CMP Journal 2026-10-05
Statistics
Nature Nanotechnology: 1
Nature Reviews Materials: 1
arXiv: 60
Research Square: 1
Nature Nanotechnology
Stereochemical origin of potential hysteresis in lithium metal batteries with lithium-rich cation-disordered rocksalt positive electrodes
Original Paper | Batteries | 2026-10-04 20:00 EDT
Yu Mei, Fanjie Xia, Hongyi Chen, Yujin Li, Jinqiang Gao, Kefu Zhu, Lunhua He, Si Wu, Hai-Feng Li, Longlong Fan, Chun Zhan, Lianshan Ni, Haoji Wang, Weishun Jian, Kai Wang, Debbie S. Silvester, Craig E. Banks, Jinsong Wu, Wentao Deng, Guoqiang Zou, Hongshuai Hou, Xiaobo Ji
Li-rich cation-disordered rocksalts (DRXs) are promising active materials for designing high-capacity positive electrodes for non-aqueous lithium-based batteries. However, the use of DRX-based positive electrodes results in pronounced cell potential hysteresis and low energy efficiency. The reasons for these detrimental behaviours remain unclear owing to the complex structural evolution of DRXs during battery operation. Here, via extensive physicochemical and electrochemical characterizations, we show that multiscale stereochemistry, particularly structure distortion at the atomic scale and short-range ordering in nanoscale domains, can thermodynamically and kinetically affect the potential hysteresis of Li||DRX cells. By using DRX models, we show that redox-inactive d0 transition metals (d0 TMs) influence the regulation of localized nanostructures. In particular, the out-of-centre distortion of d0 TMO6 octahedra, driven by the pseudo Jahn-Teller effect, decreases cation short-range order, thereby facilitating a high-rate Li+ percolation pathway. Moreover, the pseudo Jahn-Teller effect of d0 TMs is found to weaken the ligand-to-metal charge transfer process of Ni-O and thermodynamically enhance the reversibility of the lattice oxygen redox. As a result, the kinetic and thermodynamic factors contributing to the potential hysteresis of Li metal cells with Nb-containing DRX at the positive electrode are effectively mitigated.
Batteries, Characterization and analytical techniques, Structural properties, Materials for energy and catalysis
Nature Reviews Materials
Metasurfaces for the nanoscale engineering of light-matter coupling
Review Paper | Nanophotonics and plasmonics | 2026-10-04 20:00 EDT
Connor Heimig, Enrico Baù, Jonas Biechteler, Yohan Lee, Alexander A. Antonov, Andreas Tittl
Metasurfaces are planar, ultrathin arrays of subwavelength nanostructures that provide unprecedented control over optical fields. Initially demonstrated for wavefront shaping in beam steering and holography, metasurfaces are now recognized as a versatile platform for engineering light-matter interactions over broad spectral ranges. This Review surveys how the synergy between structured geometries and material excitations enables metasurfaces to act as a common photonic framework for concentrating light into deeply subwavelength volumes, substantially amplifying optical emission, interaction strengths and nonlinear responses, and giving rise to hybrid light-matter states known as polaritons. We first provide a comprehensive overview of relevant resonance mechanisms and coupling regimes before describing the predominant material excitations (plasmonic, excitonic and phononic). For each, we highlight unifying design principles, the resulting diversity of physical phenomena and the fundamental opportunities and limitations posed by metasurface integration. We close by outlining emergent directions and opportunities for the field, including tailored symmetries as well as topological and quantum metasurfaces.
Nanophotonics and plasmonics, Metamaterials, Polaritons
arXiv
Spectral Crossings Diagnose Multiply Quantized Vortex Splitting
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-10-05 20:00 EDT
Jongheon Baek, Hiroyuki Tajima, Gihwan Nam
A charge-$ r$ coupling vortex can remain as one fused order-$ r$ zero or split into $ r$ nearby unit-charge zeros after weak symmetry breaking. The two configurations have the same total winding and the same number of dark states in the lowest-Landau-level projection, so neither the imposed orbital angular momentum nor the total winding number distinguishes their local geometry. We study this distinction in a two-component Haldane-sphere model coupled by a Raman field. For monopole flux $ N$ , the detuning $ \tau_{\rm c}$ at which a defect branch crosses zero energy scales as $ |\tau_{\rm c}|\sim N^{-(r+1)}$ for a fused zero and $ N^{-2}$ for resolved unit zeros. A Feshbach reduction establishes these asymptotic laws for the full multiband Hamiltonian, and numerical calculations in a monopole-harmonic basis confirm the fused-vortex scaling for $ r=1,2,3$ . For a partially split cluster of diameter $ d$ , the scaling crosses over when $ d$ is comparable to the magnetic length $ \ell_B$ , allowing $ d$ to be inferred spectroscopically even below the spatial resolution of direct imaging.
Quantum Gases (cond-mat.quant-gas), Atomic Physics (physics.atom-ph)
5 pages, 3 figures; Supplemental Material included
Reply to “Comment on ‘Topography of Fermi arcs in t-PtBi2 using high-resolution angle-resolved photoemission spectroscopy’”
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-05 20:00 EDT
Adam Kaminski, Paul C. Canfield, Benjamin Schrunk
In a recent work [1] we demonstrated that the Fermi arcs in t-PtBi2 are indeed disconnected segments of the Fermi surface. We showed that the surface state band crosses EF between Weyl points and is has finite band gap at all other momenta until it merges with bulk bands. We did not find evidence of a superconducting gap in the spectra down to 3K. In recent Comment, Sergey Borisenko reanalyzed data from repository posted with our paper and concluded that a superconducting gap with i-wave symmetry is present in our data up to temperatures of 19K. We argue that this claim arises from incorrect identification of the location of Fermi arc and confusion between band gap and superconducting gap. This error was compounded by the fact that Author of the Comment analyzed data from interpolated images used for mapping the Fermi surface that are not suitable for extraction of energy gap on meV scale. This fact was previously communicated to the Author of the Comment during e-mail exchange. We maintain that our conclusion of absence of a superconducting gap above 3 K are valid and consistent with recent STM measurements performed on the same samples, which found surface superconductivity with Tc = 3K, below the temperature at which the data for our ARPES paper was measured.
Superconductivity (cond-mat.supr-con)
5 pages, 2 figures. Reply to arXiv:2609.22776
Fluctuation-induced magnetoresistance in graphene Hall bars at charge neutrality
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-05 20:00 EDT
Anna Grigoreva, Alex Levchenko, Eleftherios Kirkinis, Anton Andreev
In the temperature interval $ T\sim 50 - 100 K$ , the rate of electron-electron collisions in graphene devices may exceed the momentum relaxation rate due to disorder and electron-phonon scattering. In this regime, the motion of the electron liquid may be described by the hydrodynamic equations. In the hydrodynamic approximation, at the charge neutrality point the electric current is decoupled from the hydrodynamic flow, and the conductivity of the system is equal to the intrinsic conductivity of the electron liquid, $ \sigma_0$ . It was recently shown that the coupling of charge transport and hydrodynamic flow induced by the thermal fluctuations enhances the macroscopic conductivity of the system and results in very strong positive magnetoresistance (MR) at relatively weak fields. Here we develop a quantitative theory of the fluctuation mechanism of MR at charge neutrality and obtain analytic expressions for MR in graphene Hall bars. The functional dependence of MR on the magnetic field $ H$ is sensitive to the Hall bar geometry and orientation relative to the current. We also account for the effect of momentum relaxation on MR.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
11 pages, 2 figures
Traveling waves, phase separation and pattern formation in the active stepping stone model
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-05 20:00 EDT
Rashmiranjan Bhutia, Prasad Perlekar, Kabir Ramola
Selective advantage leads to the proliferation of a species into an ecosystem. On the other hand, self-propulsion can lead to dynamic clustering of individuals. To analyze the intricate effects produced by such competing processes, we introduce a minimal model for a proliferating active population, where run-and-tumble migration is combined with a stochastic birth-death process. Beginning with the microscopic dynamics of the particles, we derive the corresponding hydrodynamic equations and validate them through numerical simulations. We demonstrate that the inclusion of activity leads to the emergence of novel morphological patterns, which are sensitive to the specific rules governing migration. Furthermore, we show that activity significantly alters the characteristics of invasion waves, increasing their propagation speed. However, beyond a threshold, excessive activity disrupts the wave-like nature of the invasion process. We also extend our study to two dimensions and analyze the instabilities that lead to pattern formation in such systems.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech), Pattern Formation and Solitons (nlin.PS), Populations and Evolution (q-bio.PE)
7 pages, 3 figures, +Supplemental Material
Thickness-Controlled Ferroelectric-to-Ionic Transport in CuCrP2S6 at Room Temperature
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-05 20:00 EDT
Subhashree Chatterjee, Abhishek Bajgain, Rabindra Basnet, Ramesh C. Budhani
Ambient-temperature coexistence of ferroelectricity, photoconductivity, and ionic transport in ultra-thin van der Waals (vdW) compound CuCrP2S6 (CCPS) offers significant potential for multifunctional electronic, photonic, and neuromorphic applications. However, ferroelectricity and ionic transport can become antagonistic when sharing a common atomic origin, like the copper ions in CCPS. We address this fundamental dichotomy by systematically investigating the thickness-dependent evolution of ferroelectricity, ionic migration, and memristive behavior in CCPS diodes via electrostatic and photo-assisted interfacial band tuning. Using piezoresponse, Kelvin probe, and conductive atomic force microscopy, alongside photoexcited transport measurements, we identify distinct thickness regimes. CCPS flakes thinner than ~ 40 nm exhibit robust, reversible ferroelectric (FE) switching. Conversely, thicker samples display suppressed switchable polarization, with electrical conduction dominated by Cu+ migration, filamentary memristive switching, and rectification reversal. Optical illumination further enhances ionic mobility via photogenerated carriers, driving photo-assisted ionic transport in non-FE flakes and a coupled photoferroionic response in FE flakes. These findings clarify how ferroelectricity fundamentally alters ionic transport dynamics in vdW ferroionic systems.
