CMP Journal 2026-05-11
Statistics
Nature Materials: 1
Nature Physics: 2
Nature Reviews Physics: 1
arXiv: 69
Nature Materials
Strategies of high-accuracy memristor-based analogue computing in memory for artificial intelligence
Review Paper | Electrical and electronic engineering | 2026-05-10 20:00 EDT
Zhixing Jiang, Han Zhao, Jianshi Tang, Yuyao Lu, Qi Qin, Ze Wang, Ruofei Hu, Ruihua Yu, Yuan He, Junyang Zhang, Mingcheng Shi, Ning Deng, Bin Gao, He Qian, Huaqiang Wu
Memristor-based analogue computing in memory (CIM) offers revolutionary gains in energy efficiency and computing power for data-intensive applications such as artificial intelligence. However, it typically struggles with achieving high accuracy at the same time, owing to the noise-sensitive nature of analogue computing and the non-ideal characteristics at the device and circuit levels that inevitably result in computing errors. Although progress has been made in device engineering and hardware-algorithm co-optimization to mitigate the error and parasitic effects, many of these advances inadvertently incur a hardware or energy consumption overhead, undermining the core benefits of analogue CIM. This Review dissects the computing error sources across the CIM hierarchy from the memristor device and array to the system architecture and algorithm, and evaluates the strategies to minimize those errors. We highlight the material and device innovations, array-level techniques and algorithm-architecture co-design frameworks towards high-accuracy analogue CIM. By dissecting the trade-off between computing accuracy and implementation cost, this Review draws a roadmap for translating memristor-based analogue CIM technology from proof-of-concept prototypes to large-scale deployment for accelerating next-generation artificial intelligence.
Electrical and electronic engineering, Electronic devices
Nature Physics
Scalable generation of massive Schrödinger cat states via quantum tunnelling
Original Paper | Quantum metrology | 2026-05-10 20:00 EDT
Han Zhang, Yong-Kui Wang, Yi Zheng, Hai-Tao Bai, Bing Yang
Massive objects in spatial superposition may provide insights into the interplay between quantum mechanics and gravity. Cold-atom interferometers offer a promising platform due to extended matter-wave coherence times and precise controllability. However, high-mass spatial superpositions beyond single atoms have yet to be generated in such setups. Here we report the scalable realization of high-mass spatial entanglement via the quantum tunnelling of ultracold atoms in optical lattices. We observe the coherent tunnelling of bound clusters, forming a composite object with a mass of 608 AMU. Full control of the model parameters allows us to mitigate the usual suppression of tunnelling with increasing mass. Furthermore, we construct an interferometer to certify the entanglement and use spatially distributed Schrödinger cat states to perform quantum-enhanced measurements. These results establish an approach to generate and detect massive superposition states relevant to studies of quantum gravity.
Quantum metrology, Quantum simulation, Ultracold gases
Correlated insulator in the kagome flat band of a two-dimensional electrostatic crystal
Original Paper | Electronic and spintronic devices | 2026-05-10 20:00 EDT
Daisy Q. Wang, Zeb Krix, Olga A. Tkachenko, Vitaly A. Tkachenko, Chong Chen, Ian Farrer, David A. Ritchie, Oleg P. Sushkov, Alexander R. Hamilton, Oleh Klochan
The electronic properties of solids are determined by their crystal structure and electron interactions, giving rise to phenomena such as superconductivity, strange metals and correlated insulators. Many of these effects remain poorly understood, motivating efforts to create artificial crystals that mimic real materials while allowing controlled tuning of key parameters. Cold atoms in optical lattices offer flexibility but cannot reproduce the long-range Coulomb interactions and hopping present in solids. Solid-state systems naturally support these features, although they suffer from tunability and flexibility issues. Here we demonstrate a highly tunable artificial crystal formed by superimposing a periodic electrostatic potential onto a two-dimensional electron gas in a shallow GaAs quantum well. This engineered lattice exhibits a band structure characteristic of the artificial triangular lattice, distinct from that of the underlying cubic crystal. Electronic transport measurements show a sign change in the Hall coefficient as the chemical potential sweeps through the artificial bands. The band structure can be continuously tuned to realize linear graphene-like and flat kagome-like bands within a single device. A strong insulating state emerges at half filling of the kagome flat band, consistent with interaction-driven behaviour. This tunability provides an opportunity to explore correlated quantum states in a controlled setting.
Electronic and spintronic devices, Electronic properties and materials
Nature Reviews Physics
Black-hole thermodynamics
Review Paper | General relativity and gravity | 2026-05-10 20:00 EDT
Robert B. Mann
It has been 50 years since thermodynamics and general relativity were united in the study of black-hole thermodynamics. This Review covers the established principles in the subject, including the four laws of black-hole thermodynamics, notions of temperature and entropy, and the chemical behaviour exhibited by black holes. However, there are still many unsolved puzzles in black-hole thermodynamics: we discuss violations of the third law, non-equilibrium behaviour and black-hole microstructure, as well as the information paradox that encapsulates a deep conundrum between gravitation and quantum physics. We also assess the prospects for progress through understanding multicritical behaviour and the dynamics of phase changes, the use of holographic approaches, and, ultimately, the resolution of the information paradox. After 50 years, black-hole thermodynamics still offers much to learn about the relationship between gravitation and quantum physics.
General relativity and gravity, Theoretical physics
arXiv
Landau free energy and the absence of spontaneous magnetization of the one-dimensional Ising model
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-05-11 20:00 EDT
Z. F. Zheng, R. K. Lin, J. M. Zhang
We revisit the problem of spontaneous magnetization of the one-dimensional Ising model from the Landau free energy perspective. To this end, we define and calculate the density of states of the one-dimensional Ising model following a technique introduced by Ising. The observed monotonicity property of the density of states suggests heuristically that the model does not exhibit spontaneous magnetization at any finite temperature. Subsequently, we solve the model exactly in the thermodynamic limit by employing the maximum-term approximation, which is feasible due to the simple analytical expression of the density of states. We also show that the Landau free energy is an increasing function of $ |m|$ and its second derivative at $ m=0$ is positive and non-analytic in temperature, proving rigorously the absence of spontaneous magnetization of the model at any finite temperature.
Statistical Mechanics (cond-mat.stat-mech)
13 pages, 3 figs. To appear in European Journal of Physics. Comments are welcome
Breakdown of Adiabatic Scaling and Noise-Induced Functional Synchronization in Deeply Quiescent Excitable Systems
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-05-11 20:00 EDT
Coherence resonance (CR) characterizes noise-induced regularity in excitable systems, yet its evaluation in quiescent biological media is often obscured by flattened energy landscapes and complex nonlinear dynamics. In this study, we investigate the stochastic dynamics of a 3D Sherman-Rinzel-Keizer (SRK) model driven by multiplicative Feller noise. We show that traditional extremal evaluations of CR encounter a “bathtub effect” a broad resonance valley that can lead to statistical inaccuracies. To address this, we propose a logarithmic centroid extraction method, which filters out stochastic jitter and recovers the underlying adiabatic Kramers scaling with high linearity (R^2 > 0.95). Furthermore, we identify the physical boundary where this adiabatic approximation breaks down under the strong-noise limit. Extending our analysis to gap-junction coupled systems, we observe a noise-induced transition from sub-threshold physiological shivering (characterized by statistical correlation but negligible functional output) to macroscopic functional synchronization. Our results provide a mathematical framework for extracting optimal noise intensities in broad energy valleys and offer insights into how quiescent biological systems utilize stochastic fluctuations for functional recovery
Statistical Mechanics (cond-mat.stat-mech), Probability (math.PR), Chaotic Dynamics (nlin.CD), Biological Physics (physics.bio-ph), Molecular Networks (q-bio.MN)
12 pages, 9 figures
Diffusive transport from spatially correlated random phase kicks
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-05-11 20:00 EDT
We study the dynamics of a single-particle wave packet on a one-dimensional lattice subject to periodic random phase kicks with finite spatial correlation length. This stroboscopic setting provides a controllable model of dephasing in driven quantum systems. Using a momentum-space formulation, we show that the evolution is governed by an accumulated phase whose structure determines the spreading of the wave packet. We find that the phase kicks strongly suppress ballistic transport and induce diffusion at long times. We derive an explicit analytical expression for the diffusion coefficient as a function of the correlation length, in excellent agreement with numerical simulations. Our results uncover a simple mechanism by which spatially correlated phase noise controls quantum transport, and provide a quantitatively testable prediction for diffusion in periodically driven lattice systems. Possible experimental realizations in cold-atom platforms are discussed.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Disordered Systems and Neural Networks (cond-mat.dis-nn), Quantum Gases (cond-mat.quant-gas)
5 pages, 3 figures
Emergence of Tsallis Statistics from a Self-Referential Nonlinear Operator: A Variational Framework
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-05-11 20:00 EDT
We develop a variational thermodynamic framework for statistical systems governed by a self-referential nonlinear operator Omega characterized by structural exponents alpha > 0, beta >= 0, a symmetric kernel K, and a self-coupling constant kappa >= 0. The central object is the self-consistency entropy S[Psi] = -D_KL(Psi || Omega Psi), which vanishes at the fixed points of Omega and serves as a natural Lyapunov functional.
Within the local kernel (mean-field) approximation, minimization of the free energy F = U - T S admits the Tsallis q-exponential distribution as an equilibrium state, with the entropic index q = alpha + beta emerging directly from the fixed-point structure of the operator rather than being postulated. The framework yields a consistent thermodynamic description, including a generalized equation of state PV = (2 - q) T, response functions, and a critical temperature associated with spontaneous symmetry breaking.
The relation q = alpha + beta connects independently measurable structural exponents of the feedback mechanism to the observed tail index, providing a parameter-free criterion that distinguishes this approach from superstatistics, constrained entropy maximization, and q-deformed formalisms. This work establishes an operator-theoretic foundation for nonextensive statistical mechanics in which nonlinear self-referential feedback naturally generates Tsallis statistics in the mean-field limit.
Statistical Mechanics (cond-mat.stat-mech), Mathematical Physics (math-ph)
18 pages, 1 figure. Companion paper on dynamical aspects and H-theorem (submitted separately to arXiv)
Quantum spin liquid on a 3D bipartite lattice of spin trimers stabilized by enhanced effective anisotropy
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-05-11 20:00 EDT
M. Gomilšek, L. Mangin-Thro, T. Arh, S. Petit, B. Grenier, V. Simonet, M. Pregelj, A. Zorko, B. Koteswararao, B.-G. Jeon, B. Sana, Y. Furukawa, Y. Inagaki, T. Asano, C. Repellin, B. Fåk, J. Ollivier, F. Fauth, C. V. Colin, E. Pachoud, V. Pomjakushin, J. S. Lord, H. Luetkens, K.-H. Kim, P. Khuntia
Quantum spin liquids (QSLs) represent highly entangled states of matter in which frustration-induced quantum fluctuations suppress any symmetry-breaking phase transition down to absolute zero, giving rise to fractionalized excitations and emergent gauge fields. Theoretically, bond anisotropy can stabilize QSLs even on bipartite lattices, as exemplified by the Kitaev honeycomb model; however, no material has so far been established to realize such a state as its true ground state. Here we identify the three-dimensional spin-trimer magnet KBa$ _3$ Ca$ _4$ Cu$ _3$ V$ _7$ O$ _{28}$ as a promising candidate for a bipartite quantum spin liquid persisting to the lowest temperatures. Strongly coupled Cu$ ^{2+}$ trimers form effective pseudospin-1/2 degrees of freedom upon cooling, which in turn constitute a three-dimensional bipartite network. Bulk thermodynamic measurements, neutron scattering, $ \mu$ SR, and NMR detect no spin freezing or symmetry-breaking phase transition down to 20 mK, but instead reveal a gapless dynamical ground state with algebraic spin autocorrelations. Complementary Monte Carlo and exact-diagonalization calculations show that this state is stabilized by a strong enhancement of effective anisotropy: a weak microscopic Cu-Cu exchange anisotropy of approximately 15 percent is generically amplified at the trimer level, producing effective pseudospin-pseudospin interaction anisotropies of 60 to 100 percent. Our results establish trimer-based networks as a promising platform for realizing anisotropy-stabilized quantum entangled states, even in three-dimensional bipartite systems with only weak microscopic anisotropy.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Direct Experimental Test of Conformal Invariance via Grazing Scattering: A Proposal for X-ray and Neutron Experiments
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-05-11 20:00 EDT
Alessandro Podo, Slava Rychkov
We propose a test of conformal invariance in critical phenomena based on the study of a two-point correlation function in the presence of a boundary. This two-point function can be studied using X-ray or neutron scattering in the conditions of total reflection (so-called grazing scattering). The conformal Ward identity in momentum space is here expressed as a differential constraint on the scattering cross-section, as a function of the momentum transfer and the scattering angle. Experimental verification, using e.g. binary alloys, appears well within the existing techniques. This would be the first direct experimental test of conformal invariance in critical phenomena, a symmetry widely assumed but never directly verified.
