CMP Journal 2026-09-14
Statistics
Nature: 1
Nature Materials: 1
Nature Nanotechnology: 3
Nature Physics: 3
Nature Reviews Physics: 1
arXiv: 79
Research Square: 1
Nature
Encoded and non-genetic protein variants expand human functional proteome
Original Paper | Proteome informatics | 2026-09-13 20:00 EDT
Vyacheslav Tretyachenko, Tehila Leiman, David Morgenstern, Yishai Levin, Omer Asraf, Orna Dahan, Dvir Dahary, Yitzhak Pilpel
Each stage of the Central Dogma contributes to proteome diversity through mechanisms such as heterozygosity, somatic mutations, transcriptional errors, and translational errors. As a result, a diverse array of protein variants can coexist within a single proteome, such as that of humans. However, until now, methods to detect, quantify, and evaluate the functional consequences of these variants have been lacking. Here we examined a large-scale proteogenomic dataset from 29 healthy human tissues and uncovered 13,910 confidently localized variants representing 7,215 unique single amino acid substitutions co-existing alongside their corresponding reference proteoforms 1.We found that the abundance of both genetic (SNP’s, somatic mutations) and mistranslated protein variants mirrors their allele frequencies in the human population. Moreover, we show that non-genetic substitutions may provide a distinct route for exploring protein sequence space, circumventing the mutational constraints imposed by the genetic code. In addition, we provide experimental validation of non-genetic substitution on selected purified proteins. We demonstrate specific and recurring non-genetic variation patterns upon amino acid starvation in proteome-wide analyses of cancer-derived cell lines and identify hundreds of substituted non-genetic proteoforms that recur consistently in multiple healthy individuals or map to annotated protein functional sites. We propose that these substitutions constitute a novel class of functional protein phenotypic variants. Collectively, our findings indicate that non-genetic amino acid substitutions in human proteins provide an abundant source to expanding the functional proteome.
Proteome informatics, Proteomics, Translation
Nature Materials
Microwave-to-optical transduction using magnon-exciton coupling
Original Paper | Magneto-optics | 2026-09-13 20:00 EDT
Pratap Chandra Adak, Iris E. McDaniel, Suvodeep Paul, Caleb Heuvel-Horwitz, Bikash Das, Vitali Kozlov, Kseniia Mosina, Arun Ramanathan, Xavier Roy, Zdeněk Sofer, Tian Zhong, Akashdeep Kamra, Arno Thielens, Andrea Alú, Vinod M. Menon
Quantum networks require coherent interfaces between microwave-frequency quantum systems and low-loss optical links. However, existing microwave-optical transducers often trade conversion efficiency against added noise, bandwidth and device integrability. Here we use magnon-exciton coupling in the layered antiferromagnet CrSBr to realize coherent microwave-to-optical transduction. Unlike previous magnon-based approaches that rely on intrinsically weak off-resonant magneto-optical effects, our scheme exploits strong light-matter interactions at exciton resonances. Driving the antiferromagnetic resonance with microwaves modulates the resonant excitonic susceptibility and generates coherent optical sidebands, detected using homodyne interferometry. Even in a bulk crystal without cavity enhancement, we observe coherent conversion over an intrinsically broadband ~300-MHz window. Multiple exciton-polariton resonances inherit the magnon-coupled response, indicating a route to broaden the usable optical detuning range and mitigate optical dissipation. Magnon-coupled excitons in layered magnets thus offer a scalable platform for broadband microwave-optical interfaces, with higher cooperativity achievable through reduced magnetic volume and cavity integration.
Magneto-optics, Polaritons, Quantum optics, Spintronics, Two-dimensional materials
Nature Nanotechnology
High-resolution intrinsically stretchable quantum-dot displays through thermally assisted intaglio transfer printing
Original Paper | Electronic devices | 2026-09-13 20:00 EDT
Jisu Yoo, Kyunghoon Lee, Ji Su Kim, Yunho Kim, Chansul Park, Jinhee Lee, Jiwon Kim, Sun-Woo Lee, Eonhyoung Ahn, Sonwoo Jung, Jung Duk Seo, Soyeon Lee, Yaewon Kim, Gwang Heon Lee, Kiwook Kim, Soo Ik Park, Daewon Yoon, Jongseok Bae, Changsoon Choi, Hyungju Ahn, Taek-Soo Kim, Dong Chan Kim, Dae-Hyeong Kim, Jiwoong Yang, Moon Kee Choi
Intrinsically stretchable light-emitting devices are promising for wearable displays, soft robotics and skin-mounted optoelectronics but are limited by the trade-off between mechanical softness, charge injection and pixel definition. Stretchable quantum-dot emissive layers offer narrow, colour-tunable emission from quantum-confined nanocrystals, yet elastomeric matrices introduce insulating barriers and viscoelastic deformation that compromise efficiency and high-resolution patterning. Here we report ligand engineering at the interface and thermally assisted intaglio film transfer printing (LIFT), a strategy for high-definition intrinsically stretchable quantum-dot light-emitting diodes. Selective replacement of the polymer-rich surface of quantum-dot nanocomposites with polar short-chain ligands forms a nanoscale interfacial region that lowers the hole-injection barrier while preserving bulk mechanical compliance. Thermal assistance concentrates strain at pattern boundaries, allowing clean cleavage of soft emissive films into high-fidelity pixel arrays. The devices achieve external quantum efficiencies of up to 23.9% in conventional architectures and fully stretchable QLEDs with a luminance of 53,300 cd m⁻2, an external quantum efficiency of 8.0% and stretchability beyond 65%. The method further produces arrays up to 16,000 pixels per inch and stretchable 12 × 12 multicolour passive-matrix displays.
Electronic devices, Lasers, LEDs and light sources, Quantum dots
Single-gate, multipartite entanglement on a room-temperature quantum register
Original Paper | Electrical and electronic engineering | 2026-09-13 20:00 EDT
Joseph D. Minnella, Mathieu Ouellet, Amelia R. Klein, Lee C. Bassett
Multipartite entanglement is an essential aspect of quantum systems, needed to execute quantum algorithms, implement error correction and achieve quantum-enhanced sensing. In solid-state quantum registers such as nitrogen-vacancy centres in diamond, entangled states are typically created using sequential, pairwise gates between the central electron and individual nuclear qubits. This sequential approach is slow and suffers from crosstalk errors. Here we demonstrate a parallelized multi-qubit entangling gate to generate a four-qubit Greenberger-Horne-Zeilinger state using a room-temperature nitrogen-vacancy centre in only 14.8 μs–ten times faster than that using sequences of two-qubit gates and close to the fundamental limit set by the hyperfine coupling frequencies. Parallel three-qubit gates are also realized with all-nuclear-qubit subsets. The entangled states are verified by measuring multiple quantum coherences. The four-qubit parallel gate has a fidelity of 0.92(4), whereas the sequential four-qubit gate fidelity is only 0.69(3). The approach is generalizable to other solid-state platforms, and it lays the foundation for scalable generation and control of entanglement in practical devices.
Electrical and electronic engineering, Quantum information, Semiconductors
Demonstration of on-chip all-optical switching of magnetization in integrated photonics
Original Paper | Applied physics | 2026-09-13 20:00 EDT
Pingzhi Li, Gijs W. A. Simons, Tianyu Zhang, Philip P. J. Schrinner, Sohrab Kamyar, Ronald Dekker, Diana C. Leitao, Reinoud Lavrijsen, Yuqing Jiao, Bert Koopmans
Ultrafast all-optical switching of magnetization holds great promise for next-generation spintronic memory and hybrid spintronic-photonic systems. However, most implementations so far have relied on bulky free-space optical setups, limiting scalability and practical integration. Here, as a critical step towards integrated applications, we demonstrate the single-pulse all-optical switching of magnetization within a silicon nitride photonic integrated circuit. Using trains of femtosecond laser pulses guided through on-chip waveguides, we achieve deterministic toggle switching in a submicrometre out-of-plane Co/Gd Hall cross patterned directly atop the photonic waveguide. Electrical read-out via the anomalous Hall effect reveals a switching contrast of up to 90% for 500-nm-wide devices. In larger Hall crosses, the contrast decreases and switching becomes stochastic, consistent with spatially non-uniform optical absorption as confirmed by finite-element simulations. This behaviour is hypothetically attributed to domain-wall relaxation and thermally assisted (de)pinning processes within partially switched regions. Our results highlight the critical role of device scaling in achieving robust on-chip all-optical switching of magnetization and establish a foundation for ultrafast, energy-efficient and fully integrated spintronic-photonic platforms.
Applied physics, Magnetic devices, Optics and photonics, Spintronics
Nature Physics
Electrification mechanisms in sliding liquid and frozen drops
Original Paper | Chemical physics | 2026-09-13 20:00 EDT
Rutvik Lathia, Benjamin Leibauer, Aaron D. Ratschow, Werner Steffen, Hans-Jürgen Butt
The microscopic and fundamental origin of slide electrification, which happens when water drops move across insulating surfaces while accumulating and depositing electrical charges, is still debated. Charge transfer is often attributed to ion transfer at the receding contact line. However, it remains an open question whether ion transfer alone can fully account for the observed charge separation. Here we examined slide electrification of polar, self-ionizing liquids and non-polar liquids. By cooling them below the melting temperature, we were able to compare this process to tribocharging of the respective frozen components. Despite reduced ion mobility at sub-freezing temperatures, the frozen polar compounds continued to accumulate substantial charge. Non-polar liquids exhibited lower charging and nearly identical charging behaviour in both their liquid and frozen phases on different substrates. As non-polar liquids contain few free ions, these observations indicate an alternative charging mechanism, which could be electron transfer. Our findings suggest that slide electrification operates through at least two mechanisms, with the dominant charge transfer pathway shifting between ions and electron transfer depending on electronegativity, phase and temperature.
Chemical physics, Wetting
Generation of a high-intensity, superthermal muonium beam for gravity and laser spectroscopy experiments
Original Paper | Exotic atoms and molecules | 2026-09-13 20:00 EDT
J. Zhang, A. Antognini, M. Bartkowiak, D. Goeldi, K. Kirch, A. Knecht, D. Taqqu, R. Waddy, F. Wauters, P. Wegmann, A. Soter
The universality of free fall, a cornerstone of Einstein’s theory of gravity, has so far only been tested with neutral composite states of first-generation standard model particles, such as atoms, neutrons and antihydrogen. Muonium, the bound state of a positively charged anti-muon and an electron, offers the possibility to probe gravity in the absence of the strong interaction with second-generation standard model particles. However, the short muon lifetime and the existing diffuse thermal muonium sources rendered such measurements unfeasible. Here we report the generation of a high-brightness muonium beam, which we extract from a thin layer of superfluid helium. The mean longitudinal velocity and narrow spread of the velocity distribution indicate a superthermal beam, and yields are similar to the highest-intensity diffuse sources. This beam is expected to enable muonium interferometry and a per-cent-level measurement of its gravitational acceleration. In addition, its unprecedented brightness opens the way to sub-kilohertz 1S-2S spectroscopy, enabling the precise determination of the muon mass and stringent tests of bound-state quantum electrodynamics.
Exotic atoms and molecules, Experimental particle physics, Matter waves and particle beams
An algorithm to generate two-dimensional critical lattice models using competing anyon condensation
Original Paper | Phase transitions and critical phenomena | 2026-09-13 20:00 EDT
Kaixin Ji, Yu Zhao, Ce Shen, Yidun Wan, Ling-Yan Hung
The critical behaviour at a second-order phase transition is often described by a conformal field theory. The restrictions imposed by conformal symmetry give rise to a number of important theoretical techniques that have made these theories central to the understanding of critical phenomena. However, efforts to classify conformal field theories have run into the challenge of identifying lattice models that have a corresponding critical point. Here we introduce an algorithm that we call a conformal field theory factory for methodically generating two-dimensional lattice models that would flow to conformal field theories in the infrared limit. We realize these lattice models by engineering the boundary conditions of three-dimensional topological orders described by string-net models. The critical points are induced by a commensurate condensation of non-commuting anyons. Our structured method generates an infinite family of critical lattice models, including previously unknown critical points. We recover known conformal field theories that preserve the Haagerup symmetries and identify three further candidate theories. The critical couplings of our models are precisely encoded in algebraic data associated with the string-net models, thereby establishing a scheme for discovering and potentially classifying conformal field theories.
Phase transitions and critical phenomena, Theoretical physics, Topological defects
Nature Reviews Physics
Microscale droplets for mechanical measurement and mechanotransduction in artificial and living systems
Review Paper | Biomedical engineering | 2026-09-13 20:00 EDT
Yuyan Su, Nicholas Su, Sangwoo Kim, Alexandre Persat, Hagan Bayley, Yujia Zhang
Despite advances in the investigation of nanoscopic mechanobiology and the development of macroscale mechanotransduction, methods capable of operating at the microscale remain limited. This Review describes the physical principles and engineering of microscale droplets, including liquid constructs and hydrated polymer (hydrogel) beads, which are emerging as versatile biointerfaces for mechanical measurement and mechanotransduction in living matter. The microscale compositions and mechanical properties of droplets recapitulate key aspects of cellular mechanical responses, enabling non-invasive mechanical detection. Furthermore, droplets can contain stimulus-responsive materials that enable the transduction of mechanical cues into diverse biochemical or bioelectrical outputs. Applications of microscale droplets include cellular force and viscoelasticity sensors deployed in intercellular or intracellular environments, as well as synthetic carriers for controlled drug release and the modulation of biological activities.
Biomedical engineering, Biophysical methods, Membrane biophysics
arXiv
Diagonal Pair Coulomb Density Matrix on a Sphere: a numerical study
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-09-14 20:00 EDT
We tabulate, on the diagonal, the $ n$ th power of the primitive approximation for the pair Coulomb density matrix on a sphere, with up to $ n=5$ , and we discuss its behavior at particles contact as $ n$ grows. Our results show that even on a curved surface quantum statistical physics is fundamentally different from its classical counterpart. If in the latter one needs to artificially introduce a regularization of the divergent attractive Coulomb potential preventing particles contact, for example with a hard core, in the former this is not necessary.
