10^-5 K^-1 in Bi2O2S to 6.72 x 10^-5 and 6.61 x 10^-5 K^-1 in Bi2O2Se and Bi2O2Te, respectively, despite a 13% larger unit cell in the telluride, whereas substituting the S mass into Bi2O2Se changes its value by only 0.6%. Lone-pair-driven Bi off-centering in orthorhombic Bi2O2S makes b-axis expansion 1.63 times a-axis expansion yet leaves in-plane thermal conduction isotropic within 3%. Phonon transport calculations including four-phonon scattering and Wigner coherence predict a thermal conductivity maximum in Bi2O2Se (1.83 and 0.95 W m^-1 K^-1 in the in-plane and cross-plane directions, respectively, at 300 K) because Bi2O2S is limited by anharmonic scattering and Bi2O2Te by slow cross-plane phonons. Thermoreflectance measurements from 300 to 500 K and in situ X-ray diffraction on Bi2O2Se single crystals agree with these predictions within 6.4%. Phonon Boltzmann transport simulations of 12-nm-wide fins, which run hotter than Fourier diffusion predicts, show that Bi2O2Se minimizes the hotspot temperature and the thermal-mismatch strain at the gate dielectric.
Materials Science (cond-mat.mtrl-sci)
bismuth oxyselenide; non-van der Waals layered semiconductors; anisotropic thermal ex pansion; lone-pair electrons; four-phonon scattering; Wigner phonon coherence; FinFET self-heating
Colossal magnetoresistance in narrow-gap magnetic semiconductor Eu$_2$CdAs$_2$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Zhiyu Zhou, Zhi-Cheng Wang, Xiyu Chen, Xin-Yu Zhao, Yaran Duan, Shiran Tao, Guang-Han Cao, Shuai Dong
Discovering antiferromagnetic materials with a sizable colossal magnetoresistance (CMR) effect and precisely tuning their responses remain significant challenges in materials science. This work reports the synthesis, phase transitions, and magnetotransport properties of the narrow-gap Zintl arsenide Eu$ 2$ CdAs$ 2$ . The compound undergoes antiferromagnetic ordering at $ T\mathrm{N} = 9$ K and exhibits semiconducting behavior with a low-temperature activation energy of 3.2 meV, achieving a large CMR effect of $ -10^4%$ at 9 T. Below $ T\mathrm{N}$ , a distinct butterfly-shaped magnetoresistance hysteresis emerges without any macroscopic ferromagnetic order, revealing a transport anomaly likely dictated by AFM domain dynamics and/or the formation and percolation of localized magnetic polarons. Furthermore, a systematic survey of reported Eu-based Zintl phases uncovers a nearly exponential scaling trend between the maximum CMR magnitude and the low-temperature activation energy. This correlation demonstrates that bandgap engineering serves as an effective strategy for tailoring magnetotransport, establishing Eu-containing Zintl phases as a versatile platform for exploring and manipulating CMR effects.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Polarization-locked chiral persistent spin textures in two-dimensional lead-halide perovskites
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Palanichamy Gayathri, Biplab Sanyal, Jonas Fransson
Chiral spacer cations crystallize two-dimensional hybrid perovskites in the polar Sohncke group $ P2_1$ , which places the polar axis in the inorganic layer. We analyze the spin-orbit field that this geometry allows and test it against first-principles spin textures of ten polar chiral lead-halide perovskites, their mirror enantiomers and four halide-substituted analogues. The point group $ C_2$ with the twofold axis in the layer forbids the helical Rashba field and allows a linear term $ \gamma_1 k_x \sigma_z$ , the Rashba interaction of the in-plane polar axis, together with chirality-related Dresselhaus and radial terms. Thirty-four two-band $ k \cdot p$ models were fitted to each band pair and ranked by the agreement of their spin directions with the calculation rather than by the band energies, which cannot distinguish them. In all strongly polar compounds, the conduction band is described by the persistent term alone, with $ \gamma_1 = 1.09$ -$ 1.98$ eV Å and a spin agreement of at least 0.98, whereas the best Rashba or Dresselhaus model reaches 0.20. The $ R$ and $ S$ enantiomers of each compound have opposite polarizations, and therefore opposite $ \gamma_1$ and opposite persistent spin textures of equal magnitude, as required by the mirror that relates them; this holds in all ten compounds, so the choice of the enantiomer selects the spin direction. The magnitude of $ \gamma_1$ correlates with the disparity of the in-plane Pb-X-Pb angles ($ r = 0.95$ ). With electron masses of $ 0.26$ -$ 0.43,m_e$ along the spin-splitting directions, the associated persistent spin helices have wavelengths of 3.4-8.2 nm.
Materials Science (cond-mat.mtrl-sci)
Dissipation dilution enhances SiV coupling to vdW diamond nanomechanics
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
Guanhao Huang, Amberly Xie, Chang Jin, Evelyn Hu, Marko Lončar
Solid-state color centers embedded into mechanical resonators, where orbital states mediate interactions between spins and long-lived phonons, are a promising platform for hybrid quantum systems. The negatively charged silicon vacancy center in diamond (SiV-) is particularly favorable for strain-coupling to nanomechanical resonators because of its large spin-strain susceptibility and compatibility with device integration. Tensioned nanomechanical resonators offer an attractive route due to their ultra-long mechanical coherence times enabled by diluting defect-induced dissipation, though it is unclear if the same dilution effect undermines strain-mediated coupling to material defect centers. Here, we experimentally demonstrate a tensioned diamond nanobeam platform that enables enhanced strain coupling to SiV- orbital states. Through monitoring the optical response of the SiVs to the static and dynamical strain of the mechanical resonator, we observe that dynamical strain localizes near the clamps of these resonators under static strain. This allows us to enhance SiV-mechanical coupling and the mechanical coherence simultaneously, and provide a SiV-strain sensitivity with greatly improved accuracy over previous literature values. Thus, our work opens a pathway towards seconds-long coherence hybrid quantum systems utilizing point defects in diamond nanomechanics for quantum information processing.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
Th$^{4+}$ ion cluster structures and electric field gradients in $^{229}$Th:CaF$_2$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Yuxiang Li, Lin Li, Qiaorui Gong, Shanming Li, Chengchun Zhao, Lu Deng, Peixiong Zhang, Yin Hang, Longsheng Ma, Shining Zhu
The low-energy nuclear isomeric transition of $ ^{229}$ Th is a promising frequency reference for a solid-state nuclear optical clock. Wide-band-gap fluoride crystals such as CaF$ 2$ offer transparent hosts for embedding Th nuclei at high density. Substitution of Th$ ^{4+}$ for Ca$ ^{2+}$ requires charge compensation, linking the local defect structure to nuclear quadrupole splitting. We use first-principles calculations to examine neutral Th dimers compensated by four interstitial F ions ($ \mathrm{F}{i}^{-}$ ). Screening different compensation geometries by their relative formation energies identifies a family of low-energy configurations with closely similar local structures. These configurations share large electric field gradients and small asymmetry parameters, consistent with the experimental high-EFG site 3. Their calculated quadrupole splittings are further compared with the measured C13 spectra. Together, the energetic and spectroscopic results support $ \mathrm{F}_{i}^{-}$ -compensated Th dimers as candidate microscopic structures for site 3 in Th:CaF$ _2$ .
Materials Science (cond-mat.mtrl-sci), Optics (physics.optics)
Ten-loop fixed-dimension renormalization-group functions of the three-dimensional O(N) model from distributed GPU-accelerated parametric integration
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-30 20:00 EDT
The renormalization-group functions $ \beta$ , $ \eta$ and $ \nu$ of the three-dimensional $ O(N)$ model in fixed dimension (massive zero-momentum scheme) were known to eighth order in the coupling. We extend them to tenth order, and $ \beta$ to eleventh, for general $ N$ , which requires the two- and four-point functions to ten loops (1,593,254 graphs at the last order), and re-evaluate all lower orders. Through the Callan-Symanzik equation every coefficient follows from per-order sums that are linear in finite, zero-momentum $ \bar R$ -subtracted parametric integrals, one per graph, which we sample on GPUs by tropical Monte Carlo with densities adapted to the forest terms. The computation reproduces the known sums from two to seven loops within three standard deviations and agrees at ninth and tenth order, at lower precision, with an independent route through an intermediate scheme. The new coefficients have relative uncertainties of a few $ 10^{-5}$ or better, and the eighth-order coefficients of $ \eta$ and $ \nu$ improve by factors of 120 and 4. The time needed to integrate an order to fixed relative precision grows by only 2.4-2.9 per loop from seven loops on, while the construction of the integrands still grows factorially and, at tenth order, costs more than the integration. Resummed, the tenth-order series give $ \nu=0.62997(51)$ , $ \eta=0.0333(18)$ and $ \omega=0.803(14)$ for $ N=1$ , against $ 0.62997097(12)$ , $ 0.036297612(48)$ and $ 0.82968(23)$ from the conformal bootstrap; at $ N=3$ the deviations grow, so that the uncertainty is now dominated by the resummation rather than by the coefficients. Every result is generated automatically from, or checked against, a public ledger of independent, exactly pooled runs, hosted on GitHub, to which anyone is welcome to contribute computing time.
Statistical Mechanics (cond-mat.stat-mech), High Energy Physics - Theory (hep-th), Computational Physics (physics.comp-ph)
30 pages, 2 figures. Code, data and reproducibility checks at this https URL, archived at doi:https://doi.org/10.5281/zenodo.23750242
A Zoo of Fermionic Relative Rényi Negativities in the Sachdev-Ye-Kitaev Models
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-30 20:00 EDT
Quantum entanglement is a fundamental resource that gives rise to correlations with no classical counterpart in strongly correlated fermionic systems. However, its characterization in mixed quantum states remains challenging. Established entanglement diagnostics, such as logarithmic negativity, are computationally demanding in interacting systems, and their evaluation by exact diagonalization is restricted to small system sizes. Meanwhile, conventional Rényi proxies, including twisted and untwisted Rényi negativities, can be positive even for separable states. In this work, we introduce a family of \textit{relative Rényi negativities} that serve as entanglement witnesses. By relating fermionic partial time reversal to the size superoperator, we establish a path-integral representation for these Rényi negativities, enabling their evaluation in thermal states of the Sachdev-Ye-Kitaev (SYK) model and its generalizations via a large-$ N$ expansion. Applying this method, we investigate entanglement in both the original SYK model and the Maldacena-Qi coupled SYK model. We identify a special class of relative Rényi negativities which serve as plausible proxies for logarithmic negativity and uncover first-order entanglement transitions that are invisible to simple observables. These results highlight the utility of relative Rényi negativities as probes of mixed-state entanglement in strongly correlated fermionic systems and suggest the existence of a new class of transitions where these negativities serve as free energies.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
23 pages, 3 figures
Metastability, collective excitations, and traveling states of one-dimensional spin-orbit-coupled quantum droplets
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-10-30 20:00 EDT
Harsimranjit Kaur, Ritu, Rajat, Kuldeep Suthar, Sandeep Gautam
We study the static and traveling droplet phases of spin-orbit coupled, one-dimensional Bose-Bose mixtures with a Lee-Huang-Yang correction. For the static droplets, employing a variational analysis for an infinitely extended mixture, we show that the system can feature two ground-state droplet phases: a stripe droplet phase up to a critical Rabi coupling strength, at which it undergoes a first-order transition to a zero-momentum droplet phase. The variational results for the ground-state properties are shown to be in good agreement with numerical solutions for droplets in the thermodynamic limit as well as finite-size droplets in the “flat-top regime”. For finite-size droplets, the stripe phase can feature multiple stationary states with different numbers of peaks in their stripe density patterns. The calculation of the excitation spectrum for these stationary states confirms their stability. To study the moving droplets, we investigate the ground-state phases of the system in the droplet’s comoving frame. We show that in the comoving frame, droplets acquire a finite longitudinal magnetization. As a consequence, the phase diagram features two distinct phases: a traveling stripe droplet and a plane-wave droplet. The real-time evolution of these droplets in the space-fixed frame, complemented by the Bogoliubov analysis in the comoving frame, illustrates the stability of these traveling droplet phases.
Quantum Gases (cond-mat.quant-gas)
13 pages, 9 figures
Aging and protocol dependence of thermal activation events in structural glasses
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-30 20:00 EDT
In this study, we investigate the waiting time dependence and the protocol dependence of thermally activated events in structural glasses using molecular simulations and potential energy landscape analysis. We find a qualitative crossover in the nature of activation events; from avalanche-like events to local events. We also use the isoconfigurational ensemble analysis and reveal that the events become less diverse and more reversible. We discuss these crossovers from the perspective of the stability and the potential energy landscape of glasses. To investigate the protocol dependence, we compare the two types of glasses whose stability is controlled by waiting time and parent temperature, respectively. Surprisingly, at the same inherent structure energy level, the parent-temperature-controlled glasses are more unstable and maintain their avalanche-like nature. These results demonstrate that the activation properties of structural glasses are not determined solely by their energy levels, highlighting the essential role of state connectivity and the dynamical sampling in the complex energy landscape.
Soft Condensed Matter (cond-mat.soft), Disordered Systems and Neural Networks (cond-mat.dis-nn)
29 pages, 14 figures + 3 pages, 2 figures in Supplemental Material
Graphene Islands as a Platform for Band-Structure Engineering
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
Multilayer graphenes have emerged as a versatile avenue towards exploring novel electronic phases of matter. Recently, nanoscale multilayer graphene islands have been realized experimentally, where the island is less than 50 nm in diameter and distinct in layer configuration from the contact portion of the same graphene sheets, the latter of which act as leads for transport probes. Here, we theoretically investigate how the proximity between these islands and their chemically identical environment modifies the electronic structure. Within the tight-binding approximation, we find that the proximity effect is enhanced by the closely matched momenta between both parts, creating an unusually strong band renormalization which persists as the island size is increased, and only limited by the coherence length. An effective single-unit-cell Hamiltonian to capture these modifications is derived, expressed in terms of interlayer hopping parameters that scale with the relative island area. We predict a substantially altered low-energy density of states for 3- and 4-layer graphene islands, demonstrating the tunability of the electronic structure by spatial size.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
6+6 pages, 5+7 figures
Hop rates of H and D on Pt(111) at finite coverage: the memory equation and the collective friction
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-30 20:00 EDT
Helium scattering measures the coherent intermediate scattering function of an adlayer, the characteristic function of the separation between adparticles at two times. Published dephasing rates of H and D on Pt(111) are analysed with its memory equation and a nearest-neighbour Ising lattice gas. The measured rate belongs to the adlayer. The hop rate of a single adsorbate is extracted from it by dividing out an interaction factor, without a model of the barrier. This factor lies between $ 0.97$ and $ 1.17$ at $ 0.1$ ~ML, so that the published single-adsorbate analyses hold there. At $ 0.4$ ~ML and $ 80$ ~K it lies between $ 1.2$ and $ 4.7$ , depending on how the occupied neighbours modify a tunnelling jump. The memory function is interpreted as a friction, the collective friction, which the adlayer exerts on its own density fluctuations. The lateral coupling, fixed by the coverage series, is the free energy of a neighbouring pair, with a vibrational pair entropy. The small deformation of the measured curves from the Chudley–Elliott form, the tilt, is proposed as an observable of the coupling. The tilts at $ 0.15$ and $ 0.2$ ~ML are consistent with it, although they are hard to extract from the published curves. The memory equation provides a transition-state theory for the adlayer, with the collective friction in the role of the friction of the substrate and without divergence at the crossover. Combined with the standard quantum transition-state theory of a single adsorbate, the extracted hop rates give the friction of the substrate, $ 124$ and $ 75$ ~ps$ ^{-1}$ for H and D, independent of the coverage.