Statistical Mechanics (cond-mat.stat-mech), Materials Science (cond-mat.mtrl-sci), Soft Condensed Matter (cond-mat.soft), Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Theory (hep-th)
41 pages, 11 figures
Bootstrapping ground state properties of classical frustrated magnets
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-05-11 20:00 EDT
We introduce a method based on semidefinite programming that produces rigorous two-sided bounds on ground state energy densities and correlation functions of translation-invariant classical spin models on infinite lattices. In this method, the challenge of non-convex optimization on an infinite lattice is replaced with a hierarchy of finite-size convex optimizations arising from positivity conditions that any probability distribution over spin configurations must satisfy. This adapts the Lasserre hierarchy in the theory of polynomial optimization to the context of frustrated magnetism, and we prove convergence of this hierarchy in the thermodynamic limit. Our method subsumes the Luttinger–Tisza method and further applies to non-quadratic Hamiltonians and non-Bravais lattices, thus addressing limitations of prior analytical methods. We apply the method to various two-dimensional frustrated spin models, where it brackets the energy densities and observables accurately across large parameter ranges with typical run times of seconds per parameter point.
Statistical Mechanics (cond-mat.stat-mech), Disordered Systems and Neural Networks (cond-mat.dis-nn)
7+5 pages, 4 figures
Disentangling bulk and surface electronic structure using targeted cleave planes in RuO$_2$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-05-11 20:00 EDT
Maria H. Visscher, Sebastian Buchberger, Bruno Saika, Shu Mo, Lea Richter, Mats Leandersson, Craig Polley, Andrew P. Mackenzie, Phil D. C. King
Rutile RuO$ _2$ has attracted significant interest due to its putative unconventional electronic and magnetic properties and its proximity to superconductivity. However, the measurement and interpretation of its electronic structure has been complicated by a strongly three-dimensional crystal structure. Here, we demonstrate how the preparation of targeted $ (110)$ and $ (100)$ surfaces via focused ion beam (FIB)-engineered cleaving allows the acquisition of high-quality measurements of the electronic structure using angle-resolved photoemission spectroscopy. Our results demonstrate that ARPES spectra of RuO$ _2$ are, in fact, largely dominated by signatures of distinct surface electronic states. From comparison with density-functional theory, we resolve a surface termination-dependent variation of these, and disentangle them from highly-three-dimensional bulk states and surface resonances. Moreover, we find a marked role of the substantial spin-orbit coupling of the Ru 4$ d$ orbitals in the surface region, where a breaking of spatial inversion symmetry leads to significant Rashba-type spin splittings of the surface bands.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
11 pages, including 4+6 figures
Does a Fractional Quantum Hall Edge Have a Protected Intrinsic Dipole Moment?
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-05-11 20:00 EDT
Domagoj Perković, Konstantinos Vasiliou, S.A. Parameswaran, Steven H. Simon
We investigate the claims by Park and Haldane [Phys. Rev. B 90, 045123 (2014)] of an intrinsic protected value of the electric dipole moment at the physical edge of fractional quantum Hall (FQH) systems. Contrary to prevailing expectations, we find that the edge dipole takes the expected intrinsic value only in certain very special cases. We identify key limitations in earlier numerical studies and employ density matrix renormalization group (DMRG) methods to accurately compute the ground-state dipole. We focus on three representative systems: the $ \nu=1/3$ -vacuum edge, the $ \nu=2/3$ -vacuum edge, and the interface between Pfaffian and anti-Pfaffian phases. We find that the expected intrinsic dipole value occurs only at $ \nu=1/3$ , whereas the other systems do not exhibit the claimed intrinsic value. We give arguments based on composite fermions as to why hierarchy states should generally not have protected intrinsic dipoles. These results have important implications for the energetics and edge structure of FQH states.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Majorana bound states in chiral ferromagnet-superconductor heterostructures revisited
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-05-11 20:00 EDT
A. S. Slobodskoi, S. S. Apostoloff, I. S. Burmistrov
Majorana zero modes are central to the pursuit of fault-tolerant topological quantum computation. While traditionally sought in one-dimensional hybrid nanowires, a robust alternative platform involves heterostructures combining superconductors with noncollinear magnets. This work focuses on a particularly promising system: a chiral ferromagnet hosting a magnetic skyrmion coupled to a superconducting film containing a superconducting vortex. Such skyrmion-vortex pairs have recently been realized experimentally and are theorized to harbor localized Majorana states, offering a potential pathway for braiding operations. We present a comprehensive theoretical analysis of the low-energy quasiparticle bound states in these heterostructures. Extending previous studies, we develop an analytical framework for the Majorana wavefunctions as well as the wavefunctions and spectrum of other lowlying states within a Bogoliubov-de Gennes approach. Our analytical results explicitly demonstrate the critical role of spin-orbit coupling for the stabilization of Majorana modes and provides approximate analytical expressions for low-lying states localized at the vortex, both with and without an accompanying skyrmion. The derived analytical results show excellent agreement with numerical simulations. We further elucidate the role of realistic effects, including vector potentials and texture perturbations from stray magnetic fields, to assess their impact.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
24 pages, 10 figures
LLM-Guided Open Hypothesis Learning from Autonomous Scanning Probe Microscopy Experiments
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-11 20:00 EDT
Boris Slautin, Utkarsh Pratiush, Yu Liu, Kamyar Barakati, Sergei Kalinin
Autonomous experimentation has transformed microscopy and materials discovery by enabling closed-loop optimization including imaging and spectroscopy tuning, strucutre property relationship discovery, and exploration of combinatorial libraries. However, most current workflows remain limited to selecting measurements within fixed objective or hypothesis spaces, rather than generating new physical models from experimental data. Here, we introduce an open hypothesis-learning framework that combines symbolic regression with large-language-model-based physical evaluation and implement it for autonomous scanning probe microscopy. Symbolic regression generates candidate analytical relationships directly from sparse measurements, while the language-model evaluator ranks these candidates according to physical plausibility, scaling behavior, and consistency with known mechanisms. We demonstrate the approach on autonomous piezoresponse force microscopy measurements of ferroelectric domain switching in a PZT thin film. Starting from five seed measurements, the workflow evolves from physically incomplete candidate expressions toward interpretable voltage-time growth laws consistent with kinetic domain-wall motion. This work extends autonomous microscopy from closed-loop optimization toward open hypothesis discovery, where candidate physical laws emerge from the experiment itself rather than being specified in advance. More broadly, the framework establishes a route for integrating symbolic regression, physical reasoning, and adaptive experimentation into hierarchical autonomous scientific workflows.
Materials Science (cond-mat.mtrl-sci), Artificial Intelligence (cs.AI)
21 pages, 6 figures, 1 table
Fluctuation-driven chiral ferromagnetism
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-05-11 20:00 EDT
Rokas Veitas, Ahmed Khalifa, Francisco Machado, Shubhayu Chatterjee
In general, quantum fluctuations are suppressed in ferromagnetic materials because they admit a simple unfrustrated ground state, greatly limiting the scope of phenomena that can be observed in these materials. In this work, we show how magnetization-non-conserving couplings fundamentally alter this paradigm by demonstrating the existence of a chiral ferromagnet that is stabilized by quantum fluctuations. More specifically, we show how these spin-orbit interactions modify the classical phase diagram; whereas a classical analysis predicts only collinear states, we observe fluctuation-stabilized phases, including a ferromagnet with large orbital chirality and a chiral stripe regime. We elucidate how such couplings spontaneously generate a scalar orbital chirality, in contrast to conventional mechanisms which rely upon a field-induced canting of vector chiral order. The resultant chiral states exhibit distinct transport signatures, namely an enhanced thermal Hall effect, and are of direct relevance to moiré heterostructures, Rydberg-atom arrays, and solid-state materials featuring non-Kramers spins.
Strongly Correlated Electrons (cond-mat.str-el)
5+9 pages, 4+3 figures
Topological superconductivity in a Hubbard model for twisted bilayer cuprates
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-05-11 20:00 EDT
We investigate the emergence of nontrivial topology in a twisted cuprate bilayer described by the Hubbard model in the weak-interaction regime. Our results show that the topological character depends sensitively on the doping level. For $ U/t=3.85$ , the Chern number assumes a value of $ \pm 8$ in the electron-doped case, whereas it vanishes (0) in the hole-doped regime. The presence of nontrivial topology is further supported by an analysis the associated edge states and their chirality in a finite-width geometry, while keeping full correlations.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
7 pages, 7 figures. Associated data can be found at this https URL
Multilane Asymmetric Exclusion Process with stationary Bernoulli measure
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-05-11 20:00 EDT
We consider an Asymmetric Exclusion Process evolving on parallel mutually interacting lanes with neighbouring nearest hoppings of hardcore particles. Number of particles on each lane is conserved. We find a choice of the hopping rates, for which the process has Bernouilli stationary product measure, and calculate the stationary particle currents as a function of average particle densities.
Statistical Mechanics (cond-mat.stat-mech)
4 pages, 2 Figures
Nonadiabatic Theory of Phonon Magnetic Moments in Insulators and Metals
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-05-11 20:00 EDT
Haoran Chen, Wenqin Chen, Kaijie Yang, Ting Cao, Di Xiao
We develop a nonadiabatic theory of phonon magnetic moments applicable to both insulators and metals. By relating the phonon magnetic moment to the force-velocity response of ions in a magnetic field, we derive a gauge-invariant expression using a gauge-covariant Wigner expansion. The formalism naturally separates Fermi-sea and Fermi-surface contributions and captures the full dependence on phonon frequency. In gapped systems, our theory reduces to previous adiabatic expressions in the low-frequency limit. Beyond this limit, it reveals additional contributions arising from resonant interband processes and the Fermi surface. Applying our theory to Pb$ _{1-x}$ Sn$ _x$ Te, we find that the Fermi-surface contribution substantially enhances the phonon magnetic moment, reproducing the same order of magnitude as the experimental observation. Our results provide a unified framework for describing phonon magnetic moments beyond the adiabatic regime.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
5 pages, 3 figures
Anomalous Phase-Coherence Scaling in a Quantum-Critical Dirac Semimetal
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-05-11 20:00 EDT
Sana Nakamichi, Ryotaro Kobara, Yoshinari Unozawa, Yoshitaka Kawasugi, Sakura Hiramoto, Koki Funatsu, Toshio Naito, Masafumi Tamura, Reizo Kato, Yutaka Nishio, Naoya Tajima
We have investigated the weak antilocalization (WAL) in the pressurized Dirac semimetal $ \alpha$ -(BEDT-TTF)$ 2$ I$ 3$ across a correlation-driven quantum phase transition to a charge-ordered insulating state and evaluated the phase coherence length $ L{\phi}$ and its temperature scaling under various pressures from the low-temperature magnetoconductivity. In the high-pressure regime, the system exhibits the conventional two-dimensional dephasing behavior ($ L{\phi} \propto T^{-p}$ with $ p \approx 1/2$ ), characteristic of electron-electron scattering in diffusive conductors. As the pressure approaches the critical pressure ($ P_c \sim 1.2$ GPa), the temperature exponent is suppressed to $ p \sim 0.3$ , while $ L_{\phi}$ remains large ($ 700\text{-}800$ nm at 0.5 K). This anomalous scaling suggests nontrivial inelastic scattering associated with Dirac electrons near the quantum critical point. The persistence of WAL across the transition supports a gapless or nearly gapless quantum phase transition.