Statistical Mechanics (cond-mat.stat-mech), Strongly Correlated Electrons (cond-mat.str-el), Computational Physics (physics.comp-ph), Quantum Physics (quant-ph)
12 pages, 1 table, 1 figure
Multiple Majorana zero modes realization based on superconducting topological crystalline metal ZrRuAs
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-09-14 20:00 EDT
Xiaoxu Wang, Jinyu Zou, Gang Xu
The symmetry-protected multiple Majorana zero modes (MZMs) can be manipulated under external fields and have emerged as a promising pathway toward realizing topological quantum computing. While the suitable materials hosting multiple MZMs are still scarce, we propose a feasible candidate platform named superconducting topological crystalline metals (STCMs) that simultaneously possess symmetry-protected topological bands and intrinsic superconductivity. Model analyses demonstrate that the interplay among s-wave superconductivity, mirror symmetry-protected multiple surface Dirac cones, and the introduced spin splitting leads to high BdG Chern numbers of $ \mathcal{N} = \pm C_M$ , where $ C_M$ is mirror Chern number of the STCM. First-principles calculations identify the experimentally synthesized superconductor ZrRuAs as a promising candidate with $ C_M=2$ , hosting two symmetry-protected surface Dirac cones. When integrated into a heterostructure with the ferromagnetic insulator (FMI) such as GdI$ _{2}$ , a topological superconducting phase with $ \mathcal{N} = -2$ can be realized, giving rise to two branches of MZMs. This new scheme offers advantages of structural simplicity and tunability, making the FMI/STCM heterostructure an ideal platform for investigating multipole MZMs and novel topological qubit.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
6 pages, 4 figures
Disordered hyperuniform modulated phases and the cosmic web from one free energy
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-09-14 20:00 EDT
Disordered hyperuniformity spans twenty-five orders of magnitude, from the microscopic world of soft and condensed matter to the distribution of matter in the universe. We introduce a free-energy functional with no adjustable coupling, a phase-field-crystal ordering term and a Newtonian tail, and show that its two kinetic limits generate two of these structures. Under conserved overdamped dynamics it arrests in a bicontinuous labyrinth of the kind found in confined fluids, block copolymers, active matter and vegetation patterns, which is a class III disordered hyperuniform state; under inertial dynamics in an expanding background it generates a cosmic web whose tidal skeleton matches that of gravity alone to within $ 0.03$ in every morphological class. In both limits the suppressed long-wavelength fluctuations are inherited from the initial condition rather than made by the dynamics: the large-scale exponent of the arrested state equals the primordial one, and gravity rescales the infrared spectrum by the linear growth factor to better than one per cent over a factor $ 1363$ of growth. The two sectors are continuously connected, and their distance is measurable: once the ordering modulation saturates, its mean-field back-reaction leaves the medium with a residual pressure proportional to $ \lambda_0^2$ that suppresses the growth of the largest scales by a smooth factor and vanishes in the cold-matter limit $ \lambda_0\to0$ .
Statistical Mechanics (cond-mat.stat-mech)
Crystallographic and Electronic Phase Changes in TiTe2 via Atmospheric and Electron Beam Exposure
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-14 20:00 EDT
Bishal Pokhrel, Joel Quarnstrom, Saraswati Shrestha, Halle Helfrich, Elena Echeverria, David N. McIlroy, Andrew J. Yost
In this study, we examine the surface sensitivity of a transition metal dichalcogenide (TiTe2) grown using the Chemical Vapor Transport (CVT) technique at high pressure and study the surface changes in the sample upon exposure to air as well as its crystallographic properties upon e-beam exposure. We examine the local density of States (LDOS) of the mechanically exfoliated sample surface before and after exposure using Scanning Tunneling Microscopy/Spectroscopy (STM/STS) and find a metal-to-semiconductor transition at the surface. The STM analysis shows a clear change in surface roughness which indicates the formation of an adlayer on the surface of the sample. The crystal structure was examined using X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM), indicating a phase transition from a single-crystalline hexagonal phase to a polycrystalline state via a distorted monoclinic phase. Furthermore, the presence of a possible superlattice suggests non-stoichiometric TixTey at the surface of the exposed layer.
Materials Science (cond-mat.mtrl-sci)
15 pages, 9 figures
Catastrophes, Optical Multistabilities, and Chiral Photocurrent Hysteresis in Driven Weyl Semimetals
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-09-14 20:00 EDT
Christopher Yang, Gil Refael, Frederik Nathan
The unique band topology of Weyl semimetals provides them with a diverse array of strong photovoltaic response phenomena. Here we explore how plasma screening affects these phenomena. We find that the screening field is highly nonlinear, can contain topological contributions, and can amplify the photoresponse, with the self-consistent response exhibiting the hallmarks of bistability, including hysteresis and catastrophes. The bistability emerges from a crossover from linear to saturated polarization as a function of the field amplitude, because carriers in a Weyl cone have bounded group speed $ v_F$ . When time-reversal symmetry is broken, tilted Weyl nodes add a Berry-curvature contribution to the in-plane current, making the nonlinear screening response helicity selective.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
9 pages, 7 figures + supplemental materials
Remarks on invertible phases with non-onsite symmetry
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-09-14 20:00 EDT
Ryohei Kobayashi, Kansei Inamura, Ken Shiozaki
We study invertible phases protected by non-onsite symmetries carrying nontrivial lattice anomaly indices. While lattice anomalies are usually viewed as obstructions to symmetric short-range-entangled (SRE) states, we show that anomalous lattice symmetries can nevertheless admit invertible phases that are not SRE, and can moreover shift the set of symmetry-compatible invertible phases. In particular, we consider a fermionic $ \mathbb Z_4^F$ symmetry in (2+1) dimensions. For an onsite $ \mathbb Z_4^F$ symmetry, symmetric invertible phases have integer chiral central charge $ c_-\in\mathbb Z$ , whereas a non-onsite symmetry with nontrivial lattice anomaly index obstructs all such phases despite having trivial continuum ‘t Hooft anomaly. We resolve this by constructing an exact exponentially quasi-local $ \mathbb Z_4^F$ symmetry of a $ p+ip$ superconductor with $ c_-=1/2$ . We compute its lattice anomaly, and find that the symmetry indeed forbids $ c_-\in \mathbb{Z}$ invertible states. The allowed invertible phases are consequently shifted to $ c_-\in\mathbb Z+1/2$ . By gauging the fermion parity of the $ p+ip$ superconductor, one obtains an Ising topological order enriched by a $ \mathbb Z_4$ symmetry. We describe the corresponding symmetry structure in terms of a fusion 2-category. We further show that the $ p+ip$ state admits an enlarged non-onsite $ U(1)^f$ symmetry, providing an analogue of fractional quantum Hall response in an invertible phase. This non-onsite $ U(1)^f$ symmetry again forbids Chern insulators carrying $ c_-\in\mathbb{Z}$ , while being compatible with invertible states with $ c_-\in\mathbb{Z}+1/2$ . This result motivates a systematic study of new classes of invertible phases and spin liquids enriched by non-onsite symmetries.
Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Theory (hep-th), Quantum Physics (quant-ph)
16 pages
Optimized quantum state transfer in a quasiperiodic ultracold atomic gas
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-09-14 20:00 EDT
Andreas Völkering, Arnob Kumar Ghosh, Patric Holmvall, Paolo Molignini
Ultracold atomic systems offer a highly controllable platform for investigating quantum state transfer through the precise dynamical manipulation of system parameters. While quantized Thouless pumping has been extensively explored in these systems, adiabatic edge-to-edge transfer of localized quantum states remains largely unexplored. Here, we consider a one-dimensional ultracold atomic gas confined in a bichromatic optical lattice realizing a quasiperiodic Aubry–André–Harper system. We use its edge-localized winding states to implement quantum state transfer between opposite boundaries. Starting from the instantaneous spectral properties of the corresponding tight-binding model, we construct locally adiabatic protocols and extend the approach to higher protocol orders. We then simulate their dynamics under the full continuum bichromatic-lattice Hamiltonian. Our results reveal a tradeoff between edge localization and the minimum spectral gap: strongly localized states require longer transfer times, but can benefit substantially from higher protocol orders. We are also able to capture the main fidelity trends and coherent oscillations over a broad parameter regime using an effective two-level Landau–Zener description. Our results provide practical guidelines for selecting experimentally accessible parameters and tailoring quantum transfer protocols in quasiperiodic ultracold atomic systems.
Quantum Gases (cond-mat.quant-gas), Disordered Systems and Neural Networks (cond-mat.dis-nn), Quantum Physics (quant-ph)
25 pages, 16 figures
Staying positive: bounds for non-Gaussian noise in Schwinger-Keldysh effective field theory
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-09-14 20:00 EDT
Andrea Amoretti, Daniel K. Brattan
Modern effective field theories of dissipative hydrodynamics, built on the Schwinger-Keldysh (SK) formalism, include thermal noise that is not Gaussian. The resultant higher-order noise vertices are constrained by symmetries, but otherwise treated as free parameters. We show explicitly that symmetry constraints alone do not guarantee these vertices yield a genuine probability distribution. Requiring a probability interpretation yields sharp bounds between cumulants that are invisible to the symmetry analysis. The bounds are optimal: their boundaries are attained by explicit positive distributions, and constructive completions are provided for both negative- and positive-kurtosis noise data. This gives closed-form nonlinear response and an exact sampling algorithm, whose Monte Carlo implementation reproduces the exact cumulants and nonlinear fluctuation-dissipation relations. Confronted with microscopic results, the framework places a sharp lower bound on the time step required for a positive stochastic completion of a quartic model of the Brownian particle used in the literature, while holographically computed $ SU(2)$ noise vertices pass a nontrivial continuum fourth-order positivity test.
Statistical Mechanics (cond-mat.stat-mech), High Energy Physics - Theory (hep-th)
6 pages, 2 figures + 12 pages supplemental material
Real-space Visualization of Emergent Electron Crystals in Rhombohedral Graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-09-14 20:00 EDT
Yiming Sun, Jinghao Deng, Jiabin Xie, Donghan Ge, Hongyuan Li, Takashi Taniguchi, Kenji Watanabe, Xiaomeng Liu
Strongly interacting electrons can spontaneously break spatial symmetries to form electron crystals, exemplified by the Wigner crystal. Recent studies of topological flat bands in rhombohedral graphene have suggested more exotic forms of crystallization, including anomalous Hall crystals that entangle charge order with nontrivial topology and metallic electron crystals in which localized and itinerant carriers coexist. Direct real-space observation of these states, however, has remained elusive. Here we use scanning tunneling microscopy and spectroscopy to visualize emergent electron crystals in rhombohedral hexalayer graphene. At low electric fields and over a finite range of hole doping, we observe electronic lattice patterns that evolve from honeycomb to oblique order through a first-order quantum phase transition with increasing hole density. The Fermi surface extracted from quasiparticle-interference measurements lacks the geometry needed to account for these patterns through conventional nesting. Together with metallic transport and a crystal-site density much lower than the doped carrier density, this supports metallic electron crystals in which a subset of carriers crystallizes. The honeycomb crystal occupies the same phase space as the multiferroic orbital magnetism observed previously in transport and exhibits domain stabilization by a small magnetic field, which may suggest a possible metallic anomalous Hall crystal. With increasing magnetic field, the oblique phase develops a $ \sqrt{2}\times\sqrt{2}$ reconstruction with a crystal-sublattice energy splitting that increases linearly with field, corresponding to a $ g$ -factor of 16. This may reflect an orbital-antiferromagnetic electron crystal with alternating orbital magnetization across the lattice. These results establish a new paradigm of electron crystallization in which charge order is intertwined with orbital magnetism.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
33 pages, 5 main figures, 13 extended figures
Breakdown of Multipole Expansion in Emergent Electromagnetism
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-09-14 20:00 EDT
Tom Ben-Ami, Markus Heyl, Roderich Moessner
We find a striking departure from simple electrostatics in a family of two-dimensional lattice models whose effective description takes the form of an emergent electromagnetism: a high-order multipolar charge configuration can induce an electric field characteristic of a \textit{lower-}order multipole. Studying the archetypical hardcore dimer and U(1) spin-1/2 link models, we trace this to a breakdown of the superposition principle: for dense charge configurations, there can be a nonlinear suppression, or even enhancement, of the far field compared to the linear expectation. Our work establishes that microscopic lattice-scale constraints in models for emergent electromagnetism can change the far-field behaviour to differ from often utilized long-wavelength descriptions in standard effective continuum models.
Statistical Mechanics (cond-mat.stat-mech), Soft Condensed Matter (cond-mat.soft)
5+6 pages, 4+4 figures
Unusual phase coexistence regime across the ferroelectric - paraelectric transition
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-14 20:00 EDT
M. Kopecký, J. Kub, E. de Prado, J. Hlinka
A PbTiO3 epitaxial thin film grown on a DyScO3 substrate was studied by x-ray diffraction in the temperature range of 20-500 degrees Celsius. It is found that the ferroelectric to paraelectric phase transition proceeds through a peculiar transitional coexistence state extending between 402 degrees Celsius and 414 degrees Celsius. Within this temperature interval, at a temperature of 405 degrees Celsius, a domain structure transition occurs, at which the three-domain c/a1/a2 polytwin phase transforms into an ordinary c/a2 twinned phase. It is proposed that the coexistence of two independent twinned phases with the paraelectric phase is enabled by vertical strain gradients in the film.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
6 pages, 4 figures
Hierarchical Prototype Emergence in Modern Hopfield Models
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-09-14 20:00 EDT
Hierarchical correlations are a universal feature of any realistic model of data, and the question of how associative memory models may learn these correlations and generalize beyond them to construct new sensible images is an important step towards understanding more complex modern architectures such as diffusion models. We consider a hierarchical model for memories which are sampled and stored in a dense Hopfield network with polynomial activation. We analytically derive conditions for each level of this hierarchy to be locally stable - that is they are local energy minima. We use prototype reconstruction as a minimal model of generalization and we find that it takes only a quasi-polynomial amount of information to generalize beyond particular memories and even particular groups in the hierarchy. We observe a qualitatively analogous phase diagram in the number of memories, sharpness of the activation function (polynomial degree) for data from Fashion-MNIST.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Artificial Intelligence (cs.AI), Machine Learning (cs.LG)
5 pages, 19 page supplementary information. Additional citation requests welcome
Orbital-geometric spin response: inter-band coherence versus orbital-to-spin conversion
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-09-14 20:00 EDT
Orbitronics seeks to convert orbital angular momentum (OAM) into spin, but its microscopic dynamics is not understood. Here I show that, at moderate spin-orbit coupling, an electrically induced spin density contains a direct term and an \textit{orbital-geometric spin response} (OGSR) due to inter-band coherence of the spinless parent Hamiltonian—related to OAM but not descended from it. In massive Dirac fermions the OGSR survives as the net OAM vanishes, and generates \textit{counterflow}, opposing the direct response. These results provide guidelines for optimising orbitronic systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Models and Measures of Statistical Physics and Sociophysics for Fracture Mechanics and Earthquake Dynamics: An Introduction
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-09-14 20:00 EDT
Sudip Sarkar, Soumyajyoti Biswas, Bikas K. Chakrabarti
The breaking or fracture of materials and damages or devastations due to earthquakes have caught our attention since the earliest stage of human civilization. In fact, at around 1500, Leonardo Da Vinci made the pioneering observation that, unlike elastic constants (formalized later by Hooke in 1678) of the materials, the tensile (breaking) strengths of nominally identical iron wires decrease drastically with their length, indicating the vanishing breaking strength of materials in the large size limit, suggesting the impossibility of constructing arbitrarily large structures. This was the first observation that unlike the elasticity of disordered materials, which remains defined in the thermodynamic limit (self averaging statistics), the breaking properties of the disordered materials have extreme (non self averaging) statistics. In spite of major and some precise developments in statistical physical modelling and characterizing the fracture mechanics (starting with Allan Griffith’s crack nucleation theory in 1921 and the weakest link failure Fibre Bundle Model of Frederick Thomas Peirce in 1926) and of earthquake dynamics (starting with Robert Burridge and Leon Knopoff’s continuum dynamical model in 1967 and later other discrete or lattice train models or fractal overlap models of stick slip earthquakes), no graduate level textbook in condensed matter physics or in statistical physics introduces the basic models and their properties. And now computer scientists and social scientists (coming with their social inequality measures applied to the avalanche statistics in precursor failures) are joining their efforts to explore the new precursory inequality measures for big avalanches or failures. This introductory review is designed to fill this gap with a view to introducing these to this wider audience and to take them to the current frontiers in these fields.