Materials Science (cond-mat.mtrl-sci)
Supplementary Material is included with the main manuscript. The main manuscript includes 6 figures
Chiral Vacuum Engineering of Quantum Hall Matter
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-05 20:00 EDT
Kiran M. Kulkarni, Andrey Baydin, Motoaki Bamba, Junichiro Kono, Ceren B. Dag, Vasil Rokaj
We reveal that a chiral cavity distinguishes the resonant and antiresonant interactions between a two-dimensional electron gas and the cavity vacuum. For co-rotating helicities, the modes anticross, exhibiting vacuum Rabi splitting, and retain a bare vacuum ground state. For counter-rotating helicities, the modes cross, acquiring vacuum-mediated energy shifts and a two-mode squeezed ground state. We trace the origin of these observations to the SU(2) and SU(1,1) symmetries of the respective Hamiltonians and present their spectroscopic signatures in chiral photonic crystal cavities. We further predict that cavity chirality produces a handedness-dependent correction to Hall resistivity at finite polariton broadening, while such a correction is not present in an achiral cavity. For the longitudinal resistivity, we find an asymmetric response of the Shubnikov–de Haas oscillations for the different helicities. Finally, we present an experimentally accessible route for detecting the squeezed ground state through current fluctuations. Parameters based on a recently demonstrated terahertz chiral cavity place these effects within experimental reach.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
Projective symmetry group classification of fermionic $Z_2$ spin liquids on the dipolar-octupolar pyrochlore magnets
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-05 20:00 EDT
We construct and classify $ Z_2$ quantum spin liquids (QSLs) of fermionic partons on the dipolar-octupolar (DO) pyrochlore lattice. The DO pseudospin shares the space-group and time-reversal algebra of the effective spin-1/2 Kramers doublet, its projective symmetry group (PSG) yields the same 48 symmetric $ Z_2$ classes as the generic fermionic classification. We show, the distinct DO symmetry action, encoded in a set of sublattice-independent operators, selects a physically different set of symmetry-allowed mean-field channels, so that the resulting ansatze, spinon spectra, and observables differ from both the effective spin-1/2 case and the bosonic DO classification. Decomposing the anisotropic XYZ exchange model into all symmetric singlet and triplet hopping and pairing channels and minimizing the mean-field energy self-consistently, we obtain phase diagrams in the ($ \tilde{J_x}, \tilde{J_z}$ ) plane in which only a few $ Z_2$ states, several supporting gapless or flat-band spinon spectra, are stabilized. For these states we compute the spinon band structures, the low-temperature specific heat, and the dynamical spin structure factor, and we argue that the power-law specific-heat exponent is a diagnostic of the spinon nodal structure. A near-linear-in-temperature specific heat together with broad continua in the structure factor gives a fermionic-parton account of the gapless, fractionalized thermodynamics reported in DO materials such as $ Nd_2ScNbO_7$ , complementing the bosonic quantum-spin-ice picture of the Ce-based compounds. The work extends the fermionic-parton classification of DO pyrochlore QSLs beyond the $ U(1)$ sector, where $ Z_2$ topological order is realized equally naturally by fermionic and bosonic spinons.
Strongly Correlated Electrons (cond-mat.str-el)
24 pages, 11 figures
Distinguishing sodium-ion penetration and sustained transport in realistic hard carbon nanostructures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-05 20:00 EDT
Carolina Cruz-Cardona, Andreea Hedes, Patrick Rowe, Anderson Arboleda-Lamus, Raul Arenal, Zhenyu Guo, Heather Au, Magda M. Titirici, Celine Merlet, Carla de Tomas
Hard carbons are promising anodes for sodium-ion energy storage, yet the relationship between their heterogeneous microstructure and sodium transport remains poorly understood. Here, we combine machine-learning-generated hard-carbon structures with molecular dynamics simulations of explicit 1 M NaPF6 in ethylene carbonate/dimethyl carbonate electrolyte to investigate sodium storage and transport across carbon structures with densities from 0.5 to 2.0 g cm-3. Increasing carbon density produces less accessible pore networks and greater graphitic local ordering, allowing the influence of microstructure on electrochemical response and Na+ transport to be examined systematically. Sodium uptake increases with applied potential but decreases strongly with carbon density, while electrode charging persists even in the densest structure, where Na+ uptake remains very small. Coordination analysis shows increasing interaction with the carbon framework under applied potential, while Na+ retains a partially solvated environment. Three-dimensional trajectory analysis reveals heterogeneous, predominantly tortuous transport pathways, with the more open HC-C1 structure supporting broader penetration and greater sustained displacement. Maximum penetration depth and retained displacement are not equivalent: ions can transiently reach deep regions of denser carbon structures before returning towards the electrolyte interface. Potential-of-mean-force analysis further shows that deep penetration occurs across a range of projected free-energy changes and cannot be described by a single energetic criterion. These results show that Na+ storage and transport are governed by the interplay between electrostatic driving force, electrolyte solvation, pore accessibility and confinement, highlighting carbon microstructure as a key determinant of sustained ionic penetration.
Materials Science (cond-mat.mtrl-sci)
Highly Tunable Photon-Magnon Coupling Governed by Collective-Mode Profiles in Reconfigurable Dielectric-Resonator Arrays
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-05 20:00 EDT
Shihao Zhou, Edward Kwao, Junming Wu, Abhijit Shinde, Yin Lyu, Rene Lopez, Wencan Jin, Yi Li, Binbin Yang, Wei Zhang
The spatial structure of a microwave photon mode provides a degree of freedom for controlling its interaction with a localized magnetic excitation. We demonstrate site-selective magnon-photon coupling in modular arrays of discrete dielectric resonators mounted on a common microstrip line. The resonators can be added, removed, or rearranged on the same completed PCB, enabling post-fabrication geometrical reconfiguration of the collective photon modes and their nodal structure. A YIG sphere is positioned successively above individual resonators, while an in-plane magnetic field tunes its Kittel mode through the collective photon resonances. In a three-resonator array, modes with finite local microwave magnetic fields hybridize with the magnon at every measured site, whereas a mode containing a central field node exhibits no resolvable splitting when the sphere is positioned at that node. Full-wave simulations and a coupled-mode model show that the interaction is governed by the local amplitude of the collective photon mode rather than by spectral resonance alone. Extending this local-node selection rule to a five-resonator array successfully predicts the measured position-dependent coupling patterns. These results establish post-fabrication control of spatial magnon-photon hybridization and provide a route toward reconfigurable magnonic interfaces in future hybrid quantum microwave architectures.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
10 pages, 8 figures
Breakdown of material-time scaling in the microscopic dynamics of metallic glasses
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-10-05 20:00 EDT
Till Böhmer, Jie Shen, Jan Philipp Gabriel, Rolf Zeißler, Federico Zontone, Fan Yang, Eloi Pineda, Beatrice Ruta, Thomas Blochowicz
Physical aging in glasses is often described using the concept of material time, which assumes the underlying relaxation mechanism to remain the same as in equilibrium, but with a rate that changes during aging. Whether material time also captures the microscopic dynamics of metallic glasses, which differ qualitatively between the glass and the equilibrium supercooled liquid, is unclear. Using simultaneous time-resolved X-ray diffraction and X-ray photon-correlation spectroscopy, we follow the full equilibration of a metallic glass after small temperature jumps starting from equilibrium. The time evolution of the first sharp diffraction peak position exhibits the asymmetry between temperature up- and down-jumps characteristic of material-time aging and is quantitatively described by the Tool-Narayanaswamy-Moynihan model, which is based on this concept. By contrast, the microscopic density-density autocorrelation functions strongly violate material-time scaling. Compressed-exponential relaxation emerges even after temperature changes as small as 4K, irrespective of the direction of the temperature jump, and continuously evolves into a stretched-exponential relaxation shape following the equilibration of the average structure. This behavior is consistent with a transient stress-mediated contribution associated with volumetric frustration that disappears upon equilibration. Our results show that a material time can describe the evolution of average structural properties even when the corresponding microscopic dynamics do not obey material-time scaling.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
Universal energy barrier for plastic flow in a network glass
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-10-05 20:00 EDT
Ibrahim Ghanem, Richard Jana, Wolfram G. Nöhring, Michael Moseler, Lars Pastewka
Shear transformations are the elementary events of plasticity in glasses and underpin many mesoscopic models of plastic flow, yet their atomic origin and energetics remain difficult to establish. Here we use a machine-learned interatomic potential to show that, in amorphous carbon as a representative network glass, a shear transformation corresponds to the breaking or formation of a single covalent bond. The simplicity of the associated reaction coordinate, the bond length, enables us to extract energy landscapes and barriers. Despite the intrinsic structural disorder, we find that all energy landscapes collapse onto a universal barrier shape. What remains bond-specific is a single scale, the bond-jump distance, which fixes the barrier height through a cubic law. Combined with the activation statistics of shear transformations, this yields a model that predicts the plastic flow stress from independently determined bond-level quantities. Our results provide microscopic support for phenomenological models of plastic flow in glasses and suggest a route towards a quantitative description of amorphous plasticity.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Materials Science (cond-mat.mtrl-sci), Soft Condensed Matter (cond-mat.soft)
12 pages, 11 figures
How Does Hard Magnetic Soft Matter Deform?