Strongly Correlated Electrons (cond-mat.str-el)
12 pages, 4 figures
J. Phys. Soc. Jpn. 95, 063703 (2026)
Revisiting magnetoelectric response in collinear antiferromagnetic zigzag chains: A downfolding approach beyond conventional low-energy models
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-05-11 20:00 EDT
Magnetoelectric (ME) effects in antiferromagnets provide a fertile platform for exploring symmetry-driven cross-correlated responses. However, their microscopic origin remains elusive and is often obscured in simplified low-energy descriptions. In this study, we revisit the microscopic mechanism of the ME effect in a collinear antiferromagnetic zigzag chain by employing a multi-orbital tight-binding model that explicitly includes both $ s$ - and $ p$ -orbital degrees of freedom. Using analytical and numerical calculations based on the Kubo formula, we demonstrate that the ME response is governed by orbital degrees of freedom activated through $ s$ –$ p$ hybridization, while the spin contribution vanishes due to spin conservation. To elucidate the low-energy description, we derive an effective Hamiltonian projected onto the $ s$ -orbital subspace using the Schur complement. We show that a naive application of the Kubo formula within this effective model fails to capture the ME response. This issue is resolved by systematically incorporating vertex corrections in terms of orbital hybridization into the response functions. Furthermore, by introducing a quasiparticle renormalization scheme, we formulate a renormalized Kubo formula that preserves conservation laws and accurately reproduces the full multi-orbital results. Our analysis revisits the conventional low-energy perspective and reveals that the ME effect originates from virtual interorbital processes encoded in vertex corrections, rather than from the bare low-energy Hamiltonian. The effective framework developed here provides a unified microscopic understanding of orbital-driven ME responses and offers a systematic route to incorporate hybridization effects beyond simple low-energy models.
Strongly Correlated Electrons (cond-mat.str-el)
16 pages, 7 figures
Fine-tuning a vision-language model for fracture-surface morphology recognition
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-11 20:00 EDT
Quanliang Liu, Jungtaek Kim, Kangwook Lee, Hyunseok Oh
Vision-language models (VLMs) have shown strong potential for scientific image understanding, but general-purpose models often lack the domain-specific visual knowledge required for reliable materials characterization. In this work, we fine-tuned an open-source VLM (Qwen3-VL-32B-Instruct) for fracture-surface image analysis using a curated dataset of 13,168 open-source, literature-mined fracture-surface images. Morphology annotations were generated by GPT-5.2-Reasoning (high) from both the images and relevant excerpts of their source papers, and the dataset was further enriched with targeted manual collection and rotation-based augmentation. The resulting specialist model outperforms flagship proprietary multimodal models on a benchmark of 100 manually annotated images. It achieves a precision of 0.92, compared to 0.35 for the base Qwen3-VL-32B-Instruct, 0.58 for GPT-5.5-Reasoning (high), and 0.78 for Gemini 3.1 Pro-Reasoning (high). Dataset ablations show that manual collection of rare-feature images and augmentation via image rotation are both beneficial to improve recognition of less common fracture morphology features. We further discuss integrated use of the fine-tuned model with proprietary models to combine fracture-specific visual accuracy with broader multimodal reasoning for autonomous fractography. Although focused on fracture-surface images, this work demonstrates how VLMs can be adapted through targeted collection and fine-tuning on novel feature images to recognize those features and support downstream decision-making in autonomous microscopy workflows.
Materials Science (cond-mat.mtrl-sci), Computer Vision and Pattern Recognition (cs.CV)
Coherent Nonreciprocal Valley Transport in Dirac/Weyl Semimetals
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-05-11 20:00 EDT
Nonreciprocal electronic transport, defined as a directional asymmetry between the forward and backward two-terminal responses, typically requires a built-in inversion-breaking feature of the host material or an applied field, such as magnetic order, magnetochiral coupling, polar lattice distortion, or a superconducting state. Here, we show that a single electrostatic barrier whose shape lacks inversion symmetry can drive coherent nonreciprocal transport in a Dirac or Weyl channel without any of these ingredients. The mechanism is geometric: across a barrier with two qualitatively distinct refraction interfaces (one vertical and one oblique), forward- and backward-propagating wave packets experience different Fermi-surface-mismatch sequences at the entrance and exit faces. Using coherent split-operator Dirac wave-packet simulations with realistic device parameters, we show that in a channel with isotropic (untilted) energy dispersion, an inversion-asymmetric (right-angle) triangular barrier produces strong charge-mode rectification, establishing its purely geometric origin. Adding a Dirac-cone tilt turns the same shape into a coherent valley-resolved diode whose dichroic structure flips sign across the Dirac point. Strikingly, a mirror-symmetric (isosceles) triangle with two oblique faces exhibits valley-polarized transmission while remaining exactly reciprocal. Oblique interfaces and tilt together do not suffice; the essential ingredient is a sequence of geometrically distinct interface types.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Floquet second-order topological insulator in strained graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-05-11 20:00 EDT
Yu-Wen Xu, Xiaolin Wan, Zi-Ming Wang, Rui Wang, Dong-Hui Xu
Graphene provides a canonical setting for Floquet band engineering, where circularly polarized light can dynamically open topological gaps at Dirac points and generate nonequilibrium Hall responses. Here we show that uniaxial strain and off-resonant circularly polarized light with tunable incidence angle enable a controllable route to Floquet higher-order topology in graphene. Using a strained honeycomb tight-binding model with Peierls coupling and a high-frequency expansion for the effective Floquet Hamiltonian, we find that strain drives the Dirac cones toward the Dirac-merging (semi-Dirac) critical regime, where the light-induced mass becomes strongly anisotropic. For oblique incidence, the projected drive is effectively elliptically polarized and, in combination with strain, stabilizes a phase with gapped edges but robust in-gap corner modes in finite geometries, realizing a Floquet second-order topological insulator. We characterize the phase diagram via the Chern number and a crystalline-symmetry-quantized polarization invariant. Finally, first-principles-informed tight-binding calculations corroborate the predicted topological evolution in strained graphene nanostructures. Our results identify driven strained graphene as a realistic and tunable platform for realizing and diagnosing Floquet higher-order topological phases.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
5 pages,4 figures,accepted for publication as a Letter in Phys. Rev. B
Hybrid-order topology in two-dimensional nonsymmorphic antiferromagnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-05-11 20:00 EDT
Wei Xiong, Zi-Ming Wang, Xin-Mei Wei, Rui Wang, Dong-Hui Xu
We theoretically demonstrate hybrid-order topology in a two-dimensional nonsymmorphic antiferromagnet. Utilizing a generic antiferromagnetic Dirac model with a symmetry-allowed, momentum-dependent spin-density-wave (SDW) mass, we show that a single bulk insulating phase exhibits distinct topological boundary manifestations governed solely by the termination geometry. For screw-compatible edges, nonsymmorphic screw symmetry protects gapless first-order edge states. In contrast, for a $ 45^\circ$ diamond-shaped termination, the screw symmetry is broken at the boundary, resulting in gapped edges. However, the finite geometry still preserves magnetic mirror symmetries $ \mathcal{M}_x\mathcal{T}$ and $ \mathcal{M}_y\mathcal{T}$ , which enforce an alternating pattern of edge masses, thereby binding zero-dimensional corner states. This second-order phase is characterized by a quantized quadrupole moment, with corner states pinned to zero energy by the chiral symmetry. We further demonstrate that explicit lattice perturbations can selectively gap the first-order edge modes while robustly preserving the corner states. Our work establishes a symmetry-based route to a termination-controlled duality between first- and second-order topology in magnetic nonsymmorphic systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
5 pages, 4 figures, submitted to Phys. Rev. B
A Hardware-aware Hopfield Network with a Nonlinear Memristor Array for Robust Associative Memory with Superlinear Capacity
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-05-11 20:00 EDT
Younghyun Lee, Hakseung Rhee, Unhyeon Kang, Seungmin Oh, Kyungmin Lee, Hyun Jae Jang, Seongsik Park, YeonJoo Jeong, Inho Kim, Jong Keuk Park, Kyung Min Kim, Suyoun Lee
Associative memory retrieves complete patterns from partial or corrupted inputs and constitutes a primitive form of generative inference. Classical Hopfield networks (CHN) provide a canonical framework for associative memory but suffer from limited memory capacity. Recently, modern Hopfield networks (MHN) were introduced to achieve higher capacity by using explicit pattern-wise storage and neurons with the softmax activation function, which makes the MHN vulnerable to noise and the hardware implementation complicated due to its network size varying with the number of stored patterns. Here, we introduce a hardware-aware Hopfield network (HHN), in which the intrinsic nonlinear current-voltage characteristics of a charge-trap memristor are leveraged to engineer the energy landscape of the HN, increasing the memory capacity. Using a 25 x 25 nonlinear memristor array, we demonstrate reliable reconstruction of corrupted patterns with memory capacity far exceeding the classical limit (K ~ 0.14N, where N is the number of neurons). The HHN preserves Hopfield-type energy-minimization dynamics and remains robust to synaptic conductance noise. Large-scale simulations on high-dimensional image data reveal an empirical memory capacity scaling of K ~ 0.3 x N^1.2 under a fixed synaptic budget. These results establish HHN as a scalable hardware-native architecture for low-power associative memory and generative inference.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Applied Physics (physics.app-ph)
Physics Aware Representation Learning on Electronic Charge Density for Materials Property Prediction
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-11 20:00 EDT
Kammampati Sai Kumar, Albert Linda, Shubham Kumar Maurya, Somnath Bhowmick
The fundamental quantity governing the mechanical and thermodynamic properties of a crystalline solid is its electronic charge density. Yet, its direct use for the rapid prediction of materials properties remains challenging due to its high dimensionality. Here, we present a physics-informed deep learning framework that directly predicts mechanical and thermodynamic properties from the three-dimensional electronic charge density derived from density functional theory (DFT). The proposed approach first utilizes a three-dimensional convolutional autoencoder for unsupervised dimensionality reduction, compressing a high-resolution charge-density grid (128 x 128 x 128) into a compact latent representation (16 x 16 x 16 x 16) while preserving physically meaningful features, as confirmed by negligible reconstruction errors across diverse crystal systems. The compressed latent-space representation of charge density is then used by two different regression models for property prediction: Light Gradient Boosting Machine (LightGBM) and Attention-based 3D Convolutional Neural Networks (Att CNN), and their performance is compared. Combining composition-based descriptors (Material Agnostic Platform for Informatics and Exploration or MAGPIE) with electronic charge density data further improves the model accuracy. Using a dataset of about 6059 inorganic compounds spanning multiple crystal symmetries, the models achieve strong predictive performance for bulk modulus K (R2 = 0.94), Young’s modulus E (R2 = 0.88), shear modulus G (R2 = 0.87), formation energy Eform (R2 = 0.96), and Debye temperature {\Theta} (R2 = 0.89). This work establishes electronic charge density as a transferable, physics-grounded descriptor for materials property prediction, requiring ~ 1/25 the computational resources of full-fledged DFT calculations.
Materials Science (cond-mat.mtrl-sci)
Topological Characterization of Discrete-Time Classical Stochastic Processes: Dual Role of Point-Gap Topology
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-05-11 20:00 EDT
Masaya Nakagawa, Masahito Ueda
We present topological characterization of classical stochastic processes described by discrete-time Markov chains on lattices. We point out that point-gap topology of stochastic matrices entails two distinct physical consequences that hinge on the choice of the reference point. The point-gap topology around a generic reference point is related to the direction of transport, and nontrivial topology around the origin of the complex spectrum of a stochastic matrix implies non-Markovianity caused by, e.g., feedback control. On the basis of this characterization, we identify the topological origin of directed transport in a classic experiment of Maxwell’s demon [S. Toyabe et al., Nat. Phys. 6, 988 (2010)] and find the topological nature of feedback control beyond thermodynamic interpretation. We demonstrate that a topologically enforced non-Markovian classical stochastic process can be simulated by a Markovian quantum master equation, indicating a topological form of quantum advantage.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
14 pages, 5 figures
Physics-informed operator learning for transferable energy-dissipative microstructure dynamics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-11 20:00 EDT
Jie Xiong, Yue Wu, Xuewei Zhou, Peishuo Zhao, Jiaming Zhu
Phase-field simulations provide mechanistic descriptions of microstructure evolution, but repeated high-fidelity integration over long horizons and broad parameter spaces remains computationally expensive. We present PFNet, a physics-informed neural operator framework that advances microstructural states by learning conditional evolution operators rather than direct correlations. PFNet combines a diffusion-inspired U-Net with periodic padding, entropy-based state conditioning and thermodynamic-parameter modulation to encode boundary consistency, instantaneous ordering state and changes in the free-energy landscape. For Cahn-Hilliard coarsening, PFNet achieves accurate one-step prediction and stable autoregressive rollouts across composition, gradient-energy coefficient, coarsening stage and morphology class, with errors concentrated near diffuse interfaces and topology-changing regions. The same framework extends to a four-channel martensitic-transformation benchmark without martensite-specific redesign. These results indicate that physics-informed operator learning can provide transferable surrogates for phase-field dynamics and broader energy-dissipative dynamical systems.