Statistical Mechanics (cond-mat.stat-mech)
40 pages, 24 figures. This is an invited review article for Frontiers in Physics
Topological chirality of dissipative limit cycles in an open Dicke model
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-09-14 20:00 EDT
Nikolay Yegovtsev, Sayan Choudhury, W. Vincent Liu
In an open, $ U(1)$ -symmetric Dicke model with chiral atom-cavity couplings, we show that dissipation drives two limit-cycle phases of opposite chirality in the thermodynamic limit, obtaining exact analytical solutions. These phases are separated by a $ U(1)$ -broken superradiant state, lending the phase diagram a topological character, and persist under $ U(1)$ -preserving perturbations, making them candidates for chiral continuous time crystals. In addition to stable normal and inverted steady states, the model also exhibits multistability, where the long-time dynamics is set by the initial state. Our results establish dissipation as a resource for inducing chiral dynamical order in light-matter coupled systems.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
4.5 pages (main), 3 figures, 5 pages (suppl.)
Colloidal shadows reveal hidden solute transport
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-09-14 20:00 EDT
Haoyu Liu, Zehao Chen, Amir A. Pahlavan
An object releasing a chemical into a surrounding flow leaves behind a plume that encodes the rate of release, but for most solutes, that plume is invisible. Classical transport theory describes this configuration through a self-similar concentration boundary layer whose structure has never been resolved experimentally in forced flow at low Reynolds number: a century of measurements at these conditions has returned integrated transfer rates rather than the field itself. Here we show that both the field and the information it carries are experimentally accessible. Around hydrogel posts photopatterned inside a microfluidic channel, a released solute drives suspended colloidal particles away by diffusiophoresis, i.e., their drift along chemical gradients, carving a particle-free ``shadow’’ downstream. Using a fluorescent solute, we resolve the concentration field around the post and recover the classical self-similar structure of convective mass transfer. For an invisible surfactant, the width of the shadow, benchmarked against a directly imaged solute on the same platform, then serves as a proxy for the dimensionless rate of mass transfer from the post. Finally, comparing two orientations of a triangular post tests a classical prediction by Brenner: the local concentration fields rearrange, yet no orientation dependence of the integrated transfer rate is resolved. For solute–tracer pairs whose diffusiophoretic response is known, colloidal shadows thus turn ordinary tracer particles into quantitative reporters of chemical exchange that cannot be observed directly.
Soft Condensed Matter (cond-mat.soft), Chemical Physics (physics.chem-ph), Fluid Dynamics (physics.flu-dyn)
Collective Behavior of Intelligent Active Brownian Particles in the Presence of a Static Obstacle
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-09-14 20:00 EDT
Surya Narayan Sahoo, Arabinda Bera, Jiarul Midya
Using computer simulations, we investigate the collective behavior of two-dimensional active Brownian particles (ABPs) with excluded-volume interactions in the bulk and in the presence of a single static circular obstacle. Perception-mediated interactions are introduced through a vision-based steering mechanism that enables each particle to reorient its propulsion direction according to the instantaneous positions of neighboring particles within a prescribed vision cone. In the bulk, these intelligent active Brownian particles (iABPs) exhibit distinct collective states, including aggregated clusters, worm-like chains, worm-aggregate coexistence, and dilute gas phases. We characterize these states using a shape anisotropy parameter and construct the corresponding phase diagrams. The presence of a static obstacle, which interacts with the particles through purely repulsive forces, qualitatively alters their collective behavior. In contrast to conventional ABPs, whose isotropic accumulation around the obstacle increases with activity, iABPs exhibit the opposite trend, with boundary accumulation decreasing as the activity increases. We further identify empirical scaling relations that describe particle accumulation and cluster formation at the obstacle boundary. Consequently, the relative effective diffusion coefficient of iABPs displays a nonmonotonic dependence on self-propulsion speed, whereas that of conventional ABPs decreases monotonically with increasing activity. In addition, we show that the residence times of iABPs are orders of magnitude shorter than those of conventional ABPs, indicating that perception-mediated interactions can be useful for controlling the organization and transport of active particles in complex environments.
Soft Condensed Matter (cond-mat.soft)
11 pages, 9 figures
Functionalization-Driven Charge Redistribution Enabling Ultra-High-Capacity V2B MBene Anode for Li/Na ion batteries: A First-Principles study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-14 20:00 EDT
Amid increasing global demand for clean, sustainable energy, the search for novel electrode materials has emerged as a crucial link to advancing future energy storage technologies. Here, we explored the potential of N-functionalized 2D MBene V2BN2 as anode materials for Li- and Na-ion batteries using first-principles calculations. Phonon dispersion and ab initio molecular dynamics calculations were employed to assess the dynamic and thermal stability of the material. The intrinsic metallic properties of V2BN2 were revealed through electronic band structures and density of states analyses. Importantly, Bader charge analysis demonstrates substantial charge redistribution upon Li/Na adsorption, leading to stronger ion-substrate interactions compared to the pristine counterpart. This redistribution plays a decisive role in enhancing Li/Na ion adsorption and stabilizing ion accommodation. Furthermore, owing to favorable multilayer adsorption of Li and Na ions, V2BN2 exhibited high theoretical specific capacities of 1524 and 762 mAh/g, as well as low open circuit voltages of 0.73 and 0.23 V for Li and Na, respectively. In addition, the energy barriers were calculated to be 0.49 and 0.29 eV for Li- and Na-ion transport, respectively, indicating rapid ion transport and excellent rate capability. These results indicate that V2BN2 holds significant potential as an anode material for next-generation rechargeable ion batteries.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph), Computational Physics (physics.comp-ph)
Different critical exponents on two sides of the magnetic transition in two dimensions
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-14 20:00 EDT
P. Biswal, Ruma Khatun, G. Tripathy, Diptikanta Swain, D. Samal
The possibility of different critical exponents on two sides of a magnetic transition has been theoretically predicted [PRB 13, 2222 (1976), PRL 115, 200601 (2015)] and experimentally realized [PRL 128, 015703 (2022)] in three-dimensional systems. However, the emergence of such a scenario in two dimensions is not yet established. Here, we report distinct two-dimensional (2D) critical exponents below and above the magnetic transition temperature (TC) through critical scaling analysis in a quasi-2D non-centrosymmetric, Dzyaloshinskii-Moriya interaction (DMI) active hybrid perovskite (C7H9NBr)2CuBr4. The system exhibits critical exponents of 2D Ising-type below TC and 2D XY-type above TC . In contrast, isostructural Cl and centrosymmetric Br analogs, in which the DMI effect is expected to be weaker, exhibit symmetric 2D critical behavior. These results highlight the crucial role of DMI in (C7H9NBr)2CuBr4 as a symmetry-breaking perturbation that alters the magnetic critical behavior differently above and below TC . Our study is the experimental realization of hitherto unreported asymmetric 2D critical behavior in structurally flexible and dimensionally tunable hybrid perovskites.
Materials Science (cond-mat.mtrl-sci)
Pseudo-hybrid density functional ACBN0 for Hubbard $U$ correction in a numeric atom-centered orbital basis
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-14 20:00 EDT
Svetlana A. Artiukova, Ilia M. Odud, Sergey V. Levchenko
We present a formulation and implementation of the Agapito-Curtarolo-Buongiorno Nardelli (ACBN0) pseudo-hybrid density functional in a numeric atom-centered orbital basis. The method is realized in the all-electron, full-potential electronic-structure package FHI-aims. The implementation uses a Löwdin-orthogonalized projector, which improved the stability of the self-consistent ACBN0 iterations for the tested systems. For a benchmark set of materials including metal oxides and nitrides, ACBN0 with the fully localized limit (FLL) as the double-counting treatment reduces the aggregate band gap errors relative to the Perdew-Burke-Ernzerhof (PBE) and strongly constrained and appropriately normed (SCAN) functionals, reaching an accuracy comparable to the Heyd-Scuseria-Ernzerhof functional (HSE06). For six bulk transition metal oxides calculated with the same numerical settings, an HSE06 iteration is approximately 13-33 times as expensive as the corresponding ACBN0@PBE iteration with Petukhov mixing. The applicability of the localized-basis implementation to low-dimensional systems is demonstrated by calculations of adsorption and the oxygen evolution reaction (OER) overpotential on a $ \beta$ -NiOOH(001) surface. On regularized SCAN (rSCAN) relaxed structures, single point ACBN0 based on rSCAN (ACBN0@rSCAN) with the ``tight’’ numerical settings reduces the mean absolute deviation of the reaction-step energies from HSE06 and shifts the estimated overpotential toward the HSE06 and Perdew-Burke-Ernzerhof hybrid (PBE0) reference results.
Materials Science (cond-mat.mtrl-sci)
28 pages, 7 figures
Selective coupling of coherent phonons to intertwined charge-orbital and magnetic orders in doped manganites
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-09-14 20:00 EDT
X. Liu, M. Sander, S.-W. Huang, S. Zerdane, A. Caviezel, M. Rössle, J. Lu, D. Babich, S. Shin, E. Pomjakushina, P. Marsik, L. Wang, S. W. Cheong, C. Jia, P. Beaud, H.T. Lemke, U. Staub, R. Mankowsky
Strongly correlated materials feature technologically relevant functionalities such as high-temperature superconductivity and colossal magnetoresistance, which emerges from the competition and coexistence of electronic and magnetic phases. Uncovering the microscopic interactions underlying these phenomena remains challenging because spin, orbital, charge, and lattice degrees of freedom are inherently intertwined. Here, by combining time-resolved X-ray diffraction and polarization-resolved ultrafast optical reflectivity in La1/4Pr3/8Ca3/8MnO3, we reveal that coherent phonon modes can selectively track different ordered phases: the in-plane phonon response is predominantly sensitive to charge/orbital order, and the c-axis phonon response is sensitive to magnetic order. Moreover, a ferromagnetic-related hysteresis emerges even when solely probing the charge/orbital-ordered phase, indicating a strong microscopic coupling between the spatially separated charge/orbital-ordered and ferromagnetic-ordered phases. These results demonstrate that coherent phonons provide a direct time-domain route to disentangle intertwined electronic and magnetic dynamics in coupled phases.
Strongly Correlated Electrons (cond-mat.str-el)
Geometric Approach to the High-Throughput Identification of Honeycomb Materials
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-09-14 20:00 EDT
Lex M. Rouquette, Alannah M. Hallas
The honeycomb lattice is an iconic structural motif in condensed matter physics. However, emerging theoretical models require the identification of new honeycomb lattice materials with strict specification on their structural, magnetic, and electronic characteristics. In this work, we introduce a filtering algorithm using simple geometric arguments to detect materials with honeycomb structural motifs. We classify four unique categories of lattices: conventional honeycombs, hyperhoneycombs, staircase or zigzag honeycombs, and fully 3D honeycombs. We also identify several distortion motifs in the conventional honeycomb set: elongated, sheared, and buckled honeycombs. We describe several screening criteria for further analysis of honeycomb systems, specifically the quantification of exfoliability in 2D materials, the identification of magnetic honeycombs, and a density-of-states peak quality metric for identification of electronic instabilities. The database containing the results of the filters and subsequent analysis is a useful tool for identifying novel materials for targeted physical phenomena for experimental characterization.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
11 pages, 8 figures
Self-organisation in hard-soft granular mixtures
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-09-14 20:00 EDT
Haoran Jiang, Dominik Krengel, Takashi Matsushima, Raphael Blumenfeld
Self-organisation of granular systems is a key determinant of their macroscopic behaviour and has been studied extensively in assemblies of hard particles. We use numerical simulations to test this understanding in mixtures of hard and soft particles, focusing on cells, the smallest irreducible loops of the contact network, as structural descriptors. We show that, while the cell statistics display robust qualitative features under isotropic compaction, they depend on inter-particle friction, $ \mu$ , and soft-particle fraction, $ \kappa$ . Specifically, (i) the quadron area distributions retain a $ \Gamma$ form, albeit with parameters that vary systematically with $ \mu$ and $ \kappa$ . (ii) Predictions of the cell order distribution (COD) by maximising the entropy, without taking mechanical stability into consideration, become increasingly inaccurate at large cell orders. (iii) Irrespective of $ \mu$ , the normalised cell stress distributions collapse onto one master Weibull form, whose only shape parameter depends weakly on $ \kappa$ . This suggests a quasi-universal form that may deteriorate slightly at very high fractions of soft particles. (iv) Cells align preferentially along the local major principal stress direction, showing the same coordinated stress–structure self-organisation as in hard particles. The relative robustness of cell statistics to the addition of soft particles suggests that hard and hard–soft granular mixtures can be described by one model.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
11 pages, 18 figures
$Ab$ $initio$ Study of Substitutional Defects in Li$_{3}$OCl Solid Electrolyte for Li-ion Batteries
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-14 20:00 EDT
Carson D. Ziemke, Naveed Naemi, Ha M. Nguyen, Anthony Dorhauer, Carlos Garcia, Narendirakumar Narayanan, Yangchuan Xin, John Gahl, Thomas W. Heitmann, Carlos Wexler
Improving ion transport in solid electrolytes and cathode coatings remains a key challenge for all-solid-state Li-ion batteries because their room-temperature ionic conductivity is still substantially lower than that of liquid electrolytes. In our previous combined experimental and theoretical study, we showed that thermal neutron irradiation enables defect engineering in LiBO$ _2$ through the transmutation of $ ^6$ Li and $ ^{10}$ B, generating lattice vacancies that enhance ionic conductivity. Here, we examine whether this approach can be extended to Li$ _3$ OCl, a representative antiperovskite solid electrolyte. Using density functional theory, we investigate substitutional defects at Li sites involving B, He, and H, associated with B doping and the neutron-capture reactions $ ^{6}\mathrm{Li}+n\rightarrow,^{3}\mathrm{H}+\alpha$ and $ ^{10}\mathrm{B}+n\rightarrow,^{7}\mathrm{Li}+\alpha+\gamma$ . We evaluate defect formation energetics, the resulting structural distortions, and compare these substitutional defects with other mono-, di-, and trication substitutions at Li sites. Our results show that substitutional defects associated with neutron irradiation provide a feasible route to tune the defect chemistry of antiperovskite solid electrolytes and support neutron-driven defect engineering as a strategy for developing advanced materials for high-performance all-solid-state Li-ion batteries.