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-05 20:00 EDT
Daniel Katusele, Carmel Majidi, Liping Liu, Pradeep Sharma, Kaushik Dayal
Hard Magnetic Soft Materials, i.e., elastomers seeded with hard magnetic particles, convert magnetic energy into complex motion and have become central to the design of untethered soft robots, biomedical devices, and, in general, for enabling fast, wireless actuation. Their behavior depends critically on how the surrounding soft matrix deforms and transmits torque to each magnetized inclusion, yet there is no consensus on the correct mapping between macroscopic strain and microscopic motion. Competing models predict conflicting particle rotations and magnetic responses under identical loads. Here, we construct counterexamples that show the key shortcomings in these models, and then establish a first-principles framework that leads to an optimal deformation mapping. The resulting closed-form law unifies conflicting models and shows that they are, in fact, simply different limits of our general approach. Our work permits the rational design of magnetically actuated soft devices and a unified view of deformation in magnetic soft matter, and broadly, in similar architectured materials.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
To appear in PNAS Nexus
Magnetic-field response of generalized Wigner crystals in twisted MoTe$_2$
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-05 20:00 EDT
F. K. Wolff, S. Jiao, H. Park, J. Cai, E. Anderson, X. Liu, C. Wang, T. Taniguchi, K. Watanabe, X. Xu, D. Xiao, S. Vaitiekėnas
We report a magnetotransport study of fractional hole-filling states in the layer-polarized regime of a twisted MoTe$ _2$ homobilayer. A perpendicular magnetic field suppresses the resistance peak at the two-thirds filling while enhancing the one-third peak by several orders of magnitude. Both remain near their commensurate densities. We argue that these commensurate states are generalized Wigner crystals whose distinct charge configurations define different magnetic lattices, leading to contrasting responses to spin polarization. Near half filling, we observe a qualitatively different state whose resistance maximum shifts approximately quadratically with field and exhibits pronounced transport anisotropy consistent with a stripe phase. These results reveal a strong dependence of magnetotransport on fractional filling and open a route to magnetic control of transport in moiré charge-ordered states.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
9 pages, 3+7 figures
Quantum transmission in 1D disordered stealthy hyperuniform Kronig–Penney-like models
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-10-05 20:00 EDT
Shaobing Yuan, Carlo Vanoni, Salvatore Torquato
Disordered stealthy hyperuniform (SHU) systems are emerging as platforms for controlling classical and quantum transport due to vanishing single-scattering contributions in the stealthy regime. Here, to our knowledge, we present the first perturbation theory of one-dimensional quantum transport through a continuum of identical point scatterers with SHU positional disorder. Our perturbation theory indicates the exact cancellation of all the lower-order terms due to the Fourier-space stealthy condition $ S(q)=0$ , and the further suppression of the lowest non-vanishing fourth order in the Lyapunov exponent $ \lambda(k)$ due to the real-space hyperuniform constraint $ \lim\limits_{D\to\infty}\sigma_D^2=c<\infty$ . Our findings presents universal implications of the general wave-propagation phenomena in disordered SHU systems.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Materials Science (cond-mat.mtrl-sci), Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
10 pages, 3 figures
Quantum materials QED with van der Waals crystals
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-05 20:00 EDT
Suheng Xu, Brian Vermilyea, Ran Jing, Lukas Wehmeier, Jihoon Park, Rafael A. Mayer, Xinzhong Chen, Samuel L. Moore, Fuyang Tay, Boyi Zhou, Wenjun Zheng, Dihao Sun, Birui Yang, Cory R. Dean, Daniel Cazorla, Xu Du, Milan Delor, Andrew J. Millis, Angel Rubio, Michael M. Fogler, Mengkun Liu, D. N. Basov
A central goal of the emerging field of materials QED is to harness subwavelength electromagnetic confinement in engineered cavities to tailor light-matter interactions. Here, we demonstrate that van der Waals multilayer cavities composed of stacked graphene and hexagonal boron nitride (hBN) provide unprecedented control over hybridization between their electromagnetic resonances. By magnetically tuning graphene inter-Landau-level transitions (ILTs) into resonance with hBN phonons, we witness broadband, mode-selective strong coupling in the mid-infrared. Our quantum-material QED framework shows that cavity geometry and layer placement jointly control both coupling strength and modal selectivity. For experimentally realistic cavity parameters, the predicted mode splitting exceeds the width of the hBN Reststrahlen band, providing a direct route to the ultrastrong coupling regime. Together, these results establish van der Waals multilayer cavities as a scalable platform for tunable multimode QED and broaden the design space for reconfigurable quantum materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics)
29 pages, 4 main figures and 3 supplemental figures; includes Supplemental Material
Steady granular discharge across aperture shapes
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-05 20:00 EDT
Kevin Yifan Zhao, Ram Sudhir Sharma, Alexandre Leonelli, Eckart Meiburg, Alban Sauret
We recently proposed a framework for the steady mass flux of particles through circular apertures [R.S.Sharma \textit{et al.}, Phys. Rev. Lett. \textbf{136}, 068204 (2026)]. Here, we combine experiments and discrete-element simulations of spherical particles discharging through triangular and rectangular apertures to test this framework beyond circular openings. Despite changes in aperture shape, we observe a similar free-fall flux, with a modified relevant transport length. Deviations due to confinement reflect packing modifications, which are explained by geometry. A boundary layer dilation imposed by the aperture edge is shown to be a mechanism for the decrease of flux across various aperture shapes. By integrating the local packing deficit over the opening, we identify a hydraulic diameter $ D_h=4A/P$ , where $ A$ and $ P$ are the aperture area and perimeter, respectively, as the leading confinement length. This length also provides a reference scale, $ \sqrt{gD_h}$ , for the mean outlet velocity when the aperture is much larger than an individual particle. The same local packing model predicts the field in a lens-shaped aperture without further fitting, while the normalized discharge rates follow a common trend across the tested shapes.
Soft Condensed Matter (cond-mat.soft), Fluid Dynamics (physics.flu-dyn)
Main: 10 pages, 7 figures. Supplementary materials: 3 pages, 2 figures
triangulax: Differentiable Simulations with Triangular Meshes across Soft Matter Physics
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-05 20:00 EDT
Samuel Silliman, Qiwei Yu, Nikolas Claussen
Many physical and biological systems -foams, membranes, elastic shells, or tissue sheets- can be mathematically described as 2D surfaces. These surfaces can host complex dynamics, like reaction-diffusion systems, and undergo drastic deformations. Here, we present triangulax, an open-source Python library for simulations and geometry processing that discretizes surfaces using triangular meshes available at this https URL. It combines two features. First, discrete differential geometry provides coordinate-free discretization, which allows simulating strongly deforming surfaces. Second, the library is built on the machine-learning framework JAX, so mesh-based energies and entire simulations can be differentiated automatically (including simulations with stochastic forces or topological modifications). This simplifies multi-physics simulations by computing forces automatically and allows fitting model parameters to experimental data or design objectives. We implement an algorithm to preserve mesh quality in strongly deforming surfaces and apply it to a model of membrane mechanics coupled to an on-membrane concentration field. We validate our approach against exact solutions and existing software, and demonstrate triangulax across a range of problems, including membrane mechanics, vertex models, and inverse design of a shape-morphing elastomer sheet.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
20 pages, 11 figures
Fractionalization-Induced Time-Reversal Symmetry Breaking at Continuous Superconducting Transitions in Low-Symmetry Kondo Lattices
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-05 20:00 EDT
In conventional Landau theory, simultaneous continuous onset of superconductivity and the breaking of additional symmetries generally requires a multidimensional order parameter or fine tuning. We show that symmetry fractionalization provides a different route. In a Kondo lattice with a $ \mathbb Z_2$ spin liquid, the Kondo fields inherit the projective symmetry action of the spinons. When the projective time-reversal action on these fields squares to $ -1$ , the projective symmetry algebra forbids a condensate that preserves time-reversal symmetry and enforces twofold degeneracy of the critical modes. Because Kondo condensation in a $ \mathbb Z_2$ spin liquid also breaks electromagnetic $ U(1)$ symmetry, superconductivity and time-reversal symmetry breaking can emerge at a single continuous transition, even if crystal symmetry admits only one-dimensional irreducible representations. We demonstrate this mechanism in an anisotropic Kondo-Kitaev model, where superconductivity and the breaking of time-reversal and mirror symmetries emerge simultaneously.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
7+13 pages, 1 figure
LATHE: LAnguage-driven Toolkit for Hypothesis-based crystal Editing
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-05 20:00 EDT
Qianyu Zheng, Shuyi Jia, Victor Fung
Manipulating crystal structures towards targeted geometric properties or symmetry constraints is a longstanding challenge. Existing computational frameworks fall short: LLMs have poor spatial awareness and operate at coarse granularity in the token space, while diffusion- and gradient-based structure generation approaches generally produce complete structures \textit{de novo} rather allowing for fine-grained editing of a given input under arbitrary constraints. We present LATHE, a geometric toolkit that closes this gap by expressing seven classes of crystallographic properties — bond length, bond angle, dihedral angle, coordination environment, lattice parameters, cell volume, and space group, as differentiable objectives to enable direct geometric editing of crystal structures. To demonstrate its usage in materials design, we further expose LATHE through a Model Context Protocol server and embed it in a closed-loop multi-agent system which translates hypotheses intogeometric modifications in natural language towards a given design objective. Across single-property benchmarks, LATHE attains near-perfect constraint satisfaction on all seven property types while keeping optimized structures close to local energy minima. The LATHE-equipped agent translates over 87.5% of natural-language prompts into valid executable configurations and faithfully completes them. In a band-gap inverse-design case study, the multi-agent loop reaches the target tolerance window in nine of ten independent runs at a typical cost of thirteen hypothesis-evaluation cycles. By bridging natural-language hypothesis generation and physically grounded gradient-based structural editing, this work establishes a paradigm for interpretable, closed-loop computational materials discovery that is immediately applicable to a broad class of functional material design tasks.
Materials Science (cond-mat.mtrl-sci)
Temperature–Composition Mapping and Growth-History Dependence of rBN-Related Raman Responses in BN Grown on Fe–B under Flowing N$_2$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-05 20:00 EDT
Donghoi Kim, Ayoung Cho, Kyeongho Park, Young Duck Kim, Chinkyo Kim
BN products formed on Fe–B sources under flowing N$ 2$ were investigated primarily at 1250–1400$ ^\circ$ C over nominal B contents of 1–10wt% to determine how rBN-related Raman character depends on growth condition and history. Spatially resolved Raman mapping across 44 growth conditions identified a restricted temperature–composition region in which the integrated rBN-related low-frequency response over 750–835~cm$ ^{-1}$ , $ A{750-835}$ , is strongly developed together with the integrated total response of the main $ \sim$ 1367cm$ ^{-1}$ BN band, $ A_{1367}^{\rm{total}}$ . In addition, the asymmetric high-wavenumber extension of the $ \sim$ 1367cm$ ^{-1}$ band was quantified by subtracting a symmetric fitted core and integrating the far high-wavenumber residual, $ T_{\rm{high}}^{\rm{far}}$ . The independently defined $ A_{750-835}$ and $ T_{\rm{high}}^{\rm{far}}$ responses exhibit a strong correspondence across the full dataset, supporting their use as complementary rBN-related Raman observables. In contrast, $ A_{750-835}/A_{1367}^{\rm{total}}$ varies systematically among growth conditions, indicating that the relative prominence of the low-frequency response changes with temperature and composition rather than tracking the overall BN response through a fixed proportionality. Growth-duration experiments at 1350~$ ^\circ$ C further show that this ratio also depends on high-temperature N$ _2$ dwell time, establishing growth history as an additional kinetic variable. Powder X-ray diffraction on selected products independently confirms the presence of rBN-related stacking, while second-harmonic generation provides complementary symmetry-sensitive evidence. These results define a processing window favorable for strong rBN-related Raman response and introduce a quantitative framework for tracking both the low-frequency and band-asymmetry signatures associated with rBN-related BN structure.