Statistical Mechanics (cond-mat.stat-mech)
34 pages, 6 figures, 5 tables
Resisting Drying Stress in Laponite Bentonite Clay Composites, Two Step Yielding and Crack Peel Selection
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-30 20:00 EDT
Tapati Dutta, Agnishikha Chakrabarti, Soham Mitra, Deepshikha Das, Indranil Chakraborty
Clay films that dry on a rigid substrate crack, peel or stay intact, and which of these happens matters for coatings, barrier layers and ceramic processing. Composites of clay with polymers have been studied widely. Clay composites, whose components differ in size and charge, are much less explored. We show that mixing the nano scale clay Laponite with the micron scale clay Bentonite reduces desiccation damage on both a hydrophobic and a hydrophilic substrate, Laponite films stay essentially intact, Bentonite films fracture extensively, and on glass most intermediate compositions are less damaged than a simple average of the two would suggest. Rheology of the gelled suspensions reveals a two step yielding in every composition, and the cohesive energy derived from it depends by orders of magnitude on which step is used, a point that any rheology cracking correlation must specify. A dimensionless cohesion adhesion index, whose sign we derive from an energy balance, is consistent with compositions that peel on polypropylene and crack on glass. Replicate experiments were performed for robustness of results. The results identify composition as a simple handle on the crack resistance of clay films and open the search for the critical crack-free thickness as a function of clay composition.
Soft Condensed Matter (cond-mat.soft)
14 pages, 9 figures
Predicting unstable planar fault energies in multicomponent alloys from pure elemental components
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
C Tang, J Liu, J Yi, M R Barnett
The unstable planar fault energies (UPFEs) govern slip and twinning but are not experimentally measurable. Using EAM potentials complemented by DFT, we investigate their temperature and compositional dependence and their relationship with the shear modulus. For pure \textit{fcc} elements with low stacking fault energies (SFEs), UPFEs are substantially less temperature-sensitive than SFEs. The reported linear relationship between UPFEs and the product of shear modulus and Burgers vector ($ \mu b_{\mathrm{p}}$ ) holds for close-packed elements and solid solutions, but deviates for intermetallics and non-close-packed elements. In the Co-Cr-Fe-Mn-Ni system, binary alloys show composition-dependent deviations, while the correlation strengthens with increasing chemical complexity. Furthermore, $ \mu b_{\mathrm{p}}$ of multicomponent alloys linearly correlates with the composition-weighted elemental $ \mu b_{\mathrm{p}}$ ($ R^2=0.95$ ), despite a systematic negative deviation. This provides a simple, computationally inexpensive route for estimating $ \mu b_{\mathrm{p}}$ and screening UPFEs directly from pure elemental constituents.
Materials Science (cond-mat.mtrl-sci)
Itô versus Stratonovich for shot noise with state-dependent amplitude: why the answer is Marcus
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-30 20:00 EDT
Marco Bianucci, Riccardo Mannella
For Gaussian white noise the Itô and Stratonovich prescriptions differ by $ O(dt)$ per time step, which accumulates into the familiar spurious drift $ \tfrac12 D,II’$ . We show that for renewal shot noise with state-dependent gain, $ \dot x=-C(x)-I(x)\xi[t]$ with $ \xi[t]$ a train of Dirac spikes of finite random amplitude, the two prescriptions differ by a finite amount at every event, and that where $ I$ vanishes the difference can become qualitative. The Marcus kick, the jump-process counterpart of the Stratonovich prescription, is the flow map of $ dx/ds=I(x)$ : no kick can cross a zero $ x^\ast$ of $ I$ , for any jump and waiting-time statistics. The Itô kick is only the tangent map of that flow. For $ I(x)=1+\beta x$ it crosses $ x^\ast=-1/\beta$ if and only if $ \xi\beta>1$ and collapses the whole line onto $ x^\ast$ at $ \xi\beta=1$ ; below threshold it is itself a Marcus kick with a remapped jump law. Bounded jump laws thus have a threshold, while unbounded ones leak across the barrier for \emph{any} parameters. The discrepancy cannot be absorbed into a renormalised drift beyond lowest order, and only the Marcus kick is generated by a single operator, which makes the master equation of Bianucci, Bologna and Mannella (2026) intrinsically Marcus. Numerically, the standard Heun kick is a second-order truncation of the Marcus map that preserves the barrier only because its order is even; it shortens every jump, biasing second moments in proportion to the squared jump amplitude and the jump kurtosis, and depleting the region near the barrier. We give the exact-flow integrator that replaces it.
Statistical Mechanics (cond-mat.stat-mech), Mathematical Physics (math-ph), Data Analysis, Statistics and Probability (physics.data-an)
Submitted to FNL
Tunable periodic cascade of delocalization transitions in non-Hermitian IAAF model
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-10-30 20:00 EDT
Cascade of delocalization transitions provides a route to multi-step control of delocalization, yet achieving a programmable periodic cascade remains a challenge. Here, we demonstrate a tunable periodic cascade of delocalization transitions in a non-Hermitian interpolating Aubry-André-Fibonacci (IAAF) model by introducing an imaginary phase shift into the quasiperiodic potential. Such a periodic cascade of delocalization transitions arises from the competition between kinetic-energy-facilitated delocalization and gain-loss-regulated localization. In numerical static localization characterizations, successive regular stripe patterns for localized and extended states emerge in phase diagrams. We also derive an analytical expression for the cascade period and find that it relies solely on the imaginary phase shift. This provides a direct way of continuously tuning the cascade period via a single control parameter. Complementary static and dynamical diagnostics consistently confirm this periodic cascade of delocalization transitions in the non-Hermitian IAAF system. Our findings identify a novel class of delocalization transitions with tunable cascading periods, opening a route toward experimentally programmable control of delocalization.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
Thermalization-Controlled Superconducting Diode-Like Transport in Disordered Molybdenum and NbN Thin Films
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-30 20:00 EDT
Akhilesh Kumar, Shivani Soni, Gomathi Natarajan, Ramanathaswamy Pandian, Thameemul Ansari M, Pooja Gupta, Sanjay Rai, Edward Prabu Amaladass
Superconducting diode effects are characterized by direction-dependent critical currents in the superconducting state. Here, we investigate diode-like transport in 128-nm-thick Mo thin film deposited on Si_SiO2 substrate by DC magnetron sputtering. The thin film exhibit a superconducting transition temperature TC of 5.8 K. Pronounced current-direction asymmetry and hysteresis are observed in current-voltage characteristics measured in a closed-cycle refrigerator. In contrast, the same thin film exhibits a substantially more symmetric response in a 14T cryogenic system with improved sample thermalization. We attribute this strong dependence on the measurement environment to electrothermal effects arising from current-induced Joule heating and finite thermal relaxation. As the current approaches the superconducting-to-resistive switching condition, the emergence of a resistive component leads to a rapid increase in Joule heating, raising the sample temperature and modifying the switching condition. Conversely, during the resistive-to-superconducting transition, residual heating and finite thermal relaxation reduce the switching current. Since P is equal to I2R it is independent of current polarity, the observed asymmetry is not associated with polarity-dependent Joule heating but with the interplay of thermal relaxation, sweep history, and thermal boundary conditions. The suppression of the asymmetry under improved thermalization, together with similar behavior observed in NbN reference films, indicates that the apparent diode-like response is strongly influenced by electrothermal effects. These results highlight the need to distinguish thermal switching and hysteresis from intrinsic nonreciprocal superconductivity when identifying superconducting diode effects in transport measurements.
Superconductivity (cond-mat.supr-con)
Multiple Current Enhancement Regimes and Interaction Induced Re-entrant Transport in a Quasiperiodic Hubbard Ring with Antiferromagnetic Order
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
Souvik Roy, Ranjini Bhattacharya
We investigate persistent charge and spin currents in a one-dimensional quantum ring threaded by an Aharonov-Bohm (AB) flux, considering generalized Aubry-André-Harper (AAH) modulation with staggered onsite energies and antiferromagnetic (AFM) ordering in both the noninteracting and interacting regimes, with the latter treated using a self-consistent Hartree-Fock mean field theory (MFT). At half filling, two distinct current-enhancement peaks emerge as the modulation strength increases, with quasiperiodic hopping modulation playing a crucial role in establishing the two-peak structure within a restricted parameter regime. Spin-resolved bond-current profiles reveal a switch in the dominant spin contribution between the two peaks, while the inverse participation ratio (IPR) and flux-dependent spin-resolved ground-state energies provide complementary insights into the spatial characteristics of the eigenstates and their spin-dependent flux sensitivity. At quarter filling, the spin current exhibits a single enhancement peak, in contrast to the two-peak response observed at half filling. The Hubbard interaction affects the two half-filled peaks differently: it suppresses the primary peak, whereas the secondary peak exhibits a nonmonotonic, re-entrant response, with the current recovering at finite interaction strength. The interacting results are further characterized through the Drude weight, and comparisons with exact diagonalization (ED) and density-matrix renormalization group (DMRG) calculations for a finite half-filled system support the reliability of the MFT description. Our findings elucidate how quasiperiodic modulation, AFM order, band filling, and electronic correlations collectively govern the magnitude and spin-resolved character of persistent currents, giving rise to multiple enhancement regimes and interaction-induced re-entrant behavior.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
21 pages, 23 figures
Edge-Plasmon-Induced Magnetization in Higher Chern Insulators
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
Prathyush P. Poduval, Rofii, Muhammad S. Ukhtary, Thomas L. Schmidt, Eddwi H. Hasdeo
Higher Chern insulators host multiple dissipationless chiral edge states, one per unit of Chern number. We study the collective plasmon modes of these edge states at a domain wall between Chern numbers $ \mathcal{C}$ and $ -\mathcal{C}$ , using a semiclassical model with Coulomb interactions. The plasmon dispersion is linear at long wavelengths, with a velocity that increases linearly with $ \mathcal{C}$ . As in conventional two-dimensional metals, the edge plasmon generates an elliptically polarized electric field that decays into the bulk and drives electrons in circular orbits, producing a static orbital magnetization (inverse Faraday effect). For topological edge plasmons, the magnetization has a nontrivial spatial profile set by two competing length scales: the finite extent of the edge states and the plasmon wavelength. At fixed edge-charge amplitude, it grows strongly with $ \mathcal{C}$ . At the domain wall, it approaches a finite plateau at low frequency and decays as $ 1/\omega^2$ at high frequency. Its temperature dependence is nonmonotonic, with a maximum at an intermediate temperature. These results show how the Chern number controls plasmon-induced magnetization, in contrast to conventional edge plasmons.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
11 pages, 4 figures
Diffusion models for the $O(3)$ nonlinear sigma model
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-30 20:00 EDT
A score-based diffusion model is trained on the two-dimensional classical Heisenberg model, the lattice representation of the $ O(3)$ nonlinear sigma model. Neural networks are trained on three different coarse-grainings of the same training set to implement a multiscale sampling scheme that modestly improves both the accuracy and computational cost of direct sampling on the finest lattice. Stein (or Schwinger-Dyson) diagnostics for the two-point correlation function are introduced to assess the quality of the learned score without relying on reverse diffusion sampling. These diagnostics are also incorporated into an additional training loss. We discuss several technical considerations relevant to implementing diffusion models on $ S^2$ . These include a consideration of lifting the network input to $ S^3$ , as in the $ CP^1$ representation, and developing a boundary-layer approximation to the short-time spherical heat kernel that extends its usefulness to larger diffusion times.
Statistical Mechanics (cond-mat.stat-mech), Machine Learning (cs.LG), High Energy Physics - Lattice (hep-lat)
29 pages, 7 figures
Hidden Phase Transition in Single-Polymer Stretching under Elongational Flow
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-30 20:00 EDT
Aiqing Zhu, Fushuai Wang, Eleonore Vissol-Gaudin, Qianxiao Li, Beatrice W. Soh
Using machine learning, we identify a second transition in polymer chain stretching driven by planar elongational flow, beyond the well-known coil-stretch transition. We achieve this by developing a conditional extension of Universal and Identifiable Dissipative Dynamics (UIDD) that jointly learns reduced stochastic dynamics from microscopic trajectories across flow strengths and yields the corresponding stationary nonequilibrium free energy landscapes. As the flow strength increases, the evolving landscape exhibits the expected coil-stretch transition, and then a previously unrecognized dynamical transition. In the latter, the stretched states persist, but the distribution along a folding coordinate becomes bimodal when conditioned on small end-to-end separation. Large-deviation analysis of a simplified analytical chain model reproduces both transitions and shows that they are phase transitions in the long-chain limit. Single-molecule DNA experiments provide qualitative support for the dynamical transition through the predicted reversal of the folding response.
Soft Condensed Matter (cond-mat.soft), Machine Learning (cs.LG), Computational Physics (physics.comp-ph)
Spin-Polarized Weyl Fermions and Unconventional Spin Transport
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Chenhao Liang, Haohao Sheng, Sheng Zhang, Zhong Fang, Hongming Weng, Zhijun Wang
Large and electrically controllable spin splitting in nonmagnetic materials is highly desirable for condensed-matter physics and spintronics, enabling strongly spin-polarized quasiparticles and unconventional spin transport as well as their electrical control. Here, we establish a general framework for critical spin-polarized Weyl fermions in two-dimensional (2D) nonmagnetic systems. We predict the $ \alpha$ -Bi-like Group-V puckered-layer family of 2D ferroelectrics as a material platform combining critical spin-Weyl fermions, giant spin splitting, and electrically switchable nonlinear and spin transport. Our calculations reveal exchange-scale spin splitting induced by spin-orbit coupling and a $ p$ -wave spin texture in the BiAs monolayer. Moreover, BiAs hosts four critical spin-Weyl points, each formed within a single-spin channel. The nearly quantized $ \langle S_z\rangle$ is protected by an emergent $ S_z$ -conservation symmetry in the low-energy limit. The spin-Weyl cones also give rise to unconventional spin-transport phenomena, including a purely out-of-plane Edelstein response and a pronounced spin Nernst effect. Ferroelectric reversal further enables electrical switching of the $ p$ -wave spin texture and inversion-odd responses, while the tunability of these properties through composition, strain, and magnetic field is also systematically demonstrated across the entire family. These results establish both a general nonmagnetic framework and a promising material platform for exploring critical spin-Weyl physics, nonlinear Hall phenomena, and unconventional spin transport.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Fractal dimensions of paths on three-dimensional random-walk traces
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-30 20:00 EDT
Qiyuan Shi, Xinyi Li, Youjin Deng
We study four paths that join the starting site to the final position of a simple random walk of (N=L^2) steps on the infinite cubic lattice. The paths are selected on the walk trace—the graph of visited sites and traversed bonds—by different rules: the undirected shortest path (S_1), the directed shortest path (S_2), the time-respecting shortest path (S_3), and the depth (D_e) of the final site in a depth-first-search tree. Monte Carlo simulations for (L) up to 32768 give mean lengths scaling as (L^{d_O}), with (d_{S_1}=1.48005(9)), (d_{S_2}=1.49868(5)), (d_{S_3}=1.51205(5)), and (d_{D_e}=1.7099(7)), so that (d_{S_1}<d_{S_2}<d_{S_3}<d_{\rm LE}<d_{D_e}), where $ d_{\rm LE}=1.62400(5)$ is the known loop-erased-random-walk exponent. Imposing traversal directions increases the shortest-path exponent, and imposing time order increases it further; these constraints therefore change the scaling exponent, not only the amplitude. For every path, the standard deviation scales with the same exponent as the mean, so it is scale-invariant, unlike the visited-site mass; the rescaled length distributions collapse onto a finite-width scaling function. No analytical theory currently predicts these exponents; our results provide precise numerical benchmarks for future studies of path geometry on random-walk traces.
Statistical Mechanics (cond-mat.stat-mech), Probability (math.PR)
Ultrasound-Assisted Facile Nanoconfinement of Luminescent Guests in Zirconium Metal-Organic Frameworks
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Yiyi Wang, James D. Taylor, Jin-Chong Tan
An accelerated sonochemical route for fabricating luminescent guest-MOF (LG@MOF) composites is demonstrated, for which light-emitting molecules are nanoconfined within porous zirconium-based hosts using probe ultrasonication rather than conventional bath sonication. Ultrasonication enables the rapid synthesis of crystalline UiO-66 and UiO-67 nanocrystals within 10 minutes, with material yields of up to 92%, and facile in situ guest encapsulation within 1 hour, hence notably faster than the traditional 24-hour solvothermal route. Using UiO-66 and the larger-pore UiO-67 as porous hosts, tuneable single- and dual-guest fluorescent host-guest systems incorporating Rhodamine B (RB) and Fluorescein (F) were achieved. Photophysical characterisation showed broadband emission, tuneable colours, high quantum yield and improved lifetime, highlighting the synergy between sonochemical conditions, structural defects, and photophysical behaviour. Additionally, the sonochemically prepared LG@UiO particles show well-defined crystal facets and potential as photoactive thin films for solid-state lighting, demonstrating their promise as a tuneable light source for optical sensing and nanophotonics.