Materials Science (cond-mat.mtrl-sci)
3 Figures, 2 tables, 23 pages
ACS Applied Energy Materials 2026
Deterministic patterning and alignment of tellurium quantum wires using nanoscale templates
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-14 20:00 EDT
I K M Reaz Rahman, Scott Dhuey, Moniruzzaman Jamal, Taehoon Kim, Naoki Higashitarumizu, Selven Virasawmy, Aidar Kemelbay, Genki Ohkatsu, Aditya Nirmale, Inha Kim, Hyong Min Kim, Karen C. Bustillo, Joel W. Ager III, Daryl C. Chrzan, Mary Scott, Yutaka Majima, Ali Javey
Tellurium (Te) is an intriguing one-dimensional (1D) semiconductor that has recently attracted considerable interest as a p-type channel material. However, scalable synthesis methods have lacked control over the orientation and patterning of the Te atomic chains, thus limiting its practical use. Guided by theory, we overcome this challenge using nanowire-shaped templates to achieve oriented, single-crystal growth of Te on amorphous substrates. Strong alignment of Te atomic chains is achieved as template widths are reduced to sub-20 nm. This high structural order, confirmed by 4D scanning transmission electron microscopy, enables the observation of pristine quantum transport phenomena for deterministically patterned Te. Field-effect transistors exhibit well-defined conductance plateaus at 77 K due to population of individual 1D subbands. Furthermore, Coulomb blockade emerges at 1.7 K, with the Te channel acting as a gate-tunable quantum dot. This synthesis approach provides a scalable pathway for integration of Te-based quantum materials for future electronic and quantum technologies.
Materials Science (cond-mat.mtrl-sci)
Irreducible sub-nm$^2$ ferroelectric domains by 2D-flat polar band in perovskite superlattices
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-14 20:00 EDT
Flat polar phonon bands in ferroelectrics have been envisioned to realize irreducibly small domains for achieving the highest memory density. However, such bands are extremely rare, with only a one-dimensional flat polar band discovered in ferroelectric hafnia, which gives rise to irreducibly narrow, line-type domains with a half-unit-cell width of 2.7 Angstrom. Here, we report the discovery of a two-dimensional flat polar band in the ferroelectric (BaTiO$ _3$ )$ _1$ /(BaXO$ _3$ )$ _1$ superlattice (X = Zr, Sn), which generates extremely localized, noninteracting dipoles within its quarter-unit-cell area that form quasi-degenerate states of irreducible sub-nm$ ^2$ ferroelectric domains. The estimated ferroelectric domain density, exceeding 300 Tbit/cm$ ^2$ (assuming one bit per domain) represents a record high among the known ferroelectrics, with independently switchable dipoles at low voltages. The ferroelectric phase hosting two-dimensional flat bands constitutes a competing ground state across superlattice stacking directions and thus can be experimentally realized in both freestanding structures and epitaxial growth on MgO substrates. This discovery opens unprecedented opportunities to explore multidimensional flat polar bands in ferroelectrics and to engineer ultra-dense and low-power memory devices.
Materials Science (cond-mat.mtrl-sci)
This manuscript has 18 pages and 4 figures
Emergent magnetism, heavy electrons and pressure-induced reentrant superconductivity in the iron substituted 4d transition-metal sulfides
New Submission | Superconductivity (cond-mat.supr-con) | 2026-09-14 20:00 EDT
Yalei Huang, Lu Xin, Na Zuo, Bin Li, Wei Zhou, Dhanarajagopal Alltrin, Boning Yu, Haiyang Yang, Bin Qian, Wen-Chin Lin, Raman Sankar, Michael Smidman, Xiangzhuo Xing, Chunqiang Xu, Xiaobing Liu, Jianhui Dai, Dong Qian, Shiyan Li, Xiaofeng Xu
Superconductivity emerging from or in the vicinity of magnetic states is generally considered to be mediated by spin fluctuations and thus lies beyond the scope of conventional electron-phonon coupled BCS framework. Here we report the emergence of novel ferromagnetism in the d-electron rhodium sulfide Rh17S15 superconductor, characterized by an enhanced Sommerfeld coefficient {\gamma} arising from the flat topological band and many-body correlations. We further demonstrate that the ferromagnetism can be tuned via Fe substitution at the Rh sites, leading to a spin glass ground state induced by the competing ferromagnetic and antiferromagnetic exchange interactions. Fe doping results in a further enhancement of both the {\gamma} and electron effective masses. At a doping level of x = 0.67 in Rh17-xFexS15, {\gamma} reaches 312 mJ mol-1K-2, second only to the well-documented d-electron heavy-fermion material LiV2O4. Furthermore, upon applying pressure, superconductivity is first suppressed; under high pressures, however, we observe the reentrant superconductivity in both pristine and Fe-doped samples. Our results not only demonstrate the unusual magnetic states and possible heavy-fermion features in these frustration-free, d-based superconductors, but also suggest that the superconductivity in this system is likely mediated by the intrinsic spin fluctuations and may thus be unconventional.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
4 figures
Advanced Science 2026
Revealing Hidden Inversion Symmetry Breaking in ZrTe$_5$ via Phonon-Assisted Heterodyne Amplification
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-14 20:00 EDT
S. J. Li, J. H. Huang, H. Y. Wu, S. P. Zheng, C. J. Kong, B. Xu, H. Wang, T. Dong, L. Yue, D. Wu, Y. Wan, Z. L. Li, X. B. Wang, S. J. Zhang, N. L. Wang, Y. T. Li
ZrTe$ _5$ is a sensitive topological material where small perturbations can alter its electronic structure. Its equilibrium crystal structure has been widely regarded as centrosymmetric, while recent experiments have raised the possibility of inversion-symmetry breaking. Here we probe this hidden symmetry lowering using nonlinear optical spectroscopy. Although conventional second-harmonic generation does not resolve an equilibrium symmetry-breaking signal, terahertz-field-induced second-harmonic generation (TFISH) reveals it through phonon-assisted heterodyne amplification. A coherently driven infrared-active phonon acts as a local oscillator for the vanishingly weak second-order susceptibility $ \chi^{(2)}$ , converting an otherwise undetectable symmetry-breaking response into a phonon-frequency modulation of the TFISH signal. The field-linear scaling of this modulation demonstrates $ \chi^{(2)}$ is an equilibrium susceptibility rather than a response induced by the THz field. Polarization- and temperature-dependent measurements identify a bulk polar distortion along the crystallographic $ a$ axis that persists to room temperature, while the $ c$ axis remains nonpolar. These results provide direct optical evidence for equilibrium inversion-symmetry breaking in bulk ZrTe$ _5$ and establish a structural constraint for understanding its electronic and topological properties.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el), Optics (physics.optics)
7 pages, 4 figure
Observation of topological surface phonons in diamond with nonlinear optics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-14 20:00 EDT
Qi Wang, Xinyi Liu, Xinyue Sheng, Zhi-Kang Lin, Xiaowei Lu, Xiaosheng Yang, Peining Li, Yizhou Liu, Chang-Hui Li, Wei-Tao Liu, Jian-Hua Jiang
Topological quantum states in electronic systems have profoundly transformed the understanding of phases of matter. Recent theories predict novel vibrational topological quantum states, i.e., topological phonons in various solids. However, this paradigm is yet to be established due to the lack of convincing experimental verification of topological surface phonons—a hallmark signature of topological phonon states. Here, we report the discovery of topological surface phonons in diamond using sum-frequency spectroscopy—a nonlinear optical spectroscopy capable of probing surface phonons with high sensitivity. Diamond, known for exceptional hardness and thermal transport, is unveiled as a phonon topological semimetal hosting topological nodal-lines and nexus triple points in the bulk. With consistent theory and experiments, we uncover the resultant topological surface phonons on diamond (111) and (100) surfaces. Moreover, by chemically modifying these surfaces, we reveal the disorder effect on topological surface phonons. These findings pave the way for bridging two fundamental domains: quantum topology and lattice dynamics, besides having important implications on diamond-based devices and functional interfaces.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
comments are welcome
Mechanical control of competing magnetic order in crystalline MnPtGa membranes
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-14 20:00 EDT
R Rawat, F Fei, T Samanta, Z LaDuca, K Su, M Arnold, J Xiao, J K Kawasaki
MnPtGa hosts competing magnetic states, including ferromagnetic, canted antiferromagnetic, and spin density wave (SDW) order in the centrosymmetric $ P6_3/mmc$ structure, while a related inversion-broken structure supports chiral skyrmions. Controlling this competition motivates materials platforms that enable tunable strain and symmetry breaking, together with probes of SDW order compatible with ultrathin samples. Here, we demonstrate single crystalline MnPtGa membranes grown by molecular beam epitaxy on graphene/Ge(111) and released by mechanical exfoliation. X-ray and electron diffraction confirm high crystalline quality. SQUID magnetometry reveals a 140 K anomaly in the zero-field-cooled $ dM/dT$ that persists after exfoliation, while time-resolved reflectivity shows a coincident peak in the electronic relaxation time consistent with a quasiparticle phonon bottleneck associated with a putative SDW gap. Intentional rippling suppresses the $ \sim 140$ K magnetic anomaly, demonstrating mechanical control of the low-temperature state. These results establish MnPtGa membranes as a platform for detecting and strain-tuning competing magnetic orders.
Materials Science (cond-mat.mtrl-sci)
Chirality in Condensed Matter: Symmetry, Waves, and Quasiparticles
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-09-14 20:00 EDT
Jorge Puebla, Jun-ichiro Kishine, Masashi Shiraishi, Konstantin Y. Bliokh
Chirality has become a recurring concept throughout condensed-matter physics, appearing in contexts ranging from optical activity and chiral phonons to magnetic excitations and hybrid quasiparticles. As its use has expanded, however, the concept has often become intertwined with related notions such as angular momentum, polarization, helicity, and nonreciprocity, obscuring its precise symmetry-based meaning. Although chirality is universally associated with broken spatial-inversion ($ \mathcal{P}$ ) symmetry and preserved time-reversal ($ \mathcal{T}$ ) symmetry, its physical manifestation and quantitative characterization strongly depend on the system and phenomenon under consideration. In this review, we examine chirality across photons, phonons, magnons, and hybrid excitations. We show that, while no universal measure of chirality exists, different physical systems admit different $ \mathcal{P}$ -odd and $ \mathcal{T}$ -even quantities that characterize specific chiral phenomena. We further argue that chirality is often best understood through chirality-selective interactions between waves, matter, and quasiparticles rather than as an intrinsic property of isolated excitations. From this perspective, hybridization provides a particularly promising setting for the emergence, transfer, and control of chirality in condensed-matter systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
13 pages, 2 figures
Enhanced anomalous Nernst effect in Pr-doped kagome and honeycomb magnet LaCo$_5$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-14 20:00 EDT
Zheng Li, Yueyang Wu, Tianhao Li, Jun-jian Mi, Shu-Xiang Li, Jiang Ma, Qian Tao, Xiaofeng Xu, Sheng Xu, Zhu-An Xu
In this work, we report the successful synthesis of La$ _{1-x}$ Pr$ _x$ Co$ _5$ ($ x = 0.09, 0.21, 0.45$ ) single crystals. Magnetic field-dependent magnetization measurements reveal that Pr substitution induces negligible changes in the magnetic properties of LaCo$ 5$ , with the ferromagnetic ordering predominantly governed by the Co sublattices. Remarkably, the doped systems exhibit significant enhancements in the anomalous Nernst effect. At 300~K, the anomalous Nernst thermopower $ S^A{yx}$ reaches 6.5~$ \mathrm{\mu V/K}$ in La$ _{0.55}$ Pr$ _{0.45}$ Co$ _5$ , corresponding to a $ \sim$ 40 % enhancement compared to the parent compound. This significant improvement can be predominantly attributed to Pr-doping-induced Fermi level modification, which directly leads to a redistribution of Berry curvature across the Fermi surface. This work highlights the effectiveness of Pr doping in boosting the anomalous Nernst effect of La$ _{1-x}$ Pr$ _x$ Co$ _5$ , offering a practical strategy to design advanced materials for room-temperature energy-harvesting technologies and high-efficiency thermal sensing devices.
Materials Science (cond-mat.mtrl-sci)
6 pages, 5 figures
Enhancing Conformality in Atomic Layer Deposition through Low Growth Per Cycle
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-14 20:00 EDT
Christine Gonsalves, Jorge A. Velasco, Ahmed Othman, Ville Miikkulainen, Riikka L. Puurunen
Atomic layer deposition (ALD) is a key enabling technology for advanced microelectronics as it enables the growth of functional thin films on complex three-dimensional substrates with unmatched atomic-scale precision. Conformal film growth in high-aspect-ratio (HAR) structures is limited by slow diffusion of reactant molecules into deep, narrow features. This work elucidates an approach to grow conformal films faster by investigating the relationship between the ALD growth per cycle (GPC) and the film penetration depth in HAR structures through modeling and experiments. Diffusion-reaction simulations reveal, under Knudsen diffusion conditions, an inverse square root relationship between the film penetration depth and GPC. The prediction is validated experimentally with a model zinc oxide ALD process on rectangular lateral HAR structures, using an inhibitor molecule to decrease the GPC. While ALD is traditionally optimized for “high GPC,” this work shows that “low GPC” may increase efficiency when conformality is key.
Materials Science (cond-mat.mtrl-sci)
Tensor-network Monte Carlo approach based on time-evolving block decimation
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-09-14 20:00 EDT
Shimpei Goto, Hidemaro Suwa, Synge Todo
We propose a tensor-network Monte Carlo (TNMC) approach for unitary evolution following the compression sequence of the time-evolving block decimation (TEBD) algorithm. In the TNMC approach, the obtained results contain evaluable statistical errors rather than truncation errors, unlike ordinary singular-value-decomposition-based methods such as the TEBD algorithm. Consequently, one can estimate unbiased expectation values within statistical errors even with a finite bond dimension. Since the sampling scheme is introduced in the simulations of unitary evolution, the proposed Monte Carlo scheme may suffer from a sign problem. We observe that the sign problem can be mitigated by increasing the bond dimension. We apply the proposed TNMC approach to the Hamiltonian and the Floquet dynamics. Numerical experiments show that the TNMC approach can estimate accurate expectation values of observables even when the TEBD method with the same bond dimension cannot. The proposed approach can be a new direction for improving the classical simulatability of unitary evolution.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
10 pages, 5 figures, 1 table
Spin-polarized Superconductivity and High-Chern Insulators in Twisted Rhombohedral Graphene Family
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-09-14 20:00 EDT
Zihao Huo, Zexu Li, Wenxuan Wang, Gengdong Zhou, Qiu Yang, Xin Sui, Zaizhe Zhang, Kenji Watanabe, Takashi Taniguchi, Zhida Song, Kaihui Liu, Xiaobo Lu
Rhombohedral multilayer graphene has emerged as a remarkably versatile platform for exploring strong correlation driven quantum states arising from low-energy topological flat bands. When reconstructed by the moire superlattice, these bands host a wide range of emergent novel states, including integer and fractional Chern insulators and unconventional superconductivity. Here, we firstly report the simultaneous emergence of widespread spin polarized SC and high Chern insulators in twisted bilayer multilayer RMG system 2+n where n=4,5,6. The SC states in 2+n system exhibit different responses to the in plane magnetic field, with SC being suppressed, enhanced and induced by in plane magnetic field . The latter two are consistent with spin-triplet pairing. Along with SC, angle and layer dependent HCIs with tunable Chern numbers emerge. Moreover, the fractional high Chern insulator in the system survives under high in plane magnetic field which can induce SC in the same device. Our work not only establishs twisted bilayer multilayer rhombohedral graphene as a unified platform for studying SC and high Chern insulators, but also opens a pathway towards multiple copropagating chiral Majorana channels by coupling spin-polarized SC to high Chern insulators.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Critical current anisotropy of practical superconductors: analysis methods and application cases
New Submission | Superconductivity (cond-mat.supr-con) | 2026-09-14 20:00 EDT
V.V. Guryev, I.V. Kulikov, S.V. Shavkin
The analysis of critical current anisotropy is important for improving superconductor-based devices. This article critically evaluates contemporary techniques for analyzing the angular dependence of critical current in practical superconductors, focusing on second-generation high-temperature superconducting tapes (coated conductors). These techniques are based on the scaling model, vortex path model, or anisotropic pinning model. We present empirical findings on critical current angular dependencies in coated conductors of different chemical compositions. Distinctive features are highlighted: the complex effect of rare-earth substitution in the HTS composition on the pinning landscape, peak asymmetry, and the dependence of critical current on Lorentz force direction at fixed magnetic field direction. The described techniques are then applied to the experimental dataset. A refined anisotropic pinning model is introduced to accurately describe certain observed phenomena. Approximation accuracy of the models is assessed using the coefficient of determination adjusted for the number of fitting variables. The fundamental disparity in interpreting angular dependencies with different models is emphasized. No universal methodology yet comprehensively explains all features or links them to the defective structure of the HTS material. This is a critical gap in understanding superconductor behavior under varying conditions and highlights the need for further research.