Materials Science (cond-mat.mtrl-sci)
Emergent Noncoplanar Spin Chirality through Magnetic and Nonmagnetic Substitution in the Kagome Antiferromagnet Mn$_3$Sn
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-05 20:00 EDT
Anupam Barik, Achintya Low, Susanta Ghosh, Kapildeb Dolui, Setti Thirupathaiah
Controlling noncoplanar spin textures in centrosymmetric magnets remains a central challenge for realizing emergent Berry-phase phenomena. Here, we demonstrate that magnetic (Cr) and nonmagnetic (Cu) substitution at the Mn site provide distinct routes to engineer spin chirality and topological transport in the kagome antiferromagnet Mn$ _3$ Sn. Cr substitution enhances low-temperature spin canting, stabilizing a dense noncoplanar texture that yields a pronounced topological Hall effect (THE) at low temperatures. In contrast, Cu substitution drives a spin-reorientation transition accompanied by an easy-axis rotation, creating a broad temperature window (150–208 K) where competing magnetic anisotropies stabilize noncoplanar spin textures and generate a large THE. A concurrent carrier-type crossover signals an underlying electronic-structure reconstruction. These results reveal that exchange enhancement and exchange dilution represent two fundamentally different pathways for tuning real-space Berry curvature, establishing chemical substitution as a powerful strategy for engineering topological transport in kagome antiferromagnets.
Materials Science (cond-mat.mtrl-sci)
Accepted for publication in Materials Today Physics, 35 pages, 8 figures
Extracting the anyon charge from shot noise in complex fractional quantum Hall edges
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-05 20:00 EDT
Jinhong Park, Christian Sp{\ra}nsl{ä}tt
Shot-noise measurements with a quantum point contact provide a direct probe of the quasiparticle charge in Laughlin fractional quantum Hall (FQH) states. However, the interpretation of such measurements becomes more subtle for multichannel edges, where the point-contact tunneling noise coexists with noise generated by intermode equilibration and heating. We develop a general framework that incorporates both these contributions and apply it to the paradigmatic $ \nu=2/3$ FQH edge. We derive expressions for the drain auto- and cross-correlations in a four-terminal QPC geometry and show that equilibration-induced heating affects the auto- and cross-correlations in parametrically different way than the intrinsic partition noise. This distinction permits us to propose a specific combination of the two correlations which strongly suppresses the heating contribution and fully recovers the tunneling quasiparticle charge. Our results thereby provide a systematic framework for interpreting shot-noise measurements in complex FQH edges and can be further extended to more general counterpropagating edge structures.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
15 pages, 5 figures
Nonlocal, nonlinear electrostatics: like-charge attraction and asymmetric solvation
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-05 20:00 EDT
V. Stepanyan, Y. Sh. Mamasakhlisov, A. E. Allahverdyan
We study an equilibrium system, where linear molecules with a rigid charge distribution interact via the mean-field generated by the Coulomb coupling. We focus on the nonlinear regime, which is valid close to external charges immersed in the system. The finite molecular size in this regime leads to a nonlocal response at short distances. First, we show that the mean-field potential is non-monotonic, i.e., like charges can attract each other. Second, we show that the polarization induced by an external charge (and hence its solvation structure) depends on the sign of this charge, violating the effective C-symmetry of the macroscopic electrodynamics. We identify several scenarios of this effect, characterize it with the free energy and entropy differences, and compare it with analogous effects in asymmetric electrolytes described by nonlinear Poisson-Boltzmann equations.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech), Biological Physics (physics.bio-ph), Classical Physics (physics.class-ph)
18 pages, 6 figures
Orientation refinement for nanobeam precession electron diffraction patterns using spot intensity profiles
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-05 20:00 EDT
Arthur Després, Muriel Vérion, Edgar F. Rauch
We develop a method to measure crystallographic orientations with high angular resolution for nano-beam precession electron diffraction patterns, and applicable to 4D scanning precession electron diffraction. We show that internal variations of intensity in the diffraction spots can be simulated and correlated to experimental variations to measure the crystallographic orientation with a much better angular resolution that with the standard method of automated crystal orientation mapping (ACOM). In a tilt series carried out with long exposure time on a monocrystal of silicon around the main goniometer tilt axis, the imposed tilt angles are retrieved with a 0.044° to 0.054° precision with refinement, against 0.25° to 0.33° with the standard method. Shorter exposure times, introducing Poisson noise, marginally degrade the precision to a 0.054° to 0.066° range. The method also corrects a systematic error of ACOM near zone axis.
Materials Science (cond-mat.mtrl-sci)
Structural crossover of complex networks: bridging degree correlation and fractality
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-05 20:00 EDT
Shogo Mizutaka, Jun Yamamoto, Kousuke Yakubo
We investigate the relationship between long-range degree correlations and fractality in scale-free random networks. By analyzing degree correlations in scale-free random networks at the percolation threshold, at which a giant component emerges, we derive the ball volume $ \tilde{\nu}_k(l)$ , defined as the average number of nodes within distance $ l$ from a root node with degree $ k$ . The resulting expression predicts a degree-dependent structural crossover. For $ l\ll k^{1/(\df-1)}$ , the ball volume grows as $ \tilde{\nu}_k(l)\sim kl$ , whereas for $ l\gg k^{1/(\df-1)}$ , it crosses over to the global fractal scaling $ \tilde{\nu}_k(l)\sim l^{\df}$ . Here, $ \df$ is the fractal dimension of critical scale-free random networks. We further show that the structural crossover can be naturally understood in terms of critical branching processes and is also observed in empirical fractal networks.
Statistical Mechanics (cond-mat.stat-mech), Physics and Society (physics.soc-ph)
9 pages, 6 figures
Orientational origin of nonlinear shear rheology in unentangled polymer melts
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-05 20:00 EDT
Souta Miyamoto, Takeshi Sato, John J. Molina, Takashi Taniguchi
Universal rheological properties of unentangled polymer melts are investigated through the stretch-orientation decomposition of polymer dynamics. By externalizing stretch from the explicit state of each Rouse mode, we construct a constitutive model with orientational kinetics that preserves the Rouse relaxation spectrum. The resulting model yields the observed steady-shear scalings of the shear viscosity and first normal-stress coefficient, predicts a finite second normal-stress coefficient, and approximately reproduces the Cox-Merz and Gleissle-Osaki rules. The derived steady-oscillatory shear correspondence further identifies an elastic contribution, associated with the first normal stress difference, that is absent from the conventional Cox-Merz rule.
Soft Condensed Matter (cond-mat.soft), Fluid Dynamics (physics.flu-dyn)
5 pages, 4 figures. Companion paper: arXiv:2610.00892
Topological insulators on complex networks
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-05 20:00 EDT
Sunkyu Yu, Xianji Piao, Namkyoo Park
The landscape of topological insulators has expanded beyond its traditional domain of periodic lattices with short-range hopping. Related studies have explored topological phenomena under non-Euclidean geometries, disordered structures, and long-range hopping, progressively narrowing the gap between topological phases of matter and complex networks. Here we demonstrate that genuine complex networks, far beyond periodic lattices and their conventional variants, can themselves host topological insulating phases. By developing a nonconflicting design framework for multiple topological objectives, we realize topological insulators in high-degree Hofstadter lattices and across regular, small-world, and random networks. This generalization uncovers distinct network-specific features, including an expanded range of attainable topological characteristics, a degree-dependent transition from Hofstadter-type to Haldane-type Chern insulators, and, most notably, the superior robustness and reconfigurability of small-world topological insulators. Our graph-theoretic framework establishes network complexity as a resource for realizing high-capacity and reconfigurable topological insulators.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Disordered Systems and Neural Networks (cond-mat.dis-nn), Optics (physics.optics)
Optimizing the magnetic hyperthermia efficiency from the structural dependence of dipolar interactions in magnetic nanoparticles assemblies
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-05 20:00 EDT
Abdelhamid Morjane, François Vernay, Vincent Russier
Magnetic hyperthermia, based on the conversion of the magnetic energy of magnetic nanoparticles (MNP) under an alternating external field into heat, presents a great interest, especially because of important applications such as promising advances in cancer treatment. The underlying frequency-dependent response of the MNP assembly under the excitation field depends on the first hand on the individual properties of the MNP such as their size, shape and magnetocrystalline anisotropy and on the other hand on collective properties generated by interactions between MNP. Due to the long-range dipolar component of the latter, the first consequence is the so-called demagnetizing effects, making the response dependent on the external sample shape. This is the reason for studying the properties of MNP in assemblies of anisotropic external shapes such as films, chains, or elongated aggregates. In the present work, using a recently developed Time Quantified Monte Carlo (TQMC) framework for dynamic simulations, we focus more precisely on the importance of the local structure in such anisotropic aggregates to the dipolar interactions contribution of the response to the external field. Here the local structure is understood as both the location of the nanoparticles and the distribution of their easy axes. We show that the latter must be determined in a self-consistent way starting with the equilibrium structure of a ferrofluid modeled as the dipolar hard sphere fluid.
Materials Science (cond-mat.mtrl-sci)
17 pages, 11 figures
Sideband fingerprint of the Leggett mode in terahertz two-dimensional coherent spectroscopy of multiband superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-05 20:00 EDT
Silvia Neri, Ryo Shimano, Dirk Manske, Naoto Tsuji
Collective modes of the superconducting condensate encode fundamental information on the pairing interaction, yet their direct detection remains experimentally challenging. In multiband superconductors, the Leggett mode, i.e., a coherent oscillation of the relative phase between two condensates, is Raman-active and couples to light only nonlinearly in ordinary situations. Here we show theoretically that terahertz two-dimensional coherent spectroscopy (2DCS) provides a direct fingerprint of the Leggett mode (with frequency $ \omega_L$ ) through sideband emission at the detection frequency $ \omega_t = \omega_L\pm\Omega$ ($ \Omega$ is the central frequency of the incident pulses) in the nonlinear 2D spectrum. The key insight is that the finite duration of the THz pulses is the physical mechanism that makes the mode accessible: the broad spectral content of a finite pulse provides the nonlinear frequency combinations needed to resonantly excite the mode at {\omega}L without any prior knowledge of its value or tuning of external parameters. We demonstrate robustness of this signature against temperature and quasiparticle relaxation, and show that sweeping $ \Omega$ allows unambiguous identification of the Leggett mode.