Materials Science (cond-mat.mtrl-sci)
28 pages, 5 figures, Supporting Information
Origin and photoluminescence of a shallow hydrogen-related donor in silicon
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Miaomiao Han, Peter Deak, Bing Huang, Adam Gali
Paramagnetic color centers in silicon are being investigated recently for use in quantum technologies. While the origin of most of the prominent photoluminescence (PL) lines are well understood, that is not the case for those connected to hydrogen, even though it is almost always present in silicon, e.g., shallow hydrogen-related donors (SHDs), but their atomic structure remains elusive. Recent experiments suggested connection between the SHDs and the so-called X and the B$ _i$ (or X$ _i$ ) PL-lines. An SHD, termed the MT2 center, was tentatively assigned to a bistable, negative-U defect, arising due to the interaction of hydrogen with the self-interstitial complex I$ _4$ . Using high-level density functional theory calculations, we investigate the interaction of hydrogen with self-interstitial complexes In. A shallow effective-mass-theory donor arises when hydrogen attacks a Si-Si bond in I$ _n$ , inserting itself as a bond-center interstitial (I$ _n$ H$ _{BC}$ ) in an exothermic reaction. We demonstrate this in the case of a single self-interstitial and of a complex of four. The latter I$ _\mathrm{4}$ H$ _\mathrm{BC}$ complex shows electronic, spin and PL properties remarkably close to MT2. We find that hydrogen in the presence of I$ _4$ follows the same behavior as in pristine silicon, i.e., it is a negative-U bistable defect, only detectable under illumination. In the I$ _4$ H$ _{BC}$ complex, H can hop via photo-assisted mechanism between equivalent BC sites of the I$ _4$ complex, leading to a motional averaged tetragonal symmetry as experimentally observed for MT2. The zero-phonon line is distinct from the X-line (attributed to the bare I$ _4$ complex), and falls well into the range of the X$ _i$ lines. Our results identify the I$ _4$ H complex as a prototype for a class of SHDs, inferring that similar SHDs may arise, with the X$ _i$ lines as their PL fingerprints, when H attacks I$ _n$ clusters.
Materials Science (cond-mat.mtrl-sci)
Fluctuation-dissipation relation in branching particle systems
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-30 20:00 EDT
A fluctuation-dissipation relation (FDR) for branching particle systems is derived that reveals how fluctuations in clonal populations originating from a single ancestor encode both population growth and the dissipative structure of the single-particle dynamics. For particles whose internal states evolve according to a stationary Markov process, the FDR holds in both equilibrium and nonequilibrium stationary states. It yields an upper bound on the spectral gap that is constrained by the magnitude of clonal fluctuations and implies that clonal dynamics is asymptotically dominated by the slowest modes of the single-particle dynamics. This provides a theoretical explanation for the persistence of clonal memory and for experimentally observed clonal cofluctuations between variables with zero covariance in the single-particle stationary state. In nonequilibrium stationary states, the FDR predicts oscillatory clonal fluctuations, suggesting a route to measuring nonequilibrium fluxes in proliferating cell populations without single-cell tracking.
Statistical Mechanics (cond-mat.stat-mech), Biological Physics (physics.bio-ph), Cell Behavior (q-bio.CB)
6 pages, 3 figures + 8 pages appendix. Simulation software and computational notebooks available at this https URL
Non-Volatile Memory Devices for Neuromorphic Computing
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
This chapter explores the critical role of emerging non-volatile memory (eNVM) devices in advancing neuromorphic computing. Inspired by the human brain’s remarkable ability to perform complex tasks like pattern recognition and adaptation, neuromorphic computing offers immense potential for implementing complex neural networks (NNs) in real hardware. Despite ongoing research into the brain’s complexities, its fundamental operation relies on neurons (processing units communicating via electrochemical signals) and synapses (junctions between neurons). The modifiable strength of the synapse is key to learning and memory functionality, allowing the brain to adapt and rewire itself. For dense and low-power circuits in neuromorphic computing, these eNVM devices are ideal due to their synaptic-like behavior and non-volatile information storage. Properties such as conductance modulation of these devices emulate synaptic plasticity, which is crucial for learning, and their scalability makes them promising for large-scale neuromorphic architectures. This chapter will delve into the various types of eNVM devices such as resistive RAM (ReRAM), phase-change memory (PCM), spintronics-based memory devices, and their applications in neuromorphic computing, discussing their challenges and opportunities, and highlighting recent advances in their integration within neuromorphic systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Published as Book Chapter
VLSI Design for Artificial Intelligence and Machine Learning Applications, 2026
Temporal Correlations and Optimal Feedback Control of an Active Information Engine
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-30 20:00 EDT
How much does a feedback controller need to know about the fluctuations it exploits? We address this question using a macroscopic information engine driven by self-propelled bristle-robots. Experimentally measured occupancy time series show that temporal correlations strongly affect vacancy detection. At short measurement intervals, mean first-passage times exceed independent-measurement predictions by more than an order of magnitude. A first-order Markov approximation captures much of this effect. It does not reproduce the full first-passage distribution, revealing higher-order temporal memory. Nevertheless, Markov-selected protocols come within 0.15% of the maximum experimental power. Neglecting correlations causes power losses of several percent and favors larger compression distances. Introducing a sensing cost shifts the optimal strategy toward sparse sensing. The independent model cannot predict this shift, whereas the Markov model captures it. Cross-validation on separate time segments confirms the near-optimal performance of Markov-selected protocols. These findings demonstrate that near-optimal feedback control in correlated nonequilibrium systems can require a simpler statistical description than predicting their full temporal dynamics.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
11 pages, 5 figures
High-Field Heat Capacity of Atacamite Cu$_2$Cl(OH)$_3$ for $\mathbf{H} \parallel b$ axis: From Antiferromagnetic Order to Correlated Disorder
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-30 20:00 EDT
L. Stödter, A. Demuer, T. Kotte, A. U. B. Wolter, B. Büchner, K. C. Rule, S. Süllow
We present the heat capacity of the frustrated sawtooth-chain compound atacamite Cu$ _2$ Cl(OH)$ 3$ in high magnetic fields up to 35 T for $ \mathbf{H} \parallel b$ axis. We clearly observe the change from antiferromagnetic long-range order, indicated by a sharp transition anomaly shifted to lower temperatures when increasing field, to a field-induced spin-liquid-like state with the absence of any transition anomaly. Here, in highest magnetic fields above 32 T a broad anomaly is present which is shifted to higher temperatures as the field is increased. The low-temperature heat capacity in the high-field region can be described well by an exponential behavior indicating a thermal activation over a spin gap. The findings are consistent with our scenario for the high-field state in atacamite for $ \mathbf{H} \parallel c$ axis, where we proposed the sawtooth chains to decouple into two spin subsystems, basal and apical spin sites, leading to a partially polarized state with $ M \sim M\mathrm{sat}/2$ .
Strongly Correlated Electrons (cond-mat.str-el)
Exceptional Superconducting Interfaces between Graphene and Atomic Chains in A15-MoRe
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Hiroto Ogura, Yuto Tsukidate, Shun Kondo, Zhuoqun Li, Natsuki Sasaki, Tsunenobu Sato, Azusa Utsumi, Tomohiro Otsuka, Mitsuhiro Saito, Kazutoshi Inoue, Takashi Taniguchi, Kenji Watanabe, Yuichi Ikuhara, Toshiaki Kato
Realizing highly transparent and magnetic-field-resilient superconducting contacts is a critical bottleneck for the advancement of two-dimensional (2D) quantum devices. Molybdenum-rhenium (MoRe) alloys have been empirically favored as they uniquely yield ballistic, highly transparent contacts to graphene that survive in high-magnetic-field regimes; however, the microscopic origin of this anomalous transparency has remained a long-standing puzzle. Here, we resolve this paradox by revealing that pristine graphene/MoRe interfaces are governed by the classical A15 superconducting phase. Combining low-temperature transport, X-ray diffraction, and atomic-resolution electron microscopy, we demonstrate that as-deposited MoRe spontaneously forms the A15 phase in direct contact with graphene, whereas thermal annealing triggers a phase transition to a hexagonal close-packed (hcp) structure that severely degrades the Josephson transparency. Crucially, the one-dimensional (1D) transition-metal atomic chains unique to the A15 structure exhibit a near-perfect lattice match (mismatch < 1%) with graphene edges. First-principles calculations further prove that the d-orbitals of these historically renowned 1D chains possibly hybridize with graphene’s Dirac cone near the K point. These findings not only uncover the structural and electronic origins of optimal MoRe contacts but also establish A15-phase superconductors as a geometrically ideal, universal platform for realizing robust quantum electronics based on 2D materials.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
Observation of light-induced topological state in graphene
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Sotirios Fragkos, Ann Chantal Goutier, Umberto Dellasette, Dominique Descamps, Stéphane Petit, Wiebke Bennecke, Philip Hofmann, Marcel Reutzel, Stefan Mathias, Yann Mairesse, Michael Schüler, Samuel Beaulieu
Driving quantum materials with light can reshape not only their electronic band structures but also the geometry of their electronic wavefunctions. In graphene, circularly polarized light is predicted to open gaps at the Dirac points and induce a pseudospin texture and Berry curvature characteristic of the Haldane model, realizing a Floquet Chern insulator. Transport and all-optical measurements have provided evidence for a light-induced anomalous Hall response, but cannot resolve the underlying electronic states in both energy and momentum space. Time- and angle-resolved photoemission spectroscopy has revealed Floquet-Bloch sidebands and hybridization gaps at crossings between Floquet bands. However, these experiments used linearly polarized driving, which preserves time-reversal symmetry and thus does not induce a topological phase. Here, we combine circular-dichroic time-resolved extreme-ultraviolet momentum microscopy with ab initio theory to investigate graphene driven by circularly polarized light. We observe a pump-induced photoemission circular dichroism near the Dirac point that reverses sign with pump helicity and across the Dirac energy, in agreement with our calculations. These results link the measured dichroic response to the light-induced pseudospin texture and its associated Berry curvature, providing spectroscopic evidence for the Floquet-engineered topological insulating state in graphene.
Materials Science (cond-mat.mtrl-sci)
Pulse Laser Deposited GaFeO3 Thin Film Grown on FTO: Correlated Ferroic Orders and Strong Magnetodielectric Coupling at Room Temperature
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Ishita Jana, Sourav Sarkar, Soham Saha, Kalyan Mandal
Room-temperature single-phase multiferroics exhibiting coupled ferroelectric and magnetic order are promising candidates for next-generation magnetoelectric memory and spintronic technologies. Here, we report the growth of approximately 100.6 nm thick polycrystalline orthorhombic GaFeO3 thin films on fluorine-doped tin oxide-coated glass (FTO) substrates by pulsed laser deposition. Core-level X-ray photoelectron spectroscopy reveals a reduced Fe2+ concentration and suppressed oxygen-vacancy formation, contributing to reduced leakage current and improved ferroelectric characteristics. The films exhibit robust ferrimagnetism and ferroelectricity at room temperature, confirming the coexistence of ferroic orders within a single phase. Piezoresponse Force Microscopy further demonstrates reversible local polarization switching, accompanied by an asymmetric butterfly loop with coercive voltages of -0.31 V and +1.07 V. The films also exhibit a high relative dielectric constant of approximately 1700 with a relatively low dielectric loss tangent of approximately 2.83 at 1 MHz. Moreover, a significant magnetodielectric coefficient of approximately 2.3% is observed under a relatively small magnetic field of only 0.1 kOe, highlighting strong magnetoelectric coupling. These results establish GaFeO3 thin films as a promising platform for room-temperature multifunctional devices, mainly low-field magnetoelectric memory and spintronic architectures.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Phonon Fluctuations Enhanced Superconductivity in a Three-Band Cuprate Model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-30 20:00 EDT
The microscopic origin of high-$ T_c$ superconductivity in cuprates remains an outstanding puzzle due to the interplay of intertwined orders. Experimental observations and theoretical studies have suggested crucial roles of phonons, with the $ B_{1g}$ oxygen buckling mode emerging as a promising candidate. Here, we investigate the microscopic influence of this phonon in a three-band cuprate model. We find that the $ B_{1g}$ phonon plays opposite roles in superconductivity depending on whether it lies in the adiabatic or antiadiabatic regime at a given temperature. Thermally populated adiabatic phonons suppress $ d$ -wave pairing through the loss of quasiparticle coherence, whereas antiadiabatic phonons simultaneously enhance coherence and the attractive $ d$ -wave pairing vertex, strengthening superconductivity across multiple diagnostics. This enhancement also exhibits pronounced electron-hole asymmetry arising from the different orbital characters of doped carriers. Our results therefore establish a microscopic mechanism through which $ B_{1g}$ phonons can cooperate with electronic correlations to substantially enhance $ d$ -wave superconducting pairing in cuprates.
Strongly Correlated Electrons (cond-mat.str-el)
8 pages, 4 figures
I$_4$ complex acting as near-infrared emitter with a quantum memory in silicon
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Miaomiao Han, Song Li, Gergő Thiering, Thomas Frauenheim, Peter Deák, Bing Huang, Adam Gali
Silicon color centers emitting in the near infrared offer a route to spin–photon interfaces compatible with mature complementary metal–oxide–semiconductor fabrication. A key unresolved candidate is the X-line at 1039.7 meV in the photoluminescence (PL) spectrum, long attributed to a complex of four self-interstitials (I$ _4$ ), yet whose microscopic structure and spin properties have remained controversial and uncharacterized at a predictive level. Using hybrid-functional (HSE06) density functional theory, we unambiguously establish the bare I$ 4$ complex as the origin of the X-line: our calculations quantitatively reproduce the zero-phonon line, the complete phonon sideband structure—identifying the prominent secondary peaks as one- and two-phonon replicas of strongly coupled quasi-local modes—and the EPR hyperfine constants. The charge transition level is found at VBM$ +$ 0.08eV, conclusively ruling out the previously proposed association with the B3 EPR center and its correlated deep donor level. Most significantly, we identify a metastable spin-1 triplet excited state separated from the singlet by $ \sim$ 1.6meV, consistent with the NL51 EPR signal. The $ D{2d}$ symmetry of the defect suppresses intersystem crossing and phosphorescence by first-order spin–orbit coupling, implying an exceptionally long spin–lattice relaxation time. Combined with a spectrally resolvable zero-field splitting and near-infrared emission, the triplet state of the I$ _4$ complex constitutes a viable spin quantum memory intrinsic to silicon.
Materials Science (cond-mat.mtrl-sci)
Influence of hydrophobic polyelectrolyte composition on pH-dependent solubilization of lipid bilayer membranes
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-30 20:00 EDT
Martijn Koorengevel, Michelle N.M. de Dood, Wouter T.E. Bosker, James L. Martin Robinson, Cornelis A. van Walree, Bas G. P. van Ravensteijn, Willem K. Kegel
Lipid bilayer membranes can be solubilized in the form of disks of approximately 10 nm in diameter by several types of hydrophobic polyelectrolytes (HPE). The disks are stabilized by wrapped HPE along the rims of the disks. We compare the solubilization behavior of anionic HPE with chain lengths in between 20 - 100 monomers, and with varying molecular composition. We find that (1) HPE as short as 20 monomers can readily solubilize lipid bilayer membranes; (2) spatial intermolecular arrangement of ionic and hydrophobic groups in HPE determine if solubilization occurs; (3) anionic HPEs may exhibit two distinct pH-dependent solubilization transitions: the first is encountered in the lower-pH regime upon increasing the pH, whereas the second emerges at higher pH when the pH is decreased; (4) a binomial composition distribution of hydrophobic and ionizable groups over the chains, compared to a fixed composition, does not lead to a measurably wider pH range where solubilization occurs for the transition at low pH. We link the solubilization behavior of one of the HPE’s to pH-dependent partitioning between macroscopic oil and water phases. Finally, (5) we find that linear composition superposition of the hydrophobic groups in HPE quantitatively accounts for the composition dependence of the pH’s where solubilization occurs. This result holds within a range of compositions and breaks down below a critical fraction of hydrophobic residues in a HPE chain. Throughout, we compare the observations to a recently developed model for ligand-mediated cooperative transitions. Our findings have potential impact on anti-cancer medicine and drug delivery applications.