Superconductivity (cond-mat.supr-con)
23 pages, 14 figures
Thermodynamic Speed Limits in Isolated Quantum Systems
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-09-14 20:00 EDT
We derive thermodynamic speed limits for isolated quantum systems undergoing finite-time unitary driving. The key ingredient is a set of generalized second-law inequalities: for the Gibbs entropy and for several thermodynamically motivated observational entropies, the entropy production is bounded from below by a function of the Vu–Saito quantum Wasserstein distance between the initial and final coarse-grained states. These inequalities yield lower bounds on the operation time in terms of the average entropy-production rate. We apply the framework to system–bath coarse-graining, local-energy coarse-graining, and diagonal entropy, and illustrate the resulting bounds with numerical and analytically solvable examples. Our results provide a thermodynamic characterization of finite-time state transformations in isolated quantum systems and clarify how coarse-grained entropy production constrains macroscopic reachability.
Statistical Mechanics (cond-mat.stat-mech)
22 pages, 7 figures
Universal transverse diode effects in superconducting unconventional magnet hybrids
New Submission | Superconductivity (cond-mat.supr-con) | 2026-09-14 20:00 EDT
Pei-Hao Fu, Luca Chirolli, Jorge Cayao
We demonstrate that superconducting unconventional magnet junctions harbor transverse spin and charge diode effects with perfect rectification efficiencies. This nonreciprocal transverse transport is governed by the interplay of mirror reflections and spin rotation with respect to the Néel vector, a mechanism that is universally applicable to all unconventional magnets. Interestingly, the transverse spin diode features pure spin currents, while the charge diode yields spin-polarized charge currents, both exhibiting highly controllable rectification functionalities at vanishing net magnetization. Our results position superconducting unconventional magnets at the forefront of orthogonal engineering in next-generation transverse superconducting spintronics.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
7+1 pages; 4+1 figures
Efficient non-volatile electric control of magnetosensing in CrSBr
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-09-14 20:00 EDT
Bálint Fülöp, Yeonsu Jeong, Sofia Ferreira-Teixeira, Covadonga Álvarez-García, Tamás Prok, Xiaomin Guo, Endre Tóvári, Jong Hoon Jung, Luis Hueso, Paolo Samori, Marco Gobbi, Péter Makk, Szabolcs Csonka
In two-dimensional crystals, electrostatic gating can modulate the charge carrier density, thereby tuning their electrical properties. In magnetic materials such as CrSBr, this approach can also enable direct electrical control of magnetoresistance. Non-volatile gating is particularly attractive since it allows the carrier density to be maintained at a desired level without the need for a continuous gate bias, offering significant advantages for technological applications. Here, we demonstrate a simple device architecture in which a solution-processed ferroelectric P(VDF-TrFE) layer is integrated directly onto a CrSBr channel, enabling non-volatile control of its magnetoresistance. We investigate the magnetotransport response over a broad temperature range and demonstrate a reproducible and robust gate dependence. Notably, the ferroelectric gate achieves a gating efficiency approximately one order of magnitude higher than that of a conventional SiO$ _2$ dielectric, highlighting the potential of ferroelectric gating for electrical control of 2D magnetic materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph)
Efficient kinetic Monte Carlo simulations with long-range electrostatic interactions
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-09-14 20:00 EDT
Roya Ebrahimi Viand, Bat-Amgalan Bat-Erdene, Karsten Reuter, Sebastian Matera
Charge transport in solid-state materials is often governed by charge carrier hopping processes in the presence of long-range electrostatic interactions. Kinetic Monte Carlo (kMC) simulations provide a framework for describing such rare-event dynamics over extended timescales. However, the efficient treatment of long-range interactions remains a major computational challenge, since each particle jump modifies the energy landscape globally and, in principle, requires updating all transition rates after every carrier motion. We present an efficient and generally applicable update process for these transition rates in the presence of long-range electrostatic interactions. To illustrate the method, we study charge diffusion on a simple cubic host lattice under an external electric field. The transport behavior is investigated in high states of charge (SOC), and the influence of temperature, electric field strength, and SOC is examined. Our simulations show strongly suppressed transport at 100,% SOC (50,% occupation) caused by a freezing of the charge carriers into a Coulomb superlattice. Slight deviations from this reference in terms of charge carrier concentration lead to a rapid increase in conductivity. A deeper analysis reveals that this behavior can be rationalized as transport of non-interacting defects in the Coulomb superlattice. These results demonstrate the capability of the proposed update procedure to efficiently capture non-equilibrium transport phenomena in interacting charged systems and provide a foundation for simulations of more complex charge diffusion problems.
Statistical Mechanics (cond-mat.stat-mech)
Interfacial Packing of DNA Nanostars Regulates Dynamics on Synthetic Cell Membranes
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-09-14 20:00 EDT
Kazutoshi Masuda, Takahiro Yokoyama, Miho Yanagisawa, Arash Nikoubashman
DNA nanostructures are emerging as programmable components for engineering synthetic cell membranes, yet how their collective packing and deformability regulate molecular dynamics at membrane interfaces remains poorly understood. Here, we investigate the packing and mobility of DNA nanostars with tunable stiffness on lipid-coated droplets. The negatively charged nanostars spontaneously adsorb onto cationic membranes, and their interfacial packing is changed by the bulk DNA concentration and droplet size, which together determine the number of encapsulated nanostars. Combining fluorescence recovery after photobleaching experiments with coarse-grained simulations, we reveal distinct packing-dynamics relationships for rigid and soft nanostars. For rigid nanostars, diffusion first decreases gradually and then drops sharply with increasing interfacial packing, approaching a dynamically arrested state consistent with jamming-like behavior. In contrast, at equivalent experimental conditions, soft nanostars systematically reach lower interfacial packing fractions and show a weaker decrease in apparent mobility. This behavior is consistent with their weaker membrane affinity, which facilitates adsorption-desorption with the bulk. When this exchange is suppressed in simulations, crowding reduces the lateral diffusion of both nanostar types, but produces distinct dense configurations: soft nanostars become strongly deformed, whereas rigid nanostars largely retain their shape and form interlocked, gear-like arrangements. Nanostar adsorption also impedes lipid diffusion, while differences in membrane affinity result in distinct lipid mobile fractions. These findings reveal how the interplay between nanostar packing and deformability regulates molecular transport at membrane interfaces, providing a physical design principle for tuning lateral fluidity and crowding in artificial cells.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
Persistence of BKT phase transition in the 2D nonanalytic XY model
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-09-14 20:00 EDT
Sihan Hu, Xianzhi Pan, Kun Chen, Yi Jiang, Youjin Deng
We study the two-dimensional XY model with the nonanalytic pair potential $ 2[(1-\cos\delta)/2]^{p}$ , whose small-angle law $ \propto|\delta|^{2p}$ carries a cusp for $ p<1$ and a flat bottom for $ p>1$ , invalidating the harmonic spin-wave expansion. Two questions arise: the nature of the low-temperature ($ T$ ) phase and of the phase transition. A naive energetic argument would predict genuine long-range order and an enhanced transition temperature for $ p<1$ , and no transition at all for $ p>1$ . Large-scale Monte Carlo simulations contradict both: for every $ p>0$ the \dengrevxxi{low-$ T$ phase} is quasi-long-range ordered, with anomalous dimension $ \eta(T)\propto T^{1/p}$ , and terminates at a Berezinskii–Kosterlitz–Thouless transition. Using a vortex-free noncompact lattice-field description and utilizing a duality transformation, we show that coarse-graining drives the height-difference distribution onto a single Gaussian fixed point, renormalizing the cusp and flatness into a finite harmonic stiffness that restores the spin-wave description and the BKT scenario for all $ p>0$ .
Statistical Mechanics (cond-mat.stat-mech)
6 pages, 4 figures; Supplemental Material included
Nonequilibrium Quasiparticle Effects on Domain Wall Dynamics in Superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2026-09-14 20:00 EDT
Takuma Kanakubo, Taira Kawamura, Yusuke Kato
We study the dynamics of a domain wall (DW) in a type-II superconductor connected to two heat reservoirs. We employ a generalized time-dependent Ginzburg–Landau framework in which the superconducting order parameter and the nonequilibrium quasiparticle distribution are treated as coupled dynamical variables. Within this framework, the effect of the thermal bias is imposed through boundary conditions on the quasiparticle distribution, which are set by the reservoir temperatures. We show, both numerically and within linear response, that the DW moves toward the hotter boundary. From the local momentum-balance relation implied by the model, we identify a viscous force and a force arising from the coupling between the order parameter and the nonequilibrium distribution function. The nonequilibrium distribution separates exactly into a boundary-driven part and a part generated by the motion of the DW itself. The former sets the sign of the DW velocity, whereas the latter renormalizes the relaxation of the order parameter. These results provide a microscopic basis for the phenomenological local-temperature description developed in our previous work.
Superconductivity (cond-mat.supr-con)
23 pagesm 8 figures
Cryogenic wafer probing below one Kelvin: Characterization of normal-metal Coulomb blockade thermometers at wafer scale
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-09-14 20:00 EDT
Lassi Lehtisyrjä, Renan P. Loreto, Juho Luomahaara, Jarno Järvinen, Tuure Rantanen, Juha Vikstedt, Janne S. Lehtinen, Matti Remes, Timo Salminen, Juuso Helander, Aki Junes, Pasi Aaltonen, Vesa Henttonen, Mika Prunnila
Coulomb blockade thermometers (CBTs) have attracted more interest in recent years, as the demand for sub-one Kelvin thermometry has increased, especially due to the prevalence of dilution refrigerators in research and applications in quantum technology. CBTs can be operated both as a primary thermometer, requiring no prior calibration, or as a simple resistance thermometer in the secondary mode after calibration. As new scalable fabrication processes for quantum devices and cryogenic electronics are being developed, cryogenic wafer characterization methods must also scale up to provide statistical data on device parameters. Currently, characterization throughput of cryogenic devices is limited by the turnover time and sample capacity of traditional cryostats, where a measurement cycle for only a few devices can take several days. In this work, we demonstrate wafer-scale cryogenic characterization of a recently developed TiW/Al-AlOx/TiW normal-metal tunnel junction technology using CBTs. Measurements performed in a 300 mm cryogenic wafer prober (CWP) show on-chip electron temperatures below 700 mK across a full 150 mm wafer, as determined by primary thermometry. These results establish wafer-level testing below 1 K as a viable approach for large-scale cryogenic characterization of electrical devices, opening a pathway toward high-throughput screening of quantum devices and direct wafer-scale characterization of aluminum-based superconducting circuits.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
12 pages, 8 figures
Certifying Hidden Dissipation from Observed Current Fluctuations
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-09-14 20:00 EDT
A single-molecule experiment on a driven enzyme or motor resolves only a few of the transitions the machine makes, yet one would like to know how much free energy it dissipates in total, including on the steps that stay hidden. The mean and the fluctuations of the currents on the watched transitions are shown to certify this hidden dissipation, with no knowledge of the transition rates and no access to the hidden transitions: when the watched transitions span the cycles of the network, the observed-current covariance recovers the full density-contracted quadratic current geometry, including the contribution of transitions that are never seen. The mechanism is that fluctuations are set by the dynamical activity, or traffic, the symmetric partner of the current. Contracting the large-deviation cost of empirical currents over density fluctuations identifies the observed-current covariance with a traffic-weighted metric, and turns partial observation into a minimum-energy completion problem over the unseen cycles, whose solution is the certified hidden cost. Existing current-fluctuation uncertainty relations bound dissipation from chosen currents but do not say when partial observation fixes the hidden contribution; the cycle-observability condition derived here does. The statements concern long-time means and fluctuations; finite-time estimates require separate error control.
Statistical Mechanics (cond-mat.stat-mech), Biological Physics (physics.bio-ph)
6 pages, 3 figures
Confinement-Induced Pumping of Chiral Active Fluids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-09-14 20:00 EDT
Joscha Mecke, Yongxiang Gao, Marisol Ripoll
Chiral active fluids, composed of continuously rotating active constituents, exhibit a wealth of nonequilibrium phenomena arising from the interplay of activity, hydrodynamic interactions, and broken mirror symmetry. While these systems naturally generate circulating flows and active turbulence, converting their microscopic rotational motion into directed macroscopic transport remains an open challenge. By means of mesoscale hydrodynamic simulations, here we show that channels with an intrinsic asymmetry result in the spontaneous formation of a persistent net flux in the absence of externally imposed pressure gradients or body forces. Our results can be extrapolated to various geometric confinement strategies providing efficient and versatile strategies for transforming chiral activity into autonomous fluid transport, such that they can be utilized as a promising platform for self-powered microfluidic pumping.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
Magnetically activated optical visibility of many-body excitons in NiPS$_3$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-09-14 20:00 EDT
Shuta Matsuura, Shohei Imai, Naoto Tsuji
NiPS$ _3$ is a layered van der Waals magnet that provides a unique platform for exploring the interplay between excitons and magnetic order. In its antiferromagnetic phase, strong many-body interactions give rise to a many-body exciton, which manifests itself as an exceptionally sharp resonance near $ 1.47 , \mathrm{eV}$ in optical absorption spectra and photoluminescence. Previous theoretical studies have assigned the local ground state and the many-body exciton to spin-triplet and spin-singlet states, respectively, both with even parity. This picture, however, cannot account for the observed optical visibility of the many-body exciton because one-photon transitions between these states are forbidden by spin and parity selection rules. Here, using group-theoretical analysis and exact diagonalization of single- and two-cluster models, we show that zigzag antiferromagnetic order breaks the relevant symmetries and activates the otherwise forbidden transition. We further find that trigonal distortion of the local ligand environment and the inter-cluster exchange interaction relax additional spatial and spin constraints on the transition, producing an exciton signal in the optical conductivity that is distinguishable from the spectral background. These results provide a microscopic explanation for the optical visibility of the many-body exciton and its connection to antiferromagnetic order in NiPS$ _3$ .
