CMP Journal 2026-04-06
Statistics
Nature Materials: 2
Nature Physics: 2
arXiv: 47
Nature Materials
Two-dimensional materials for integrated sensing
Review Paper | Electronics, photonics and device physics | 2026-04-05 20:00 EDT
Hangyu Xu, Zhihao Xu, Qinqi Ren, Yuan Meng, Sangmoon Han, Zhaoqing Wang, Yang Chai, Sang-Hoon Bae, Weida Hu
Recent advances in electrical multiply-accumulate (MAC) operations leveraging resistive-switching materials have catalysed significant progress in optoelectronic sensing and computing technologies through the exploration of emerging materials. These innovative approaches facilitate the encoding of optical amplitude information such as retina-like functionalities. However, a critical dimensional mismatch persists between electrical and optical information, resulting in a substantial portion of high-dimensional data channels remaining unexplored in conventional MAC operation schemes. Combined with advanced device architectures and data algorithms, two-dimensional materials are considered promising candidates to realize in situ encoding and optoelectronic sensing of multi-dimensional optical information under precise control owing to their tunable physical properties. In this Review, we outline the progress of emerging two-dimensional-materials-based ‘integrated sensors’, and benchmark electrical inputs with optical scenarios in a framework unifying information encoding. Exciting opportunities for integrated sensors are discussed as well, highlighting the requirements and differences in the encoding of different dimensions of information and exploring the potential for integrated sensors in other fields.
Electronics, photonics and device physics, Sensors and biosensors
Bulk nano-heterointerface secures molecular contacts in perovskite solar cells
Original Paper | Materials science | 2026-04-05 20:00 EDT
Yixin Luo, Jiahui Shen, Ke Zhao, Shenglong Chu, Yuan Tian, Lu Jin, Caner Değer, Bo-jun Zhao, Xuechun Sun, Libing Yao, Xiaohe Miao, Li Zhang, Qingqing Liu, Seung-Gu Choi, Qinggui Li, Runda Li, Hengyu Zhang, Haimeng Xin, Jiazhe Xu, Jingjing Zhou, Donger Jin, Rui Wang, Jin-Wook Lee, Ruzhang Liu, Ilhan Yavuz, Hong-fei Wang, Hyo Jae Yoon, Zhenyi Ni, Deren Yang, Jingjing Xue
The development of molecule-based selective contacts has boosted the power conversion efficiencies of inverted perovskite solar cells. However, these molecular films, often assembled as monolayer or multiple layers on the substrate, are prone to molecular desorption and structural deformation, limiting the long-term stability of devices. This instability, in essence, originates from the weak contacting structure between the transparent conductive oxide and molecular layer, with a limited interface offering insufficient adhering forces to immobilize the molecules. A general architectural strategy that circumvents this fundamental limitation without compromising electronic functionality is highly demanded, but remains underexplored. We now report a universal architecture of a bulk nano-heterointerface that reconstructed the molecule-based selective layer. The substantially increased chemical interface and strengthened binding force between the molecules and rationally designed nanoscale scaffolds greatly improved the device operational stability, achieving high efficiency. The strategy proved versatile, successfully applied to various molecular systems to enhance device performances, and remained effective in upscaled devices produced via scalable blade coating.
Materials science, Solar cells
Nature Physics
Length-scale dependence of the anomalous atomic motion in metallic glasses
Original Paper | Glasses | 2026-04-05 20:00 EDT
Jie Shen, Fan Yang, Antoine Cornet, Eloi Pineda, Kirsten Martens, Yuriy Chushkin, Federico Zontone, Irene Festi, Alberto Ronca, Nico Neuber, Maximilian Frey, Ralf Busch, Marco Cammarata, Marco di Michiel, Gavin Vaughan, Michael Sprung, Beatrice Ruta
Establishing microscopic structure-dynamics relations in glasses is essential for developing a comprehensive theory yet remains challenging owing to limited access to the relevant time and length scales. Here we probe density fluctuations in three metallic glasses and describe a complex organization of the dynamics that provides a framework of the anomalous compressed relaxation universally observed in metallic glasses at the atomic level. We demonstrate that this faster-than-exponential motion occurs only at length scales characterized by medium-range order and originates from internal stresses stored during the freezing of rigid domains across the glass transition. At larger length scales, the dynamics becomes stationary and heterogeneous, with stretched exponential relaxations reflecting the statistically averaged motions of different domains. We also identify a second independent relaxation, associated with persistent liquid-like motions, whose strength increases at large wavelengths. These findings reveal the cooperative, multiscale nature of relaxations in glasses.