Soft Condensed Matter (cond-mat.soft)
19 pages, 7 figures
Moiré-enabled chiral plasmons in twisted bilayer graphene nanoislands
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
Magnus Husted, Viktor Kanstrup, Eduardo J. C. Dias, Joel D. Cox
Twisting two stacked graphene layers superimposes a moiré superlattice that reshapes their electronic structure, yet how it shapes the collective optical response of finite, nanoscale bilayers remains largely unexplored. Using an atomistic tight-binding and self-consistent density-matrix approach, we compute the twist-dependent plasmonic response of twisted bilayer graphene nanoislands comprising thousands of atoms. The spectra are strongly tunable and split into two regimes at a critical angle where a single moiré wavelength spans the island; beyond it, an ordered ladder of resonances emerges whenever an integer number of moiré periods fits within the overlapping bilayer. In doped islands, the interlayer coupling also produces a moiré-enabled Born–Kuhn chiral plasmon: opposite transverse dipoles in the two layers form an electric quadrupole that hybridizes with the bright dipole, opening an anticrossing near the critical angle, with a handedness that reverses with the twist direction. Triangular islands confirm that the moiré lattice, not the flake boundary, governs both effects, establishing twist as a mechanical handle on chiral graphene plasmons.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics)
15 pages, 11 figures
Direct Observation of Electron Trapping States in SiO$_2$ by Constant-Final-State Photoelectron Yield Spectroscopy: Insights into the Electron-Transfer Model of Contact Electrification
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Renjiro Shibuya, Manato Tateno, Runa Hoshikawa, Tomohiro Ishibashi, Hirohiko Fukagawa, Hisao Ishii
Understanding electrostatic charging of silicon dioxide (SiO$ _2$ ) is important for electrostatic control in a wide range of applications. Contact electrification (CE) is a major source of such charging, and electron transfer is considered one of its leading mechanisms. Several electron-transfer models have been proposed to explain CE; however, the density of states (DOS) involved in electron transfer has not been experimentally characterized. Determining this DOS is therefore essential for understanding the charging mechanism. However, measuring the DOS of insulating materials such as SiO$ _2$ remains challenging: photoemission spectroscopy, the standard technique for probing the DOS of materials, is unsuitable for highly insulating materials because sample charging during measurement can cause spectral distortion or even complete signal loss. Here, we directly and quantitatively determined the in-gap DOS of amorphous SiO$ _2$ using constant-final-state photoelectron yield spectroscopy (CFS-YS). Weak occupied states were observed within the band gap, and their marked increase after electron injection revealed that electron-trapping states are distributed over a broad energy range. Vacuum annealing markedly altered the in-gap DOS and electron-trapping behavior. The observed changes suggest a role for surface adsorbates, including water, in the charging behavior of SiO$ _2$ . Charging simulations based on the experimentally measured in-gap DOS approximately reproduced the previously reported charging behavior and showed that the accumulated charge was concentrated near the surface. These findings indicate that in-gap states distributed over a broad energy range mediate electron transfer during CE and highlight the importance of considering experimentally determined DOS when evaluating proposed electron-transfer models.
Materials Science (cond-mat.mtrl-sci)
14 pages, 8 figures. This manuscript has been submitted to Applied Physics Letters
Sign reversal of ST-FMR signals in CoFeB/Pt explained by contributions beyond spin-orbit torque
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Christian Berg, Ao Du, Durgesh Kumar, Sinan Shu, Sourabh Manna, Sachin Krishnia, Mathias Kläui
Spin-orbit torques (SOT) provide an efficient route for electrical control of magnetization and is of central interest for low-power magnetic memory applications. Spin-torque ferromagnetic resonance (ST-FMR) is a widely used technique to quantify SOT efficiencies. However, the rectified voltage measured in ST-FMR can contain contributions that are not directly related to SOTs, which affects the accuracy of the extracted torque efficiencies. This may contribute to the large variation of reported SOT efficiencies in literature. In this study, we investigate the damping-like torque efficiencies in CoFeB/Pt heterostructures as a function of Pt thickness. Conventional ST-FMR analysis yields an apparent sign reversal of the extracted efficiency at a Pt thickness of approximately 10 nm. By combining complementary measurement geometries and analysis approaches, we separate the torque-induced signal from additional voltage contributions that share the same angular dependence. Our results show that non-torque voltage contributions can produce an apparent sign reversal in conventional ST-FMR analysis, highlighting the need to distinguish SOT-induced signals from parasitic contributions and we show how to reliably determine the SOT efficiencies.
Materials Science (cond-mat.mtrl-sci)
Growth and morphology of core-shell nanowires incorporating dissimilar hexagonal semiconductors: the case of InAs-ZnTe
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Danylo Mosiiets (NEEL - NPSC), Susheng Tan (PITT), Sergey Frolov (PITT), Moïra Hocevar (NEEL - NPSC), Joel Cibert (NEEL - NPSC), Edith Bellet-Amalric (PHELIQS)
Core-shell nanowires incorporating semiconductors from two groups, III-V for the core and II-VI for the shell, have been grown by molecular beam epitaxy in two dedicated chambers connected under ultra-high vacuum, and studied by electron microscopy. During the growth of the shell, the wurtzite structure of the core is replicated in the shell, without any creation of defects. This is true for a wide range of shell thickness, from about one monolayer, up to 25 nm thanks to the good lattice match between the InAs material of the core and the ZnTe material of the shell. While (1 100) m-facets and (11 20) a-facets coexist on the sidewalls of the core, during the growth of the ZnTe shell the size of the m-facets progressively increases at the expense of the a-facets which eventually disappear. A fast growth of the ZnTe shell is observed for the first few monolayers, with a high sticking; this is followed by a slower growth, of the same order of magnitude as observed on a ZnTe core, with a dependence on the nanowire radius which points to the occurrence of mononuclear nucleation
Materials Science (cond-mat.mtrl-sci)
Two-dimensional binary Lennard-Jones mixtures with ECMC
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-30 20:00 EDT
Kush Patel, Gabriele Tartero, Werner Krauth
We discuss reversible and non-reversible local Monte Carlo algorithms for long-range two-dimensional binary Lennard-Jones mixtures. We illustrate how the factorized Metropolis filter efficiently handles long-range interactions even for binary mixtures, using an adapted cell-veto strategy. We then benchmark the non-reversible event-chain Monte Carlo (ECMC) algorithm against the factorized Metropolis algorithm. For simple test cases, we demonstrate speedups of several orders of magnitude in the equilibrium and the out-of-equilibrium dynamics. Using the ECMC algorithm, we provide an overview of the physics of binary Lennard-Jones mixtures, from the case without depletion (no interaction between solute and solvent) all the way to the depletion limit (with a diverging number of solvent particles). We analyze the algorithms in different thermodynamic phases and in the corresponding limits.
Statistical Mechanics (cond-mat.stat-mech)
10 pages, 8 figures
High-temperature expansion of the inverse-square Ising chain in a magnetic field: exact coefficients and finite-size reconstruction
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-30 20:00 EDT
The one-dimensional Ising chain with inverse-square interactions is a paradigmatic long-range system: it exhibits the unusual Thouless transition, with a discontinuity in the spontaneous magnetization, yet its full field-dependent thermodynamics remains unknown in closed form. We develop the high-temperature expansion of its free energy while retaining the dependence on a uniform magnetic field at every order. We prove that, after a natural rescaling of the coupling, each coefficient is a rational polynomial in the squared hyperbolic tangent of the reduced field. Remarkably, at each order $ n$ the field-dependent free-energy coefficient of a finite, periodically repeated ring is an exact polynomial of degree at most $ n$ in $ L^{-2}$ . The infinite-chain coefficient is its constant term and can therefore be reconstructed from $ n+1$ finite rings without numerical extrapolation. Using this reconstruction, we determine the full field-dependent expansion through order 26: 26 polynomials containing 377 rational coefficient entries. We further derive exact formulas, valid at every order, for the coefficients of the two highest powers of the field variable using matching determinants and a cycle-Laplacian reduction. These results reveal an unexpected algebraic structure in the microscopic thermodynamics of the inverse-square chain and provide high-order information about its magnetic response.
Statistical Mechanics (cond-mat.stat-mech), Mathematical Physics (math-ph)
70 pages 1 figure
Steering interfacial molecular structures by substrate-molecule charge transfer
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
Benjamin Achatz, Matthias Zeilerbauer, Marco Thaler, Milan Ončák, Shadi Fatayer, Laerte L. Patera
Intermixed self-assembled monolayers (SAMs) provide a powerful approach for tuning inorganic-organic interfaces, but their local structure and energetics often remain elusive. Here, an intermixed stripe phase of fullerene $ C_{60}$ and Zn(II)-5,10,15,20-tetrakis(4-aminophenyl)porphyrin (Zn-TAPP) on a Ag(111) surface is identified, establishing a direct link between molecular assembly and charge transfer. Scanning tunnelling spectroscopy (STS) and Kelvin probe force spectroscopy (KPFS) have been used to map electronic states and local contact potential differences (LCPD). Compared to close-packed $ C_{60}$ islands, the stripe phase exhibits a larger interfacial dipole and increased occupation of previously unoccupied $ C_{60}$ states, consistent with enhanced charge transfer from Ag(111) to $ C_{60}$ . Analysis indicates that larger $ C_{60}$ spacing in the stripe geometry reduces Coulomb repulsion, stabilizing the intermixed phase and enhancing charge transfer with respect to close-packed domains. These results provide direct evidence of charged $ C_{60}$ molecules in stripe structures and guidelines for engineering intermixed SAMs with tailored interfacial electronic properties.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
24 pages, 6 figures in main text, 15 figures in supporting information
Epitaxial Magnon Junctions with Y3Fe5O12/Gd3Ga5O12/Pt-nanoparticles/Y3Fe5O12
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Jianing Lin, Haoyu Zhuang, Tianyi Zhang, Jiyang Ou, Jihao Xia, Hongyu Wang, Jiang Niu, Qinglong Yu, Caihua Wan, Guoqiang Yu, Richeng Yu, Xiufeng Han
The excitation, propagation, manipulation, and detection of magnons lie at the core of magnonics. Among various device architectures, high-quality magnon junctions with a ferromagnetic insulator (FI)/antiferromagnetic insulator (AFI)/ferromagnetic insulator (FI) configuration are predicted to exhibit a near-100% magnon junction ratio (MJR), making them promising candidates for high-performance non-volatile memory applications. Yttrium iron garnet (Y3Fe5O12, YIG) is widely employed as the FI material in such structures for its exceptionally low magnetic damping. However, in previously reported magnon junctions, the epitaxial relationship between the two YIG layers is often disrupted by lattice-mismatched AFI spacers. Although this leads to distinct coercivities, it simultaneously degrades the crystalline quality of the top YIG layer, thereby limiting the magnontransmission efficiency. Here, an epitaxial magnon junction is demonstrated incorporating a hybrid Gd3Ga5O12 (GGG)/Pt-nanoparticles spacer that maintains coherent epitaxy while enabling an antiparallel magnetic configuration. Compared with nickel oxide-based magnon junctions, the coercivity-tuned top YIG layer in our structure exhibits superior crystalline quality and much lower magnetic damping. A clear magnon junction effect is observed with a 43% MJR achieved. The interlayer coupling between the two ferrimagnetic insulators is found to enhance the MJR. These results offer valuable insights for the development of advanced magnon-based spintronic devices.
Materials Science (cond-mat.mtrl-sci)
Quantum Hamiltonian time crystals from covariant quantum Landau–Lifshitz–Gilbert relaxation
New Submission | Other Condensed Matter (cond-mat.other) | 2026-10-30 20:00 EDT
Classical Hamiltonian time crystals are constrained energy minima that move along symmetry orbits at frequencies set by Lagrange multipliers. We construct quantum counterparts by minimizing the energy over density matrices with fixed spectrum and charge expectations. A symmetry-covariant quantum Landau–Lifshitz–Gilbert equation selects them as periodic attractors, preserving the spectrum and fixing the multipliers dynamically. A chiral spin trimer motivated by Cu$ _3$ molecular magnets realizes this motion at a prepared magnetization, without a Zeeman term.
Other Condensed Matter (cond-mat.other)
1 figure
Ammonium thiocyanate enables in-situ structural templating of MAPbI3 via quasi-2D perovskite scaffold
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Sophie Tucker, Isaac Metcalf, Rachel C. Kilbride, Elena J. Cassella, Jessica H. Persaud, Faiz Mandani, Niranjana Raj, Max Allen, Charlie H. G. Nicholls, David G. Lidzey, Alice L. B. Pyne, Robert D. J. Oliver, Silvia Motti, Jacky Even, Aditya D. Mohite, Alexandra J. Ramadan
Ammonium thiocyanate (NH4SCN) has been used extensively to improve the current extraction and device performance of quasi-two-dimensional perovskite solar cells. Whilst this additive has been shown to influence quasi-2D perovskite crystallisation, a detailed understanding of its mechanism has not yet been established. Through spectroscopic and structural studies, we demonstrate that NH4SCN enables quasi-2D perovskite phases to structurally template the dominant 3D phase. Contrary to previous reports, we suggest that the benefit of this additive comes from an improvement to the 3D perovskite structure, not from charges transferring through vertically oriented 2D perovskite layers. We show that this additive provides kinetic control over the quasi-2D phase formation, suppressing the unfavourable n = 1 perovskite phase and promoting the growth of high-n 2D scaffold phases by extending the nucleation window. This promotes the in-situ templated growth of MAPbI3. We provide robust structural analysis demonstrating highly (110)-ordered 3D perovskite, with the mechanism confirmed by close lattice matching between this phase and quasi-2D phases. Furthermore, we show that this structural control is cation dependent, requiring both close lattice matching between quasi-2D and 3D perovskite phases, and successful kinetic control of the relevant quasi-2D phases.
Materials Science (cond-mat.mtrl-sci)
Excitons in solid molecular hydrogen from quantum Monte Carlo
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Edgar Josué Landinez Borda, Ravindra Shinde, Claudia Filippi, Markus Holzmann, Saverio Moroni
We use quantum Monte Carlo (QMC) methods to investigate the lowest neutral excitation of solid molecular hydrogen in phase-I under increasing compression, with emphasis on structural and response properties. We employ QMC wave functions for the excited state that feature only a single orbital substitution, or a multideterminant expansion including every single particle-hole transition, and compare the results with the Bethe-Salpeter equation (BSE) and time-dependent density-functional theory (TDDFT). We examine a number of nuclear configurations representing thermal and quantum fluctuations. The effect of the multideterminant expansion is marginal on the QMC excitation energies but crucial on the exciton localization and related quantities, irrespective of full optimization and imaginary time projection. In the strong insulating regime at low density, multideterminant QMC results match and in some cases surpass the degree of localization afforded by BSE. A similar trend is observed for transition dipole moments and excitation-induced forces, with generally good agreement between QMC and BSE but marked discrepancies for nuclear configurations where localization differs significantly. TDDFT generally gives a more extended exciton with correspondingly weaker transition dipole moments. These differences decrease upon compression, as the system approaches a semiconducting regime where multiple particle-hole transitions are less important.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el), Computational Physics (physics.comp-ph)
Main document 9 pages, 6 figures, supplementary information 14 pages, 13 figures, to appear on PRB
Kelvin-Wave Multiplication by Sound Emission
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-10-30 20:00 EDT
A subsonic Kelvin quantum can emit a phonon and split into two softer quanta, increasing Kelvin population while losing energy. In the soft-phonon limit, rotational invariance relates the leading acoustic shear amplitude, odd under reversal of phonon axial momentum, to the energy released. Microscopic calculations support this dispersion dependence. In a reflecting cavity with coherent sound and Kelvin seeds, Gross–Pitaevskii evolution shows Kelvin gain, larger mean-square displacement and smaller mean-square slope; a $ \pi$ shift of the initial sound phase reverses these changes.