Materials Science (cond-mat.mtrl-sci), Disordered Systems and Neural Networks (cond-mat.dis-nn)
None
Frustration of harmonic and solitonic helimagnetism on the body-centered tetragonal lattice of GdAlSi
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-05-11 20:00 EDT
Ryota Nakano, Rinsuke Yamada, Oleg I. Utesov, Masaki Gen, Akiko Kikkawa, Hajime Sagayama, Hironori Nakao, Yasujiro Taguchi, Masashi Tokunaga, Taka-hisa Arima, Yoshinori Tokura, Se Kwon Kim, Max Hirschberger
The triangular lattice antiferromagnet (TLAF) with nearest-neighbor exchange interaction is a model platform in the field of frustrated magnetism. Here, anharmonic (‘up-up-down’) and harmonic magnetic states compete, because a helimagnetic wave and its higher harmonic are degenerate in energy. We show that a body-centered tetragonal lattice (BCTL) can realize a similar frustration of harmonic and anharmonic helimagnetic states, and that the tetragonal magnetic Weyl semimetal GdAlSi realizes this scenario. In an applied magnetic field, resonant elastic X-ray scattering reveals a competition of harmonic cycloidal and solitonic double-Q states, well consistent with mean-field calculations. Our work provides a new paradigm for frustration physics in BCTL materials.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Breaking the Trade-off: Bulk 2D Ising Superconductivity with High Tc and Giant Interlayer Spacing via a Unique Chain Intercalation in (BaS)1/3TaS2
New Submission | Superconductivity (cond-mat.supr-con) | 2026-05-11 20:00 EDT
Ziyi Zhu, Leiming Chen, Xiangqi Liu, Haonan Wang, Chen Xu, Ze Yan, Zhengyang Li, Wei Xia, Jiawei Luo, Na Yu, Xia Wang, Ke Qu, Zhenzhong Yang, Yanfeng Guo
Two-dimensional (2D) transition metal dichalcogenides (TMDs) are promising platforms for low dimensional superconductivity. However, in conventional intercalated systems, achieving a high superconducting transition temperature (Tc) often comes at the expense of reduced interlayer spacing and weakened 2D character. Here, we overcome this long-standing compromise through a unique chain-like intercalation strategy. We report the synthesis and properties of a new polymorph, (BaS)1/3TaS2, in which a distinctive Ba-S-S-Ba chain structure is inserted between TaS2 bilayers. This unique configuration breaks the bulk c axis mirror symmetry while achieving exceptional interlayer decoupling, with an inter-bilayer spacing of 12.75 Å-more than three times that of pristine 2H-TaS2. By suppressing interlayer electronic coupling, this structural evolution allows local inversion symmetry breaking within individual TaS2 layers to dominate. This prevents compensation of the Ising spin-orbit fields typical of centrosymmetric bulk phases, enabling robust 2D Ising superconductivity. Remarkably, the compound exhibits an enhanced Tc without sacrificing its large interlayer spacing, thereby breaking the conventional trade-off between large spacing/high anisotropy and high Tc. Comprehensive transport, magnetic, and thermodynamic measurements confirm its robust superconducting state. Our work establishes a versatile intercalation framework for designing bulk-like 2D Ising superconductors, providing a new route to reconcile competing material demands and expanding the scope of Ising superconductivity research.
Superconductivity (cond-mat.supr-con)
Mian Text 26 pages, 6 figures abd SI 6 pages, 1 figure, 3 tables
Journal of The American Chemical of Society, 2026
Water adsorption on a model silicate surface: wollastonite (100)
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-11 20:00 EDT
Luca Lezuo, Andrea Conti, Alexander Hoheneder, Elena Vaníčková, Domitilla Alessandra Aloi, Rainer Abart, Florian Mittendorfer, Michael Schmid, Ulrike Diebold, Giada Franceschi
Water adsorption on silicate surfaces is a critical yet poorly understood process relevant to, e.g., mineral weathering and cement hydration. This study investigates the structure of water overlayers on a model calcium silicate, the lowest-energy (100) surface of wollastonite (CaSiO3). It combines atomically resolved non-contact atomic force microscopy (nc-AFM), acquired with qPlus sensors and functionalized tips in ultrahigh vacuum (UHV), with density functional theory (DFT) calculations employing the metaGGA r2SCAN+rVV10 functional. Adding incremental doses of water to the sample at cryogenic temperatures produces distinct structures governed by the competition between water-surface and water-water interactions. With two water molecules per surface unit cell, water-surface interactions dominate: In line with previous theoretical predictions, adsorbates follow the surface lattice. As the coverage increases, intermolecular hydrogen bonding competes with bonding to the surface, leading to the emergence of complex, coexisting patterns. While their small energy differences prevent an unambiguous identification of the most stable structure by DFT, the experimentally observed symmetries help constrain plausible structural models. Above a critical density of four water molecules per unit cell, water-water interactions prevail, and water clusters are formed. The results provide an atomic-scale framework for understanding water interactions with calcium silicate surfaces.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
18 pages, 5 figures
Rabi-coupling-induced three-component quantum droplet in ultracold Bose gases
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-05-11 20:00 EDT
Xiao Ding, Dajun Wang, Xiaoling Cui
We uncover a new mechanism for realizing three-component quantum droplets in ultracold Bose gases, where only one inter-species interaction is attractive. In this scheme, the inter-species attraction leads to a self-bound binary droplet, and the third component joins through Rabi coupling with one component of the binary droplet. We find that a stronger Rabi coupling leads to a larger fraction of the third component, but also destabilizes the entire droplet due to the involvement of more repulsive forces. Such instability can be remedied by a finite detuning between the Rabi-coupled components. We demonstrate these results in realistic Na-Rb mixtures, using both thermodynamic analyses and numerical simulations based on extended Gross-Pitaevskii equations. Our work outlines a general route for stabilizing multi-component droplets by bridging an existing binary droplet with additional components via suitable single-particle fields.
Quantum Gases (cond-mat.quant-gas)
8 pages, 5 figures
Revisiting Ferroelectricity Beyond Polar Space Groups
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-11 20:00 EDT
Yudi Yang, Changming Ke, Shi Liu
Ferroelectricity, a hallmark of spontaneous inversion-symmetry breaking, has been a central concept in condensed matter physics and functional materials research, yet recent discoveries are revealing that switchable polarization can emerge in forms far richer than allowed by the conventional symmetry-based paradigm. Fractional quantum ferroelectricity and ionic-conductor ferroelectricity challenge the long-standing association of ferroelectricity exclusively with polar space groups. In this Review, we reconcile these emerging phenomena within the Berry-phase modern theory of polarization. We emphasize that polarization in insulating periodic crystals is not a single-valued vector, but a multivalued lattice quantity defined modulo a polarization quantum. Consequently, nonpolar crystals may possess nonzero formal polarization, and adiabatic paths connecting symmetry-equivalent structures can produce quantized changes in polarization without violating symmetry principles. The symmetry of this multivalued formal polarization is governed by a generalized Neumann principle. We further show that the large polarization changes induced by long-range ion migration in both fractional quantum ferroelectrics and ionic-conductor ferroelectrics can be naturally understood through the topological definition of oxidation state, which links ionic transport to quantized charge transfer and polarization change. We discuss the physical accessibility of these unconventional polarization states, highlighting the roles of switching pathways, boundary conditions, and domain-wall dynamics, particularly in systems such as $ \alpha$ -In$ _2$ Se$ _3$ . Finally, we suggest that the most promising functionality of these materials may lie not in conventional bulk ferroelectric switching, but in the creation and control of charged interfaces and domain walls arising from discontinuities in formal polarization.
Materials Science (cond-mat.mtrl-sci)
Effective Gilbert damping in the stochastic Landau-Lifshitz-Gilbert equation
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-05-11 20:00 EDT
Mexx. E.Y. Regout, Bertrand Dupé, Matthieu J. Verstraete
Quasi particle based (e.g. Boltzmann equation) studies of spin wave transport often assume that their scattering rates follow the simple form $ \eta=\alpha \omega$ , with the Gilbert damping $ \alpha$ and frequency $ \omega$ . In this work, we examine the effective damping $ \alpha_{eff,T}=\eta/\omega$ observed in atomistic spin dynamics, when temperature and spin wave interactions are introduced for a 1D spin chain. We extract the dynamical correlation functions from spin trajectories propagated using the stochastic Landau-Lifshitz-Gilbert equation, and fit the dynamical structure factor, yielding the dispersion and scattering rates for a wide range of temperatures. The resulting effective damping can be very different from the initially constant Gilbert value. It exhibits a temperature and crystal momentum scaling which we explain based on interactions with the Gilbert bath and spin wave scattering by changes in local magnetic order.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Point-gap topology of damped magnon excitations in skyrmion strings
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-05-11 20:00 EDT
We theoretically study the non-Hermitian topology of magnons with finite lifetimes due to Gilbert damping. By incorporating the spin-wave theory and perturbation theory for the Landau-Lifshitz-Gilbert equation including nonlocal damping terms, we analytically evaluate the spectral winding number for point gaps, which indicates the existence of the non-Hermitian skin effect (NHSE). We find that the NHSE can occur even in the absence of nonlocal damping. In the presence of nonlocal damping along one direction, we show that the winding number for an energy band with a unique minimum is determined from the sign of the wave number at the band minimum. We demonstrate these results using a model that hosts a skyrmion-string lattice as a steady state. We further investigate spin-wave propagation dynamics excited by a magnetic-field pulse and show that the propagation direction changes drastically from band to band depending on the presence of local and nonlocal damping, consistent with the nontrivial winding numbers.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Spin-lattice coupling enables adaptive adsorption in magnetically-driven electrocatalysts
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-11 20:00 EDT
Arnold Gaje, Lulu Li, Felipe A. Garcés-Pineda, Camilo A. Mesa, Ghazaleh Abdolhosseini, Aditya K. Kushwaha, Dora Zalka, Elzbieta Trzop, Nicolas Godin, Raffaella Torchio, María Escudero-Escribano, Eric Collet, Sixto Giménez, Niels Keller, José Ramón Galán-Mascarós, Núria López, Ernest Pastor
A major challenge in electrochemistry is to decouple the reactive intermediates of a catalytic cycle to optimise their energies independently. During the oxygen evolution reaction (OER), such energy interdependence results from the need to generate multiple adsorbates at the same site and sets the minimum overpotential. Here, we show that an external stimulus, such as a magnetic field, can relax the scaling relationships between intermediates during the OER. Spectroscopic measurements and Density Functional Theory simulations in Ni-Fe oxyhydroxides reveal that applying a magnetic field alters surface chemisorption and injects structural flexibility at the interface. We interpret these observations as a consequence of stimulated changes in the spin-lattice coupling, which allow access to quasi-degenerate oxygenated intermediates that modulate the reaction energy demands. Our findings redefine the scaling limitations as state-projected rather than intrinsic and establish external stimulation as a strategy to navigate multi-state energy landscapes in electrocatalysis and sensing applications.
Materials Science (cond-mat.mtrl-sci)
Dislocations in (011)-oriented vertical Bridgman $β$-Ga$_2$O$_3$ substrates
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-11 20:00 EDT
Yongzhao Yao, Daiki Katsube, Hirotaka Yamaguchi, Yukari Ishikawa
Dislocation in (011)-oriented $ \beta$ -Ga$ _2$ O$ _3$ substrates grown by the vertical Bridgman method was investigated using X-ray topography (XRT), combined with X-ray reticulography. Transmission XRT reveals dislocations lying on the (001) plane and extending along [010], forming arrays associated with domain boundaries. Dislocations on the (011) plane were also identified but differ from those responsible for line-shaped pits on (001) epilayers. Reflection XRT shows good agreement with transmission XRT and enables classification of dislocation types based on contrast features. Reticulography confirms domain boundaries with misorientation on the order of 1E-5 rad, providing insight into defect formation relevant to epi-growth and device performance.