Superconductivity (cond-mat.supr-con)
14 pages, 11 figures
Ab initio design of enhanced and sign-reversible spin Hall and spin Nernst conductivity in skutterudite materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-05 20:00 EDT
Saikat Debnath, Babu Baijnath Prasad, Shishir Kumar Pandey
The search for novel materials capable of robust spin-current generation remains an active area of research. Here, we investigate the intrinsic spin Hall and spin Nernst effects in Co- and Rh-based skutterudites and explore their enhancement through heavy-metal substitution and site-selective doping. Using first-principles calculations and Wannier-based tight-binding models, we analyze the spin Berry curvature and spin-transport responses of pristine MX$ _3$ , where M = Co, Rh and X = As, Sb, as well as chemically modified systems. Despite sizable momentum-resolved spin Berry curvature, the pristine compounds exhibit relatively small net spin Hall responses due to substantial cancellation across the Brillouin zone. Isoelectronic Ir and Bi substitution at 8$ c$ Wycoff M site produces little enhancement near the E$ _F$ , whereas non-isoelectronic Pt substitution yields a relatively better response. Most interestingly, the incorporation of Pt at the interstitial $ 2a$ Wycoff site of RhAs$ _3$ nearly doubles the spin Hall conductivity to $ \sim400(\hbar/e)(\Omega,\mathrm{cm})^{-1}$ near the E$ _F$ when compared to Pt substitution at 8$ c$ position. At 300 K, the same interstitially filled system exhibits a spin Nernst conductivity of $ \sim1.46(\hbar/e),\mathrm{A,m^{-1}K^{-1}}$ at the E$ _F$ , nearly an order of magnitude larger than that of $ M$ -site Pt substitution. The enhanced responses arise from Pt $ 5d$ states, strong spin-orbit coupling, and avoided crossings that generate pronounced spin-Berry-curvature hot spots. These results demonstrate that site-selective chemical engineering can effectively overcome momentum-space cancellation resulting in enhanced spin Hall and spin Nernst responses in skutterudites. Our results provide a possible route towards robust spin-current generation in this class of materials.
Materials Science (cond-mat.mtrl-sci)
Binary kagome superconducting candidates hosting topological electronic states
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-05 20:00 EDT
Xin-Wei Yi, Jing-Yang You, Gang Su
Topological superconductivity has attracted broad interest because of its connection to Majorana fermions and quantum computation. Kagome materials provide a natural setting in which interesting electronic structures, topological surface states, and superconductivity may occur in nearby energy windows. Here we carry out a systematic first-principles search for binary kagome superconducting candidates with topological electronic states across several structural families $ A_mB_n$ ($ m$ :$ n$ =3:1; 3:2; 1:1). The screening combines formation-energy and phonon-stability filtering, magnetic-ground-state searches, electron-phonon-coupling calculations, and topological electronic-structure analysis. We identify 286 nonmagnetic dynamically stable candidates for electron-phonon-coupling analysis, among which 84 have estimated transition temperatures above 3 K and seven exceed the $ \sim 9$ K reference scale of existing ambient-pressure kagome superconductors. In addition, several systems are predicted to host abundant topological surface states near the Fermi level. NbBi is identified as a $ \mathbb{Z}_2$ topological metal with clear Dirac-cone topological surface states and a kagome-derived flat band near $ E_F$ . Ti$ 3$ Si, with the largest estimated $ T\text{c}=15.2$ K in this dataset, shows nodal-line-derived drumhead surface states and selected nodes that survive spin-orbit coupling near $ E_F$ . Combining superconductivity with nontrivial topological electronic structures, the binary kagome compounds predicted here represent compact and chemically tunable candidate platforms for topological superconductivity and for exploring kagome-related quantum phenomena.
Superconductivity (cond-mat.supr-con)
7 pages, 4 figures, 1 table
Phys. Rev. Materials 10 (2026), L091802
Quantum critical superconductivity in a dense fermi dilute bose mixture close to mechanical instability
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-05 20:00 EDT
We couple a metal to an uncondensed bose gas with repulsive bose-fermi interactions in two dimensions. Within the random phase approximation, we show that the density fluctuations of the bosons, which mediate the effective fermion-fermion attraction, become long ranged on appropriate tuning of interactions. This leads to parametrically enhanced superconducting temperatures $ T_c \propto g$ as opposed to $ T_c \propto \exp(-1/g)$ for the BCS case. The dilute bose gas density acts as the primary bottleneck to the enhancement. We discuss the conceptual difficulties of implementing this idea in electron-exciton mixtures.
Superconductivity (cond-mat.supr-con)
Evaluating Chern Topology in Discretized Brillouin Zones Using Bargmann Invariants
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-05 20:00 EDT
We develop a finite-state geometric framework based on third-order Bargmann invariants for evaluating Chern numbers and characterizing local quantum-state geometry. Using gauge-invariant state overlaps, the framework evaluates the Chern number directly on discretized parameter spaces while retaining local geometric information through the phase-derived density and the complementary amplitude density, as well as signatures associated with changes in topological character. We apply the construction to the Qi–Wu–Zhang, $ 1/3$ - and $ 1/4$ -flux Hofstadter, SSH, and Rice–Mele models, including a rank-$ 2$ extension for isolated composite subspaces and applications to closed-loop and parameter-space topology. The resulting framework organizes Chern topology and local geometric information directly from finite-state data, providing a compact state-based description without relying on dynamical evolution.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
22 pages, 13 figures
ParABS system induces topological modifications to spatio-temporally organize its mother and daughter chromosomes in the replicating C. crescentus cell
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-05 20:00 EDT
Shailesh Sathe, Apratim Chatterji
We identify an entropy-mediated mechanism underlying the spatiotemporal organization of the chromosome in the bacterial cell Caulobacter crescentus. Effective entropic interactions between replicating DNA segments emerge from their topological modifications of daughter DNA polymers caused by transient ParA-ParB binding. Enthalpic contributions arising from the ParABS system further influence their dynamics. In C. crescentus, chromosome replication and segregation occur concurrently before cell division. The origin of replication oriC of the mother chromosome of C. crescentus is tethered to the old cell pole. Replication generates two daughter oriCs, one of which remains anchored at the old pole. The other oriC is actively transported toward the new pole by the ParABS system of proteins even as replication of the rest of the chain is in progress. How ParABS generates a directed force to transport a daughter oriC to the opposite pole during chromosome replication remains unclear. Furthermore, the two daughter chromosomes get neatly segregated into two halves of the cell. In a bead-spring polymer model of the replicating C. crescentus chromosome, we model transient ParA-ParB contacts that generate DNA loops and an effective entropic repulsion. This repulsion drives chromosome segregation and produces oriC trajectories consistent with experiments, aided by the ParA concentration gradient near the new pole. This minimal framework, incorporating the physics of topologically modified (ToMo) polymers, allows us to quantitatively reproduce the time-dependent spatial organization of different tagged loci and replisomes observed in multiple experiments. Incorporating a minimal model of extrusion also allows us to recover the linear arrangement of the chromosome arms, as is inferred from the characteristic diagonals of Hi-C maps.
Soft Condensed Matter (cond-mat.soft)
Correlated Metals, Metamagnetism, and Orbital Nematic Order in moiré Materials with Neural Quantum States
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-05 20:00 EDT
Wei Zhang, Ataç İmamoğlu, Tao Shi, Eugene A. Demler, Ivan Morera
In this work, we investigate a continuum model of two-dimensional electrons interacting via long-range Coulomb forces and subject to a triangular periodic potential at filling factor $ \nu=2$ . Using neural quantum states based on message-passing neural networks optimized with variational Monte Carlo, we determine the ground-state phase diagram as a function of periodic potential strength and Zeeman field. Although the noninteracting system is expected to form a conventional band insulator, we show that strong correlations can qualitatively reshape the insulating state and, in part of the phase diagram, suppress the band insulator in favor of a correlated metallic phase, with a first-order transition separating the two regimes. Moreover, the metal–insulator transition exhibits a strong dependence on spin polarization: the unpolarized system becomes insulating at substantially weaker periodic potentials through the formation of an $ s$ -wave molecular insulator, where opposite-spin electrons bind near each potential minimum, whereas the fully polarized system requires a significantly deeper potential and instead forms a symmetry-broken orbital nematic molecular crystal. This spin-dependent molecular transition gives rise to discontinuous magnetization curves, metamagnetic transitions, and several multicritical points in the phase diagram, together with clear signatures in the density profiles, real-space correlation functions, and structure factors. To further elucidate the role of the long-range character of the Coulomb interaction, we also study short-range repulsive interactions, which can be realized with ultracold-atom platforms. We find that the qualitative structure of the many-body phase diagram remains unchanged, demonstrating the robustness of our results across different interaction models.
Strongly Correlated Electrons (cond-mat.str-el)
Cup and Cap Topological Neural Network
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-10-05 20:00 EDT
Marta Niedostatek, Ferran Hernandez Caralt, Runyue Wang, Federica Baccini, Lorenzo Giambagli, Pietro Lió, Ginestra Bianconi
Topological Deep Learning (TDL) is designed to learn features associated with higher-dimensional simplices including not only nodes but also edges, triangles and so on. However, most TDL approaches, being based on boundary operators and Hodge Laplacians, have the limitation that features and signals cannot be lifted or lowered across more than one dimension per layer. To overcome this limitation, in this work, we propose the adoption of the cup and cap products. Specifically, we formulate the Cup and Cap Topological Neural Network (CCNN), a topological deep learning architecture designed to learn node-based variables (or 0-cochains) by taking into account their many-body interactions (e.g. triangles) present in the data. We validate CCNN by assessing its performance on the TopoBench datasets, revealing its competitiveness with respect to other simplicial complex neural networks.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
9 pages, 1 table + appendices
Coercivity-Aware Machine Learning Discovery of Rare-Earth-Free Soft Magnetic Alloys with First-Principles Magnetic Benchmarks
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-05 20:00 EDT
Coercivity-aware machine learning is developed to screen rare-earth-free soft magnetic alloys using Curie temperature and coercivity as coupled design targets. A compiled experimental magnetic-material dataset is evaluated using composition-grouped partitioning to avoid overlap of identical compositions between training and testing, and elemental fractions and composition-weighted elemental descriptors are examined for prediction of the two magnetic properties. Residual-based prediction intervals and distance-to-training filters are then incorporated to screen Fe-Co-Ni-Mn-Al-Si compositions. Composition-grouped evaluation shows lower predictive accuracy than conventional random partitioning, demonstrating the importance of evaluating transfer to previously unseen compositions. Combining weighted elemental descriptors with elemental fractions improves Curie-temperature prediction, whereas the additional descriptors do not improve coercivity prediction, consistent with the strong dependence of coercivity on processing and microstructure. Uncertainty-aware screening substantially narrows the candidate space and identifies Fe-Co-rich compositions for further evaluation. First-principles calculations independently show strong magnetic polarization and magnetovolume effects in representative Fe-Co structures, while finite-temperature atomistic spin simulations place the Fe-Co benchmark systems on high magnetic-ordering-temperature scales. The combined approach provides a computational framework for prioritizing rare-earth-free soft-magnetic chemistries while distinguishing composition-level screening from candidate-specific physical validation.