Strongly Correlated Electrons (cond-mat.str-el)
17 pages, 10 figures
Direct observation of reversible ionic polarization at a buried solid-state battery interface
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-14 20:00 EDT
Giovanni Ceccio, Romana Miksova, Jiri Vacik, Zoltan Szaraz, Josef Dobrovodsky, Pavlina Zavadilová, Pavol Noga, Ivan Mastronardo
Electric fields control ionic distributions at solid-solid interfaces. However, whether buried interfaces possess an intrinsic ionic reversibility has remained experimentally unresolved. Here, we directly observe reversible ionic polarization at the buried amorphous LiCoO2/Li1.5Al0.5Ge1.5P3O12 electrolyte interface. By combining the Elastic Recoil Detection Analysis (ERDA) method, utilizing time-of-flight (ToF) measurements and nanometer-scale resolution, with the Neutron Depth Profiling (NDP) method for the absolute quantification of lithium, we show that an applied bias of +-1 V results in a reversible redistribution of approximately 9.3% of lithium in the interface region, while conserving its total content. Upon polarity reversal, the lithium redistribution is completely reversed, indicating reversible interfacial ionic polarization rather than irreversible lithium loss or permanent interphase formation. These results demonstrate that buried interfaces in solidelectrolyte systems can behave as electrically reconfigurable ionic regions with an intrinsic reversible freedom for ion motion, thereby providing direct microscopic insight into the physics of space-charge formation and low-voltage interfacial response in solid-state electrochemical systems.
Materials Science (cond-mat.mtrl-sci)
Fluctuation-induced antiparallel spin polarization near the boundaries of chiral metals
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-09-14 20:00 EDT
Kosuke Yoshimi, Yusuke Kato, Yuta Suzuki, Shuntaro Sumita, Takuro Sato, Hiroshi M. Yamamoto, Yoshihiko Togawa
The spin response of chiral conductors to nonequilibrium electrical fluctuations remains largely unexplored. We develop a low-frequency semiclassical Boltzmann theory coupled to Gauss’s law for a chiral metal with spin-orbit coupling of hedgehog type, treating impurity scattering beyond the conventional relaxation-time approximation. We first determine the quadratic response to a local ac current and its frequency dependence, and then show that zero-mean stationary current fluctuation and electric-field fluctuation near boundaries generate finite time-averaged spin polarizations in the two boundary regions of the chiral metal. The polarizations are normal to the boundaries and antiparallel: for one chirality they point inward at both boundaries, and for the other they point outward. Within this model, the dominant contribution arises from the linear Edelstein effect driven by a quadratic effective electric field localized near each boundary. This picture may provide a qualitative explanation for CISS-related spin polarization reported in the absence of an applied bias. More broadly, we expect other externally maintained stochastic drives to induce spin polarization through the same mechanism.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
29 pages, 10 figures
Nonequilibrium Broken-Symmetry States from Retained Observables
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-09-14 20:00 EDT
Sankha Subhra Bakshi, Gia-Wei Chern
In equilibrium, broken-symmetry states are selected by the competition between energy and entropy. Out of equilibrium, slowly relaxing observables retain information about the preparation and may reshape this competition, allowing orders that are not thermally favored. Identifying such states ordinarily requires following slow, protocol-dependent dynamics. Here we recast this dynamical selection as a static constrained variational problem. A small set of experimentally measurable or numerically accessible quantities-particle number, energy, and slow observables-defines a constraint space. The underlying dynamics determines where the system lies in this space, while entropy maximization over both quasiparticle occupations and a prescribed class of candidate orders determines which order is selected. Restricting the variational states to the Gaussian manifold yields a computationally inexpensive constrained Hartree-Fock implementation. For photoexcited Hubbard models, the approach reproduces the long-time TDHF suppression of square-lattice antiferromagnetism and identifies incommensurate spiral order in place of the equilibrium $ 120^\circ$ state on the triangular lattice. For a continuously driven ferromagnetic double-exchange model, evaluating the constrained order map at the stationary NESS energy reveals a restricted region in which Neel order is favored. The framework therefore turns the search for nonequilibrium broken-symmetry states into a practical static screening problem, without requiring simulations of every preparation protocol.
Strongly Correlated Electrons (cond-mat.str-el)
10 pages, 4 figures
On non-phononic modes and glassy dynamics
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-09-14 20:00 EDT
Felix C. Mocanu, Dmytro Khomenko, Matteo Paoluzzi, Giancarlo Ruocco, Walter Schirmacher, Grzegorz Szamel, Francesco Zamponi
The relationship between vibrational modes and glassy dynamics has been an important and controversial topic of study for many decades. We introduce a family of glass-forming model potentials that have identical molecular and swap dynamics but different low-frequency vibrational modes. In sufficiently small systems low frequency modes do not hybridize with phonons, and this enables us to study their statistical properties independently. We investigate i) the role of the optimization algorithm used to find a minimum; ii) that of the finite-size effects; iii) that of the truncation of the interaction potential; and, iv) that of the parent temperature. We find that models with identical supercooled liquid structure and dynamics can have dramatically different non-phononic vibrational modes at low frequency, based on how the potential is truncated. These findings challenge ideas relating the low-frequency non-phononic vibrational modes with the slow supercooled liquid relaxation.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
11 pages, 11 figures
Chirality enhances diffusion in disordered environments
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-09-14 20:00 EDT
Joshua Uhlig, Jan Wójcik, Ralf Metzler, Erik Kalz
Chirality, a systematic rotational bias in the motion of a particle, arises in a wide range of physical and biological systems, from charged colloids in magnetic fields to swimming bacteria near surfaces. While its effects in homogeneous environments are well understood, the interplay between chirality and structural disorder has remained largely unexplored. Here we investigate the chiral random walk on two-dimensional percolation clusters above the percolation threshold, combining numerical simulations with an analytically tractable annealed-disorder approximation. We find that the long-time diffusion coefficient depends non-monotonically on both the chirality parameter and the obstacle density: for every obstacle density above the percolation threshold, there exists an optimal chirality that enhances diffusion relative to the achiral walk. We show that the optimal chirality is set by an edge-adhering mechanism: maximum diffusion is achieved when the persistence length of the wall-adhering motion matches half the typical obstacle cluster perimeter. This yields a closed-form prediction for the optimal chirality in terms of geometric properties of the medium alone, which we verify across the full range of obstacle densities studied. The enhancement extends to first-passage statistics, where chirality shortens typical search times at strong disorder while lengthening them at weak disorder, with direct implications for biological navigation in disordered environments.
Statistical Mechanics (cond-mat.stat-mech), Soft Condensed Matter (cond-mat.soft), Chemical Physics (physics.chem-ph)
Inferring Dislocation Microstructures from X-ray Diffraction via Cross-Modal Contrastive Learning
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-14 20:00 EDT
Benjamin Udofia, Nicolas Bertin, Markus Stricker
Understanding and inferring dislocation microstructures from diffraction patterns remains an open challenge in materials characterization, as diffraction measurements provide only indirect information about the underlying dislocation structure. In this work, a cross-modal learning framework is developed to enable the prediction of 3D dislocation structures directly from diffraction data. Dislocation density fields generated from discrete dislocation dynamics simulations are paired with corresponding virtual X-ray diffraction patterns and embedded into a shared 2D latent space using contrastive learning. The alignment between structural and diffraction representations of dislocation structures is evaluated directly in the learned latent space using correlations between corresponding latent features. To estimate the role of dataset size for this approach, farthest point sampling is employed to construct representative and diverse training subsets of varying sizes. The results show strong cross-modal alignment and that model performance improves rapidly with increasing dataset size. Near-saturation is achieved with approximately 500 representative observations from a dataset of 10,000 observations, enabling accurate prediction of dislocation density fields from previously unseen diffraction data of the same distribution. Qualitative comparisons confirm that the predicted structures capture the dominant spatial features of the underlying dislocation microstructures. These findings demonstrate an efficient approach for learning structure-diffraction relationships and highlight the potential for inferring structural characteristics of dislocation networks directly from diffraction patterns, providing a pathway toward diffraction-based structural analysis and future extension to experimental data.
Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG)
15 pages, 9 figures, preprint
In-plane anomalous and third-harmonic Hall response in an easy-plane trigonal magnet
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-09-14 20:00 EDT
Arnab Das, Soumik Mukhopadhyay
We report the emergence of an in-plane anomalous Hall effect (IPAHE) and a pronounced third-harmonic Hall response in an easy-plane trigonal magnetic system achieved via tuning of magnetic anisotropy. Angle-dependent Hall measurements reveal a clear departure from conventional sinusoidal behavior, revealing a strong sin(3{\theta}) component at elevated fields, which increases as the magnetic anisotropy is reduced, accompanied by a finite in-plane Hall signal. Consistently, the observed nonlinear Hall signal exhibits a cubic field dependence, indicative of a leading third-order contribution to the transverse conductivity. The enhancement of the third harmonic reflects the evolution toward coherent in-plane magnetization and symmetry-governed nonlinear transport. These observations support an intrinsic, symmetry-controlled transport mechanism enabled by reduced magnetic anisotropy and establish a direct link between anisotropy, crystal symmetry, and higher-order Hall response.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Crack propagation threshold in single-crystal silicon: a cleavage plane-crackons model
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-14 20:00 EDT
Experiments revealed the discontinuities in the dependence of the crack speeds on the crack driving force. Despite great efforts, until now, previous theoretical methods, such as linear elastic fracture mechanics and molecular dynamics calculations, failed to elucidate the issue of speed gap. Herein, the cleavage plane-crackons model for crack propagation has been proposed. The normalized crack propagation speed of silicon is proportional to the one-fourth power of the quantum numbers. This motion equation is consistent with experimental results of silicon. It clarifies the underlying mechanism of the long-standing issue of the speed gap. The relationship between quantum numbers and the roughness of the surface of the cracks has been established. The critical quantum number for the onset of unstable crack propagation in single-crystal silicon has been determined. The correspondence between the critical quantum number and fracture toughness has been discovered. This methodology lead to insights into the underlying mechanism of the fracture processes. It is not limited to silicon and can be extended to other crystalline material to understand and predict the fracture behaviors.
Materials Science (cond-mat.mtrl-sci)
Agent-authored deposition recipes for X-ray multilayer mirrors: schema-bound LLM control of a magnetron sputtering system with reflectivity-verified outcomes
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-14 20:00 EDT
Oleksiy V. Penkov, Haoyu Fu, Yueying Zhan, Pengyuan Wu, Jiong Jin
Periodic multilayer mirrors for X-rays require a layer period held to about 0.02 nm, set by deposition rates held in the laboratory’s own notebook. A large language model agent was given a target multilayer specification and read access to a laboratory archive. Deposition recipes were authored in the native recipe language of a magnetron sputtering system and submitted through a Model Context Protocol bridge of 17 tools in three tiers, with enforcement held in the control application. The target was a 30-bilayer Ru/C multilayer with a period of 6.85 nm, a pair chosen because each period is fitted as two layers. The agent could write only inside a working project of its own, so it could alter neither the calibration it read nor the measurements that scored it. Mirrors were scored against a human-authored reference by X-ray reflectivity, and the 3% acceptance threshold on relative period difference was fixed before deposition. Across four scored agent-authored depositions the relative period difference fell from 20% on the calibration as given to 2.26% after one measured-feedback iteration and 0.79% after a second. Sixteen failure modes of the agent-facing interface were identified. The result is bounded to the period, pair and chamber observed.
Materials Science (cond-mat.mtrl-sci), Instrumentation and Detectors (physics.ins-det)
Superfluorescence in CdS/CdSe/CdS Spherical Quantum Wells Modulated by Excitation Geometry
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-09-14 20:00 EDT
Chunzheng Bai, Qihao Sun, Yiying Zhu, Ruilin Xu, Bin Gu, Jinsong Qi, Fengrui Hu, Xiaoyong Wang, Jiayu Zhang
Superfluorescence (SF) originates from the spontaneous buildup of macroscopic coherence among initially incoherent emitters. Its formation is highly sensitive to dephasing and collective coupling in the system. Here, we observe room-temperature SF in CdS/CdSe/CdS spherical quantum wells. With increasing excitation fluence, the peak emission intensity shows a nearly quadratic increase, while the emission delay and pulse width decrease. Burnham-Chiao ringing is also observed, revealing the characteristic collective radiation dynamics of SF. Further experiments with stripe excitation show that shortening the excitation length L changes the dominant fast emission from amplified spontaneous emission to SF. More importantly, the threshold for SF under stripe excitation is only about 1/30 of that under spot excitation. This large reduction indicates that the propagating radiation field provided by spatially extended excitation favors the buildup of cooperative coherence. These findings provide direct experimental evidence for understanding ultrafast many-body coherence dynamics and offer a route to actively control collective emission at room temperature.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics)
11 pages, 3 figures
Ultrastrong Au-Te bonding drives disorder in monolayer ZrTe$_5$ on gold
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-14 20:00 EDT
Konrád Kandrai, Zoltán Tajkov, Péter Kun, Levente Tapasztó, János Koltai, Péter Nemes-Incze
Monolayer ZrTe$ _5$ is predicted to host a large-gap quantum spin Hall phase, motivating efforts to isolate single layers of the material. Gold-assisted exfoliation produces clean monolayers of many chalcogen-terminated van der Waals crystals, but the strong Te-Au bond may compete with the bonding network of the ZrTe$ _5$ layer itself. Across tens of samples, low-temperature scanning tunneling microscopy on gold-exfoliated flakes shows a disordered monolayer surface in the overwhelming majority of cases, while thicker flakes preserve the characteristic quasi-one-dimensional chain structure. \emph{Ab initio} calculations of the ZrTe$ _5$ /Au(111) interface reproduce this asymmetry and resolve its mechanism: the Te atoms facing the gold chemisorb, rupturing the weak zigzag Te-Te bonds that cross-link the ZrTe$ _3$ chains, turning the discrete bond-length spectrum of the crystal into a continuous one, while the chains persist as distorted units. Charge analysis shows the signature of covalent Te-Au bonding with a modest transfer that hole-dopes the monolayer; in the bilayer, the distortion and the doping stay confined to the layer contacting the gold, and the chemisorption and disorder each preclude the predicted quantum spin Hall phase. The same quasi-covalent Te-Au bond may perturb the contact layer of other gold-exfoliated Te-terminated crystals, particularly those with weakly connected intralayer networks.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
supplementary information in ancillary files. Data is published at: this https URL
Diversifying time evolution of matrix product states using BUGs
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-09-14 20:00 EDT
Kornél Kapás, Dominik Sulz, Charlotte Verhoeven, Miklós Antal Werner, Örs Legeza, Christian Lubich
Time evolution of tensor-network states is a central tool for studying nonequilibrium dynamics in strongly correlated quantum systems. In the past decade, using the time-dependent variational principle (TDVP) discretized by projector-splitting has become the gold standard for evolving matrix product states (MPS) with long-range Hamiltonians. More recently, a conceptually different class of discretizations of the TDVP, the class of Basis Update and Galerkin (BUG) integrators, has been developed within the framework of dynamical low-rank approximation, offering an alternative, more flexible approach. In this work, we formulate two BUG integrators explicitly for MPS. The BUG integrators result in “single-site” MPS integrators that are robust with respect to small singular values, avoid backward-in-time substeps, and naturally allow for the adaptive choice of bond dimensions. We consider the augmented BUG integrator of first order and the midpoint BUG integrator of second order and clarify their relation to the projector-splitting discretization of the TDVP. Using representative models of strongly correlated quantum systems, like the XY spin model with long-range interaction and two-dimensional lattice models of fermions and spins of various lengths, we perform a systematic numerical comparison between BUG and projector-splitting time discretizations of the continuous-time TDVP, focusing on scalability, numerical complexity, and accuracy. We find that BUG integrators, due to their reduced numerical cost and the flexibility of the concept, provide a competitive and, in certain regimes, advantageous alternative to the well-established time-stepping by projector-splitting in TDVP, especially in models with large local dimensions, and in cases where observables are extracted with high temporal resolution.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech), Computational Physics (physics.comp-ph), Quantum Physics (quant-ph)
14 pages, 9 figures
Chiral Valence-Bond Solid and Chiral Triplons
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-09-14 20:00 EDT
Shinnosuke Koyama, Kazumasa Hattori
We propose a chiral valence-bond solid (VBS) state that spontaneously breaks inversion and mirror symmetries. It is characterized by a finite electric toroidal (ET) monopole, whose sign distinguishes the two enantiomorphic states. Using a spin-lattice model with Dzyaloshinskii-Moriya interactions, we show that the chiral VBS produces spin-split triplon bands with enantiomer-dependent spin textures governed by its ET monopole. Under a temperature gradient, these spin textures generate a net spin response whose sign is tied to the handedness of the VBS. More importantly, we show that the imaginary off-diagonal components of the dynamical spin structure factor change sign between the two enantiomers, providing a direct neutron-scattering probe of the selected handedness. These results establish a route to spontaneous chirality in a valence-bond system and to its direct detection through magnetic excitations.