Quantum Gases (cond-mat.quant-gas), Atomic Physics (physics.atom-ph), Quantum Physics (quant-ph)
12 pages, 5 figures
Ensemble-dependent effect of disorder on multicritical points in a system with long-range interactions
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-30 20:00 EDT
We introduce two variants of the Blume–Emery–Griffiths model with long-range, mean-field-like interactions and quenched disorder. Although the two variants are described by different Hamiltonians, they yield the same free energy. Moreover, both Hamiltonians lead to the same average energy and hence to the same microcanonical entropy. The canonical and microcanonical phase boundaries differ markedly, and so does the multicritical behaviour of the two ensembles. In the microcanonical ensemble, tricritical points appear for any fraction of active spins, whereas in the canonical ensemble they emerge only when this fraction is sufficiently large. At lower fractions, canonical critical endpoints arise instead. We also report the formation of gaps in the entropy as a function of magnetization, another manifestation of ensemble inequivalence.
Statistical Mechanics (cond-mat.stat-mech)
Majorana Zero Modes in Fractional Vortices
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-30 20:00 EDT
Lecheng Fang, Haotian Li, Haijiao Ji, Quanxin Hu, Hong Ding, Noah F. Q. Yuan
Majorana zero modes (MZMs) are promising for topological quantum computation, with vortices in topological superconductors serving as a leading platform. Recent experiments show that integer Abrikosov vortices in iron-based superconductors can split into fractional vortices (FVs) carrying fractional flux quanta. We show that due to topological protection, MZMs hosted by FVs are spatially unfolded over the FV cores, while fermionic bound states remain localized at individual FV cores. This yields zero-bias conductance peaks in both local tunneling and nonlocal crossed Andreev reflection, offering an alternative MZM signature.
Superconductivity (cond-mat.supr-con)
9 pages, 5 figures
Monte Carlo simulation of mixed spin-orbit ordering
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-30 20:00 EDT
The effect of a magnetic field on the thermodynamic properties of the Kugel-Khomskii model with maximal entanglement using the quasi-classical Monte Carlo method with the heat bath algorithm. The temperature dependencies of single-site correlators show that the application of a magnetic field results in non-zero magnetization and the simultaneous appearance of an orbital ordering at the same point in the Brillouin zone where a non-zero spin-orbit correlator exists.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech)
8 pages, 2 figures; report at the conference “Materials Science and Nanotechnology” (Ekaterinburg, Russia, August 24-27, 2026)
Microscopic Mechanism and Control of Reentrant Localization
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-10-30 20:00 EDT
Pei-Jie Chang, Quanfeng Lu, Wentao Yang, Dong Ruan, Gui-Lu Long
Increasing quasiperiodic modulation can restore extended states after localization, raising the question of how the same modulation drives both localization and recovery. We identify a microscopic mechanism in quasiperiodic dimer chains by resolving scattering between Fourier channels. Specifically, scattering into neighboring channels and back shifts the spectral edge relative to a localization boundary determined by a neutral auxiliary resonance. Their successive crossings drive the same spectral packet with fixed integrated-density-of-states (IDS) labels into localization and back into an extended regime. This recovery persists across finite parameter ranges in both gap-opening families, including relative-phase detuning. Furthermore, an exact sublattice mapping enables compensated control of the recovery window and predicts recovery thresholds for individual IDS labels.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
Selective effects of selenium substitution on superconductivity and magnetic memory in 4Hb-TaS2
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-30 20:00 EDT
Shalev Gur, Sajilesh K.P., Shubam Purwar, Irena Feldman, Ilay Mangel, Nitzan Ragoler, Amit Kanigel, Beena Kalisky
Disorder plays a central role in correlated quantum materials, but its effects can be highly selective when several electronic orders coexist. The van der Waals heterostructure 4Hb-TaS2 provides such a case, combining superconductivity, charge-order tendencies, strong scattering, and magnetic memory manifested through spontaneous vortices. Here we use Se substitution as a controlled local perturbation of the disorder landscape in 4Hb-TaS2. We find that superconductivity remains remarkably robust while the magnetic memory is strongly suppressed at higher Se concentrations. These results show that Se substitution does not create the hidden magnetic memory, but instead selectively weakens its macroscopic manifestation. More broadly, they reveal a sharp separation between robust superconducting and hidden-memory phases, and a highly disorder-sensitive spontaneous-vortex response in 4Hb-TaS2.
Superconductivity (cond-mat.supr-con)
Nonequilibrium statistical thermodynamics of a small quantum system coupled to quantum reservoirs
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-30 20:00 EDT
Jeremy Schofield, Raymond Kapral
A statistical mechanical formulation where nonequilibrium averages of selected quantum observables are given exactly as averages over local density operators is used to describe the dynamics and thermodynamics of a small quantum system coupled to reservoirs. The local density operators are functionals of constraint variables that play the role of thermodynamic forces that satisfy a set of equations of motion. A focus of the work is on the evolution of the average internal energy of the quantum subsystem that may be subject to external autonomous driving that does work on the system, and on entropy production in the system. The nonequilibrium statistical thermodynamics the quantum subsystem coupled to reservoirs, as well as that for the isolated subsystem and reservoirs, are discussed. When the subsystem is coupled to large quantum reservoirs, the effects of the quantum subsystem on the reservoirs can be captured through boundary conditions on the reservoir equations, and these boundary conditions are derived. The formulation is illustrated by considering the heat transfer through a system comprising a quantum system coupled to two heat reservoirs with different temperatures.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
16 pages, 1 figure
Confinement Controlled Phase-Pure 2D Layered Perovskites for Band-Edge Engineering
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Danila A. Tatarinov, Alexander Schleusener, Roman Krahne
Controlling the number n of connected octahedra layers in two-dimensional metal halide perovskites enables fine control of the semiconductor band gap that is highly advantageous for optoelectronic and light emission applications. Phase purity in terms of n is crucial towards narrow emission bands and the design of band structure alignment for charge carrier funneling. We present a simple and scalable synthesis method using cesium and butylammonium as A-cations to fabricate microcrystal powders of 2D lead bromide perovskites that results in samples with very high n-phase purity. The obtained microcrystals show a sharp onset in absorbance and single narrow emission peak in UV-blue spectral range, and we confirm their structure and composition with X-ray diffraction and energy dispersive spectroscopy. We show that we can tailor the spectral absorption of microcrystals samples by controlled mixing of the n-phase pure powders, and we demonstrate this capability with spectral photocurrent measurements using pellets pressed from pure and mixed powders. Both the spectral and dynamic response of the photocurrent of the pellets depend strongly on the composition of the powders, highlighting the design potential of our approach towards band-edge engineering.
Materials Science (cond-mat.mtrl-sci)
Main Manuscript and Supporting Information
Small Structures 2026, 7, e70580
Electronic liquid crystals and superconductivity from doping a moiré Mott insulator
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-30 20:00 EDT
Yichi Zhang, Yiyu Xia, Zhongdong Han, Jekwan Lee, Brandon Bauer, Kenji Watanabe, Takashi Taniguchi, Wenjin Zhao, Kin Fai Mak, Jie Shan
Electronic liquid crystals, such as stripe phases and nematics, are self-organized states of matter with spontaneously broken rotational symmetry. They are expected to emerge in a doped Mott insulator as a compromise between short- and long-range Coulomb interactions, and are believed to be intimately connected to the emergence of high temperature superconductivity either as a competing order or an intertwined order. Moiré semiconductors provide a controllable platform to explore the relationship between stripe phases and superconductivity near a Mott insulator. Here we report the generic appearance of stripe phases in a doped moiré Mott insulator and the observation of a stripe to-superconductor quantum phase transition in twisted bilayer WSe2. The stripe phases were revealed by electrical transport studies as a thermodynamic phase transition from a high temperature isotropic phase to a low-temperature anisotropic phase accompanied by a Fermi surface reconstruction. Near the stripe-to-superconductor transition, we also observed an additional thermodynamic phase transition from metallic stripes to pinned insulating stripes. The stripe-to-superconductor transition further exhibits an intriguing self-similarity that highlights the intimate relationship between the two orders. Our results pave the path for studying intertwined orders in moiré materials.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
Evidence for an effective gauge field in flakes of superconducting 4Hb-TaS2
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-30 20:00 EDT
Shalev Gur, T.R. Devidas, Eylon Persky, Roni Anna Gofman, Irena Feldman, Avior Almoalem, Sudip Kumar Saha, Mark H. Fischer, Avraham Klein, Jonathan Ruhman, Amit Kanigel, Beena Kalisky
Understanding the normal state of unconventional superconductors is central to uncovering the origin of superconductivity itself. Unconventional superconductivity often emerges from correlated electronic states characterized by intertwined symmetry-breaking orders. A striking example is 4Hb-TaS2, whose superconducting state exhibits a remarkable range of phenomena, including an unusual magnetic memory effect. Previous experiments showed that magnetic memory can be encoded above Tc and later revealed through spontaneous vortices below Tc, suggesting time-reversal symmetry breaking. However, since memory and vorticity are intertwined, this prevents establishing whether the effect results from trapped flux, weak conventional magnetism, or a true hidden electronic order. Here, we show that magnetic memory persists in the vortex-free Meissner regime of exfoliated 4Hb-TaS2 flakes, where it appears as a stable remanent modification of the superconducting screening response. Our results rule out explanations based on trapped vortices. Furthermore, the spatial profile of the flux generated by trained samples at zero field is inconsistent with conventional weak magnetism, suggesting a hidden electronic phase that imprints an effective flux on the superconducting condensate.
Superconductivity (cond-mat.supr-con)
Thermodynamic Crossovers in Supercritical Matter: One, No One, and One Hundred Thousand
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-30 20:00 EDT
Beyond a critical point, two thermodynamic phases become continuously connected, without being separated by any thermodynamic singularity. The paradigmatic example is the liquid-gas transition, where several criteria have been proposed to distinguish liquid-like and gas-like regimes within the supercritical region. Recently, a pair of thermodynamic crossover lines, $ L^\pm$ , was introduced to address a proposed incompatibility of previous definitions with the universal critical behavior of the Ising model. These lines divide the supercritical region into three regimes, meet only at the critical point, and obey the expected critical scaling laws. Here, we demonstrate that these requirements do not uniquely determine the crossover boundaries. Instead, infinitely many pairs of lines satisfy the same conditions, with different choices of thermodynamic paths selecting different crossover boundaries. We further show that the Lee-Yang formalism, despite providing an intrinsic characterization of critical singularities, does not resolve this ambiguity in defining real-axis crossover boundaries. Restricting to regular probing paths that respect the $ Z_2$ symmetry of the critical point recovers the Widom and $ L^\pm$ prescriptions asymptotically. This restriction, however, is a choice of protocol rather than a property of the system, and even then two inequivalent prescriptions survive. Our results demonstrate that universal critical behavior alone does not select privileged supercritical thermodynamic crossover boundaries. While such lines may identify physically meaningful changes in thermodynamic, structural, or transport properties, their precise locations and the widths of the regions they delimit remain dependent on the operational criteria used to define them.
Statistical Mechanics (cond-mat.stat-mech), High Energy Physics - Theory (hep-th)
v1: comments welcome
Non-Bloch Dynamical Quantum Phase Transitions with Memory
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
Zhesen Yang, Wei-Wei Yang, Henning Schomerus, Jiangping Hu
Dynamical quantum phase transitions (DQPTs) of periodic chains are determined by real Bloch momenta. We identify non-Bloch DQPTs, which occur only in open chains and are determined by complex momenta instead. They arise in a Hermitian chain coupled to a simple substrate, whose memory is treated exactly, and originate from the point-gap winding number $ W$ of the projected propagator: for $ W\neq0$ , open boundaries change both the dynamical free energy and the critical times, even in the thermodynamic limit. We find that both follow from an analytic continuation to complex momenta, and show that $ W$ can be measured by particle counting. This reveals a dynamical bulk-boundary correspondence, in which non-Hermitian topology emerges from Hermitian dynamics with memory.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics), Quantum Physics (quant-ph)
13 pages, 10 figures: Letter (4 figures) with End Matter (1 figure, 1 table) and Supplemental Material (5 figures, 1 table)
Influence of pairing and correlations on transport properties in three-terminal superconducting nanostructure
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
G. Górski, V. Pokorný, T. Domański
We study the local and nonlocal charge transport properties of three-terminal nanostructure, consisting of the correlated quantum dot embedded between two metallic electrodes and superconductor. Using the linear response theory, we analyze interplay of the induced on-dot pairing with the correlation effects, inspecting their influence on the conductance and thermopower. Our calculations predict negative values of the nonlocal conductance and reversal of the Seebeck coefficient when the quantum dot ground state is represented by the BCS-type singlet configuration. These phenomena are realized when the subgap charge transport is predominantly contributed by the crossed Andreev scattering. In contrast, on the doublet side, we obtain signatures for the Kondo effect manifested by the low-temperature enhancement of the charge conductance and clearly evident in the thermopower. Such temperature-dependent local and nonlocal transport properties can unambiguously identify the specific configuration of the correlated quantum dot and reveal the rich physics emerging in the doublet-to-singlet crossover region.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
17 pages, 17 figures
Dynamical mean-field theory for associative memory with block-correlated patterns
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-10-30 20:00 EDT
Andrea Callegaris, Yoshiyuki Kabashima
In associative memories storing correlated patterns, retrieval of individual memories can compete with symmetric mixed states. A dynamical description is needed to determine how the initial state selects between these outcomes. We extend the generating-functional dynamical mean-field theory (DMFT) for independent patterns to independent blocks of correlated binary patterns of fixed finite size. The resulting effective single-neuron process has a self-consistent cross-talk noise covariance and self-feedback coefficients that depend on the block-covariance eigenvalues. For hierarchically correlated patterns with nonmonotonic transfer, increasing the loading can permit retrieval from an imperfect initial state before further loading prevents it. DMFT reproduces the retrieval trajectories and basin geometry found in direct simulations. Near the lower boundary of this re-entrant region, direct networks reveal stationary saddles separating coexisting mixed and target-retrieval states. Parameter sensitivities of DMFT trajectories predict nearby shifts of this boundary. At the tested upper boundary, retrieval remains accessible from initial states with larger target overlap, indicating a change in basin access. Under fixed-point convergence assumptions, the theory recovers the equations of generalized self-consistent signal-to-noise analysis.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
36 pages, 12 figures
Quantum Metric Scaling and Its Exceptions in Classical Flat Bands
New Submission | Other Condensed Matter (cond-mat.other) | 2026-10-30 20:00 EDT
Kin Hung Fung, K. T. Law, C. T. Chan
The quantum metric length has been proposed as the localization length scale in one-dimensional flat bands. Here, we study this quantum metric scaling and the exceptions to it in a classical flat band formed by a locally resonant mass–spring system. We find that the localization length follows the quantum metric length near the flat band but departs from this proportionality at the exact flat-band frequency. Selective mass disorder also produces divergent localization lengths or arbitrarily short tails near the flat-band frequency without changing the clean metric. These exceptions show that disorder can select localization scales beyond those predicted by the quantum metric alone.