Materials Science (cond-mat.mtrl-sci)
18 pages, 4 figures
Exciton-mediated optical control of liquid-solid friction
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-05-11 20:00 EDT
Timur Pryadilin, Alexey Kavokin, Baptiste Coquinot
Interfacial friction in nanofluidic systems can arise from fluctuation-induced coupling between liquid charge fluctuations and the internal excitations of the confining solid. Here, we develop a microscopic theory of exciton-mediated solid-liquid friction based on the coupling between optically generated excitons and charge fluctuations in water. We distinguish between static excitons, localized by disorder or functionalization, and dynamic excitons, which interact with water through polarization fluctuations. In both cases, we derive analytical formulas for the excitonic friction, which is experimentally tunable and can significantly reduce the slip length and thereby the hydraulic permeability of nanochannels. Applying our framework to carbon nanotubes, we quantitatively reproduce the recent measurements of Kistwal et al., showing a reduction of nanotube diffusion under optical excitation, without fitting parameters. More broadly, our results establish excitons as a mechanism to optically control nanofluidic transport and suggest that excitonic photoluminescence could provide an optical probe of flow velocity inside nanochannels.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Soft Condensed Matter (cond-mat.soft), Optics (physics.optics)
6 pages, 2 figures
Noncollinear antiferromagnetic structure and physical properties of CrRhAs with distorted kagome lattice
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-05-11 20:00 EDT
Chenglin Shang, Daye Xu, Bingxian Shi, Xuejuan Gui, Zhongcen Sun, Juanjuan Liu, Jinchen Wang, Hongxia Zhang, Hongliang Wang, Lijie Hao, Peng Cheng
CrRhAs was theoretically proposed to be a kagome metal with unusual magnetic ground states; however, little is known about its magnetic structure and physical properties experimentally. Here, we present an experimental investigation of CrRhAs with ZrNiAl-type structure and a distorted Cr kagome lattice. CrRhAs is an antiferromagnet with TN = 149 K. Powder neutron diffraction analysis reveals a noncollinear antiferromagnetic structure with propagation vector k = (1/3, 1/3, 1/2), which features a ferromagnetic second nearest neighbor coupling in the kagome plane that is different from the prediction in previous density functional theory calculations. Furthermore, CrRhAs exhibits anomalous electrical transport properties which are possibly related to multiband effects and strong spin fluctuations. For the temperature-dependent longitudinal resistivity \r{ho}xx, it is semiconductinglike above TN and becomes metallic below TN . The Hall coefficients exhibit two sign changes near 70 and 300 K. Combined with the results of heat capacity measurements, a large Kadowaki-Woods ratio {\alpha} = 33.9 {\mu}{\Omega} cm mol2 K2/J2 is obtained. The above results suggest CrRhAs is a strongly correlated kagome metal with multiband and noncollinear magnetic structure features.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci), Superconductivity (cond-mat.supr-con)
8 pages, 5 figures. Published in PHYSICAL REVIEW B 113, 184430 (2026)
Phys. Rev. B 113, 184430 (2026)
Nonreciprocal McKean-Vlasov Equations: From Stationary Instabilities to Travelling Waves
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-05-11 20:00 EDT
Arjun R, Pratyush Prakash Patra, A. V. Anil Kumar
Nonreciprocal interactions, in which action-reaction symmetry is broken, provide a powerful route to collective dynamics that cannot be captured by equilibrium free-energy minimisation. Here, we introduce and analyse a two-species nonreciprocal McKean-Vlasov equation derived from an underlying system of interacting stochastic particles. Combining linear stability analysis, weakly nonlinear arguments, pseudo-spectral simulations, and Langevin particle dynamics, we show that the structure of nonreciprocity controls the onset and nature of collective order. For spatially uniform weak nonreciprocity, asymmetry shifts the critical diffusion threshold but produces only stationary instabilities, indicating that uniform imbalance alone is insufficient to generate sustained time-dependent motion. In contrast, spatially modulated nonreciprocity fundamentally enriches the dynamics: depending on its symmetry and coupling to the interaction potential, the homogeneous state can lose stability through Hopf bifurcations, giving rise to standing and travelling wave states. We identify both subcritical and supercritical Hopf transitions, relate the selected patterns to Landau saturation coefficients, and show that travelling waves can emerge even in the weak-nonreciprocity regime without explicit microscopic run-and-chase rules. Direct Langevin simulations confirm that these oscillatory and travelling states persist at the particle level and are not artefacts of the continuum mean-field description. Our results establish nonreciprocal McKean-Vlasov equations as a minimal framework for understanding how spatially structured asymmetric interactions generate self-organized motion, dynamical phase transitions, and nonequilibrium collective order.
Statistical Mechanics (cond-mat.stat-mech)
27 pages, 8 figures
Emergent Dynamic Magnetic Ground State in a Mixed 3d/5d Heavy Fermion System CaCu3Ir4O12
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-05-11 20:00 EDT
J. Ming, Abhisek Bandyopadhyay, G. B. G. Stenning, M. T. F. Telling, N. N. Wang, G. Wang, J.-G. Cheng, D. T. Adroja
Quantum-disordered magnetic ground states are challenging to identify in three-dimensional (3D) oxides, where strong exchange pathways typically favour long-range magnetic order or spin freezing. The quadruple perovskite $ \mathrm{CaCu_3Ir_4O_{12}}$ , crystallizing in the cubic $ Im\bar{3}$ structure, provides a 3D lattice where $ \mathrm{Cu^{2+}}$ $ 3d$ moments are coupled to an extended Ir $ 5d$ network, offering a rare platform for probing quantum-disordered magnetism in a mixed $ 3d/5d$ electron system. Here, we combine bulk probes, including DC and AC magnetic susceptibility, and heat capacity measurements (down to $ 50\mathrm{mK}$ ), along with the local microscopic probe muon spin relaxation ($ \mu$ SR) (down to $ 40\mathrm{mK}$ ), to investigate the true magnetic ground state of $ \mathrm{CaCu_3Ir_4O_{12}}$ . Despite strong antiferromagnetic interactions ($ \theta_{\mathrm{W}} \sim -200\mathrm{K}$ , with an applied-field dependence), no signature of long-range magnetic ordering or spin freezing is detected down to the lowest measured temperatures. Furthermore, our in-depth zero-field (ZF) and longitudinal-field (LF) $ \mu$ SR characterizations confirm strong quantum spin fluctuations and the truly dynamic nature of the local moments down to $ 40\mathrm{mK}$ . These results establish $ \mathrm{CaCu_3Ir_4O_{12}}$ as a promising 3D quantum-disordered magnet and a well-characterized platform for exploring fluctuation-dominated states in correlated $ 3d/5d$ oxides.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
38 paages, 9 figures
Hydrodynamics and boundary-induced phase transitions in the $n$-species particle-exchange process
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-05-11 20:00 EDT
The $ n$ -species particle-exchange process (PEP($ n$ )) is an exclusion process in which particles of $ n$ different species exchange positions on neighbouring sites with rates chosen such that the invariant measure on the discrete torus is a product measure. We address the large-scale hydrodynamic behaviour of this process which yields a system of $ n$ coupled inviscid Burgers equations. This system of conservation laws is shown to admit Riemann invariants for arbitrary $ n$ from which explicit solutions of the Riemann problem in terms of shock waves and rarefaction fans are obtained. We also introduce the open PEP($ n$ ), in which particles are exchanged with boundary reservoirs. For a distinguished manifold of boundary rates, we prove that the invariant measure is the same product measure as in the periodic system. The hydrodynamic description in terms of Riemann invariants is used to derive the stationary phase diagram explicitly in terms of microscopic boundary rates. In the generic case, the steady state exhibits $ 2n+1$ phases, with boundary-induced phase transitions analogous to those of the single-species asymmetric simple exclusion process.
Statistical Mechanics (cond-mat.stat-mech), Mathematical Physics (math-ph)
Bias-Engineered Synthetic Antiferromagnets Hosting sub-20 nm Zero-Field Skyrmions at Room Temperature
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-05-11 20:00 EDT
Emily Darwin, Riccardo Tomasello, Reshma Peremadathil Pradeep, Mario Carpentieri, Giovanni Finocchio, Hans J. Hug
Synthetic antiferromagnetic skyrmions (SAFsk) are nanoscale, topologically protected spin textures with strong potential for spintronic technologies because of their high stability and the absence of the skyrmion Hall effect. However, robust zero field stabilization remains a central challenge. Here, a synthetic antiferromagnetic (SAF) bias system is introduced as a novel strategy to stabilize both ferromagnetic skyrmions (FMsk) and SAFsk at zero field. Ferromagnetic (FM) and SAF multilayers are designed, fabricated and integrated with the SAF bias system to enable controlled skyrmion stabilization and polarity setting via multilayer design and a preparatory field cycle. Combining quantitative and high-sensitivity magnetic force microscopy (MFM) with micromagnetic modeling, reliable zero field skyrmion formation is demonstrated and sub 20nm SAFsk are directly observed, the smallest SAFsk reported to date. Moreover, the SAF bias system concept introduced here offers a robust and scalable route to bias future skyrmion multilayers, as its compensated nature suppresses domain formation and preserves a uniform exchange field.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Finite temperature pair density wave superconductivity in $d$-wave altermagnets
New Submission | Superconductivity (cond-mat.supr-con) | 2026-05-11 20:00 EDT
Amrutha N Madhusuthanan, Madhuparna Karmakar
We demonstrate that altermagnetism provides a field-free mechanism for stabilizing finite-momentum superconductivity in two dimensions. Using a non-perturbative static path approximation Monte Carlo approach, we show that a d-wave altermagnet supports a robust pair-density-wave (PDW) phase that persists over a finite temperature window despite strong thermal fluctuations. The underlying mechanism originates from momentum-dependent spin splitting, which effectively enhances pairing instabilities at finite center-of-mass momentum without Zeeman fields. We identify distinct thermal scales associated with phase coherence, gap closing, and pseudogap formation, and establish characteristic spectroscopic and real-space signatures of the PDW state. Our results reveal altermagnetism as a robust route to thermally stable finite-momentum superconductivity and provide experimentally testable signatures for altermagnetic materials.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
13 pages, 10 figures. This manuscript supersedes arXiv:2603.25314
Harnessing Structural Disorder: Unraveling Hydrogen Evolution in Monolayer Amorphous Carbon via First-Principles Simulations and Machine-Learned Potentials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-11 20:00 EDT
Sreehari M S, Ashutosh Krishna Amaram, Raghavan Ranganathan
Disorder and defective coordination in the catalytic plane are crucial for enhancing the Hydrogen Evolution Reaction (HER) on two-dimensional catalysts. Amorphous materials are disordered, making them catalytically adaptive for many reactions. In this work, the HER capabilities of Monolayer Amorphous Carbon (MAC) were studied in comparison with crystalline carbon derivatives, such as pristine graphene (GE) and graphyne derivatives. MAC generated from melt-quench simulations revealed a diverse framework of predominantly sp2 and sp3 carbons with numerous 5-, 6-, and 7-membered rings. Density Functional Theory (DFT) calculations investigated free-energy variations in hydrogen adsorption for each material. According to Sabatier’s principle, optimum activity is achieved when the Gibbs free energy (Delta GH) change approaches zero. Crystalline carbon materials possess limited active sites, with beta-graphyne showing the best Delta GH value of +0.34 eV. The adsorption study for MAC was conducted in 30 distinct local environments, where core structural properties were analyzed against varying radii. Calculations showed a Delta GH distribution for MAC ranging from -0.02 eV to +1.35 eV. To evaluate activity across the entire MAC surface, a MACE MLIP foundation model was finetuned, achieving optimal energy and force fitting of 1.67 meV/atom and 29.15 meV/A, respectively. The MLIP predicted Delta GH values from -0.91 eV to +1.70 eV, with approximately 15% of sites exhibiting values below +0.25 eV. Feature analysis revealed that 7-membered rings, curvature, and ripple height enhance HER activity. Our findings suggest that, with careful optimization of local features, MAC can be tuned to compete with noble metal catalysts.