Glasses, Metals and alloys
Quantum ground-state cooling of two librational modes of a nanorotor
Original Paper | Quantum mechanics | 2026-04-05 20:00 EDT
Stephan Troyer, Florian Fechtel, Lorenz Hummer, Henning Rudolph, Benjamin A. Stickler, Uroš Delić, Markus Arndt
Controlling the motion of nanoscale objects at the quantum limit promises opportunities to test fundamental quantum physics and advances in quantum sensing. Rotational motion is of particular interest, as its nonlinear dynamics in a compact, closed configuration space provides access to phenomena such as rotational interferometry, tunnelling between angular configurations and quantum-enhanced torque sensing. A key requirement for such experiments is the capability to trap nanorotors and cool their orientation close to the two-dimensional librational quantum ground state. When rotational motion is confined in a harmonic potential, it becomes librational. Here we demonstrate that coherent scattering into a high-finesse cavity enables the ground-state cooling of two orthogonal librational modes of an optically levitated SiO2 nanoparticle. Using a laser-induced desorption loading technique, we trap and cool several dimers and trimers of silica nanospheres to their respective ground states, all within a single day. The simultaneous cooling of both librational degrees of freedom allows us to align an individual nanorotor with respect to a space-fixed axis with an angular precision better than 20 µrad–close to the quantum-mechanical zero-point fluctuations.
Quantum mechanics, Quantum optics
arXiv
Transport and Temperature 1: Exact spectrum and resistivity for the one-dimensional infinite-$U$ Hubbard model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-04-06 20:00 EDT
Shuo Liu, Yuhao Ma, Hitesh J. Changlani, Philip W. Phillips, B. Andrei Bernevig
Understanding charge transport in strongly correlated systems remains a central challenge in condensed matter physics, particularly in light of the ubiquitous linear-in-$ T$ resistivity observed in strange metals across many platforms from bulk cuprates to twisted bilayer graphene. Here, we investigate charge transport in the one-dimensional Hubbard model in the infinite-interaction limit. Focusing on the dilute limit with a fixed number of doped holes, we first construct the exact \emph{and explicit - i.e. beyond Bethe ansatz} energy spectrum and then derive a closed-form analytical expression for the charge Drude weight at arbitrary temperatures. We further analyze the low-temperature scaling and identify a linear-in-$ T$ correction to the Drude weight. Upon regularizing the singular Drude contribution to the DC conductivity, we find that this behavior corresponds to an effective linear-in-$ T$ resistivity, which may provide analytical insight into the emergence of strange-metal transport in two-dimensional strongly correlated systems.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
The main text contains 5 pages and 2 figures
Detection of spin- and valley-polarized states in van der Waals materials via thermoelectric and non-reciprocal transport
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-04-06 20:00 EDT
Oladunjoye A. Awoga, Pauli Virtanen, Tero T. Heikkilä, Stefan Ilić
We predict thermoelectric and current rectification effects in hybrid junctions formed by Ising superconductors and materials hosting valley-polarized states. Both effects originate from the interplay of intrinsic Ising spin-orbit coupling, spin-splitting from an exchange or Zeeman field, and valley polarization. The resulting transport signatures provide experimentally accessible probes of valley-polarized states in van der Waals heterostructures, such as junctions of few-layer transition metal dichalcogenides and twisted bilayer or rhombohedral graphene.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
Superconductivity and fractionalized magnetic excitations in CeCoIn5
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-04-06 20:00 EDT
Pyeongjae Park, Shang-Shun Zhang, Pietro M. Bonetti, Andrey A. Podlesnyak, Daniel M. Pajerowski, Matthew B. Stone, C. Petrovic, C. Stock, Subir Sachdev, Cristian D. Batista, Andrew D. Christianson
Recent experiments on CeCoIn5 – a prototypical d-wave superconductor – indicate that its normal state lies near an unconventional quantum critical point (QCP). One intriguing hypothesis is that quantum-critical fluctuations promote fractionalization of localized 4f moments into fermionic spinons. This fractionalized Fermi liquid (FL\ast) scenario provides a comprehensive framework for the unconventional QCP and superconductivity, and can reconcile a “missing” Fermi-surface volume relative to the Luttinger count in the normal state of CeCoIn5. To test this possibility, we performed inelastic neutron scattering (INS) measurements on CeCoIn5 across the superconducting transition and corresponding theoretical analysis. Our high-precision spectra reveal detailed momentum and temperature dependence of the spin resonance and a structured spin excitation continuum persisting even in the normal state, placing stringent constraints on the physical picture of pairing in a d-wave superconductor. We show that a Kondo-lattice framework incorporating proximity to FL\ast physics and d-wave pairing reproduces key features of the data. The model suggests that both the quasi-localized nature of the f-moments above Tc and the resonance below Tc arise from common underlying gauge dynamics, implying a unifying organizing principle linking spin fractionalization and unconventional superconductivity in strongly correlated metals.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