Other Condensed Matter (cond-mat.other)
5 pages, 3 figures
Magnetotransport experiments on side-contacted topological insulator three-terminal Josephson junctions
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
Christoph Wassmer, Ella Nikodem, Oliver Breunig, Yongjian Wang, Yoichi Ando, Jakob Schluck
Multiterminal Josephson junctions have recently attracted substantial attention. The ability to study Andreev bound states in a multi-phase parameter space opens up exciting avenues for generating topologically non-trivial phases in superconducting devices. A particularly interesting case is the trijunction based on a topological insulator (TI), which is predicted to host Majorana zero modes for suitable phase configurations (Fu and Kane, PRL 2008). Here we turn to the platform of the side-contacted TI trijunction and present experimental evidence for a multiterminal Josephson effect. We study the transport properties and find typical features of a two-dimensional critical current contour (CCC) as well as bias regimes in which only a single junction remains dissipationless. We pay particular attention to these features and study the effects of magnetic fields on single junctions within the trijunction, where, depending on the field direction, the supercurrents show Fraunhofer patterns, SQUID oscillations, or a monotonic decay. We find good agreement with semiclassical simulations for a single TI junction that take into account the top and bottom surface states. We observe pronounced non-convex shape deformations of the CCC under perpendicular magnetic fields that reflect the flux buildup in the loop formed by our trijunctions and provide a simple model sufficient to explain the observed effect. Our results provide the foundations for future studies of Majorana zero modes on this platform.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Static Response of the Strongly Coupled Electron Gas from Diffusion Monte Carlo
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-30 20:00 EDT
Muhammed H. Güneş, Yubo Yang, Vitaly Gorelov, Miguel A. Morales, Matteo Gatti, Lucia Reining, Shiwei Zhang
The local field factor $ G(q)$ of the HEG describes how exchange and correlation modify the response to a static perturbation, and enters dielectric screening, effective electron–electron interactions, and the xc kernel of TDDFT. Accurate zero-temperature data for $ G(q)$ , however, remain limited to metallic densities, $ r_s\leq10$ . In this work, we present diffusion Monte Carlo calculations of the static density response function $ \chi(q)$ and of $ G(q)$ for $ 2\leq r_s\leq100$ , and describe and discuss the methodological steps that enabled these calculations. We show how optimization of the perturbing potential in the trial wave function has an important effect, as a poor choice can reverse the sign of the response. A closed-form expression is provided for its optimal value, together with the density dependence of the linear-response window. We further show that backflow correlations leave $ \chi(q)$ unchanged and that $ G(q)$ depends only weakly on system size even at very low density, so that Slater–Jastrow wave functions and modest system sizes suffice. Together, these results provide a practical guide for future QMC calculations of response properties of the electron gas and real materials. Our results agree with previous DMC data at metallic densities for $ q>k_F$ , and extend them below $ k_F$ . They also agree with diagrammatic QMC at $ r_s=2$ . At lower densities, our results show that $ G(q)$ develops a nonmonotonic structure at intermediate-$ q$ , where the response approaches that of the noninteracting gas. Quantitative agreement is seen with finite-temperature path integral Monte Carlo, suggesting that the previously reported finite-temperature structure is inherited from the ground state. Using a parametrization of $ G(q)$ that reproduces our data throughout the liquid phase, we relate this structure to short-range order in the pair correlation function and the static structure factor.
Strongly Correlated Electrons (cond-mat.str-el), Other Condensed Matter (cond-mat.other), Computational Physics (physics.comp-ph)
Single-atom billiards in an ultracold bath with energy-tunable collisions and threshold-sensitive detection
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-10-30 20:00 EDT
Silvia Hiebel, Sabrina Burgardt, Julian Feß, Artur Widera
Transport processes at the microscopic scale can differ strongly from their macroscopic counterparts, particularly when the environment is not a well-defined surface but an unordered thermal medium. Ultracold quantum gases offer a high degree of controllability and directly observable dynamics, thereby providing a versatile platform to study such transport processes under precisely controllable conditions. Here, we realize an energy-tunable single-atom collider by transporting individual cesium atoms at controlled velocity through an ultracold rubidium bath. The constant lattice velocity sets the directed contribution to the collision-energy distribution, while the lattice depth provides a tunable energy threshold for collision-induced transport disruption. By independently varying these parameters together with bath density and temperature, we separate the number of collision events from their probability to disrupt transport. Across a regime with only a few expected collisions per passage, the inferred single-collision ejection probability rises from small values to near unity as the collision energy exceeds the lattice confinement scale. The experiment thus converts microscopic collisional energy transfer into a binary single-atom observable and provides a controlled link between individual scattering events and emergent dissipative transport.
Quantum Gases (cond-mat.quant-gas), Atomic Physics (physics.atom-ph)
12 pages, 7 figures
Continuous tuning of quantum critical behavior in hybrid Josephson junction arrays
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
E. Fugl, L. L. Olsen, S. Sasmal, M. Efthymiou-Tsironi, G. Nagda, F. Krizek, L. Casparis, S. Vaitiekėnas
We report finite-temperature scaling of voltage-driven quantum phase transitions in hybrid Josephson junction arrays. A dual-gate geometry separately tunes interisland coupling and proximity-induced superconductivity, providing access to superconducting, insulating, and metallic transport regimes. The critical resistivity and scaling exponent evolve continuously with electrostatic tuning. Where the three regimes converge, the critical resistivity approaches $ h/4e^2$ , consistent with the self-dual limit, while the scaling exponent approaches the quantum-percolation estimate. Tuning toward stronger insulating behavior raises the critical resistivity and shifts the scaling exponent toward the classical-percolation value, while both parameters decrease toward the metallic regime. These results connect scaling regimes previously reported in different two-dimensional superconducting systems through continuous electrostatic control.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
10 pages, 4+4 figures
Non-Gaussian transport in tempered fractional Laplace motion
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-30 20:00 EDT
Yiming Zhao, Wei Wang, Ralf Metzler
We study a minimal stochastic model for active transport featuring a non-Gaussian displacement probability density function and transient superdiffusion. Our approach is based on a combination of an exponential tempering in the parental fractional Brownian noise correlations, augmented by a gamma-distribution of the diffusivity across the ensemble. For the resulting tempered fractional Laplace motion we derive analytical expressions for the mean-squared displacement, the kurtosis, the non-Gaussianity parameter and the displacement probability density function. We also show via stochastic simulations that the model quantitatively reproduces the main experimental observations in a recent study of active cargo particle transport by a carpet of amoeba cells.
Statistical Mechanics (cond-mat.stat-mech)
Adiabatic Variational Principle: Born-Oppenheimer Theory for Emergent Electronic-Order Dynamics
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-30 20:00 EDT
Yang Yang, Ali Rayat, Ho Jang, Yunhao Fan, Sankha Subhra Bakshi, Gia-Wei Chern
Recent advances in microscopic many-body methods have enabled increasingly accurate descriptions of equilibrium quantum states, yet large-scale simulations of emergent-order dynamics typically rely on phenomenological equations with prescribed free-energy functionals. We introduce the Adiabatic Variational Principle (AVP), a framework for deriving order-parameter dynamics directly from an interacting many-body Hamiltonian. When microscopic relaxation is fast compared with order-parameter evolution, the many-body state follows the collective configuration adiabatically, in analogy with the Born–Oppenheimer separation of electronic and nuclear motion. This assumption makes explicit the adiabatic closure implicit in conventional phase-field descriptions. Each instantaneous order-parameter configuration then defines a constrained quasi-stationary many-body state, and the Lagrange multipliers enforcing these constraints directly provide the thermodynamic forces driving the collective evolution. Nonlinear Mori–Zwanzig projection theory further connects the reversible dynamics to the microscopic algebra of the collective variables and relates dissipation and fluctuations to the eliminated degrees of freedom. Applications to charge- and spin-density-wave dynamics recover Allen–Cahn domain growth, resolve evolving domain networks together with their microscopic electronic structure, and yield generalized Landau–Lifshitz dynamics for itinerant magnetism. The AVP thus provides a solver-independent microscopic foundation for phase-field-like simulations of the nonequilibrium dynamics of emergent electronic order.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech), Computational Physics (physics.comp-ph)
35 pages, 13 figures
Investigation of perovskite related oxides: structural and magnetic properties
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-30 20:00 EDT
Perovskites exist in varied structures and show structure dependent magnetic properties which is of great interest in the field of multiferroics, magnetocaloric and spintronic devices. Here we intend to study the various rare-earth(R) and transition metal (TM) ion interactions depending on their structures. Different Curie temperature, spinglass transition and spin reorientation transitions were observed depending on the degree of interactions and structural properties. It is interesting to study the role of orbital interactions, disorder in magnetic transitions leading to change in superexchange and double exchange interaction. On substitution at A-site or B-site results in change in magnetic interactions, as well as creates structural distortions. We also obtained results where the spin interaction of the transition metal and rare-earth interaction, magnetic anisotropy, orientations of orbitals, disorder induced interactions were observed.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Spin-Orbit Coupling Response Theory within the Oriented Spin Space Group Framework
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Yuntian Liu, Xiaobing Chen, Yutong Yu, Jesús Etxebarria, J. Manuel Perez-Mato, Qihang Liu
Spin-orbit coupling (SOC) plays a pivotal role in a broad range of phenomena in condensed matter physics. The recently developed spin space group theory offers a new perspective for characterizing the fundamental symmetry-breaking features of SOC-related phenomena, yet its full potential remains to be explored. Here, we provide a general framework that relates the SOC-induced symmetry breaking to modifications of physical properties and emergence of new physical effects. This approach incorporates the recently developed oriented spin space group (OSSG) formalism, which can explicitly describe the symmetry reduction induced by SOC. By parameterizing the SOC Hamiltonian using a SOC tensor that connects real and spin spaces, an expansion in terms of the SOC components can be constructed for the response tensor describing any physical quantity. This framework determines not only whether a SOC-induced response is symmetry allowed, but also the lowest order in SOC at which it emerges and its dependence on magnetic anisotropy. As representative applications, we analyze the magnetoelectric coupling in Type-II multiferroics and show that magnetically induced electric polarization in different systems can be the result of SOC effects of different orders, and can exhibit varying characteristics of magnetic anisotropy. We further apply this theory to the anomalous Hall effect and spin magnetization in antiferromagnets, demonstrating that their distinct transformation properties under the OSSG allow a large anomalous Hall response to coexist with weak spin magnetization. A high-throughput analysis of materials in the MAGNDATA database identifies several symmetry-based material classes favorable for this coexistence. Overall, the proposed framework provides a unified symmetry description of SOC-induced phenomena and offers a systematic way for the identification of SOC-driven functional materials.
Materials Science (cond-mat.mtrl-sci)
Cubic-Zn(1-x)Mn(x)Te optical modes across the phonon and phonon-polariton regimes
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
M. Mina, A. Elmahjoubi, T. Ngulezhu, S. Thiam, A. V. Postnikov, T. Tite, P. Bourges, F. Bourdarot, N. Biniskos, A. Polian, Y. Le Godec, N. Guignot, J.-P. Itie, S. Diliberto, S. Michel, A. Maillard, A. En Naciri, L. Broch, P. Franchetti, K. Strzalkowski, O. Pages
Alloying offers a convenient route to tune the physical properties of semiconductors, at the price, however, of local lattice/bond distortions needed to accommodate the lattice mismatch. Being nearly lattice-matched and moreover highly resistant to lattice and bond distortions thanks to a largely covalent bonding, cubic Zn(1-x)Mn(x)Te sets a benchmark to test the sensitivity of lattice vibrations to minimum lattice and bond distortions induced by alloying. We explore experimentally the two transverse optical regimes of cubic Zn(1-x)Mn(x)Te (x<0.7), with ab initio calculations in support: (1) the phonon-polariton regime at quasi-infinite (photon-like) wavelengths averaging over the alloy disorder, probed by forward-Raman scattering, and (2) the purely-mechanical phonon regime down to minimum wavelengths nearly matching the lattice constant zooming into the alloy disorder, achieved by inelastic neutron scattering. The short Zn-Te bond is found to exhibit a compact optical duo distinguishing homo from hetero local bond environments (1 bond: 2 mode), as explained by the percolation model. This deviates from the historical Zn(1-x)Mn(x)Te MREI (modified-random-element-isodisplacement) scheme inspired from classical Raman and infrared studies, in which the optical modes are blind to the bond environment (1-bond: 1-mode). So, the test is positive, reinforcing the status of the percolation scheme as a robust decryptor of (even small) lattice distortions induced by alloying through the lattice dynamics.
Materials Science (cond-mat.mtrl-sci), Optics (physics.optics)
14 pages, 5 figures and supplementary information
Coexistence of Superconductivity and Chern insulators with |C| $\geq 1$ in twisted rhombohedral bilayer-trilayer graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
Qiu Yang, Zihao Huo, Le Liu, Tianqi Song, Fankun Wang, Jingwei Dong, Kenji Watanabe, Takashi Taniguchi, Weibo Gao, Xiaobo Lu, Guangyu Zhang, Wei Yang
Rhombohedral multilayer graphene (RMG) has been demonstrated as a promising platform for investigating strongly correlated phases of matter. Here, we observe a coexistence of superconductivity and Chern insulators in a twisted rhombohedral bilayer-trilayer graphene moiré superlattice. Superconductivity, evidenced by a sharp transition with a critical temperature of ~180 mK, nonlinear I-V with a BKT temperature of 135 mK, and a signature of phase-sensitive interference patterns, emerges from a symmetry-breaking Fermi surface near v = -2 and D = 0, and it survives at a large in-plane magnetic field up to 2 T, strongly deviating from the Pauli limit. Moreover, we observe a strong modulation of the Ginzburg-Landau coherence length from 467 nm to 145 nm as the in-plane magnetic field increases from 0 to 2 T, whereas the critical current Ic barely changes. Unlike previous studies in RMG, we observe a competition between superconductivity and a correlated insulator at v = -2, monitored by displacement fields and twist angles. Note that we also observe integer Chern insulators with C = 1, 3, and -3 at v = 1/2, 1, and 3, respectively, for large D > 0 in the same superconducting device. The observations establish twisted rhombohedral graphene multilayers as a fascinating system to investigate unconventional superconductivity, high Chern number topology, and their interplay.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
12 pages, 4 figures
Cage-related crystal-field effects in the paramagnetic range of PrB$_6$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-30 20:00 EDT
Mehdi Amara, Christine Opagiste, Natalya Yu. Shitsevalova
New insights into the paramagnetic range of PrB$ _6$ below 50 K are revealed through specific-heat, thermal-expansion and magnetic measurements. The latent heats of the two successive magnetic transitions, together with an improved description of the lattice contribution, enable a detailed determination of the thermal variation of the magnetic entropy. Immediately above the first-order magnetic ordering temperature ($ T_N = 6.7$ K), the magnetic entropy per Pr$ ^{3+}$ is close to that of a doublet, instead of the triplet crystal-field ground state identified by inelastic neutron scattering. Temperatures in excess of 30 K are required to reach the entropy of the threefold-degenerate ground state. This is reminiscent of the CeB$ _6$ case and, similarly, strongly suggests a dynamical splitting of the crystal-field ground state within the boron cage. Further evidence of this splitting is provided by the analysis of the low-temperature paramagnetic susceptibility, which resembles that of a non-magnetic ground state. In addition, a large thermal-expansion anomaly is observed below 20 K, consistent with the expected centrifugal Jahn-Teller effect.
Strongly Correlated Electrons (cond-mat.str-el)
Néel vector switching by magnetization-dependent layer-resolved spin-orbit torque
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Sheng Pan, Weiwei Wang, Jie-Xiang Yu
Layer-resolved spin-orbit torques offer a route to controlling antiferromagnetic order through local spin-charge conversion. First-principles calculations show that the layer-resolved spin Hall conductivity of the antiferromagnetic topological insulator $ \mathrm{Mn{Bi}{2}{Te}{4}}$ consists of a magnetization-independent spin Hall term plus two spin anomalous Hall terms that are even in the Néel vector yet evolve with the local magnetic order, while local inversion asymmetry differentiates surface and inner layers. This response enables reversible, field-free switching of the Néel vector in finite-septuple-layer films. Although the magnetization-independent spin Hall term alone can reverse the order, the spin anomalous Hall terms provide magnetization-dependent feedback that redistributes the layer-resolved torques and reshapes the switching trajectory, offering a route to tailoring current-driven switching through layer and interface engineering.
Materials Science (cond-mat.mtrl-sci)
Stabilizing fluctuating Cooper pairs with a terahertz resonator
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
Frieder Lindel, Jonathan B. Curtis, Jérôme Faist, Eugene Demler
Coupling quantum materials to electromagnetic cavities or resonators without external driving has gained prominence as a new control mechanism. Here we develop an equilibrium theory of a mesoscopic, disordered two-dimensional superconductor coupled to a subwavelength terahertz resonator, focusing on the interplay between superconducting phase fluctuations in the sample and electromagnetic fluctuations of the resonator. Modeling the resonator as a lumped-element circuit, we show that the coupling enhances, rather than suppresses, the superconducting transition temperature $ T_c$ . When the sample is smaller than the Pearl length, phase fluctuations near the Berezinskii–Kosterlitz–Thouless (BKT) transition strongly amplify this enhancement. Crucially, the resistive quasiparticle response of the sample must be included in the analysis: at low frequencies the superfluid shunts the normal-fluid channel, reducing the total sample impedance. For representative parameters, a $ 1 ,\mu\mathrm{m} \times 1 ,\mu\mathrm{m}$ , $ 8 $ nm-thick disordered film, we find a relative $ T_c$ enhancement of about $ 1%$ , an order of magnitude larger than the $ 0.1% $ obtained when phase fluctuations are neglected. These results identify superconductors with soft phase fluctuations as promising platforms for equilibrium control with terahertz resonators.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
10 pages, 6 figures
Chiral superconductivity on a closed Klein bottle: a chirality wall and its Majorana seam spectrum
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-30 20:00 EDT
We study a spinless $ \pi$ -flux lattice superconductor whose normal-state momentum-space fundamental domain is a Klein bottle. Within this model, a glide lift and a hidden antiunitary symmetry independently force the Bogoliubov–de Gennes (BdG) Chern number to vanish. A diagonal pairing breaks the antiunitary obstruction exactly when its real part is nonzero; this is necessary, not sufficient, for a chiral phase. We derive explicit Pfaffians determining Chern parity and identify three analytic families of gap closings in a real-pairing section. For a chiral state on a closed real-space Klein bottle, the prescribed pairing and gluing produce a $ \Delta C=2$ chirality wall. A translation-invariant unfolding resolves two co-propagating Majorana branches. Their finite-size levels depend on circumference and holonomy; the near-zero pair is lifted at first order by allowed local seam perturbations. A cut-cylinder control has the same low-energy channel count, so gluing reconnects existing gapless content. We also distinguish literal gluing from deck projection: particle–hole symmetry exchanges the deck eigenblocks, precluding their interpretation as independent BdG quotient Hamiltonians. The contribution is a model-specific account of pairing compatibility and closed-surface seam spectra. The energy cost is evaluated for a fixed pairing background; neither a protected zero mode nor a self-consistent wall solution is claimed.