Materials Science (cond-mat.mtrl-sci)
Ground states of quantum XY dipoles on the Archimedean lattices
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-05-11 20:00 EDT
Marcus Bintz, Ahmed Khalifa, Vincent S. Liu, Johannes Hauschild, Michael P. Zaletel, Shubhayu Chatterjee, Norman Y. Yao
We report numerical ground states for the dipolar XY spin model, which describes extended antiferromagnetic interactions in two-dimensional arrays of polar molecules and two-level Rydberg atoms. Carrying out large-scale density matrix renormalization group (DMRG) calculations, we compute ground state properties on nine of the eleven Archimedean lattices–tilings of the plane by regular polygons. Four of these host trivial paramagnets, while another four develop collinear Neel magnetic order, as was found previously for the square lattice. For the ordered states, we calculate the hydrodynamic parameters (magnetization, susceptibility, and stiffness) and compare to linear spin wave theory. We also investigate the triangular lattice, for which we find several competing phases including coplanar magnetism, stripe density wave order, and a possible spin liquid; their relative stability is sensitive to the long-range couplings present in our dipolar model. Finally, the Archimedean classification is completed by the kagome lattice, which we argue in a companion work is likely to be a Dirac spin liquid.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Gases (cond-mat.quant-gas), Atomic Physics (physics.atom-ph)
16 pages, 12 figures
Epitaxial growth of beta-bismuthene on Sb2Te3
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-11 20:00 EDT
Giorgia Sementilli, Arslan Masood, Fabio Ronci, Stefano Colonna, Marilena Carbone, Marco Papagno, Ziya S. Aliev, Evgueni V. Chulkov, Sergey V. Eremeev, and Roberto Flammini
Over the past decades, two-dimensional crystals have attracted considerable interest as promising materials for electronic and optoelectronic applications. Among them, graphene analogs composed of heavy atoms occupy a particularly distinctive niche due to their enhanced spin-orbit interaction. Here, we present an epitaxial heterointerface formed by beta-bismuthene on Sb2Te3, a well-known three-dimensional topological insulator. Using scanning tunneling microscopy, we systematically investigated the effects of Bi coverage and substrate temperature on nucleation processes, island morphology, and atomic structure. In addition, substrate-induced defects were identified throughout the bismuthene lattice.
Materials Science (cond-mat.mtrl-sci)
7 pages, 3 figures
Selectivity- and Activity-Aware Catalyst Descriptors for CO$_2$ Hydrogenation on Alloy Nanocatalysts using Machine-Learned Force Fields
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-11 20:00 EDT
Prajwal Pisal, Ondřej Krejčí, Patrick Rinke
Adsorption energy distributions (AEDs) have emerged as a powerful and increasingly adopted descriptor for catalytic performance in high-entropy alloys and, more recently, in conventional metallic alloy nanocrystal catalysts. By accounting for diverse adsorption sites and crystallographic facets, AEDs more fully represent nanoparticle-based catalytic surfaces and show strong promise for accelerating rational design and discovery of heterogeneous catalysts, especially for CO$ _2$ hydrogenation. However, previous approaches have not sufficiently resolved facet-specific contributions, despite the catalytic significance and prevalence of certain Miller planes in nanoscale catalysts, limiting their applicability in predicting activity and selectivity. Here, we introduce an updated facet-resolved framework for predicting catalytic activity, which also enables insight into selectivity toward C1 products. Universal machine-learned force fields trained on Open Catalyst Project data were employed to compute adsorption energetics across 226 experimentally observed metals, binary alloys, and ternary alloys, encompassing 1.4 million adsorption sites on 2,626 crystallographically distinct surfaces. Using statistical and unsupervised learning techniques, we analyzed facet-specific AEDs to identify highly active and methanol-selective facets. Our approach provides insight into the relationship between structure and catalytic performance metrics like activity and selectivity, and presents a set of alloy compositions and their respective surface orientations for experimental validation toward highly selective CO$ _2$ hydrogenation.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph), Computational Physics (physics.comp-ph), Data Analysis, Statistics and Probability (physics.data-an)
30 pages, 5 figures + 1 toc, 2 tables, Supplementary Information
Exploring the Potential of Ternary Blending for Two and Three-Junction RAINBOW Solar Cells
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-11 20:00 EDT
Francesc Xavier Capella-Guardià, Jolanda Simone Muüller, Muhammad Ahsan Saeed, Xabier Rodríguez-Martínez, Miquel Casademont-Viñas, Albert Harillo-Baños, Jaime Martín, Jenny Nelson, Alejandro R. Goñi, Mariano Campoy-Quiles
The efficiency of organic photovoltaics (OPV) has been steadily increasing over the past decade until reaching the 20% milestone. Multijunction architectures provide a promising approach to further enhance performance. Here we explore the potential of a spectral splitting geometry, referred to as RAINBOW, in which subcells are placed side-by-side and externally connected, thus minimizing the fabrication and current matching challenges found in vertically stacked configurations. First, we tested 7 different binaries with bandgaps spanning from 1.98 to 1.16 eV. The systems with the widest and narrowest gaps suffered greater losses and so we evaluate if ternary mixing could help to overcome these limitations by evaluating 5 different ternaries. Generally speaking, ternary mixing tunes the Voc, and when morphology and energy levels are well aligned, the overall PCE can be boosted in the spectral region where the subcell should absorb, as is the case for PTB7-Th:COTIC-4F:BTP-eC9 when operating as red subcell. Device simulations help to identify the 2-junction and 3-junction configurations with highest PCEs, all of which include ternaries. We fabricate proof-of-concept RAINBOW devices using scalable methods in which the subcells are deposited by meniscus-guided blade coating. The efficiency improves from 12.9% in single-junction devices to 15.9% in 2-junction devices (16.4% in simulations) and 17.3% in 3-junction devices (17.7% in simulations), confirming the viability of the RAINBOW architecture for scalable, high-efficiency OPVs. Finally, detailed balance analysis indicates that the potential of this geometry can be very high provided that high efficiency wide bandgap (2-2.5eV) materials become available.
Materials Science (cond-mat.mtrl-sci)
28 pages, 8 figures, 3 tables
Beyond the conventional Emery model: crucial role of long-range hopping for cuprate superconductivity
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-05-11 20:00 EDT
Eric Jacob, M. O. Malcolms, Viktor Christiansson, Leonard M. Verhoff, Paul Worm, Liang Si, Philipp Hansmann, Thomas Schäfer, Karsten Held
The Emery model is the quintessential model for cuprate superconductors. In his eponymous paper, Emery only considered the next-nearest-neighbor oxygen-copper hopping. Later, also the relevance of nearest- and next-nearest oxygen-oxygen hoppings has been pointed out. Using dynamical vertex approximation, we find a superconducting dome consistent with cuprates. However, long-range hoppings beyond the three conventional hopping parameters are necessary for the quantitatively correct phase diagram and for a proper d-wave order parameter.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci), Superconductivity (cond-mat.supr-con)
4 pages, 4 figures, 2 tables
Droplet Deformation and Emulsion Rheology in Two-Dimensional Odd Stokes Flow
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-05-11 20:00 EDT
Thomas Appleford, Hugo França, Maziyar Jalaal
We study the deformation of a two-dimensional viscous droplet in simple shear in the presence of odd viscosity.
We derive an analytical solution for the droplet shape and surrounding flow field within the framework of odd Stokes flow, allowing for differences in both even and odd viscosity between the droplet and the surrounding fluid.
This solution yields closed-form expressions for the macroscopic apparent even and odd viscosities of a dilute emulsion.
We show that, provided all viscosity differences remain moderate, the steady-state Taylor deformation parameter satisfies
$ D_T^\infty = \text{Ca} + \mathcal{O}(\text{Ca}^2)$
so that the leading-order droplet deformation is unchanged from the classical (even-viscous) result.
Nevertheless, pronounced effects emerges beyond leading order, where our direct numerical simulations reveal odd-viscous differences to the droplet deformation.
In addition, we show that the flow is influenced only by the difference in odd viscosity between the droplet and the medium and not on their individual values.
Our analysis clarifies how odd viscosity might modify the effective rheology of dilute emulsions and provides a framework for interpreting droplet-based measurements of odd-viscous response.
Key words: odd viscosity $ |$ droplets $ |$ emulsions $ |$ surface tension $ |$ chiral fluids
Soft Condensed Matter (cond-mat.soft), Fluid Dynamics (physics.flu-dyn)
Elastocapillary morphing of self-encapsulated droplets floating at the oil-air interface
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-05-11 20:00 EDT
D. Andrini, D. Riccobelli, L. Gazzera, S. Molteni, P. Metrangolo, P. Ciarletta
Self-encapsulated droplets floating at an oil–air interface undergo striking shape changes during evaporation, including flattening and localized loss of membrane tension leading to crumpling and wrinkling. Here we combine experiments, modeling and simulations to obtain predictive morphological maps. We perform contact-angle and evaporation experiments on water droplets coated by a hydrophobin protein film and floating in a fluorinated oil, providing reference profiles and volume-loss sequences for quantitative validation. We develop an axisymmetric mechanics framework in which equilibria follow from minimization of a total free energy combining surface energies, membrane strain energy and gravitational potential, subject to volume and contact-line constraints. A quasi-convex tension-relaxation rule accounts for compression-free states and enables coexistence of taut, wrinkled (one principal tension vanishes) and crumpled (both vanish) membrane domains. A finite element algorithm computes quasi-static morphing under volume reduction; key parameters are identified by fitting the reference contact-angle profile and then used without further tuning. The model reproduces the experimentally observed shape evolution and resolves the associated stress redistribution. Systematic parameter scans yield morphological phase diagrams governed by the Bond number, the oil–droplet surface-tension ratio and the density ratio. For buoyant droplets, crumpling relocates between exposed and submerged caps as parameters vary; for heavy droplets, a crossover to circumferential wrinkling along the immersed sidewall emerges. Wall-meniscus variations shift phase boundaries and can suppress bottom crumpling, consistent with wall-affected experiments.
Soft Condensed Matter (cond-mat.soft), Fluid Dynamics (physics.flu-dyn)
Ferroelectric domains in methylammonium lead iodide perovskite thin-films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-11 20:00 EDT
Holger Röhm, Tobias Leonhard, Michael J. Hoffmann, Alexander Colsmann
We explore the ferroic properties of methylammonium lead iodide perovskite solar cells by Piezoresponse Force Microscopy (PFM). In vertical and horizontal PFM imaging, we find domains of alternating polarization with a width of 90 nm which we identify as polarized ferroelectric domains. High-resolution photo-conductive atomic force micrographs under illumination also show alternating charge carrier extraction patterns which we attribute to the local vertical polarization components within the ferroelectric domains. The correlation of the sample properties with Atomic Force and Kelvin Probe Force Micrographs evidence the piezo-electric nature of the domains.
Materials Science (cond-mat.mtrl-sci)
6 pages main manuscript + 7 pages Supplementary Information
Energy Environ. Sci., 2017, 10, 950
Probabilistic denoising for reliable signal extraction in spectroscopy
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-05-11 20:00 EDT
While deep learning offers powerful capabilities for scientific research, its application is often hindered by a lack of quantitative reliability. To address this, we introduce a probabilistic denoising framework that simultaneously extracts denoised signals and element-wise predictive uncertainties from noisy data. We demonstrate this approach on three-dimensional angle-resolved photoemission spectroscopy data, showing that the model reliably recovers the spectral features of a cuprate superconductor from Poisson-distributed noise with an average count of only 0.02 electrons per voxel. Crucially, we show that these predicted uncertainties can be propagated into subsequent superconducting gap analyses, enabling quantitative parameter extraction with scientifically meaningful error bars. Furthermore, we validate the broad applicability of our approach by successfully extending it to two-dimensional X-ray diffraction data. Ultimately, this approach establishes uncertainty-aware deep learning not merely as a visualization tool, but as a rigorous framework for scientific data analysis.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con), Data Analysis, Statistics and Probability (physics.data-an)
8 pages, 5 figures
Tamed Feynman-Kac diffusion processes: Killing-branching intertwine
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-05-11 20:00 EDT
Piotr Garbaczewski, Mariusz Żaba
Relaxation to equilibrium of a drifted Brownian motion is quantified by a probability density function, whose main (multiplicative) entry is an inferred Feynman-Kac kernel of the Schrödinger semigroup operator. Although seemingly devoid of a natural probabilistic significance (except for its explicit path integral definition), the pertinent kernel relaxes to equilibrium as well. The implicit Feynman-Kac potential $ {\cal{V}}(x)$ , continuous, confining and bounded from below, may take negative values. If positive, $ {\cal{V}}(x)$ can be interpreted as the killing rate of the decaying diffusion process. In case of relaxing F-K kernels the killing effects are tamed (often overcompensated). The taming inavoidably appears in conjunction with the existence of the negativity subdomains of $ {\cal{V}}(x)$ in $ R$ . If locally $ {\cal{V}}(x) < 0$ , its sign inversion $ - {\cal{V}}(x)$ can be interpreted as the branching (cloning, alternatively bifurcation) rate in the course of the other wise free random motion. The arising killed diffusion processes with branching, we interpret as the possible path-wise background of tamed (relaxing) Feynman-Kac diffusions. We present acomputer-assisted path-wise arguments, towards a consistency of the killing/branching taming scenario, for a number of nonlinear model systems in one space dimension. Special attention is paid to Feynman-Kac potential shapes, presumed to be in the double well form, where an analytic access to eigenvalues and eigenfunctions is scarce beyond the semiclassical regime.