12 pages, 4 figures
CARBON-2D Topological Descriptor (C2DTD): An Interpretable and Physics-Informed Representation for Two-Dimensional Carbon Networks
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-06 20:00 EDT
Felipe Hawthorne, Marcelo Lopes Pereira Junior, Fabiano Manoel de Andrade, Cristiano Francisco Woellner, Raphael Matozo Tromer
Two-dimensional (2D) carbon networks, from pristine graphene to defect-rich and amorphous monolayers, exhibit a complex structure-energy landscape governed not only by local bonding but also by medium-range order and network topology. Capturing these multi-scale effects in a compact, interpretable, and data-efficient manner remains a major challenge for machine learning (ML) in low-dimensional materials. In this work, we introduce the CARBON-2D Topological Descriptor (C2DTD), a physically informed structural representation specifically designed for 2D carbon systems. The descriptor integrates local geometric statistics, a compact radial structural signature, and explicit primitive ring topology into a fixed-length, invariant vector that is both computationally efficient and directly interpretable. Benchmarking on diverse datasets of 2D carbon allotropes and defect-engineered graphene sheets demonstrates that C2DTD achieves robust predictive performance in small-data regimes, outperforming generic high-dimensional featurization schemes while preserving physical transparency. Unsupervised manifold analysis reveals a smoother alignment between descriptor space and the DFT energy landscape, and feature-importance and ablation studies confirm that ring topology emerges as a dominant energetic driver, particularly under vacancy-induced reconstruction. Furthermore, controlled simulations with 5-15% random vacancies show that C2DTD naturally captures the progressive transition from hexagon-dominated graphene to topologically disordered networks, enabling both dataset-level and structure-specific interpretation. Owing to its compactness, interpretability, and strong physics-based inductive bias, C2DTD provides a fast and generalizable framework for data-driven modeling, defect analysis, and high-throughput screening of 2D carbon materials.
Materials Science (cond-mat.mtrl-sci)
22 pages and 06 figures
AQVolt26: High-Temperature r$^2$SCAN Halide Dataset for Universal ML Potentials and Solid-State Batteries
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-06 20:00 EDT
Jiyoon Kim, Chuhong Wang, Aayush R. Singh, Tyler Sours, Shivang Agarwal, AJ Nish, Paul Abruzzo, Ang Xiao, Omar Allam
The demand for safe, high-energy-density batteries has spotlighted halide solid-state electrolytes, which offer the potential for enhanced ionic mobility, electrochemical stability, and interfacial deformability. Accelerating their discovery requires extensive molecular dynamics, which has been increasingly enabled by universal machine learning interatomic potentials trained on foundational datasets. However, the dynamic softness of halides poses a stringent test of whether general-purpose models can reliably replace first-principles calculations under the highly distorted, elevated-temperature regimes necessary to probe ion transport. Here, we present AQVolt26, a dataset of 322,656 r$ ^2$ SCAN single-point calculations for lithium halides, generated via high-temperature configurational sampling across $ \sim$ 5K structures. We demonstrate that foundational datasets provide a strong baseline for stable halide chemistries and transfer local forces well, however absolute energy predictions degrade in distorted higher-temperature regimes. Co-training with AQVolt26 resolves this blind spot. Furthermore, incorporating Materials Project relaxation data improves near-equilibrium performance but degrades extreme-strain robustness without enhancing high-temperature force accuracy. These results demonstrate that domain-specific configurational sampling is essential for the reliable dynamic screening of halide electrolytes. Furthermore, our findings suggest that while foundational models provide a robust base, they are most effective for dynamically soft solid-state chemistries when augmented with targeted, high-temperature data. Finally, we show that near-equilibrium relaxation data serves as a task-specific complement rather than a universally beneficial addition.
Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG)
Temperature-dependent Raman spectra of 2H-MoS2 from Machine Learning-driven statistical sampling
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-06 20:00 EDT
Samuel Longo, Aloïs Castellano, Matthieu J. Verstraete
Molybdenum sulfides are in the spotlight of materials science thanks to their interesting properties for applications in optoelectronics, nanocomposites, lubricants, and catalysis. The structural characterization of Molybdenum sulfides is a crucial step to understand and tune their properties. Vibrational techniques, such as infrared and Raman spectroscopy, can directly link to structural features, but the experimental literature suffers from large variability. Theoretical calculations are a powerful tool complementing and explaining empirical measurements. The reliability of first-principles calculation depends on the level of approximation made, taking into account disorder, doping, or temperature to yield a good description of the phonon statistics and related measurable quantities, such as the infrared and Raman peaks. In this study we calculate the Raman spectrum of crystalline 2H-MoS2, including broadening and shifts due to thermal and anharmonic effects. Our results demonstrate excellent agreement with experimental measurements; notably, the calculated temperature trends in frequencies and linewidths align with empirical observations. These findings establish a robust computational framework, paving the way for similar studies on amorphous Molybdenum sulfides.
Materials Science (cond-mat.mtrl-sci)
Fermionic mean-field dynamics for spin systems beyond free fermions
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-04-06 20:00 EDT
Rishab Dutta, Marc Illa, Niranjan Govind, Karol Kowalski
We introduce the fermionized time-dependent Hartree-Fock (fTDHF), a real-time quantum dynamics method for spin-1/2 Hamiltonians following their mapping to fermions via the Jordan-Wigner transformation. fTDHF is formally equivalent to exact dynamics in the case of free fermions and can efficiently handle non-local string operators arising from long-range interactions via transition matrix elements between non-orthogonal Slater determinants. We show that the fTDHF method can be implemented on a classical computer with a cost that scales polynomially with system size, and linearly with the time steps. We benchmark fTDHF against exact dynamics on three separate spin-1/2 models, representing adiabatic preparation of states with long-range correlations, disorder-driven observation of many-body localization, and particle production in the Schwinger model. For each of these systems, fTDHF is shown to reproduce the qualitative dynamics generated by the exact evolutions, while maintaining a simple physical picture due to its mean-field nature.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
13 pages including references, 4 figures
Reducing Bias and Optimising Execution Time in Iterative Solutions of the Time Dependent Ginzburg Landau Equations
New Submission | Superconductivity (cond-mat.supr-con) | 2026-04-06 20:00 EDT
The importance of simulating pinning arrays in superconducting samples for the increase of critical currents has been increasing in the last few years. Since the Time Dependent Ginzburg Landau (TDGL) can be more accurate than alternative methodologies, the simulation procedures involving it are critical to design devices that can sustain higher critical currents and, therefore, to the field of applied superconductivity. In this article, a simple novel algorithm is presented for the reduction of bias and optimisation of execution time in iterative time dependent simulations, applied to TDGL solutions of superconducting samples. Taking a time series approach to the magnetic response of the sample, stationary solutions are found for each step in the evolution of the applied external field, leading to bias reduction and minimisation of iterations needed to be spent at each step in the applied field. The results are presented for a pure superconductor, in a framework of simulations via link variable technique, with simple Euler algorithm for the solution in time, but the implementation can be adapted easily to deal with adaptive step size solutions or semi-implicit methods, which are not exempt from the bias and iterations tradeoff.
Superconductivity (cond-mat.supr-con)
Evolution from Landau Quantization to Discrete Scale Invariance Revealed by Quantum Oscillations in Topological Materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-06 20:00 EDT
Jiayi Yang, Nannan Tang, Yunxing Li, Jiawei Luo, Huakun Zuo, Gangjian Jin, Ziqiao Wang, Haiwen Liu, Yanzhao Liu, Donghui Guo, XinCheng Xie, Jian Wang, Huichao Wang
Dirac materials have been a unique solid state platform for exploring relativistic quantum phenomena including supercritical atomic collapse, which leads to emergent discrete scale symmetry and logperiodic quantum oscillations. In the relativistic regime, the fundamental effect in quantum electrodynamics, vacuum polarization, can further modulate the atomic collapselike state by screening bare charges but is rarely harnessed in condensed matter system. Here, we report a continuous progression from low field Shubnikov de Haas oscillations to high field log periodic oscillations in the Dirac material HfTe5, with both phenomena modulated by Fermi surface anisotropy. This maps the transition from single particle Landau levels to an interaction-driven, discrete scale invariant energy spectrum of quasi-bound states. Crucially, our findings suggest vacuum polarization provides a compelling mechanism for renormalizing the effective impurity charge, quantitatively explaining the carrier-density dependent scale factor. By revealing the intricate interplay between Landau quantization, many body electronic screening, and scale-symmetry breaking, our results establish Dirac solids as a controllable platform for exploring relativistic vacuum effects and emergent novel symmetry.