Materials Science (cond-mat.mtrl-sci)
Probing fluctuating hydrodynamics through current fluctuations in hard rod gas
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-05 20:00 EDT
Tirthankar Mondal, Indranil Mukherjee, Anupam Kundu
We study the full counting statistics of the integrated current in a one-dimensional hard-rod gas in equilibrium, employing two recently proposed fluctuating hydrodynamic frameworks: (i) Ballistic Macroscopic Fluctuation Theory (BMFT) and (ii) diffusive fluctuating hydrodynamic theory based on correlated Brownian motion approximation of hard-rod quasiparticles (CBFHD). We investigate how the predictions of these two approaches compare with each other and with the underlying microscopic dynamics. We show within BMFT that the current distribution admits a large-deviation form under ballistic scaling, and we derive an explicit expression for the large-deviation function, valid for an arbitrary inhomogeneous initial state factorized in point-particle coordinates. The corresponding current cumulants are also obtained. We subsequently analyze the current statistics within the CBFHD framework, which explicitly incorporates stochastic noise and dissipative terms, and demonstrate that the current distribution likewise obeys a large-deviation principle in this approach. We find that, while BMFT predictions for the first few cumulants and the rate function are in excellent agreement with direct numerical simulations of the microscopic hard-rod dynamics, CBFHD prediction is not. We further verify the predictions of the CBFHD independently using a collection of correlated Brownian motions, which provides an approximate description of the dynamics of hard-rod quasiparticles. Our findings indicate that CBFHD does not accurately capture large-scale current fluctuations in the hard-rod gas, whereas BMFT yields predictions in quantitative agreement with the microscopic dynamics, at least in the context of full counting statistics.
Statistical Mechanics (cond-mat.stat-mech)
34 pages, 5 figures
Plasmon modes in tilted three-dimensional nodal-ring semimetals. II. Vortex nodal ring
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-05 20:00 EDT
We investigate collective charge excitations in three-dimensional vortex nodal-ring semimetals (VNRs), whose pseudospin texture winds around the nodal ring and differs qualitatively from that of the conventional $ \mathcal{PT}$ -symmetric nodal-ring semimetal (PTNR). While plasmon modes in PTNRs have been studied in a companion work, arXiv:2609.35373. Here, we focus on how a VNR’s pseudospin texture changes the response compared with the former. Within a low-energy two-band description and the random-phase approximation, we analyse the density response, density-of-states, Drude weights, dielectric function, and plasmon modes at low doping. We consider the untilted system together with in-plane and axial band-tilts. Although the VNR and PTNR have distinct Hamiltonians, pseudospin textures, and Berry-curvature distributions, their linearised energy dispersions coincide. The vortex texture, however, introduces a toroidal-angle dependence in the band-overlap factor and quantum metric, thereby modifying the charge response. We examine how these effects enter the dielectric screening and collective modes for different wavevector orientations. Our results clarify how pseudospin texture, beyond the band dispersion alone, influences collective charge dynamics in three-dimensional nodal-ring semimetals.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), High Energy Physics - Theory (hep-th)
companion paper of arXiv:2609.35373
Discontinuous buckling from cytoplasmic mechanics in vertex models of epithelia
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-05 20:00 EDT
Chandraniva Guha Ray, Pierre A. Haas
The cell cortex and cell adhesion contribute to the mechanics of epithelial cells and hence tissues. Vertex models of epithelia represent the cell cortex and cell adhesion, but these models mostly ignore the other subcellular structures that compose the cytoplasm surrounded by the cortex. Here, we reveal the mechanical consequences of these structures in a minimal vertex model of an epithelial monolayer, in which the single-cell energy includes a cytoplasmic contribution that represents, e.g., the cost of confinement of cytosolic polymers. Strikingly, our simulations show that the buckling transition of the monolayer under compression becomes discontinuous in an intermediate range of values of the associated cytoplasmic modulus. By asymptotic solution of this buckling problem in the continuum limit of the model, we explain this reentrant behaviour in terms of the tricritical points of a sixth-order Landau theory. Our results thus underline how cell-scale mechanics beyond the cortex and cell adhesion can change emergent, tissue-scale behaviour even qualitatively.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
12 pages, 6 figures
Algebra of symmetry allowed physical properties of crystals
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-05 20:00 EDT
Piotr Fabrykiewicz (1 and 2) ((1) Jülich Centre for Neutron Science at Heinz Maier-Leibnitz Zentrum, Forschungszentrum Jülich GmbH, Garching, Germany, (2) Institute of Crystallography, RWTH Aachen University, Aachen, Germany)
The symmetry of a physical system given by the 122 magnetic point groups (MPGs) leads to only 21 sets of restrictions on any physical tensors. Those, so called, tenor forms were labeled by letters from A to U by R. R. Birss (Symmetry and Magnetism, North Holland, Amsterdam, 1964). A new concept of property-related point groups (PRPGs) is proposed. It is shown that the 21 PRPGs isomorphic to the 21 non-centrosymmetric crystallographic point groups (CPGs) corresponds to the 21 tensor forms. Therefore instead of a symbols from A to U one can use PRPGs as mathematical objects corresponding to the tenor forms. From the Neumann’s principle given multipole component is only allowed in a system when a group describing symmetry of the system is a subgroup of the multipole component symmetry. Each tensor can be expressed in the terms of the multipole degrees of freedom, i.e. it corresponds to a subset of all multipole components allowed by given PRPG. Those relations leads to the algebra of tensor forms, where space of allowed tensor components and space of PRPG operators are somehow dual to each other.
Materials Science (cond-mat.mtrl-sci)
Second-order Raman and anharmonic lattice dynamics in lead-halide perovskites
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-05 20:00 EDT
Chao Shen, Florian Kluibenschedl, Ayan A. Zhumekenov, Mikhail Lemeshko, Osman M. Bakr, Artem G. Volosniev, Zhanybek Alpichshev
We explore the microscopic origin of THz-driven lattice dynamics in methylammonium lead bromide CH$ _3$ NH$ _3$ PbBr$ _3$ using two-dimensional THz Kerr-effect spectroscopy. The analysis of the experiment enables discrimination between competing nonlinear excitation mechanisms and reveals that the dominant pathway is phonon-mediated rather than purely photonic. In particular, we argue that the commonly observed 1.15THz Raman-active $ A_g$ mode is not excited directly by the THz electric field. Instead, it emerges through cubic anharmonic coupling to an infrared-active phonon at 0.68THz. Furthermore, a satellite feature at 1.36~THz is identified as a two-phonon Raman response of the same infrared-active mode. The observation of strong quadratic coupling involving the infrared-active phonon suggests an unconventional form of electron-phonon dressing present in lead-halide perovskites.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph), Optics (physics.optics)
Illuminating early ZrC oxidation using ensemble small-cell DFT with dynamic gas management
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-05 20:00 EDT
Philip Wurzner, Boyang Chen, Matthias Möller, Sebastian Feld, Qi-Jun Hong, Yinglu Tang
During zirconium carbide oxidation, liberated carbon can remain beneath the oxide or escape as gas, complicating the interpretation of mass measurements. We adapt the small-cell ensemble method using sixteen 140 ps ab initio molecular dynamics trajectories at 873-1273 K under a sustained high oxygen flux with gas removal. The average rates of net mass gain and total carbon transfer into gas or retained chains follow Arrhenius trends. Above 973 K, gas evolution levels off while total carbon transfer increases. The fraction of transferred carbon retained in chains rises from 40 % at 973 K to 66 % at 1273 K. Fits after 40 ps suggest declining carbon transfer rates over time, although not in every trajectory. These results show that carbon partitioning during early oxidation depends on temperature, with increasing temperature above 973 K favouring chain formation over gasification.
Materials Science (cond-mat.mtrl-sci)
Beyond Pure Dephasing: Quantum Error Correction in Single Molecules Requires Multiple Spins
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-05 20:00 EDT
Matteo Mezzadri, Silvia Macedonio, Luca Lepori, Emilio Macaluso, Francesco Albarelli, Richard E.P. Winpenny, Alessandro Chiesa, Stefano Carretta1
We propose multi-spin molecules as a viable architecture for fault-tolerant quantum computing. To this aim, we introduce a correction protocol handling both diagonal and off-diagonal errors, typically associated with dephasing and relaxation. The scheme is based on a hybrid encoding which combines dephasing-tolerant units suppressing the leading pure dephasing error into a multi-spin molecule implementing a multi-qubit code for residual off-diagonal errors. Our proposal leverages peculiar properties of molecular spins, i.e. the strong hierarchy between different errors and the possibility to engineer multi-spin molecules at the synthetic level. Moreover, it addresses the important issue of the loss of coherences in anharmonic systems subject to off-diagonal errors, which hampers their correction at the single spin level. Thanks to the huge suppression of dephasing by the first-level code, we numerically demonstrate the potential performance of this strategy even with a limited number of spins per logical unit.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Quantum Physics (quant-ph)
Functional renormalization group in an external field: constant field versus constant order parameter
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-05 20:00 EDT
Julia von Rothkirch, Andreas Rückriegel, Peter Kopietz
Renormalization group (RG) flows for systems subject to an external field can be derived either by fixing the field or by fixing the conjugate order parameter. We show how to implement these boundary conditions within the functional renormalization group approach. We derive and compare the corresponding flow equations for $ \phi^4$ theory and show that some scaling variables and scaling exponents associated with the linearized flow of the relevant three-point vertex in the vicinity of the Ising fixed point depend on the boundary conditions. We also discuss the effect of elasticity on Ising criticality. In this case two of the fixed points (namely the renormalized Ising fixed point and the spherical fixed point) obtained for constant strain are shifted to physically inaccessible regimes of parameter space when we perform the RG at constant stress.
Statistical Mechanics (cond-mat.stat-mech)
16 pages, 5 figures
TUR Violation, Minimal Power Fluctuation, and Enhanced Efficiency
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-05 20:00 EDT
We investigate the performance characteristics of an active magneto gyrator that consists of an inertial charged active particle confined in a two-dimensional asymmetric parabolic potential, coupled to two thermal baths maintained at two different temperatures and in the presence of a magnetic field applied perpendicular to the plane of motion. In contrast to the passive Brownian gyrator, where the power-efficiency trade-off imposes strict operational limits, the active magneto gyrator exhibits striking violations of this rule, allowing regimes in which both output power and efficiency increase simultaneously with load strength. Moreover, while the Thermodynamic Uncertainty Relation (TUR) predicts that highly efficient engines necessarily produce strongly fluctuating power, rendering the Brownian gyrator unusable as the efficiency approaches the Carnot bound, the active magneto gyrator circumvents this constraint. Specifically, it achieves high efficiency with minimal power fluctuations, thus defying the TUR. Remarkably, the efficiency can even surpass the Carnot limit and approach 100%, without compromising stability. These results highlight the active magneto gyrator as a promising setup for designing stochastic heat engines that can transcend Carnot efficiency.