Statistical Mechanics (cond-mat.stat-mech), Mathematical Physics (math-ph), Exactly Solvable and Integrable Systems (nlin.SI), Quantum Physics (quant-ph)
33 pp. 26 figures
Finite-q photon-drag shift current in two-dimensional massive chiral Dirac fermions
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-05-11 20:00 EDT
We investigate the photon-drag shift current in an isotropic single-valley two-dimensional massive chiral Dirac model with chirality index $ J=1,2,3$ by directly evaluating the full finite-$ q$ non-vertical response beyond the perturbative small-$ q$ regime. Our central result is that chirality qualitatively reorganizes the sign topology of the finite-$ q$ photocurrent $ \mathbf{ j}(\mathbf{ q})$ . For $ J=1$ , the photocurrent remains broadly positive, whereas higher-chirality sectors ($ J \ge 2$ ) generically develop internal zero-current contours and sign reversals within the kinematically allowed region. We further show that the photocurrent is symmetry-constrained to be purely transverse, $ \mathbf{j}(\mathbf{q}) \propto \hat{\mathbf{z}}\times\mathbf{q}$ , and vanishes in the strictly vertical-transition limit $ q=0$ in centrosymmetric systems. Pauli blocking further shapes the response by selecting the active portion of the resonance contour, while its extinction at large $ \Delta$ or $ q$ follows from a simple kinematic cutoff. These results establish the isotropic massive chiral Dirac problem as a symmetry-controlled benchmark for chirality-dependent finite-$ q$ shift currents.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
15 pages, 5 figures
Electronic excitations in the Shastry-Sutherland compound SrCu$_2$(BO$_3$)$_2$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-05-11 20:00 EDT
Tariq Leinen, Ola K. Forslund, Eugenio Paris, Nicola Colonna, Marco Caputo, Johan Chang, Gabriel Nagamine, Takashi Tokushima, Conny Såthe, Pascal Puphal, Jeremie Teyssier, Thorsten Schmitt, Nikolay A. Bogdanov, Maria Daghofer, Adrian L. Cavalieri, Flavio Giorgianni
SrCu2(BO3)2 (SCBO) is a paradigmatic realization of the Shastry-Sutherland model, hosting geometrically frustrated spin dimers and a variety of quantum magnetic phases and phenomena. Although its magnetic properties have been extensively studied, the high-energy electronic excitations that determine the crystal-field environment and Cu-O hybridization have remained largely unexplored. Here we combine Cu L3-edge resonant inelastic x-ray scattering (RIXS), broadband optical spectroscopy, and electronic-structure calculations to determine the relevant local and interband excitation energy scales in SCBO. RIXS resolves a well-defined manifold of localized Cu2+ d-d excitations between 1.8 and 2.4 eV, whose energies and polarization dependence are well reproduced by multireference quantum-chemistry calculations. In contrast, optical spectroscopy identifies charge-transfer excitations with an absorption onset near 1.2-1.6 eV and a broader higher-energy structure around 4.5 eV, which are qualitatively captured by DFT+U calculations. Taken together, these results define the characteristic energy scales of d-d and CT excitations, offering quantitative benchmarks for computational frameworks and providing essential input for refining superexchange-based magnetic models of this prototypical frustrated quantum antiferromagnet.
Strongly Correlated Electrons (cond-mat.str-el)
Cluster Dynamics Stay Fast-Until Tricriticality
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-05-11 20:00 EDT
Minjun Jeon, Alexandros Vasilopoulos, Dong-Hee Kim, Víctor Martín-Mayor, Nikolaos G. Fytas
Cluster Monte Carlo algorithms are widely regarded as the most effective route to overcoming critical slowing down in lattice spin systems. Whether this acceleration persists in the presence of vacancies and multicritical fluctuations, however, remains unresolved. We address this question through a systematic dynamic-scaling study of hybrid cluster-local update schemes in the two-dimensional Blume-Capel model, which exhibits a line of continuous Ising-like transitions terminating at a tricritical point. Along the entire critical line, hybrid dynamics retain the near-optimal efficiency of pure cluster updates despite the presence of annealed vacancies. Strikingly, this acceleration collapses precisely at tricriticality, where the dynamic critical exponent reverts to the local-update value. We trace this breakdown to the correlated percolation of vacancies, whose emergent system-spanning geometry obstructs nonlocal relaxation in the spin sector. Our results identify a fundamental geometric limitation of cluster acceleration at tricriticality and establish vacancy percolation as the mechanism controlling dynamic universality in hybrid Monte Carlo dynamics.
Statistical Mechanics (cond-mat.stat-mech)
8 pages, 5 figures, 3 tables
Spectral Dynamics in Deep Networks: Feature Learning, Outlier Escape, and Learning Rate Transfer
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-05-11 20:00 EDT
Clarissa Lauditi, Cengiz Pehlevan, Blake Bordelon
We study the evolution of hidden-weight spectra in wide neural networks trained by (stochastic) gradient descent. We develop a two-level dynamical mean-field theory (DMFT) that jointly tracks bulk and outlier spectral dynamics for spiked ensembles whose spike directions remain statistically dependent on the random bulk. We apply this framework to two settings: (1) infinite-width nonlinear networks in mean-field/$ \mu$ P scaling and (2) deep linear networks in the proportional high-dimensional limit, where width, input dimension, and sample size diverge with fixed ratios. Our theory predicts how outliers evolve with training time, width, output scale, and initialization variance. In deep linear networks, $ \mu$ P yields width-consistent outlier dynamics and hyperparameter transfer, including width-stable growth of the leading NTK mode toward the edge of stability (EoS). In contrast, NTK parameterization exhibits strongly width-dependent outlier dynamics, despite converging to a stable large-width limit. We show that this bulk+outlier picture is descriptive of simple tasks with small output channels, but that tasks involving large numbers of outputs (ImageNet classification or GPT language modeling) are better described by a restructuring of the spectral bulk. We develop a toy model with extensive output channels that recapitulates this phenomenon and show that edge of the spectrum still converges for sufficiently wide networks.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Artificial Intelligence (cs.AI), Machine Learning (stat.ML)
Bulk-mediated reflection of chirality-protected surface spin waves
New Submission | Other Condensed Matter (cond-mat.other) | 2026-05-11 20:00 EDT
Vitaliy I. Vasyuchka, Florin Ciubotaru, Andrii V. Chumak, Burkard Hillebrands, Alexander A. Serga
Surface spin waves of the Damon-Eshbach type exhibit intrinsically nonreciprocal transport properties with a chiral dynamical field structure that localizes counterpropagating waves at opposite film surfaces. Such chirality has been predicted to suppress direct backscattering in thin films within frequency ranges free of bulk modes. However, how chirality influences reflection in thicker three-dimensional magnetic media, where a dense spectrum of bulk excitations overlaps with surface waves, remains unclear. Here we demonstrate that, in micrometer-thick yttrium iron garnet films, reflection of the chiral Damon-Eshbach wave from the boundary of the magnetic medium is accompanied by excitation of spatially localized thickness-quantized bulk modes, whereas reciprocal backward-volume waves reflect nearly elastically. Brillouin light scattering spectroscopy, infrared thermography, and micromagnetic simulations reveal standing bulk excitations at the reflecting boundary and quantify the associated magnon energy accumulation and dissipation. These results identify bulk-mode excitations as the physical pathway enabling reversal of chirally localized surface waves in thick films, thereby defining the limits of chirality-based backscattering immunity and providing a general framework for wave transport in nonreciprocal magnetic media.
Other Condensed Matter (cond-mat.other), Pattern Formation and Solitons (nlin.PS), Applied Physics (physics.app-ph), Classical Physics (physics.class-ph)
Shuttling of $\mathbb{Z}_4$ parafermions in an electronic ladder model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-05-11 20:00 EDT
Botond Osváth, Gergely Barcza, László Oroszlány
Parafermions with non-Abelian statistics have been proposed as a promising platform for quantum computation, potentially enabling a broader set of topologically protected gates than Majorana fermions. The experimental and theoretical exploration of these exotic quasiparticles remains challenging, as their stability is linked to strong electron-electron interactions. A key step toward practical applications is the controlled shuttling of parafermionic modes, which is required for implementing geometric braiding operations. In the present work, we investigate the real-time dynamics of the elementary shuttling process by applying a combination of the density matrix renormalization group and the time-dependent variational principle approaches. We analyze the transport of $ \mathbb{Z}_4$ parafermion edge states and assess the corresponding adiabatic speed limit under experimentally relevant conditions.
Strongly Correlated Electrons (cond-mat.str-el)
9 pages, 5 figures
Anomalous magnetotransport in a non-collinear correlated kagome ferromagnet MgMn6Sn6
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-11 20:00 EDT
Kakan Deb, Sourav Kanthal, Jyotirmoy Sau, Chandra Shekhar, Manoranjan Kumar, Matthias Gutmann, Jhuma Sannigrahi, Nitesh Kumar
Magnetic kagome metals provide a fertile platform for exploring unusual magnetotransport phenomena arising from the intricate interplay between electronic topology, electron correlations, and magnetic order. MgMn6Sn6 is a room-temperature kagome ferromagnet with strong in-plane magnetic anisotropy. Here, we report a combined study of single-crystal neutron diffraction (SCND) and magnetotransport properties of MgMn6Sn6, supported by first-principles calculations. Our SCND measurements reveal a non-collinear arrangement of Mn magnetic moments within the basal plane of the kagome bilayer. The Hall conductivity shows a substantial intrinsic contribution of approximately 0.29 e^2/h per kagome layer, which is nearly isotropic with respect to the field orientation. At low temperatures, the anomalous Hall conductivity develops a pronounced anisotropic extrinsic component, highlighting the directional sensitivity of scattering processes. The significantly large value of the Sommerfeld coefficient, in the absence of f-electrons, underscores enhanced electron correlation. Therefore, the non-collinear kagome ferromagnet MgMn6Sn6 is a promising candidate for studying the effects of electron correlation on magnetotransport properties.
Materials Science (cond-mat.mtrl-sci)
14 pages, 8 figures, 3 tables
Checkerboard Bose Hubbard Ladders using Transmon Arrays
New Submission | Other Condensed Matter (cond-mat.other) | 2026-05-11 20:00 EDT
Pranjal Praneel, Thomas G Kiely, Andre G Petukhov, Erich J Mueller
Adding a sublattice bias to the two dimensional Bose Hubbard model greatly enriches the available physics, and introduces knobs which can be used to control and interrogate the quantum state. We describe the physics of this checkerboard Bose Hubbard model and how it can be explored using transmon arrays. We show that the sublattice bias brings the commensurate superfluid phase into an experimentally accessible regime, and gives new probes. We characterize the superfluid and insulating phases, with careful attention to finite size effects.
Other Condensed Matter (cond-mat.other), Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
16 pages, 11 figures
Interfacial control of hot-carrier extraction and photostability in two-dimensional materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-11 20:00 EDT
Claudia Gollner, Mohammad Taghinejad, Chenyi Xia, Zhepeng Zhang, Fang Liu, Francesco Laudani, Annette Foelske, Mark L. Brongersma, Andrew J. Mannix, Tony F. Heinz, Aaron Lindenberg
Two-dimensional transition metal dichalcogenides (TMDCs) are promising materials for next-generation optoelectronic devices, yet their implementation is hindered by limited sample stability and challenges in forming reliable electrical contacts. Here, by utilizing time-domain THz emission spectroscopy we directly probe charge carrier dynamics in monolayer WS2 on gold (Au) and fused silica (SiO2) as a function of interface morphology. For laser excitation above the band gap of WS2, we independently extract effective transport times for both electrons and holes and find that discontinuous WS2 contacts on rough Au generate larger net photocurrents than uniform, strongly coupled interfaces - a counterintuitive observation attributed to imbalanced electron and hole transfer from WS2 to Au. Crucially, we demonstrate that ultrafast charge extraction and separation suppress recombination-driven energy release and thereby prevent photo-induced degradation under ambient conditions, eliminating the need for encapsulation. These findings redefine interfacial design as a central control parameter for both performance and stability in 2D optoelectronic devices.