Materials Science (cond-mat.mtrl-sci)
19 pages, 4 figures
Nonlinear Magnetic Orbital Hall Effect Induced by Spin-Orbit Coupling
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-06 20:00 EDT
Hui Wang, Huiying Liu, Yanfeng Ge, Xukun Feng, Jiaojiao Zhu, Jin Cao, Cong Xiao, Shengyuan A. Yang, Lay Kee Ang
Electrical readout of 180$ ^\circ$ switching in strictly compensated collinear antiferromagnets remains a major challenge in antiferromagnetic spintronics. Electrical writing of perpendicularly magnetized ferromagnets by out-of-plane orbital torque remains an important challenge in orbitronics. In this work, we propose a second-order nonlinear magnetic orbital Hall effect in the source antiferromagnet as a simultaneous recipe for both difficulties. This orbitronics effect is induced by spin-orbit coupling and is odd in the Néel vector, thus is a unique effect that integrates both functionalities via electric control of the Néel vector in the source antiferromagnet. Our first-principles calculations in CuMnAs predict significant non-perturbative orbital effects from spin-orbit coupling, with a orbital Berry-curvature dipole mechanism. These findings unveil new possibilities opened by topological antiferromagnetic orbitronics.
Materials Science (cond-mat.mtrl-sci)
Unraveling Intrinsic Thermal Conductivity in Layered Conductive MOF Single Crystals
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-06 20:00 EDT
Jinkun Guo, Dongyang Wang, Zhiyi Li, Haoyang Zhang, Jiaxiang Zhang, Zeyue Zhang, Lei Sun, Junliang Sun, Jiawei Zhou, Chongan Di, Jinhu Dou
Layered conductive metal-organic frameworks (LCMOFs) show great promise in energy and electronics due to their high electrical conductivity and tunable pore structures. They are considered ideal “phonon-glass, electron-crystal” materials. However, their intrinsic thermal transport properties, particularly the thermal conductivity in the single-crystalline state, have never been explored before. The applicability of the Wiedemann-Franz law to such complex porous materials is a key scientific question to describe their thermoelectric relationship. We investigated single crystals of three LCMOFs (Cu3HHTP2, Co9HHTP4, Nd3HHTP2) using the microfabricated suspended device. Results showed ultralow thermal conductivities (0.075-0.194 W m-1 K-1) along the {\pi}-{\pi} stacking direction. Crucially, Nd3HHTP2 exhibited a high electrical conductivity of 398 S cm-1, yet its thermal conductivity (0.148 W m-1 K-1) was comparable to the other two LCMOFs with significantly lower electrical conductivities. Structural characterization revealed that the incommensurate modulation, and in-plane correlated disorder within the Nd3HHTP2 structure are the potential causes of strong phonon scattering and the observed ultralow thermal conductivity.
Materials Science (cond-mat.mtrl-sci)
Some typical delusions in the theory of Bose-Einstein condensation
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-04-06 20:00 EDT
Despite the long history of the theory of Bose-Einstein condensation, there exist till nowadays some slippery points that are often misunderstood and result in confusion. The report touches some of these points, explaining the following: Global gauge symmetry breaking is the necessary and sufficient condition for the existence of Bose-Einstein condensate. There is no any grand canonical catastrophe". The stability of the ideal Bose gas depends on the spatial dimensionality and the shape of a trap. Symmetry-broken averages cannot be neglected. The so-called Popov approximation”, ascribed to Popov, suggesting to neglect anomalous averages, is neither an approximation nor has anything to do with Popov. There are no thermodynamically anomalous fluctuations in stable equilibrium systems. Representative statistical ensembles are equivalent.
Statistical Mechanics (cond-mat.stat-mech)
conference report
J. Phys. Conf. Ser. 3183 (2026) 012007
MatClaw: An Autonomous Code-First LLM Agent for End-to-End Materials Exploration
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-06 20:00 EDT
Chenmu Zhang, Boris I. Yakobson
Existing LLM agents for computational materials science are constrained by pipeline-bounded architectures tied to specific simulation codes and by dependence on manually written tool functions that grow with task scope. We present MatClaw, a code-first agent that writes and executes Python directly, composing any installed domain library to orchestrate multi-code workflows on remote HPC clusters without predefined tool functions. To sustain coherent execution across multi-day workflows, MatClaw uses a four-layer memory architecture that prevents progressive context loss, and retrieval-augmented generation over domain source code that raises per-step API-call accuracy to $ {\sim}$ 99 %. Three end-to-end demonstrations on ferroelectric CuInP2S6 (machine-learning force field training via active learning, Curie temperature prediction, and heuristic parameter-space search) reveal that the agent handles code generation reliably but struggles with tacit domain knowledge. The missing knowledge, such as appropriate simulation timescales, equilibration protocols, and sampling strategies, is the kind that researchers accumulate through experience but rarely formalize. Two lightweight interventions, literature self-learning and expert-specified constraints, bridge these gaps, defining a guided autonomy model in which the researcher provides high-level domain knowledge while the agent handles workflow execution. Our results demonstrate that the gap between guided and fully autonomous computational materials research is narrower than ever before: LLMs already handle code generation and scientific interpretation reliably, and the rapid improvement in their capabilities will accelerate materials discovery beyond what manual workflows can achieve. All code and benchmarks are open-source.