Strongly Correlated Electrons (cond-mat.str-el)
5 pages, 5 figures,
Slow activity decay in excitable models with discontinuous phase transitions
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-09-14 20:00 EDT
Paulo H. Lorenzoni, Géza Ódor, Silvio C. Ferreira, Róbert Juhász
As a simple model of interacting systems of excitable degrees of freedom, we consider a threshold contact process on various lattices and networks, in which a successful activation event requires the presence of more than one active neighbors. We show by combining numerical simulations and a phenomenological theory that, in the two-phase coexistence region and for a sufficiently low initial activity, a slower-than-exponential temporal decay of the global density emerges, caused by the spontaneous formation of slowly vanishing and non-communicating clusters of activity. This slow-decay phenomenon is found to appear generally for regular lattices and also for finite-dimensional random lattices such as the Voronoi-Delaunay network. However, the slow-decay is impeded by small-world property, as demonstrated by simulations on random-regular networks. In the case of a power-law decay of the order parameter, which is valid among others on two-dimensional regular lattices, our phenomenological theory points out that the decaying state is stable against unbounded nucleation only if the decay exponent exceeds $ 1/2$ . Besides the well-known Griffiths effects of quenched random systems, this slow-decay phenomenon rooted in the threshold condition provides an alternative mechanism of off-critical but scale-free dynamics, occurring also in the absence of disorder.
Statistical Mechanics (cond-mat.stat-mech), Disordered Systems and Neural Networks (cond-mat.dis-nn)
15 pages, 16 figures
Decoupling support-dependent transport profiles from molecular water motion
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-09-14 20:00 EDT
Jannik Mehlis, Matthias Wessling
Pressure and concentration profiles from non-equilibrium molecular dynamics (NEMD) simulations are often used to infer water transport mechanisms in dense and swollen polymer membranes. However, the mechanical restraints needed to stabilize simulated membranes can alter these profiles and their interpretation. Here, we test whether restraint-induced differences in pressure and water concentration profiles are accompanied by changes in molecular water dynamics. Crosslinked poly(ethylene glycol) diacrylate (PEGDA) membranes were simulated using three support strategies: a graphene support lattice, frozen membrane atoms near the permeate interface, and homogeneously distributed frozen membrane atoms. The restraints produced markedly different profiles, ranging from solution-diffusion-like to pore-flow-like, while overall water fluxes remained comparable. Molecular water dynamics, however, changed little. Interfacial exchange was strongly bidirectional and far exceeded the net permeation flux, membrane water diffusivities were similar, and complete crossings occurred in both directions. Local water associations were short-lived, and directional velocity correlations decayed rapidly with time and distance. Thus, substantially different pressure and concentration profiles can arise despite similar molecular water dynamics. Such profiles alone are therefore insufficient to identify transport mechanisms in mechanically restrained NEMD simulations. In PEGDA, water motion is dominated by stochastic diffusion with a small net directional bias.
Soft Condensed Matter (cond-mat.soft)
NEMO: A Framework for Nematic and Morphological Analysis of Curved and Multi-layered Biological Surfaces
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-09-14 20:00 EDT
Konstantinos Andreadis, Oriol Mañé-Benach, Claire A. Dessalles, Lodovico Mazzei, Aurélien Roux, Guillaume Salbreux
Across biological scales, from cytoskeletal networks to whole tissues, orientational order and topological defects arise within complex three-dimensional geometries. However, quantifying nematic order orientational order with head-to-tail symmetry remains challenging: 2D projections introduce geometric distortions, while current 3D methods often struggle to resolve distinct nematic fields within curved or multilayer structures. Here, we introduce NEMO, a modular Python framework for the depth-resolved quantification of tangential nematic order and surface morphology. By reconstructing biological surfaces as triangulated meshes, NEMO projects curved intensity layers, extracts local nematic directors, and computes locally averaged nematic tensors within the tangent plane. The pipeline identifies topological defects and computes their topological charge by accounting for the Gaussian curvature of the underlying surface. Furthermore, NEMO quantifies tissue morphology through inter-surface distance and surface-fitted estimates of Gaussian and mean curvatures. We show the capacities of this framework using a synthetic nematic film on a vesicle and experimental actin organisation in Hydra. By combining customisable projections with surface-constrained analysis, NEMO provides a unified framework for quantifying the interplay between orientational order and geometry across scales.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
Intrinsic excitations and a proposed ground state in an Ammann-Beenker artificial spin ice
New Submission | Other Condensed Matter (cond-mat.other) | 2026-09-14 20:00 EDT
E Weightman, L O’Brien, S Coates
Artificial spin ices built on quasiperiodic geometries remain under-explored. Here we investigate an ASI based on the octagonal Ammann-Beenker tiling, whose six vertex types present local environments inaccessible in periodic lattices. Combining Monte Carlo simulations of dipolar-coupled macrospins with micromagnetic calculations of individual vertex energies, we find that vertex types freeze in an order set not by coordination number, but by quasi-degenerate levels at five-island vertices and their local environment. Excitations in the low energy state are correspondingly localised to specific, geometrically determined sites. Using twice-inflated substitution rules as an energetic backbone, we propose an analytical ground state combining a long-range ordered fixed spin network with a sparse set of degenerate regions.
Other Condensed Matter (cond-mat.other)
15 pages, 11 figures
Spin splitting without symmetry: a nearly compensated ferrimagnet and the origin of altermagnetism
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-09-14 20:00 EDT
The spin splitting of collinear altermagnets is usually attributed to the crystal symmetry relating the opposite-spin sublattices — a rotation or mirror in place of the translation or inversion of a conventional antiferromagnet. We show that this symmetry organizes the splitting but does not produce it; its origin is the anisotropic arrangement of the magnetic orbitals and their ligands, which also fixes the symmetry itself. Two results establish this. A triclinic ($ P1$ ) \ce{Mn} oxide, a fully compensated ferrimagnet whose two inequivalent sublattices are related by no symmetry, is spin split throughout the Brillouin zone; repositioning the same ligands, atom for atom, to restore an inversion centre relating the two metal sites collapses the splitting to a residual two orders of magnitude smaller, so the splitting follows from the arrangement rather than the symmetry. Symmetry, we show formally, can only ever reverse or forbid a splitting that already exists: it cannot create one between sublattices an arrangement has left electronically identical, nor where the underlying orbitals carry no anisotropy to arrange in the first place. Organizing the analysis through an operation-resolved symmetry hierarchy and reading the crystal classes as a single axis, the enforced nodal planes fall from two to one to zero across the orthorhombic, monoclinic, and triclinic classes while the arrangement-generated splitting persists to the base. The altermagnet and the fully compensated ferrimagnet are thus the two ends of one axis — the same splitting, organized by symmetry at one end and unorganized at the other — and the search for compensated spin-split magnets is a search over orbital arrangements rather than symmetry labels.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
43 pages,6 figures
Density-matrix quantum kinetics of spin-mode crossover and ac Edelstein response in spin–orbit-coupled chiral metals
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-09-14 20:00 EDT
To establish a reference for angular-momentum dynamics driven by spin–orbit coupling (SOC) in chiral conductors, we formulate a density-matrix quantum kinetic theory for a three-dimensional isotropic chiral metal with hedgehog SOC and nonmagnetic impurity scattering. The formulation retains interband coherence, and its collision integral conserves charge, energy, and spin during impurity scattering. We identify three spin modes that evolve continuously from a long-lived D’yakonov–Perel’ relaxation mode and two strongly damped precessional modes at weak SOC to one relaxational and two coherent precessional modes at strong SOC. Comparison with a band-diagonal Boltzmann equation shows that interband coherence is essential for both the weak-SOC relaxation mode and the strong-SOC precessional modes. We further derive the ac Edelstein susceptibility and the reciprocal current response to a time-dependent Zeeman field, show that their poles coincide with the spin modes, and verify Onsager reciprocity. The theory thus provides a unified analytic description of spin relaxation, precession, and spin–charge conversion across the weak-to-strong SOC crossover.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
19 pages, 5 figures; comments are welcome
Geometric theory of elastic curves constrained on rigid curved surfaces
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-09-14 20:00 EDT
Fahim Bin Selim, C. Nadir Kaplan
Slender elastic objects constrained to curved surfaces are ubiquitous in soft systems, with examples ranging from DNA wrapping around histones to actin filaments forming contractile rings on the cell membrane during cytokinesis. In the continuum limit, the conformation of these effectively one-dimensional (1D) objects is governed by both the geometry and mechanics of the embedding surface, and the elasticity of the object. Existing phenomenological typically describe such behavior through elastic energy minimization that incorporates bending and twisting, but neglect stretching that may be important for filaments with finite cross-section or are highly incompatible with the underlying surface. Here we present a coarse-grained geometric theory of 1D elastic curves constrained on rigid surfaces, derived from the first principles. For an isotropic material, our model emerges naturally in terms of the Young’s modulus, Poisson’s ratio, and area moments of inertia. The resulting effective energy functional explicitly includes stretching in addition to bending and twisting. We minimize it to determine the equilibrium curve conformations on different zero, positive, or negative Gaussian rigid surfaces. Our theory provides a general framework for analyzing the equilibrium configurations of surface-bound elastic curves in biologically and physically relevant settings.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
22 pages, 13 figures
Orbital Hall effect and orbital altermagnetism in even- and odd-parity-wave magnetic Lieb lattices
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-09-14 20:00 EDT
Börge Göbel, Ersoy Şaşıoğlu, Samir Lounis
Altermagnets combine compensated antiferromagnetic order with ferromagnet-like signatures such as spin-polarized bands and, under appropriate conditions, an anomalous Hall response. Their characteristic momentum-dependent spin splitting originates from the interplay of magnetic order and crystal structure and therefore does not require spin-orbit coupling (SOC), whereas the anomalous Hall effect relies on SOC. This raises the question whether the ferromagnet-like transport character of altermagnets can manifest already in the nonrelativistic limit. Here, we investigate the transport of orbital angular momentum in magnetic Lieb lattices. We show that a collinear antiferromagnetic texture realizes a d-wave altermagnetic state and simultaneously generates an orbital Hall effect, both in the complete absence of SOC. In this nonrelativistic limit, the orbital Hall response closely resembles that of the corresponding ferromagnet. When SOC is included, the orbital Hall effect is accompanied by a spin Hall response, while the altermagnetic spin texture acquires a corresponding orbital texture, realizing orbital altermagnetism. In contrast, an anomalous, or crystal, Hall effect requires SOC and is additionally subject to crystal-symmetry constraints. We extend the analysis from d-wave altermagnetism to odd-parity p-wave magnetism, where the orbital Hall effect becomes anisotropic and the orbital conductivity tensor develops a symmetric transverse component analogous to the planar Hall response in charge transport. Our results establish the orbital Hall effect as a nonrelativistic transport manifestation of the close relation between altermagnets and ferromagnets and extend this connection to unconventional magnetic orders beyond altermagnetism.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
8 pages, 5 figures. This work was supported by the EIC Pathfinder OPEN grant 101129641 “Orbital Engineering for Innovative Electronics” and by Deutsche Forschungsgemeinschaft (DFG): Project No. 328545488 - CRC/TRR 227, Project No. B12 and by the German Excellence Strategy -EXC3112/1 -533767171 (Center for Chiral Electronics)
Assessing the magnetic states and the accuracy of first-principles Hubbard corrections for the battery cathode Li$_x$CoO$_2$ ($x=0,1$)
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-14 20:00 EDT
Valentina Sanella, Cristiano Malica, Alberto Carta, Maria Andolfatto, Nicola Marzari, Livia Giordano, Iurii Timrov
Li$ _x$ CoO$ _2$ is a prototypical layered cathode material for Li-ion batteries, yet its accurate description from first principles remains challenging because of self-interaction errors, weak interlayer interactions, and a complex magnetic energy landscape. Here, we present a systematic investigation of the structural, electronic, magnetic, and electrochemical properties of Li$ _x$ CoO$ _2$ ($ x=0,1$ ) using density-functional theory augmented with self-consistent Hubbard corrections and long-range van der Waals interactions, together with a systematic exploration of possible magnetic states. The on-site interactions on Co-$ 3d$ and O-$ 2p$ states, as well as inter-site Co-O interactions, are determined from first principles using linear-response theory in the framework of density-functional perturbation theory, with Löwdin-orthogonalized atomic orbitals employed as Hubbard projectors. For LiCoO$ _2$ , the inclusion of Hubbard corrections provides an accurate description of the structural properties, while the electronic structure is very sensitive to the choice of Hubbard projectors. In particular, frontier Wannier-function projectors substantially improve the description of the occupied electronic states compared with localized atomic orbitals. For CoO$ _2$ , we demonstrate that a systematic exploration of the magnetic energy landscape is essential to identify the lowest-energy low-spin ground state. However, the resulting Hubbard-corrected electronic structure is insulating, consistent with the prediction of the HSE06 hybrid functional, but in contrast to the experimentally observed metallic behavior. Structural relaxation further drives the system toward a different metallic solution with an electronic configuration inconsistent with low-spin Co$ ^{4+}$ character. Despite these limitations, the calculated intercalation voltages agree well with experiment, with deviations as small as 2%.