Soft Condensed Matter (cond-mat.soft)
12 pages, 4 figures
Fracture under body forces: An accessible test and analysis
New Submission | Other Condensed Matter (cond-mat.other) | 2026-10-05 20:00 EDT
Farhad Kamarei, Sarah Bueno De Castro, Jeffery R. Roesler, Oscar Lopez-Pamies
Fracture in large-scale structures — from failing concrete dams to calving glaciers — is dominated by self-weight. Yet, owing to their immense scale, directly studying when and where cracks nucleate and propagate in these systems under gravity is unfeasible. To date, experimental investigations have largely relied on mimicking self-weight in scaled-down specimens via centrifugal forces, necessitating specialized centrifuge facilities. In this Letter, we introduce a simple benchtop test that bypasses the need for this infrastructure. The method utilizes a cantilever beam containing a downward-pointing V-notch, loaded solely by its self-weight. Through appropriate selection of the notch geometry and placement and the beam dimensions, the setup forces a crack to nucleate at the notch tip and propagate through the specimen in a measurable manner. We demonstrate the utility of this self-weight fracture test on a 3D-printable mortar and analyze the results using the fracture theory recently introduced in (\citeauthor{LPKFG2026}, 2026). \emph{Inter alia}, the findings provide a first validation of the theory for fracture driven by body forces.
Other Condensed Matter (cond-mat.other), Materials Science (cond-mat.mtrl-sci)
Floquet density response in laser-assisted fast-electron scattering from solids
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-05 20:00 EDT
Ferdinand Evers, Sascha Schäfer, Richard Korytár
We extend the Bethe–Floquet formalism of Joachain and coworkers, originally developed for laser-assisted electron–atom collisions, to inelastic scattering of fast electrons from a many-body condensed-matter target in a time-periodic light field. At first order in the projectile–target interaction, the general Floquet–Fourier cross section separates into exact laser-dressed projectile kernels and a matrix-valued Floquet density response of the target. For spatially structured or translationally non-invariant systems, the latter is the bi-momentum Floquet structure factor; its momentum diagonal defines the Floquet generalization of the dynamic structure factor, constrained by Hermiticity, positivity, and sum rules. As a controlled realization of the general projectile kernel, an eikonal–Volkov approximation for slowly varying inhomogeneous fields yields a finite-momentum-resolution convolution of the target response. In the homogeneous-field dipole limit, the projectile kernel reduces to Bessel-function sidebands and the cross section takes the familiar Bethe–Floquet form. The Floquet density correlator separates exactly into the outer product of the pump-induced coherent mean density and connected fluctuations. In the straight-trajectory nonrecoil limit, the coherent, target-elastic sector defines the weak-coupling PINEM amplitude; repeated coherent insertions generate the PINEM Bessel ladder, with an explicit no-double-counting prescription for combining this channel with connected losses. As worked examples, we evaluate the connected, target-changing cross section analytically for a metal in the Drude and diffusive limits, recovering Bessel-weighted plasmon-loss and diffusive combs, and for a driven two-level model that exhibits off-diagonal Floquet coherences through Bessel-channel interference.
Materials Science (cond-mat.mtrl-sci), Atomic Physics (physics.atom-ph)
Recrystallization as a tool to characterize and control the properties of cold sprayed materials: case study on 316L steel
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-05 20:00 EDT
Petr Haušild, Jaroslav Čech, Petr Králíček, Tomáš Heller, Jan Cizek
Owing to the unique buildup mechanisms, recrystallization in cold sprayed materials significantly differs from that in conventional counterparts. In this study, the relationship between deformation-induced microstructural heterogeneity, recrystallization behavior, and mechanical properties of cold sprayed materials was investigated using EBSD and nanoindentation. The 316L stainless steel was selected as a model material. The deposit was characterized in its as-sprayed condition and after annealing at temperatures between 900 and 1100 K. Thermomechanical estimates suggest that locally, temperature can rise over 1000 K and very high dislocation densities (up to 1017 m-2) form at particle boundaries during impact, providing a strong driving force for subsequent recrystallization. The EBSD observations confirmed the intense defect accumulation and grain fragmentation localized near the particle interfaces. Recrystallization initiated preferentially in these highly strained areas after annealing at 1000 K and progressed with increasing temperature and holding time, leading to complete recrystallization after 1 h at 1100 K. The recrystallized grain-size distribution was well described by a heavy-tailed log-normal distribution, which indicates extremely heterogeneous strain partitioning generated during particle impacts. Nanoindentation measurements showed that the high hardness of the cold sprayed deposit remained largely unchanged after annealing at 900 K but gradually decreased as recrystallization progressed. We further demonstrate that controlled post-spray recrystallization can serve as a powerful tool for characterizing deformation during deposition and for tailoring the microstructure and mechanical properties of cold-sprayed materials.
Materials Science (cond-mat.mtrl-sci)
Manuscript for a submission to JTST
Magnetic-Order-Driven Nonlinear Photocurrents in PT-Broken Antiferromagnetic MnS2 and Altermagnetic MnSe2
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-05 20:00 EDT
Fu Li, Rajyavardhan Ray, Xiaoxiong Liu, Babu Baijnath Prasad, Chen Shen, Yaqian Guo, Jeroen van den Brink, Hongbin Zhang, Harish K. Singh
Nonlinear photocurrent responses generally require inversion-symmetry breaking, but its origin can be magnetic rather than structural. In this study, we investigate the bulk photovoltaic effect in antiferromagnetic MnS2 and altermagnetic MnSe2, two pyrite-type semiconductors whose magnetic ordering breaks inversion symmetry P and its combination with time reversal PT, while the accompanying lattice distortion is minute. We calculate the shift current (SC) and injection current (IC) responses under linearly and circularly polarized light with and without spin-orbit coupling (SOC) and identify their symmetry-allowed tensor components using the corresponding magnetic and spin point groups, respectively. Linear SC and circular IC are symmetry-allowed in both MnS2 and MnSe2 irrespective of SOC, whereas linear IC and circular SC remain forbidden in MnS2 but become allowed in MnSe2 only when SOC is included. These results highlight the importance of SOC and the corresponding MPG analysis for a complete description of nonlinear charge photocurrents in magnetic materials. Beyond charge responses, MnSe2 supports linear shift and circular injection spin photocurrents in the nonrelativistic limit, whereas all spin-photocurrent responses are forbidden in MnS2. Our findings therefore establish inversion symmetry breaking induced by compensated magnetic order as a route to generating and controlling nonlinear photocurrents.
Materials Science (cond-mat.mtrl-sci)
Complete Magnetic Hierarchy in Bichromatically Driven Unconventional Magnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-05 20:00 EDT
Pei-Hao Fu, Sayed Ali Akbar Ghorash
We establish a general framework for engineering unconventional magnetism using bichromatic driving. We identify a sharp hierarchy: for a bichromatic drive with a generic even commensurate frequency ratio, the leading continuum $ q$ -wave magnet generates components only up to order $ q-2$ , whereas lattice higher-gradient terms supply the missing $ q-1$ and $ q$ parities and complete the hierarchy through order $ q$ . We explicitly illustrate this new revised hierarchy on a $ d$ -wave altermagnet irradiated by a circularly-linearly polarized light, and show that the asymmetry of the driving field is transferred to the light-dressed electronic structure, producing momentum-asymmetric dispersions beyond the static and single-frequency limits. We further show that this band asymmetry is absent in the leading continuum expansion and originates from higher-gradient lattice terms that are converted by the bichromatic drive into odd-in-momentum contributions. Extending the analysis to higher-order unconventional magnets, we further obtain complete magnetic hierarchies for all $ q$ -parity unconventional magnets. Our results establish bichromatic Floquet driving as a general route for generating mixed-parity magnetic hierarchies and dynamically engineering unconventional magnetism.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
5 + 2 Pages; 2 Figures
Minimax entropy production for arbitrary processes
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-05 20:00 EDT
Mahran Yousef, Ben Ansbacher, David H. Wolpert
For any physical process, varying the initial distribution over its states will change the resulting expected entropy production (EP). An initial distribution that minimizes the EP of a particular process is called the prior of that process. Varying the microphysical details of the process will change its this http URL consider the following question: if an engineer wants to design a system to implement a given map, what prior should they design into the system to minimize the EP for the worst-case actual distribution? We derive the closed-form solution to this problem when the map is deterministic. We also show that for stochastic maps, a worst-case actual distribution can always be chosen to be a point mass on a single state, and that the associated minimax prior resembles a Boltzmann-Gibbs equation, and can be found by a globally convergent numerical algorithm. We also show that the associated minimax mismatch cost is the maximum uncertainty about the input that remains after observing the output. Finally, we extend the analysis to the continuous-time regime, showing that the minimax instantaneous mismatch-cost diverges, while the corresponding finite-time minimax mismatch cost has a universal short-time scaling set by the largest escape rate of the dynamics.
Statistical Mechanics (cond-mat.stat-mech)
6 pages, 3 figures, 16 pages of Supplemental Material
Melting phase diagram of the two-dimensional electron solid in a perpendicular magnetic field
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-05 20:00 EDT
M. Yu. Melnikov, D. G. Smirnov, A. A. Shashkin, S.-H. Huang, C.W. Liu, S. V. Kravchenko
We determine the thermal melting phase diagram of the electron solid by measuring the onset density of the double-threshold voltage-current curves in the insulating state in the ultra-high mobility two-dimensional electron system in SiGe/Si/SiGe quantum wells at different temperatures in perpendicular magnetic fields. The introduction of a magnetic field leads to a considerable increase in the onset density, which is strongest at the lowest temperatures and decreases with increasing temperature, and the melting temperature increases with magnetic field. These data are in agreement with theoretical predictions. Unexpectedly, the melting temperature as a function of electron density in a fixed magnetic field reveals a plateau, which can be interpreted in terms of resonance modes in the crystallites.