Materials Science (cond-mat.mtrl-sci), Software Engineering (cs.SE)
The unique control features of topological stochastic and quantum systems
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-04-06 20:00 EDT
Ziyin Xiong, Aleksandra Nelson, Evelyn Tang
Topological phases support edge states that can be robust to material deformations and other perturbations. While well-studied in quantum systems, topological phases have also been observed in stochastic and biochemical systems, yet it remains unclear which of their properties remain similar or different from those in quantum systems. In this paper, we derive analytical expressions for the spectral properties of simple quantum and stochastic models on the same lattice to rigorously characterize these complex systems. Intriguingly, we find that non-reciprocity moves states away from the steady-state in stochastic systems while clustering states at zero-energy in quantum systems. In contrast, making the system more topological does the opposite: it clusters more states around the steady-state in stochastic systems but moves states away from the zero-energy state in quantum systems. These results provide control parameters for selection and modulation of different purposes while quantifying the size of gap which protects the longest-lived states. Lastly, we discover a mode unique to stochastic systems that we dub the topologically emerging state, which persists across different models and dimensions, including in the presence of non-equilibrium currents.
Statistical Mechanics (cond-mat.stat-mech), Soft Condensed Matter (cond-mat.soft)
14 pages, 6 figures
Effective electron coupling to phonon mechanical angular momentum in helical systems
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-06 20:00 EDT
Akihito Kato, Nobuhiko Yokoshi, Jun-ichiro Kishine
In chiral crystals, two types of phonon angular momenta have been introduced. One is crystal angular momentum (CAM) arising from the rotational or screw-rotational symmetry and the other is mechanical angular momentum (MAM) associated with the circular motion of atomic displacements about equilibrium positions. Recently, the electron–phonon coupling that respects the screw-rotational symmetry is derived, whereby the CAM between electrons and phonons is interconverted. Here, we show that, in addition to CAM, MAM can also be converted to the electronic degrees of freedom by deriving a second-order perturbative Hamiltonian proportional to phonon MAM. This finding highlights that the electronic motion is directly affected by phonon MAM, and consequently, that phonon degrees of freedom can play a crucial role in phenomena related to electronic orbital and spin polarizations.
Materials Science (cond-mat.mtrl-sci)
8 pages, 1 figure
Noble-Gas Solubility in Solid and Fluid Metallic Hydrogen
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-06 20:00 EDT
Jakkapat Seeyangnok, Udomsilp Pinsook, Graeme J Ackland
Metallic hydrogen dominates the deep interiors of giant planets, where trace elements interact with dense quantum matter under extreme pressure. We investigate the thermodynamic stability of noble-gas impurities (He, Ne, Ar, Kr, Xe) in metallic hydrogen at 500 GPa using ab initio molecular dynamics combined with first-principles free-energy calculations. In the solid metallic phase, all noble gases exhibit positive formation free energies, driven by unfavorable electronic enthalpy and zero-point vibrational contributions. By contrast, heavier noble gases (Ar, Kr, Xe) appear soluble in liquid hydrogen, while He and Ne phase separate. This crossover reflects a competition between electronic repulsion and disorder-driven stabilization intrinsic to the liquid phase. Our results reveal noble-gas retention in metallic hydrogen, providing a microscopic mechanism for noble-gas fractionation in giant-planet interiors.