Superconductivity (cond-mat.supr-con)
17 pages, 10 figures. Reproducibility archive: this https URL
Large Magnetocaloric Effect and Adiabatic Temperature Change in the Tellurate: Gd2TeO6
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Abhijit Nayak (1), Gurunathan Angusamy (2), Kusampal Yadav (3), S. K. Panda (4), Devajyoti Mukherjee (3), Raivo Stern (2), Tanmoy Chakrabarty (5), Krishnamurthy Jyothinagaram (1) ((1) Department of Physics, National Institute of Technology, Andhra Pradesh, Tadepalligudem, India, (2) National Institute of Chemical Physics and Biophysics, Tallinn, Estonia, (3) School of Physical Sciences, Indian Association for the Cultivation of Science, Kolkata, West Bengal, India, (4) Department of Physics, Bennet University, Greater Noida, Uttar Pradesh, India, (5) Division of Sciences, Krea University, Sri City, Andhra Pradesh, India)
We investigate the structural, magnetic, thermodynamic, and magnetocaloric properties of polycrystalline Gd2TeO6, a rare-earth tellurate unexplored for cryogenic magnetic refrigeration. Powder X-ray diffraction confirms single-phase orthorhombic symmetry (P212121), featuring two crystallographically distinct seven-coordinate Gd sites. Magnetization measurements reveal no conventional long-range magnetic ordering down to 2 K, although low-field magnetic irreversibility emerges below approximately 4 K. Curie-Weiss analysis yields a Weiss temperature of -1.25 K, indicating weak predominantly antiferromagnetic interactions. The magnetization reaches approximately 97% of the theoretical saturation moment at 7 T with negligible hysteresis. Heat-capacity measurements reveal no sharp zero-field anomaly above 2 K, while a broad field-induced maximum indicates redistribution of low-energy magnetic entropy. Debye-Einstein analysis separates the lattice and magnetic contributions. At 2.5 K, the maximum magnetic entropy changes (-DeltaSM) reach 21.40, 48.51, and 54.81 J kg-1 K-1 for field changes of 0-2, 0-5, and 0-7 T, respectively. The corresponding volumetric entropy change reaches 400.50 mJ cm-3 K-1. Measurements up to 14 T yield (-DeltaSM) = 63.51 J kg-1 K-1, approaching the theoretical limit of 64.25 J kg-1 K-1. The estimated adiabatic temperature change is approximately 22.7 K for 0-7 T. First-principles calculations with GGA+U approximation reveal competing antiferromagnetic states, highlighting Gd2TeO6 as a promising candidate for cryogenic magnetocaloric applications.
Materials Science (cond-mat.mtrl-sci)
Magnetic and magnetocaloric studies on Gd2TeO6 Tellurate
Topological Quantum Spin Liquids in a Ladder with Majorana fermions and p-wave Superconductivity
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-30 20:00 EDT
Magali Korolev, Fan Yang, Erik S. Sørensen, Karyn Le Hur
In this article, we address the possibility of topological quantum spin liquids with only short-range (spin) correlations in the whole phase diagram in a ladder system, through an exactly solvable model which represents a generalization of the two-dimensional Kitaev honeycomb spin model to a ribbon geometry. This system gives rise to $ \mathbb{Z}_2$ gauge fields emerging in a static way in the ground state through Majorana fermions which then produce either $ 0$ or $ \pi$ flux. Through a quantum field theory perspective, mathematical and Density Matrix Renormalization Group results, we present our progress on the geometrical, topological and physical classification of this model through observables navigating on the whole phase diagram presenting three spin-liquid phases with a spin gap and a metallic phase in the sense of Majorana fermions. We propose a bulk-edge correspondence revealing the presence of protected zero-energy Majorana fermions at the edge in the phases with a gap and revealing also the presence of itinerant Majorana fermions in the bulk in the topological liquid phase. The proposed approach allows us to distinguish between properties of the brickwall ladder giving rise to a special line and those of the square ladder allowing for the gapless Majorana liquid phase. This model gives some hope on finding solutions for topological quantum spin models, e.g. with $ \pi$ flux, on a square lattice geometry. This approach also allows for a correspondence onto models of topological superconductivity.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Superconductivity (cond-mat.supr-con), Mathematical Physics (math-ph)
23 pages, 12 Figures, To be Submitted to Reports on Progress in Physics
Structural signatures of primary and secondary relaxation during physical aging of a metallic glass
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-10-30 20:00 EDT
Beatrice Baraldi, Stefano Marchesin, Davide Marchesi, Lara Piemontese, Francesco Dallari, Søren S. Sørensen, Eloi Pineda, Marco Di Michiel, Giulio Monaco, Peihao Sun
Physical aging drives glasses toward equilibrium and changes their thermodynamic and mechanical properties, but the accompanying microscopic structural evolution remains poorly understood. Here, using our recently developed low-background setup combining fast scanning calorimetry with \emph{in-situ} X-ray total scattering, we investigate microscopic structural changes during physical aging in Pd$ _{42.5}$ Cu$ _{30}$ Ni$ _{7.5}$ P$ _{20}$ metallic glass. The measurements span an unprecedented six orders of magnitude in time and a temperature range extending from above the glass transition temperature to more than 150,K below it. We observe dominant structural changes near the first and second peaks of the structure factor. Near and above the glass transition temperature, changes in the first sharp diffraction peak closely follow enthalpy relaxation and are associated predominantly with increasing degrees of medium-range ordering. At lower temperatures, the enthalpy evolution can no longer be described by this contribution alone, revealing an additional, faster relaxation process that correlates with changes near the second diffraction peak and thus short-range structural rearrangements, including increased Pd–Pd correlations. These results establish a direct connection between thermodynamic relaxation and structural evolution, providing strong evidence that primary and secondary aging processes are associated with distinct structural length scales.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
12 pages, 8 figures
Transport in spinful non-Hermitian gauge lattices
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
Hamed Ghaemi-Dizicheh, Shahram Dehdashti, Janis Nötzel
We extend the generalized transfer-matrix method introduced in [H. Ghaemi-Dizicheh, Phys.\ Rev.\ B \textbf{107}, 125155 (2023)] to one-dimensional spinful non-Hermitian tight-binding lattices with matrix-valued Abelian and non-Abelian gauge couplings. We derive a minimal channel-resolved transfer matrix and identify its eigenvalues with the generalized Bloch factors. The same transfer matrix determines the periodic- and open-boundary spectra, generalized Brillouin zone, skin localization, and finite-sample scattering conditions. In the Abelian limit, the model separates into fixed spin sectors, yielding exact spectral results and closed finite-length transport expressions in terms of Chebyshev polynomials. These results reveal bipolar spin-dependent skin localization and distinguish the reciprocal hopping scale, which governs poles, zeros, and reflectionlessness, from the directed-amplification factor controlling transmission asymmetry, transparency, and invisibility. For non-Abelian gauge fields, noncommuting link matrices coherently mix the spin sectors, such that four transfer eigenmodes jointly determine the non-Bloch spectrum and transport eigenchannels. We show that this mixing produces spin-hybridized lasing and coherent-perfect-absorption channels, Zeeman-tunable lasing thresholds, and direction-dependent reflectionless transport accompanied by pronounced spin conversion. The resulting boundary-condition criteria describe lasing, coherent perfect absorption, reflectionlessness, transparency, and invisibility, while identifying spin polarization and conversion as experimentally accessible signatures that distinguish Abelian from non-Abelian non-Hermitian transport.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Mathematical Physics (math-ph), Quantum Physics (quant-ph)
28 pages, 7 Figures
Multidimensional revival dynamics in a bosonic many-body system
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-10-30 20:00 EDT
Denis Ullmo (1), Steven Tomsovic (1 and 2), Gabriel M. Lando (1), Peter Schlagheck (3) ((1) LPTMS, Université Paris-Saclay / CNRS, Orsay, (2) Department of Physics and Astronomy, Washington State University, Pullman, (3) CESAM research unit, University of Liege, Liege)
The collapse and revival of localized states in many-body systems is a quintessential example of a quantum interference phenomenon that cannot be explained purely within mean-field theories. Historically, the majority of previous work on quantum revivals has been in a Schrödinger mechanics context, typically for effectively 1D systems with a focus on the autocorrelation function as the key detection observable. The general revival subject acquires a far greater complexity in the bosonic many-body context that offers a larger variety of observables and intrinsically implies high dimensionality. Here, the focus is on the simplest nontrivial (i.e., not 1D) bosonic many-body system, namely a symmetric two-site Bose-Hubbard model. The non-equilibrium situation of a coherent initial state prepared on one of the two sites of this integrable 2D system in the strongly self-trapping regime is considered. The revival behaviors emerging from the resulting dynamics within expectation values, coherences, and the autocorrelation function are theoretically derived, and the entanglement behavior is illustrated. Several new features, unknown so far in the Schrödinger context and identified here in terms of five ``puzzles’’, are encountered and discussed, among them, a synchronized resurgence behavior, differing revivals times depending on the specific observable, and a manifestation of a precession that appears in the underlying mean field dynamics. These new phenomena can be entirely understood through a comprehensive semiclassical theory, building upon the underlying classical (mean-field) phase-space structure. A quantitative comparison of the latter with semiclassical predictions and quantum perturbative calculations yields an overall excellent agreement and confirms that a full semiclassical theory is pivotal for the understanding of these genuinely quantum many-body interference phenomena.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
92 pages, 14 figures
Soliton-Lattice Origin of Incommensurability in High-Pressure Antimony
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
M. Smirman, K. Sun, H. Sheng, I. I. Mazin
The microscopic origin of incommensurability in host-guest crystals remains unresolved. Here we show that the high-pressure antimony host-guest phase Sb-II is a soliton lattice, where localized guest-host misregistries decorate a
commensurate 4/3 reference structure. First-principles calculations reveal a corrugated and hysteretic registry landscape, motivating a Frenkel-Kontorova description that accounts for soliton-lattice approximants of the form
$ (4n+1)/(3n+1)$ . Machine-learning-potential calculations of these approximants show an energetically preferred soliton spacing, and their localized misregistry cores are also verified by first-principles relaxations. At finite
temperature, the thermally broadened soliton lattice appears as an atomic density wave along the guest chains, consistent with experimental diffraction. This soliton-registry picture provides a microscopic mechanism for host-guest
incommensurability in Sb-II.
Materials Science (cond-mat.mtrl-sci)
6 pages, 4 figures; Supplemental Material (20 pages) included; submitted to PRL
Light-induced chiral altermagnets from conventional antiferromagnets
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Jorge Cardenas-Gamboa, Devika Jayadeep, Aritz Leonardo, Gregory A. Fiete, Jeroen van den Brink, Maia G. Vergniory
Altermagnets combine compensated collinear magnetic order with momentum-dependent nonrelativistic spin splitting, offering new opportunities for spintronic applications. Here, we propose a route to optically induce altermagnetism through coherent lattice control. Using symmetry analysis, we identify phonon distortions that lift the spin degeneracy of conventional antiferromagnets while preserving the rotational symmetries connecting opposite-spin sublattices. Among these, geometric chiral phonons provide a particularly appealing pathway, linking the emergence of altermagnetism to structural chirality. Taking Fe$ _2$ TeO$ _6$ as a prototype, we demonstrate that a linearly polarized mid-infrared pulse can drive a structural instability through negative biquadratic coupling between an infrared-active phonon and an optically silent, symmetry-breaking mode. First-principles-based lattice dynamics reveal the emergence of a transient chiral distortion, while electronic-structure calculations establish that the light-induced structure exhibits nonrelativistic spin splitting characteristic of altermagnetism. Our results establish a symmetry-guided pathway toward the ultrafast optical control of altermagnetic states through nonlinear phononics.
Materials Science (cond-mat.mtrl-sci)
7 pages, 2 figures
Micromagnetic Lagrangian and Hamiltonian Normal-Mode Formulation of Cavity Magnon-Photon Interactions
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
Claudio Serpico, Marco Lembo, Giovanni Miano
We investigate magnon-photon interactions in a resonant cavity starting from the coupled Maxwell and Landau-Lifshitz equations linearized about an arbitrary micromagnetic ground state. By introducing an electric vector potential and a suitable interaction Lagrangian, the formulation avoids the cancellation of large magnetostatic contributions that arises in the conventional magnetic-vector-potential description and becomes inaccurate under modal truncation. The magnetization and cavity fields are expanded in the normal modes of the uncoupled magnetic and electromagnetic subsystems, with coupling coefficients given by overlap integrals of the corresponding eigenfunctions. The resulting multimode Lagrangian has a noncanonical structure due to the gyrotropic terms, and the corresponding Hamiltonian formulation is obtained using the Faddeev-Jackiw approach. The radiative magnon-photon interaction is encoded in the resulting Poisson-bracket structure, while the cavity-induced modification of the magnetostatic field enters explicitly in the Hamiltonian. The coupled system is diagonalized through a generalized Bogoliubov transformation, yielding canonical polariton variables that provide a natural basis for quantization. Application to a perpendicularly magnetized YIG disk in a rectangular microwave cavity shows hybridization between the cavity mode and several magnetostatic modes, together with appreciable cavity-wall-induced frequency shifts when the sample is placed close to the conducting walls.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Quantum Physics (quant-ph)
29 pages, 6 figures; Supplemental Material provided as ancillary file
Seeding and Amplification of Chaos in Long-Range Interacting Spin Chains
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-30 20:00 EDT
Truncating weak interactions is a natural simplification of a many-body Hamiltonian, but the validity of this approximation need not be uniform in distance and time. In a chaotic system, a weak long-range coupling can seed a small disturbance far from its source, after which the local dynamics can amplify that disturbance exponentially. We study this mechanism in an infinite-temperature classical Heisenberg spin chain with a dominant nearest-neighbor exchange and a weak interaction tail. Using a classical decorrelator, we compare exponentially and power-law decaying tails over several decades in interaction strength. For exponentially decaying interactions, the long-distance front remains ballistic when the tail is sufficiently shallow, with a velocity controlled by the competition between the spatial decay of the seed and the local chaotic growth. For sufficiently rapid exponential decay, the nearest-neighbor front, which is defined by an intrinsic butterfly velocity $ v_b$ , is recovered within the accessible space-time window. For power-law interactions, the arrival time is logarithmic in distance for all exponents studied, corresponding to an exponentially expanding spatial front; the power-law exponent controls the coefficient of this logarithm. We interpret both behaviors using a seeding-and-amplification picture in which long-range couplings generate weak disturbances throughout the chain whose growth is governed primarily by the local nearest-neighbor dynamics. In this picture, the overall strength of the tail primarily controls when the long-range front becomes visible, while its spatial decay controls the propagation law. Thus a weak interaction tail can leave conventional spin-dynamical observables essentially unchanged while qualitatively altering the long-distance propagation of decorrelation.