Materials Science (cond-mat.mtrl-sci)
Reliable training of neural hyperelastic models via full-field data
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-14 20:00 EDT
Konrad Friedrichs, Franz Dammaß, Karl A. Kalina, Markus Kästner
We present a systematic investigation of the robustness and limitations of equilibrium gap-based calibrations for hyperelastic physics-augmented neural networks (PANNs), where we consider the special case of isotropic and polyconvex PANNs. In full-field parameterizations, it is commonly assumed that the displacement field is captured with sufficient spatial resolution for an accurate evaluation of the deformation field, and that the specimen is thin enough for plane stress to hold to a good approximation. Since these assumptions are never ideally satisfied in real experiments, we investigate, using synthetically generated data, how severely an under-resolved surface measurement and a non-negligible specimen thickness can affect the model parameterization. Furthermore, we perform calibration on real experimental data for a set of inhomogeneous specimen geometries. We show that the coverage of the admissible deformation states during calibration governs the ability of a model to generalize to unseen geometries and load cases; this ability can be improved further by appropriate combinations of specimens. Accurately depicting the material behavior underlying this rich data, however, requires a sufficiently flexible constitutive model, for which PANNs are well suited. Yet a rich coverage of deformation states alone is not sufficient: unless the calibration data comprise biaxial-tension-like states, models that include the second deformation invariant extrapolate unphysically towards equi-biaxial tension, whereas restricting the PANN to the first invariant remains reliable.
Materials Science (cond-mat.mtrl-sci)
Mesoscale Crystallographic Helicity in Confined Tellurium Quantum Wires
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-14 20:00 EDT
Moniruzzaman Jamal, I K M Reaz Rahman, Ke Ma, Juhyeok Lee, Karen C. Bustillo, Mark Asta, Matthew P. Sherburne, Daryl C. Chrzan, Ali Javey, Mary Scott
Helical order can facilitate symmetry breaking and emergent physical responses in crystalline materials, yet how intrinsic chirality manifests beyond atomic length scales remains poorly understood. Here, the direct observation and quantitative characterization of long-range crystallographic helicity in template-grown tellurium (Te) quantum wires on amorphous substrates are reported. Four-dimensional scanning transmission electron microscopy (4D-STEM) enables quantitative mapping of crystallographic orientation with nanometer-scale spatial resolution. The resulting orientation maps establish continuous mesoscale lattice twisting, providing direct evidence of long-range crystallographic helicity. Correlated orientation and strain mapping reveal pronounced lateral strain heterogeneity, with compressive strain concentrated within the wire interior. Systematic analysis across multiple wires suggests that higher twist rates are generally associated with weaker lateral compressive strain, narrower wires, and better atomic chain - template axis alignment. Complementary first-principles calculations on finite Te nanorods further suggest that twisting is intrinsically accessible in nucleus-scale Te clusters and strain can bias the preferred torsional state. Together, these results support a growth-incorporated, strain-biased picture in which nanoscale confinement and anisotropic strain facilitate torsional relaxation and stabilize mesoscale helicity in Te nanostructures highlighting strain and confinement as potential routes for engineering chiral lattice states in van der Waals nanostructures.
Materials Science (cond-mat.mtrl-sci)
42 pages, 5 figures, 10 supplementary figures
2D Weak Localization in Trilayer Ruddelsden-Popper Nickelates
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-09-14 20:00 EDT
Hyo-Bin Ahn, Xinglong Chen, Yu Zhang, Hong Zheng, Michael R. Norman, J. F. Mitchell, Daniel Phelan, Ulrich Welp
Ruddlesden-Popper (RP) nickelates superconduct when pressure suppresses intertwined charge- and spin-density waves. Here, we employ measurements of quantum corrections to magnetoconductivity as a probe of the dimensionality, phase coherence, and scattering mechanisms of the underlying single crystal trilayer RP nickelate Pr4Ni3O10 and La4Ni3O10. We observe signatures of 2D Weak Localization (WL), implying that the in-plane electron transport is in the quantum diffusive regime, while the out-of-plane transport is incoherent, and the electronic ground state is a quasi-2D disordered Fermi liquid. Application of pressure up to 3 GPa continuously suppresses signatures of WL, potentially signaling a 2D/3D dimensional crossover and an eventual pressure-driven transition into a superconductor.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
19 pages and 4 figures for manuscript, and 11 pages and 3 figures for supplementary information
Visualizing Chiral Edge Modes in Twisted Cuprate Superconductors via Scanning-Probe Quantum Sensing
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-09-14 20:00 EDT
Senlei Li, Xiaomeng Cui, Renzhi Sun, Lingjie Zhou, Yiran Zhao, Kenji Watanabe, Takashi Taniguchi, Genda Gu, Hailong Wang, Kartiek Agarwal, Philip Kim, Chunhui Rita Du
Recently, unconventional superconductivity hosted by twisted van der Waals (vdW) heterostructures has received immense interest due to the exotic pairing symmetry, electronic interactions and nontrivial topological nature that are naturally relevant to the fast-advancing quantum technologies. Here, we report scanning-probe quantum sensing of nanoscale electromagnetic behaviors of twisted vdW cuprate superconductors. Using single-spin relaxometry, we directly visualize edge modes spontaneously formed in twisted Bi2Sr2CaCu2O8+x (BSCCO). By investigating temperature dependent variations of edge-state-induced quantum spin relaxation, we experimentally evaluate the magnitude of nontrivial topological band gap opened at nodal points in twisted BSCCO and its critical temperature behaviors under different twist angles. We further observe alternating chiral domains defined by edge modes, exploring experimental signatures of in-plane magnetic field-induced topology in 45° twisted BSCCO. Our results advance the current understanding of twisted vdW nodal superconductors, presenting an appealing high-temperature topological superconducting material platform for cutting-edge quantum innovation.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
An on-lattice model for two-dimensional melting
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-09-14 20:00 EDT
Antonin Rogé, Peter Holdsworth, Alexis Poncet
We introduce an on-lattice minimal model of two-dimensional melting, a clock model with vacancies with control parameters temperature, chemical potential and external field. We study the full phase diagram using cluster Monte Carlo, Tensor Network Renormalisation Group and selfconsistent mean field methods. A non-universal ensemble of melting scenarios is observed including the KTHNY scenario of two Berezinskii-Kosterlitz-Thouless phase transitions delimiting a quasilong-range ordered phase. The upper transition evolves into first-order transition in analogy with simulations on hard and soft discs and at low chemical potential there is a single transition between ordered high density and disordered low density phases. The evolution is via a special tricritical point that is accessed in detail. This work therefore provides a framework for understanding the crossover between 2D melting scenarios and offers insights into the behavior of realistic systems.
Statistical Mechanics (cond-mat.stat-mech)
Laser-induced metastable (anti-)skyrmion states with higher-order topological charge
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-09-14 20:00 EDT
Tim Titze (1), Marcel Möller (2), Timo Schmidt (3), Mariam Hassan (3), Sabri Koraltan (4), Stefan Mathias (1 and 5), Manfred Albrecht (3), Claus Ropers (1, 2 and 5), Daniel Steil (1) ((1) University of Göttingen, Germany and (2) Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany and (3) University of Augsburg, Germany and (4) Technical University of Vienna, Austria and (5) ICASEC, University of Göttingen, Germany)
Ultrafast creation and manipulation of topologically non-trivial spin objects promises significant potential for spintronic applications. Here, we demonstrate laser-induced nucleation of skyrmions and antiskyrmions with topological charge up to $ |Q|=3$ from the saturated magnetization state of a Co/Ni-multilayer which does not intrinsically host a skyrmionic ground state. The resulting configuration of spin objects thus constitutes a metastable, thermodynamically hidden magnetic state. We control the number and type of spin objects by the excitation fluence and the external out-of-plane magnetic field.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
10 pages, 7 figures
Modification of Surface Properties in Ruthenium Thin Films through Nitrogen Ion Irradiation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-14 20:00 EDT
Anmol Sharma, Arnab Tripathy, Rajeev Gupta, Raj Kumar, Harsh Vardhan, Ratnesh Kumar Pandey, Atul Thakur, Shalendra Kumar, Ranjeet Kumar Brajpuriya, Vishakha Kaushik, Sachin Pathak
Surface modification is an important strategy for tailoring the physical and chemical properties of materials for advanced technological applications. In thin films, changes in surface structure, roughness, and composition can strongly influence their functional behavior. In this work, we studied the effect of N+-ion irradiation at 20 keV energy on Ru thin films of two different thicknesses, 100 Å and 1000 Å, over a fluence range of ~1014 to 1017 ions/cm2. The main objective of this study is to investigate the evolution of the structural and wettability properties of Ru thin films of different thicknesses under increasing ion fluence. Overall, the results reveal that increasing ion fluence promotes surface roughening in both film thicknesses, which is correlated with an increase in contact angle. This indicates a clear transition from hydrophilic to hydrophobic behaviour, with the highest contact angle of ~95.54° observed at a fluence of 1017 ions/cm2. TRIM simulations reveal that for the 100 Å film, the projected ion range exceeds the film thickness, allowing interaction with the bottom substrate, whereas in the 1000 Å film, ion penetration remains largely confined within the Ru layer. GIXRD confirms fluence-dependent structural modification, including peak broadening with preferred orientation changes from Ru (101) to (002). Overall, this study demonstrates that N+-ion irradiation serves as an effective route for tuning both the surface morphology and wettability of Ru thin films, enabling controlled enhancement of hydrophobicity.
Materials Science (cond-mat.mtrl-sci)
Active elastic theory of self-aligning solids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-09-14 20:00 EDT
Sander C. Kammeraat, Silke Henkes
Active disordered solids including dense human crowds and epithelial cells under confinement exhibit striking system-scale oscillatory spatiotemporal patterns. These are linked to a local feedback mechanism, self-alignment, that aligns the direction of a particle’s motility vector to the total force. Simulations and experiments of solids made of such agents show these spontaneous oscillation patterns. Theoretically, they have been linked to both a nonlinear bifurcation and to selection of long-wavelength normal modes. Here we derive a closed nonlinear equation for the displacement field of active self-aligning 2d solids subject to angular noise. Along the normal modes of the solid, the dynamics of the mode amplitudes correspond to nonlinearly damped and stochastically driven harmonic oscillators. To linear order, we show that the system transitions from Active Brownian type correlated motion to oscillatory motion that increasingly condenses onto the lowest modes of the solid. We compare the analytical predictions for the mode spectra with simulations, finding excellent agreement approaching the transition from the disordered side. Strong nonlinearities manifest deep in the oscillating phase at strong alignment and small noise, consistent with the previous observations. At the continuum level, we derive a closed-form nonlinear wave equation for self-aligning solids. The transition to undamped oscillations is a second order dynamical phase transition driven by the competition between noise and alignment. At the linear level, we predict travelling acto-elastic waves, together with the emergence of system-scale oscillations for confined systems, consistent with observations in tissues and crowds. Our framework extends the understanding of self-aligning solids, which are pervasive among artificial and biological systems across multiple scales.
Soft Condensed Matter (cond-mat.soft)
17 pages, 10 figures
Magnon-induced hybridization brightens excitons in ferromagnetic semiconductors
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-09-14 20:00 EDT
Excitons in magnetic semiconductors have energies and spin structures that are sensitive to the underlying magnetic order. We study this coupling in a minimal one-dimensional lattice model of a conduction electron and a valence hole moving in a ferromagnetic background of localized quantum spins, treating the electron, the hole, and the magnon(s) as explicitly resolved degrees of freedom. At zero temperature, spin conservation closes the relevant Hilbert subspaces at the one- or two-magnon level, so the model can be solved essentially exactly with a real-space Green’s function method. Comparison against a frozen-spin approximation in which the local moments are replaced by their ordered values identifies which effects are due to emission and absorption of quantum magnons. A frozen background already lifts the spin degeneracy of the exciton and, if the two carriers couple with different strengths to the local moments, it mixes the singlet with the spin-zero triplet exciton. The emission and absorption of quantum magnons goes qualitatively further: it splits and shifts the exciton energies nonlinearly in the exchange coupling even when all frozen-spin effects vanish; for carriers with unequal hopping integrals, it hybridizes the singlet and spin-zero triplet excitons, thereby brightening the dark triplet; and it increases the exciton radius, which in turn enhances the magnon dressing by removing an on-site cancellation. These quantum effects are therefore strongest for extended, Wannier-like excitons, which is precisely the regime that is commonly modeled assuming a static (frozen-spin) magnetic order.
Strongly Correlated Electrons (cond-mat.str-el)
14 pages, 8 figures
RS-CIDER: A non-local machine learning model for approximating screened hybrid functionals
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-09-14 20:00 EDT
Zhuotao Jin, Mohamed S. Abdallah, Boris Kozinsky, Kyle Bystrom
Screened hybrid functionals such as HSE06 improve the description of band gaps, charge localization, and redox energetics relative to semilocal approximations, but their explicit Hartree-Fock exchange term is computationally costly for large, periodic systems, especially in plane-wave basis set calculations. Here we present RS-CIDER, a machine-learned non-local exchange functional that approximates the short-range Hartree-Fock exchange term in HSE06 by explicitly fitting both ground-state energies and single-particle energy levels. RS-CIDER combines scale-invariant semilocal and non-local density descriptors and can be evaluated self-consistently without explicitly applying the short-range Hartree-Fock exchange operator. RS-CIDER shows close agreement with HSE06 for molecular reaction energies and solid-state band gaps. Further tests across distinct materials show agreement between RS-CIDER and HSE06 for local magnetism, Cu-O phase competition, polaron localization, and neutral-defect energetics. For an Fe olivine, chemistry-specific fine-tuning recovers the HSE06 Li intercalation voltage. A timing benchmark shows that RS-CIDER reduces the measured per-SCF-step wall time by more than an order of magnitude relative to HSE06. Together, these molecular and solid-state results establish RS-CIDER as an efficient self-consistent machine-learned surrogate for HSE06.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
Research Square
Statistical mechanics of data-driven modeling
Article | Computational science | 2026-09-13 20:00 EDT
Luis Diambra
Model selection and parameter estimation in data science rely heavily on heuristic penalties that lack a unifying physical foundation. Here, we present a thermodynamic framework grounded in Jaynes’ Maximum Entropy Principle that maps data-driven modeling onto statistical mechanics and treats inference itself as a physical thermodynamic process. By linking informational temperature and Massieu potentials to empirical constraints, we show that parameter estimation obeys exact thermodynamics, including a First Law of informational thermodynamics that decomposes each learning step into work performed on the data and changes in internal energy. For finite sample sizes, the informational temperature sets a natural resolution floor: parameter distributions progressively concentrate as data accumulates, converging toward a sharp optimum without ad-hoc regularization. Crucially, model architecture selection emerges endogenously as a critical phase transition: the informational heat capacity exhibits a sharp anomaly and sign inversion at the true model order, providing an unyielding diagnostic for over-parameterization and noise fitting. Validated on linear autoregressive processes, the framework reveals a characteristic crossover scaling law connecting noise-dominated finite regimes to asymptotic Fisher information limits, and demonstrates that each learning step satisfies an exact First Law balance between informational work and internal energy changes. By establishing that finite-sample inference is a physical thermodynamic process - inherently irreversible and subject to Landauer-type energy costs - this work replaces arbitrary statistical penalties with fundamental physical bounds, opening new avenues for understanding the energetic limits of complex, over-parameterized learning architectures.
Research Square:rs-10483518 (2026)
Posted on Research Square
Physical sciences/Mathematics and computing/Computational science, Physical sciences/Physics/Statistical physics, thermodynamics and nonlinear dynamics/Statistical physics, Physical sciences/Physics/Information theory and computation