Materials Science (cond-mat.mtrl-sci)
8 pages, 4 Figures
Boundary Potential Method for Describing Electron Teleportation in an Interferometer with a Topological Superconductor
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-04-06 20:00 EDT
Kyosuke Mizuno, Yuto Takarabe, Yositake Takane
One-dimensional topological superconductors accommodate a pair of Majorana zero modes at their ends. In an interferometer containing such a topological superconductor, electron transport is significantly affected by the Majorana zero modes constituting a non-local state localized near both ends of the superconductor. When the number of electrons $ \mathcal{N}$ in the superconductor is constrained by a charging effect, the resonant tunneling through the non-local state is expected to result in unusual transport properties. This resonant tunneling, called electron teleportation, is not easy to describe because there is no simple method to handle the constraint on $ \mathcal{N}$ . Here, we propose a boundary potential method based on scattering theory for calculating the conductance of the interferometer under a given constraint on $ \mathcal{N}$ . This method enables us to calculate the conductance taking account of relevant charging energy and details of the system.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
10 pages, 8 figures
Zero-Freeness of the Hard-Core Model with Bounded Connective Constant
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-04-06 20:00 EDT
We study the zero-free regions of the partition function of the hard-core model on finite graphs and their implications for the analyticity of the free energy on infinite lattices. Classically, zero-freeness results have been established up to the tree uniqueness threshold $ \lambda_c(\Delta-1)$ determined by the maximum degree $ \Delta$ . However, for many graph classes, such as regular lattices, the connective constant $ \sigma$ provides a more precise measure of structural complexity than the maximum degree. While recent approximation algorithms based on correlation decay and Markov chain Monte Carlo have successfully exploited the connective constant to improve the threshold to $ \lambda_c(\sigma)$ , analogous results for complex zero-freeness have been lacking. In this paper, we bridge this gap by introducing a proper definition of the connective constant for finite graphs based on a lower bound on the number of $ k$ -depth self-avoiding walks. We prove that for any graph family with a lower connective constant $ \mu$ , the partition function is zero-free in a complex neighborhood of the interval $ [0, \lambda]$ for all $ \lambda < \lambda_c(\mu)$ . As a direct consequence, we establish the uniqueness and analyticity of the free energy density for infinite lattices up to the connective constant threshold, extending the known regions derived from maximum degree bounds. Our proof utilizes a block contraction technique that lifts the correlation decay property from a real interval to a strip-like complex neighborhood.
Statistical Mechanics (cond-mat.stat-mech), Data Structures and Algorithms (cs.DS), Mathematical Physics (math-ph), Probability (math.PR)
Semiclassical representation of the Hubbard model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-04-06 20:00 EDT
Yuki Yamasaki, Hidemaro Suwa, Cristian D. Batista, Shintaro Hoshino
By revisiting the path-integral formulation of the Hubbard model, we propose a theoretical approach based on a semiclassical approximation employing an unconventional coherent-state representation. Within this framework, a subset of the dynamical variables is treated as static, yielding a nonperturbative scheme that is applicable at finite temperature, incorporates intersite correlations, and can be naturally extended to multiorbital systems. We assess the validity of the approximation by comparing its results with exact solutions for one- and two-site systems, focusing in particular on the particle number, double occupancy, hopping amplitude, and spin correlations, and find that the present approach qualitatively reproduces the exact behavior. Quantitatively, deviations arise, which is associated with the continuum (non-discretized) character of the underlying density of states. Furthermore, we derive the exact transformation associated with the coherent-state construction, thereby providing additional insight into the representation of the Hubbard model.
Strongly Correlated Electrons (cond-mat.str-el)
21 pages, 5 figures
Dense Associative Memory with biased patterns: a Replica Symmetric analysis
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-04-06 20:00 EDT
Linda Albanese, Andrea Alessandrelli, Federico Carella
We investigate dense higher-order associative memories in the high storage regime when the stored patterns are biased, namely when the entries of the patterns are not symmetrically distributed around zero. In this setting, the standard Hebbian prescription must be modified by recentering and rescaling the pattern entries, and an additional term must be introduced in the Hamiltonian to enforce consistency between the average activity of the network and that of the stored patterns. As a first step, we perform a signal-to-noise analysis in the zero-temperature limit and show that the bias reduces the effective storage capacity through a multiplicative correction factor (1-b^2)^P, while preserving the superlinear scaling with the system size. We then derive the quenched statistical pressure within the Replica Symmetric framework by means of Guerra’s interpolation method and obtain the corresponding self consistency equations for the relevant order parameters. The analytical treatment confirms the heuristic prediction of the signal-to-noise argument, showing that the same bias dependent renormalization naturally emerges in the variance of the cross-talk noise. Finally, we discuss the resulting phase behavior of the model and its implications for retrieval performance in the model.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
A Route to Nonrelativistic Altermagnetic Spin Splitting via Ultrafast Light
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-06 20:00 EDT
Huang-Zhao-Xiang Chen, Lin-Ding Yuan, Wen-Hao Liu, Lin-Wang Wang, Jun-Wei Luo, Zhi Wang
We identify a nonequilibrium route for generating altermagnetic spin splitting in antiferromagnet by ultrafast light. Unlike existing strategies, this route does not require relativistic angular-momentum transfer, static symmetry breaking, or auxiliary external fields. Using real-time time-dependent density functional theory, we demonstrate in the antiferromagnetic perovskite KNiF3 that linearly polarized light can induce momentum-dependent altermagnetic spin splitting by breaking the effective time-reversal symmetry through photoexcited charge redistribution and the resulting lattice distortion. We provide a general symmetry selection rule for this route. These results establish a mechanism for ultrafast control of altermagnetism and extend its material realization into the nonequilibrium regime.