Strongly Correlated Electrons (cond-mat.str-el)
Electrostatic Doping of Moiré Superlattices Controls the Optical Fingerprint of a WSe_2 /Twisted Bilayer Graphene heterostructure
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-05 20:00 EDT
Houssem Eddine Hannachi, Sihem Jaziri
We theoretically investigate the optical response of the WSe2 monolayer vertically stacked on twisted bilayer graphene (tBG) under electrostatic doping. In this heterostructure, the doped moiré superlattice of tBG generates a spatially modulated electrostatic potential that couples to the electron and hole constituents of the WSe2 exciton through the screened Coulomb interaction, thereby providing a microscopic mechanism for exciton coupling to the charge-density landscape of the moiré Fermi sea. Focusing on twist angles below the magic angle (1.1°), where electronic correlations are strongly enhanced, we demonstrate that electrostatic doping induces pronounced modifications of the excitonic absorption spectrum, including the emergence of multiple satellite resonances. We show that these spectral features originate from the interplay between the exciton center-of-mass and internal degrees of freedom, together with doping-induced hybridization between Rydberg exciton states of different orbital symmetry. The calculated spectra are in good agreement with previously reported experimental observations and theoretical predictions. Our results establish electrostatic doping in tBG as an effective means of engineering excitonic states in adjacent semiconducting monolayers and provide a pathway toward novel optical sensor devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Symmetry Engineering Enables Deterministic Ensemble Polarization Control in Hexagonal Boron Nitride
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-05 20:00 EDT
Aqiq Ishraq, Eric Herrmann, Pragya Agnihotri, Alexander Hutchinson, Ramiro M. dos Santos, Shahidul Asif, Lottie Murray, Abhijith Puthiya Veettil, Luke Stockl, Muhammad Hassan Shaikh, Collin Maurtua, Kenji Watanabe, Takashi Taniguchi, Matthew Doty, Cyrus E. Dreyer, Anderson Janotti, Xi Wang, Chitraleema Chakraborty
Optical polarization is a key degree of freedom in quantum photonic and sensing technologies, enabling efficient light–matter coupling and directional emission. However, in defect ensemble-based quantum systems, orientational averaging across many defects suppresses optical anisotropy and eliminates a deterministic polarization axis. Here, symmetry engineering is introduced as a strategy to restore collective optical anisotropy in negatively charged boron vacancy (V_B^-) ensembles hosted in hexagonal boron nitride (h-BN). By imposing anisotropic in-plane tensile strain through lithographically defined nano-ridge arrays, in-plane symmetry is broken and the ensemble emission dipole is aligned with the ridge-defined strain symmetry axis. Polarization-resolved photoluminescence reveals that the polarization visibility scales with the magnitude of strain anisotropy, while the emission orientation rigidly follows the engineered symmetry axis across devices with varying strain direction. This deterministic alignment is independent of crystal orientation, establishing the optical foundation for polarization-defined ensemble spin readout and programmable photonic integration in two-dimensional quantum materials
Materials Science (cond-mat.mtrl-sci)
Consistent perturbation expansions in screened interactions
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-05 20:00 EDT
Abdallah Arthur El Sahili, Francesco Sottile, Lucia Reining
Many-body perturbation theory is a powerful framework to calculate spectroscopic quantities, as well as the total energy. However, the field suffers from the fact that different flavors of approximations lead to a wide range of results. We present several in principle exact expansions and discuss how to use them consistently. We concentrate on the first two orders in the respective screened Coulomb interaction. Of special interest is a consistent expansion around the Kohn-Sham system. We illustrate the performance of the various choices using the symmetric Hubbard dimer over a wide range of correlation strength. In particular, the expansion based on exact Kohn-Sham ingredients stands out as a promising route towards good energies and good spectra.
Strongly Correlated Electrons (cond-mat.str-el)
29 pages, 10 figures
Layer-Asymmetry-Induced Topological Superconductivity in High-T$_c$ Bilayer Nickelates
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-05 20:00 EDT
Zhongyi Zhang, Congcong Le, Hoi Chun Po, Jiangping Hu, Xianxin Wu, Shengshan Qin
The recent discovery of high-T$ _c$ superconductivity in bilayer nickelates has highlighted the crucial role of interlayer coupling and motivated proposals for dominant interlayer pairing. Whether such pairing can support topological superconductivity, however, remains unexplored. Here, we demonstrate that substrate-supported bilayer nickelate thin films can host an intrinsic time-reversal-invariant topological superconducting phase protected by diagonal mirror symmetry. Using a two-orbital model derived from first-principles calculations, we show that a modest layer-asymmetric potential and layer-staggered Rashba spin-orbit coupling drive the system into this topological phase over a broad parameter range with a dominant interlayer pairing. The nontrivial topology arises from a reversal of the pairing sign on one of the spin-split bonding Fermi surfaces and is characterized by a nonzero mirror winding number along the diagonal direction, as well as a Majorana Kramers pair at the [11] edge. The phase also features bulk gap nodes located slightly away from the diagonal directions, featuring chiral charge and zero-energy flat bands. We discuss experimental routes for realizing and tuning this phase. Our results establish high-T$ _c$ bilayer nickelates as a promising platform for topological superconductivity, where tunable topological transitions and Majorana boundary modes can provide probes of unconventional pairing.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
8 pages, 4 figures
Decohering Kitaev’s Sixteenfold Way: A Holographic Approach
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-05 20:00 EDT
Shuyu Zhang, Linhao Li, Zhen Bi, Tzu-Chieh Wei, Zijian Song
We study anyon decoherence in 2D topological order, with the fermion decoherence in Kitaev’s sixteenfold way as explicit examples. The sixteenfold way includes chiral topological phases, which are believed to admit no commuting projector Hamiltonian, making it challenging to study their decoherence directly. We further conjecture the density matrix produced by this decoherence induced phase transition can be obtained by a three-step procedure: first lift the topological order to its Walker-Wang model, followed by a transition to another Walker-Wang model, and finally trace over the bulk degrees of freedom. This establishes a connection between the decoherence of a topological order and a pure state phase transition in its 3D counterpart. Many examples are given. In particular, we show that decohering the fermion in each of the sixteen states always yields an intrinsically mixed-state topological order, a consequence of the fact the corresponding 3D bulk always transits into the 3D fermionic toric code (fTC). Our result suggests a systematic method for studying anyon decoherence in chiral topological orders at the level of commuting projector Hamiltonians.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
31 pages, 6 figures, 1 table
Surface Charge–Potential Relation for Spherical Particles in Electrolyte Solutions
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-05 20:00 EDT
Olga I. Vinogradova, Elena F. Silkina
Predicting the relationship between surface charge density and electrostatic potential for spherical particles remains a fundamental challenge in colloid science. Because the governing non-linear Poisson–Boltzmann equation lacks a general exact analytical solution, researchers typically rely on numerical calculations or various semi-empirical approximations. In this paper, we overcome these limitations by developing a dual-asymptotic framework that provides explicit, closed-form expressions for this surface charge–potential relationship across the entire spectrum of particle curvature. For weakly curved systems, where the Debye length $ \lambda_D$ is much smaller than the particle radius $ R$ ($ \lambda_D/R \ll 1$ ), a formal mathematical derivation rigorously establishes the Ohshima–Healy–White formula as an exact regular perturbation expansion. Conversely, for highly curved spheres ($ R/\lambda_D \ll 1$ ), we employ singular perturbation analysis using the scaled particle radius as the small parameter. This approach provides a first-principles mathematical justification for the spherical Debye–Hückel theory, proving that its leading-order expansion remains asymptotically exact within the full non-linear Poisson–Boltzmann framework due to the geometric deactivation of non-linearity. Crucially, we map the exact limits of this geometric regulation, demonstrating how non-linear screening re-emerges as the particle radius increases, with the breakdown threshold governed by the interplay between curvature and surface charge density.
Soft Condensed Matter (cond-mat.soft), Chemical Physics (physics.chem-ph)
Finite-momentum pairing and magnetic halos in a spin-imbalanced Holstein model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-05 20:00 EDT
Chunhan Feng, George Batrouni, Richard Scalettar
Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) superconductivity, Cooper pairing at finite-momentum driven by spin imbalance, remains difficult to study numerically in two dimensions. The fermion sign problem in the spin-imbalanced attractive Hubbard model severely limits quantum Monte Carlo access to the low temperatures where pairing correlations are most pronounced. We show that the Holstein model, in which the effective attraction is retarded by phonon dynamics, strongly suppresses sign fluctuations under spin imbalance, enabling unbiased determinant quantum Monte Carlo simulations deep in this regime. With increasing magnetization, zero-momentum pairing evolves into finite-momentum FFLO pairing, evidenced by oscillating real-space pair correlations and a shift of the pairing susceptibility peak to finite $ \vec{Q}$ . The finite-momentum susceptibility substantially exceeds its zero-momentum value. At high density $ n \sim 0.875$ , near magnetization $ m \approx 1-n$ where the majority-spin density approaches half filling, FFLO pairing coexists with checkerboard charge-density-wave order at short range, while staggered longitudinal spin correlations emerge as a magnetic halo at larger distances. These spatial textures provide experimentally accessible signatures of finite-momentum pairing and motivate cold-atom realizations of FFLO physics.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Gases (cond-mat.quant-gas), Superconductivity (cond-mat.supr-con)
Research Square
Monolithic all-optical phase regenerator via parity-time symmetry
Article | Integrated optics | 2026-10-04 20:00 EDT
Jing Xu, Zhuang Fan, Yukun Huang, Wu-Qiang Chi, Wenchan Dong, Haodong Yang, Jiahao Hu, Yizheng Chen, Kunpeng Zhai, Ninghua Zhu, Huashun Wen, Xinliang Zhang, Kun Qiu, Heng Zhou
Optical phase represents a fundamental dimension of electromagnetic waves, where the elimination of phase noise is crucial in various applications. Kerr-mediated all-optical phase regeneration can mitigate noise on-the-fly but requires complicated and bulky phase-locking circuits to yield high-fidelity optical phase coherence. Extending this approach to practical applications, the challenges are to develop miniaturized regenerators without trading off performance, a critical barrier rooted in the fundamental conflict between the high-Q environment required for phase locking and the low-Q environment needed for high processing speed. Here we demonstrate a monolithic all-optical phase regenerator within an integrated coupled resonator, with processing rate exceeding the high-Q cavity linewidth by a factor of over 30. The key is exploiting Kerr-induced synchronization (KIS) as a passive, electronics-free phase-locking mechanism within a parity-time (PT) symmetric design, which simultaneously supports high-Q mode for KIS and low-Q mode for high-speed signal processing. Experimentally, phase regeneration at Gigabits per second rates is achieved using MHz-linewidth cavity, with phase distortion up to ± 45° fully regenerated to the back-to-back level. This work demonstrates a paradigm shift in optical phase regeneration from benchtop assemblies to a monolithic chip via non-Hermitian optics, opening new avenues for next-generation, densely integrated chip-scale photonic processors across communications, quantum technologies, sensing, and metrology.
Research Square:rs-11185660 (2026)
Posted on Research Square and Under Review at Nature Portfolio
Physical sciences/Optics and photonics/Applied optics/Integrated optics, Physical sciences/Optics and photonics/Optical materials and structures/Microresonators, Physical sciences/Optics and photonics/Applied optics/Fibre optics and optical communications