Statistical Mechanics (cond-mat.stat-mech)
14 pages, 11 figures
Electric field control of anisotropic spin traffic between spin-filtering and magnon-scattering in a layered antiferromagnet
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
Mohamed Soliman, Jaime Garrido Aldea, Davy Borowski, Dorye L. Esteras, Neeraj K. Rajak, Niels Chapuis, Abdelkarim Ouerghi, Arnaud Gloppe, Jérôme Robert, Bernard Doudin, Takashi Taniguchi, Kenji Watanabe, José H. García, Stephan Roche, Jean-François Dayen
Layered A-type antiferromagnetic (AFM) semiconductors offer a unique platform for spintronic devices by combining robust magnetism with gate-tunable semiconducting properties. We present a dual-gate field-effect transistor based on CrSBr, a layered A-type AFM with pronounced transport anisotropy and complex spin dynamics. Our device provides independent control over carrier density and displacement field. Systematic transport measurements reveal that the displacement field, rather than doping, predominantly governs the sign and magnitude of magnetoresistance ratio (MRR). We identify the origins of both negative and positive MRR components and connect them to interlayer and intralayer spin-dependent transport mechanisms. We interpret these findings with ab initio calculations and an effective spin-circuit model that reproduces the anisotropic magnetotransport. Our results identify the displacement field as an efficient electrical control parameter of spin transport in CrSBr and suggest that multi-gate architectures could provide similar control in other layered antiferromagnetic semiconductors.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph), Quantum Physics (quant-ph)
Teleported free energy simulations
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-30 20:00 EDT
Davide Carbone (1), ((1) Centre d’Études et de Recherche en Informatique et Communications (CEDRIC), Conservatoire National des Arts et Métiers (Cnam), 292 rue Saint-Martin, 75003 Paris, France)
Escorted free energy simulations reduce dissipation with a flow field that follows the equilibrium distribution. A continuous flow, however, cannot transfer probability between metastable basins. We show that any escort then faces a variance floor set by the change in basin weights, and lift it by adding teleportation: jumps at a rate proportional to the driving rate. We derive the corresponding nonequilibrium identity, the zero-dissipation condition, and the minimal number of jumps it requires, and illustrate the gain on an exactly solvable model and a tilted double well.
Statistical Mechanics (cond-mat.stat-mech), Mathematical Physics (math-ph)
Time Reflection-Refraction Crossover at Topological Kramers Edge States
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
Time-reversal symmetry protects helical edge states against static nonmagnetic backscattering. We show that spatially uniform temporal modulation produces a time reflection-refraction crossover within the same quantum spin Hall phase while preserving time-reversal symmetry of the instantaneous Hamiltonian. A finite gap to the bulk and an edge splitting that vanishes at the Kramers crossing allow the modulation to suppress bulk excitation while remaining nonadiabatic between the edge channels. Virtual transitions through bulk states enable coherent conversion between counter-propagating edge channels at fixed crystal momentum. Near the crossing, $ qT$ governs the leading crossover dynamics for a fixed ramp shape, where $ q$ is the momentum offset and $ T$ the ramp duration. Coherent interference can suppress and restore reflection as the ramp slows. In the adiabatic limit, two initially time-reversed wave packets follow their respective propagation branches and acquire equal geometric displacements. Their group-velocity contributions cancel, isolating the contribution from the Berry curvature to be directly observable. Temporal modulation thus controls protected states and quantum geometry along a topological edge.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Gases (cond-mat.quant-gas), Optics (physics.optics)
13 pages, 7 figures
Static dipolar impurity in a Fermi gas
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-10-30 20:00 EDT
Eugen Dizer, Xin Chen, Richard Schmidt, Arthur Christianen
We consider a static dipolar impurity immersed in a Fermi gas and show how dipolar interactions shape both the few-body scattering properties and the resulting polaron physics. Using Fumi’s theorem, we connect the anisotropic phase shifts directly to the ground-state energy, and compute the exact impurity spectrum via the functional determinant approach. The resulting spectrum is a convolution of independent even- and odd-wave contributions, giving rise to a ground state with simultaneously occupied even- and odd-wave bound states whose separation is tunable via the dipole length. A variational ansatz limited to one particle-hole excitation fails to capture this doubly occupied ground state. We further find that long-range dipolar interactions weaken Anderson’s orthogonality catastrophe, reducing the power-law decay of the quasiparticle weight. These effects can be tested with ultracold polar molecules, where microwave shielding and independent tunability of interactions enable experimental access to the predicted regimes.
Quantum Gases (cond-mat.quant-gas), Atomic Physics (physics.atom-ph), Quantum Physics (quant-ph)
Chiral $p$-Wave Superconductivity Proximate to a Fractional Chern Insulator and a Topological Charge Density Wave in a Moiré Chern Band
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-30 20:00 EDT
We study a spin-polarized moiré Chern band of twisted MoTe$ 2$ with short-range repulsion, finding superconductivity proximate to a fractional Chern insulator at filling $ \nu=2/3$ and a topological charge density wave at $ \nu=3/4$ . Exact diagonalization reveals pair binding over $ 0.7\lesssim\nu\lesssim0.77$ , consistent with experiment, along with finite superfluid stiffness, chiral $ p$ -wave pairing correlations, and adiabatic connectivity to an attractive model. At weak repulsion, Kohn-Luttinger theory supports a Fermi-surface instability with the same pairing symmetry. The superconducting state has a Bogoliubov-de Gennes Chern number $ C{\mathrm{BdG}}=-1$ , opposite to the normal-state Chern number at $ \nu=1$ . Our results reveal interplay among superconductivity, fractional topology, and charge order.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
6 pages, 4 figures
High-throughput quantification of interfacial protein load in monodisperse oil-in-water emulsions
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-30 20:00 EDT
Varun Potdar (1), Alexander Favela (1), Michael Boehm (2), Stefan Baier (3), Siva Vanapalli (1) ((1) 1Department of Chemical Engineering, Texas Tech University, Lubbock, TX, USA, (2) Motif FoodWorks, Inc., Boston, MA, USA, (3) School of Chemical Engineering, The University of Queensland, Brisbane, QLD 4072, Australia)
Food proteins play a critical role as emulsifiers, where adsorption at the oil and water interface governs emulsion formation and stability. However, quantitative characterization of interfacial protein load remains challenging due to polydispersity in conventional emulsification methods. We combine microfluidic generation of monodisperse emulsions with colorimetric protein quantification to measure the post-collection initial interfacial load ($ \Gamma_0$ ) and subsequently monitored over 48 h to obtain the saturation load ($ \Gamma_\infty$ ). Interfacial load exhibited a strong bulk concentration-dependent trend and was well described by a pseudo-first-order model. Both $ \Gamma_0$ and $ \Gamma_\infty$ followed sublinear scaling with concentration ($ \Gamma_0$ ~ C^{0.21}$ , $ \Gamma_\infty$ ~ C^{0.12}$ ). Interfacial loads were largely independent of droplet diameter, with modest reductions in initial loading for the smallest droplets at low protein concentration. Measured loads exceeded idealized monolayer predictions and fell between bilayer and trilayer bounds, consistent with accumulation beyond a simplified monolayer model. Additionally, high-throughput mapping was performed across three proteins, seven concentrations, three pH values, and two ionic strengths, revealing that $ \alpha$ -Casein exhibited higher interfacial loads than $ \beta$ -Casein and Whey protein Isolate, with maximum adsorption near the isoelectric point and at elevated ionic strength. In summary, this study establishes a quantitative experimental framework for linking protein properties, formulation conditions, and interfacial behavior using monodisperse microfluidic emulsions, while requiring only milligram-scale protein quantities.
Soft Condensed Matter (cond-mat.soft)
26 pages, 7 figures
Quasi-Phases of Quantum Matter
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-30 20:00 EDT
Nick G. Jones, Paul Fendley, Nathanan Tantivasadakarn, Ruben Verresen
Within quantum many-body phase diagrams, continuous transition lines can appear and then terminate. However, it has remained unclear whether the neighboring regimes can be meaningfully described as distinct phases, akin to water and vapour, since any sharp characterization would have to go beyond the usual notion of phases of matter. We answer this in the affirmative by introducing quasi-phases: gapped regimes near a critical point that are connected in the broader phase diagram, but not by any gapped path accessible from small perturbations of the critical theory. The physical consequences include interface modes between regimes in the same phase of matter. More striking still, describing both the extended critical line and the gapped path connecting the regimes requires a bigger multicritical parent theory. In spin-chain examples with continuous terminating lines with central charge $ c=1$ , we find multicritical $ c=3/2$ and $ c=9/5$ orbifolds describing so-called ‘quotient symmetry protected’ and ‘representation symmetry protected’ topological phenomena. While one-dimensional symmetry-protected topological phases are labeled by projective representation classes, these quasi-phases can have interface modes carrying higher-dimensional linear representations. We turn this into a constructive principle through a weakening of the Lieb-Schultz-Mattis anomaly. Supporting distinct quasi-phases makes an unnecessary critical point infrared-necessary, even if it is unnecessary at the ultraviolet scale. This condition is more restrictive than simply having a codimension-one critical line, revealing richer structure within phases of matter than their conventional classification suggests.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
Odd Elasticity in Strain-Gradient Continua: Anisotropy Classification and Non-Hermitian Elastodynamics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-30 20:00 EDT
Odd elasticity extends continuum mechanics to active nonconservative systems containing internal energy sources, such as robotic active metamaterials with nonreciprocal feedback. Modeling these systems as effective continua requires relaxing Maxwell-Betti reciprocity, which results in stiffness tensors lacking major symmetry. In this contribution, we extend this framework to 3D strain-gradient odd elasticity to incorporate the length scales inherent in these heterogeneous systems. By applying the full hierarchy of 3D point-group symmetries along chiral and achiral branches, we derive the exhaustive set of fourth-, fifth-, and sixth-order odd elastic stiffness tensors. Further, utilizing the dynamic principle of virtual work, we formulate the equilibrium equations, higher-order boundary conditions, and the generalized acoustic tensor for elastodynamic analysis. The results demonstrate that nonreciprocal moduli survive even under full isotropy in the sixth-order stiffness, under hemitropy in the fifth-order stiffness, and under cubic symmetry in fourth-order stiffness. In contrast, the elastodynamic analysis reveals that under isotropic and hemitropic limits, despite the underlying odd stiffness moduli, the acoustic tensor remains unconditionally Hermitian. Non-Hermitian elastodynamics is shown to require anisotropy. By numerically analyzing a transversely hemitropic odd elastic continuum, we demonstrate that this symmetry reduction results in non-Hermitian elastodynamic phenomena including exceptional points in the dispersion spectra and active energy exchange through simultaneous amplification and attenuation of the elastic wave components. These results provide the necessary theoretical foundation for future multiscale homogenization frameworks for anisotropic strain-gradient active microstructures, and for the design of nonreciprocal strain-gradient metamaterials.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Other Condensed Matter (cond-mat.other), Soft Condensed Matter (cond-mat.soft), Classical Physics (physics.class-ph)
41 pages, 4 figures. Currently under peer review
Algebraic theory of abelian fractons and beyond
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-30 20:00 EDT
Wilbur Shirley, Evan Wickenden, Bowen Yang, Agnès Beaudry, Michael Hermele
We develop an algebraic theory of fusion, mobility, and statistics in abelian gapped fracton orders and topological phases. The framework generalizes the algebraic description of abelian anyons to systems with restricted-mobility and spatially extended excitations. We consider translation-invariant bosonic systems whose pointlike and extended excitations have finite fusion order. The basic objects are braided fusion complexes (BFCs): chain complexes encoding fusion and mobility, equipped with a braiding chain map encoding statistics. Their equivalence classes define braided fusion theories (BFTs). Our framework encompasses arbitrary translation-invariant Pauli codes, as well as all abelian anyon theories in two spatial dimensions, including chiral theories. We give evidence for the conjecture that every nondegenerate BFT can be realized as the excitation theory of a gapped phase and that the BFT describing such a phase is a phase invariant. We derive constraints on pointlike fusion and mobility, showing, for example, that neither the Pauli X nor Z sectors of the X-cube and anisotropic models can occur alone in a nondegenerate BFT. For nondegenerate theories with only pointlike excitations, we extract a simpler theory of mutual statistics, consisting of a fusion module and a map to its statistical dual. This theory of mutual statistics is an invariant of the BFT and, at odd fusion order, gives an equivalent description of the full braided fusion theory. We interpret remote detection as the generalization of mutual statistics to fracton orders. In the BFC setting, we give a precise formulation of the excitation-detector principle: every nontrivial excitation can be detected by an operator supported at spatial infinity, and every nontrivial detector detects some excitation. Assuming a unique infinite-space ground state, we prove that this principle is equivalent to nondegeneracy.
Strongly Correlated Electrons (cond-mat.str-el), Mathematical Physics (math-ph), Quantum Physics (quant-ph)
81 pages + 73 pages of appendices. 7 figures
Light-Cone Friedel Oscillations: a Window into van Hove Superconductivity
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-30 20:00 EDT
Archisman Panigrahi, Vladislav Poliakov, Leonid Levitov
Van Hove (vH) singularities can enhance superconductivity by generating a large pairing susceptibility. Yet, it remains challenging to experimentally establish whether pairing really occurs near these points. We show that the saddle-point dispersion near a vH point gives rise to a `light-cone’ vH-selective behavior of Friedel oscillations, which is drastically different from the familiar concentric circles. Each vH point maps onto its own real-space light-cone sector, allowing STM around a single impurity to measure whether—and how strongly—that saddle-point quasiparticle sector is gapped. A superconducting gap near vH points suppresses the oscillations in the directions corresponding to peaks in the gap function angular dependence, a behavior that provides a signature of vH-related pairing at STM-accessible length scales. This STM protocol, targeting vH superconductivity, is capable of determining whether superconducting pairing emerges near the vH points or elsewhere on the Fermi surface.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Renormalization for Robust Memory without Synchronization
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-30 20:00 EDT
Shashwat Chakraborty, Jong Yeon Lee
Local error correction can preserve classical information against noise, but protection under synchronized updates need not survive when sites evolve at independent random times. Establishing stability is particularly challenging when protection relies on the collective action of competing local rules. Here we develop a spacetime renormalization framework that reveals how independently acting local updates can collectively stabilize memory. We identify sufficient conditions under which the geometry of stable interfaces and suppression of defect propagation produce reliable erosion at large scales. Applying this framework, we prove stability of the asynchronous \textsf{R} squeezing code and introduce robust processes in two and three dimensions. In these systems, both encoded phases persist under sufficiently weak noise, even when the noise favors one phase. Our results provide a criterion for designing autonomous memories sustained by competing local stochastic dynamics.
Statistical Mechanics (cond-mat.stat-mech), Soft Condensed Matter (cond-mat.soft), Quantum Physics (quant-ph)
13 pages main
Variational wavefunctions for ideal anyon gas: superfluid and skyrmion Hall crystal
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-30 20:00 EDT
The ground state of an ideal gas of anyons with statistical angle $ \theta\in(0,\pi)$ is a long-standing open problem, with renewed interest from the recent observations of fractional Chern insulators. In this work we construct variational wavefunctions that build in the exact anyon statistics and combine theory-guided composite-boson, composite-fermion and parton wavefunctions with neural-network correlations on the sphere. For spinless and SU(2) semions we confirm the paired anyon superfluid, well below the best crystal states. At $ \theta=\pi/3$ liquids and crystals are closer in energy for the spinless case. For $ \theta=\pi/3$ anyons with SU(3) flavor, we find two candidates. One is a skyrmion Hall crystal, in which the anyons form an integer quantum Hall state in the effective magnetic field from the spin texture. The other is a chiral color superconductor of six-anyon clusters, the color-flavor-locked pairing descendant of a holon metal with SU(3) color gauge symmetry and SU(3) flavor symmetry; its wavefunction is a hyperdeterminant rather than a product of parton determinants. Within our variational ansatz the color superconductor has better energy than both crystals and the color-flavor locked phases with U(1)$ ^2$ and Z$ _3$ gauge groups. For twisted MoTe$ _2$ this suggests that the reentrant integer quantum anomalous Hall phase is the skyrmion Hall crystal of the doped anyons, and that the observed superconductivity may be the color superconductor, which can undergo a transition to an $ f+if$ BCS superconductor with a jump of the chiral central charge by 3.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
31 pages, 10 figures (2 in the main text), including Supplemental Material