Materials Science (cond-mat.mtrl-sci)
MatterSim-MT: A multi-task foundation model for in silico materials characterization
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-11 20:00 EDT
Han Yang, Xixian Liu, Chenxi Hu, Yichi Zhou, Yu Shi, Chang Liu, Junfu Tan, Jielan Li, Guanzhi Li, Qian Wang, Yu Zhu, Zekun Chen, Shuizhou Chen, Fabian Thiemann, Claudio Zeni, Matthew Horton, Robert Pinsler, Andrew Fowler, Daniel Zügner, Tian Xie, Lixin Sun, Yicheng Chen, Lingyu Kong, Yeqi Bai, Deniz Gunceler, Frank Noé, Hongxia Hao, Ziheng Lu
Accurate property characterization is a major bottleneck in materials design. While first-principles methods and task-specific machine-learning models have driven important progress, they remain fundamentally limited in scalability and generalizability across the vast space of structures and properties relevant to real-world materials design. We present MatterSim-MT, a multi-task foundation model for in silico materials simulation and property characterization. The model is pretrained on over 35 million first-principles-labeled structures covering 89 elements, temperatures up to 5000 K and pressures up to 1000 GPa, and is fine-tuned on various properties including Bader charges, magnetic moments, Born effective charges, and dielectric matrices. Out of the box, MatterSim-MT not only serves as a foundation model for predicting material structure, dynamics and thermodynamics, its multi-task architecture also enables a wide range of complex simulations that cannot be captured by potential energy surfaces alone. For example, we demonstrate pressure-dependent LO-TO phonon splitting in SiC with close agreement with experiment, electric hysteresis in ferroelectric BaTiO3, and the cationic-to-anionic redox transition during delithiation of a Li-rich cathode material. Finally, we show that MatterSim-MT scales well with more data and parameters, can be efficiently fine-tuned to higher levels of theory, and can be efficiently extended to new systems via active learning. Overall, we believe this approach provides a scalable route to accurate in silico materials characterization.
Materials Science (cond-mat.mtrl-sci)
Microscopic Magnetism of A(TiO)Cu4(PO4)4 (A = Ba, Pb, Sr): 31P and 63,65Cu NMR Study
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-05-11 20:00 EDT
Riho Rästa, Ivo Heinmaa, Joosep Link, Yusuke Kousaka, Tsuyoshi Kimura, Yoshihiko Ihara, Kenta Kimura, Raivo Stern
We report a comprehensive NMR study of the chiral square-cupola antiferromagnet Pb(TiO)Cu$ 4$ (PO$ 4$ )$ 4$ and compare its microscopic hyperfine and local-field parameters with the Ba/Sr analogues in the $ A$ (TiO)Cu$ 4$ (PO$ 4$ )$ 4$ family. Above $ T{\rm N}\simeq 6.7$ K, the $ ^{31}$ P Knight shift tracks the bulk susceptibility and yields nearly isotropic transferred hyperfine couplings $ H{\rm hf}^{[010]}=6.77(3)$ and $ H{\rm hf}^{[001]}=6.19(3)$ kOe/$ \mu{\rm B}$ . Below $ T{\rm N}$ , the frequency-swept $ ^{31}$ P spectrum splits into three lines, in contrast to the four-line pattern reported for BaTCPO. The line separation tracks the onset of the static $ ^{31}$ P internal field with a power-law exponent $ \beta\simeq 0.23$ , consistent with quasi-two-dimensional criticality. Crystal-rotation $ ^{31}$ P NMR in the ordered state resolves all eight symmetry-related P sites and their site-dependent anisotropy. In the ordered state, zero-field $ ^{63,65}$ Cu NMR gives a Cu-site internal field $ B{\rm int}=14.50(6)$ T and a quadrupole frequency $ \nu_Q=32.72(5)$ MHz, while point-charge electric-field-gradient calculations including Sternheimer corrections yield an on-site Cu hole occupancy $ n_d=0.20(4)$ , consistent with a ligand-hole-dominated charge-transfer character. Comparing PbTCPO with BaTCPO and SrTCPO, we find that the transferred hyperfine coupling $ H_{\rm hf}$ varies across the series, reflecting changes in local Cu-O-P covalency, whereas the ordered-state $ ^{31}$ P internal field in PbTCPO is $ 69.5$ mT, considerably higher than in BaTCPO ($ 35.6$ mT) and SrTCPO ($ 34.6$ mT). This enhancement is not captured by dipolar terms alone and points to the combined effects of transferred contributions and stacking-dependent cancellation.
Strongly Correlated Electrons (cond-mat.str-el)
13 pages, 11 figures, 5 tables
Phys. Rev. B 113, 184428 (2026)
Energy-Resolved Quantum Geometry from Středa Response: Driven-Dissipative Bosonic Lattices and Disordered Systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-05-11 20:00 EDT
Anaïs Defossez, Baptiste Bermond, Lucila Peralta Gavensky, Nathan Goldman
The Středa formula links the Hall conductivity of an insulator to the magnetic-field response of its particle density, providing a local and universal probe of the topological Chern number. Beyond this quantized response, an energy-resolved Středa marker can be defined from the magnetic response of the density of states, revealing detailed features of the quantum geometry of Bloch bands. We show that driven-dissipative bosonic lattices provide direct access to both the integrated and energy-resolved Středa responses. Our scheme uses controlled pumping with uniform strength and random phases across the lattice, together with uniform loss, to yield a Lorentzian filter of eigenmode occupations. For generic dispersive bands, this enables reconstruction of a coarse-grained energy-resolved Středa response, establishing these platforms as versatile probes of anomalous spectral flow and energy-resolved quantum geometry. As a striking application, we show that this marker elucidates the fate of topological bands under strong disorder, capturing the quantum-geometric structure underlying topological Anderson insulators.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Disordered Systems and Neural Networks (cond-mat.dis-nn), Quantum Gases (cond-mat.quant-gas), Optics (physics.optics)
12 pages, 9 figures (including Appendix)
Mutual Linearity in Nonequilibrium Langevin Dynamics
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-05-11 20:00 EDT
Understanding how nonequilibrium systems respond to perturbations is a central challenge in physics. In this work, we establish mutual linearity in nonequilibrium overdamped Langevin systems. This theory provides a framework for controlling and designing nonequilibrium responses in continuous systems. When a dynamical parameter is locally perturbed at a single position, the stationary densities at any two positions are linearly related. It further leads to mutual linearity among different stationary state-current observables. We also extend the mutual linearity to non-stationary relaxation processes in the Laplace domain. Our theory reveals that mutual linearity in both discrete and continuous systems originates from the same one-dimensional response structure. We further show that mutual linearity is robust under finite-width perturbations. As an application, we demonstrate the mutual linearity and its finite-width robustness in the F$ _1$ -ATPase rotary motor model.
Statistical Mechanics (cond-mat.stat-mech)
Light-driven octupolar inverse Faraday effect and multipolar order in Mott insulators
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-05-11 20:00 EDT
Saikat Banerjee, Tara Steinhöfel, Florian Lange, Matthias Eschrig, Holger Fehske
Hidden multipolar orders in spin-orbit-coupled Mott insulators provide a promising setting for correlated quantum matter, yet their control and detection remain major challenges. Here, we demonstrate that circularly polarized light enables both in $ 4d^2/5d^2$ systems with edge-sharing octahedra. Using a Floquet Schrieffer-Wolff expansion of a driven Hubbard-Kanamori model, we derive a low-energy multipolar Hamiltonian with two qualitatively new light-driven terms. One is an effective static field that couples linearly to the magnetic octupole, realizing an octupolar inverse Faraday effect. The other is a bond-dependent anisotropic exchange interaction absent in equilibrium. These two couplings are the key result of this work: the first provides a direct optical handle on hidden octupolar order, while the second reorganizes the multipolar exchange landscape and opens an enlarged Kitaev-like multipolar liquid regime. Their interplay produces a nonequilibrium multipolar phase space inaccessible in equilibrium, enabling optical tuning among antiferro-octupolar, ferro-octupolar, partially polarized ferro-quadrupolar, Ising octupolar, and multipolar liquid phases. We further show that the induced multipolar order couples to the lattice, generating reversible trigonal and tetragonal distortions that provide structural fingerprints in pump-probe experiments. Our work establishes a general mechanism for the optical generation, control, and detection of hidden multipolar quantum states.
Strongly Correlated Electrons (cond-mat.str-el)
28 pages + 12 Figures, Comments are welcome
Anisotropic Defect Diffusion in Layered CsPbBr$\mathrm{x}$I$\mathrm{3-x}$ Perovskites
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-05-11 20:00 EDT
Konrad Wilke, Mike Pols, Titus S. van Erp, Geert Brocks, Shuxia Tao
Mixed-halide perovskites offer a route to enhance phase stability and modify optoelectronic properties. Here, we use large-scale molecular dynamics simulations with a reactive force field to investigate defects in CsPbBr$ _\mathrm{x}$ I$ _\mathrm{3-x}$ perovskites, focusing on how defect mobility can be controlled and the stability of the material may be improved by layered ordering of Br and I anions in layers. Our results show that layered halide ordering induces strongly anisotropic defect diffusion: migration proceeds readily along the layers, whereas diffusion across them is strongly suppressed. For Cs defects, this anisotropy originates from directional lattice strain and the associated octahedral tilting, while halide migration is governed by an interplay between strain and preferential local halide bonding configurations.
Materials Science (cond-mat.mtrl-sci)
Gapped 1/9 Magnetization Plateau in the Anisotropic Kagome Antiferromagnet Y-kapellasite
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-05-11 20:00 EDT
Dipranjan Chatterjee, Paul A. Goddard, Ewan R. P. Thomas, Katharina M. Zoch, Hank C. H. Wu, Benjamin M. Huddart, Cornelius Krellner, Edwin Kermarrec, Mladen Horvatić, Steffen Krämer, Pascal Puphal, John Singleton, Stephen J. Blundell, Fabrice Bert
Fractional magnetization plateaus provide a sensitive probe of many-body spin states in frustrated quantum magnets, yet their microscopic origin in kagome antiferromagnets remains unresolved. This is particularly true of the mysterious $ 1/9$ plateau, which is predicted by theory but infrequently observed in experiment. Here, we investigate this problem in the $ S = 1/2$ anisotropic kagome antiferromagnet Y-kapellasite, Y$ _3$ Cu$ _9$ (OH)$ _{19}$ Cl$ _8$ , using pulsed-field magnetization measurements on single crystals and high-field $ ^{35}$ Cl NMR. We identify a hierarchy of field-induced fractional features, including $ 1/3$ and $ 1/9$ plateaus, as well as a weaker low-field feature. Analysis of the NMR spectra and the magnetic susceptibility across the $ 1/9$ plateau demonstrate that it is accompanied by an ordered local spin configuration, a strong suppression of low-energy spin fluctuations and activated behavior, consistent with a gapped fractional state. These features differ from those in the only other material YCu$ _3$ (OH)$ _6$ Br$ _2$ [Br$ _{1-y}$ (OH)$ _y$ ] in which this plateau is observed, implying a surprising robustness of the $ 1/9$ state to the details of the underlying magnetism.
Strongly Correlated Electrons (cond-mat.str-el)
7 pages, 4 figures
Multiscale Structure of Eigenstate Thermalization
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-05-11 20:00 EDT
Pavel Orlov, Rustem Sharipov, Enej Ilievski
The eigenstate thermalization hypothesis provides a framework for understanding thermalization in isolated quantum many-body systems by characterizing statistical properties of local observables in energy eigenstates. Here we demonstrate that distributions of matrix elements in macroscopic systems may depend not only on the macrostate parameters, such as the densities of local conserved charges, but generally also on the properties of ensembles used in sampling eigenstates. To this end, we depart from the conventional analysis of microcanonical windows and consider statistical ensembles with an adjustable scale parameter prescribing the magnitude of charge fluctuations. We specifically consider an integrable field theory that permits efficient numerical sampling of matrix elements and reliable extrapolation to the thermodynamic limit. Moreover, in this system, we identify a class of states that enables explicit closed-form computation of the suppression rate of matrix elements. Our findings reveal an underlying multiscale structure of matrix elements captured by a non-analytic fluctuation-scale dependence of algebraic exponents governing their statistical properties.
Statistical Mechanics (cond-mat.stat-mech), High Energy Physics - Theory (hep-th), Mathematical Physics (math-ph)
21 pages, 14 figures