Materials Science (cond-mat.mtrl-sci)
Elasticity-Driven Periodic Polarization Patterns in Confined Chiral Ferroelectric Nematic Fluid
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-04-06 20:00 EDT
Anej Sterle, Peter Medle-Rupnik, Luka Cmok, Aitor Erkoreka, Marta Lavrič, Natan Osterman, Calum J. Gibb, J. Hobbs, Josu Martinez-Perdiguero, Richard J. Mandle, Alenka Mertelj, Nerea Sebastián
Ferroelectric nematic phases are a new class of polar fluids in which spontaneous polarization is directly coupled to the orientational order, providing unique opportunities for creating self-organized materils with spatially modulated electric polarization and nonlinear optical response. Here we report the spontaneous emergence of polarization modulated textures in a chiral ferroelectric nematic material close to the transition to the chiral twist-bend ferroelectric nematic phase. By systematically varying cell thickness and surface anchoring conditions, we map the formation of these modulated states, revealing stripe, square and hexagonal morphologies determined via confinement conditions. These structures are directly translated into periodic modulation of the nonlinear optical response, as evidenced by second-harmonic generation imaging. Comparison with an elasticity based theoretical framework and numerical free energy minimization shows that the instability originates from the softening of the bend elastic constant in the chiral nematic phase as the system approaches the lower-temperature heliconical polar phase. The resulting elastic frustration, combined with confinement, drives the formation of spatially periodic director distortions, highlighting ferroelectric nematic fluids as a promising platform for self-assembled nonlinear optical materials.
Soft Condensed Matter (cond-mat.soft)
13 pages manuscript, 6 images, 15 pages Supplementary Information
Disorder-induced chirality in superconductor-ferromagnet heterostructures revealed by neutron scattering and multiscale modeling
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-06 20:00 EDT
Annika Stellhorn, Juan G. C. Palma, Alicia Backs, Anders Bergman, Angela B. Klautau, Emmanuel Kentzinger, Connie Bednarski-Meinke, Steffen Tober, Elizabeth Blackburn, Juri Barthel, Nina-Juliane Steinke, Helena M. Petrilli, Ivan P. Miranda
Chirality in superconductor-ferromagnet hybrids strongly influences phenomena such as the observable signatures of long-range triplet superconductivity, but its microscopic origin in nominally centrosymmetric ferromagnets is still unclear. Here, we combine structural characterization, polarization-analyzed grazing-incidence small-angle neutron scattering (PA-GISANS), first-principles calculations, and deep-learning-assisted multiscale modeling to study FePd and Nb/FePd heterostructures. Experimentally, we observe partial L1$ _0$ order, atomic intermixing, anti-phase boundaries, and a depth-dependent defect gradient across the FePd layer, together with a finite net magnetic chirality at room temperature. The GISANS asymmetry indicates that the main chiral contribution lies in-plane, with an additional out-of-plane component associated with depth-dependent magnetic inhomogeneity. Theoretically, we show that chemical disorder in FePd, especially when combined with a compositional gradient, produces finite Dzyaloshinskii-Moriya interactions and stabilizes chiral finite-$ \mathbf{q}$ magnetic modulations with mixed Bloch-Néel character. In the mesoscopic model, the resulting in-plane modulation length approaches the experimentally observed range. These results identify disorder and compositional gradients as intrinsic microscopic sources of net chirality in FePd-based films, showing that the observed chirality does not arise only from interface effects.
Materials Science (cond-mat.mtrl-sci)
Mechanistic insights into the spatial organization of RNA polymerase proteins and the chromosome in E. coli cells
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-04-06 20:00 EDT
Debarshi Mitra, Jens-Uwe Sommer
Along the bacterial chromosome, regions called rrn operons contain genes that are transcribed into ribosomal RNA. These operons are among the most transcriptionally active sites in the genome. It has been observed in E. coli that RNA polymerase (RNAP), while binding to these genetic loci along the chromosome during transcription, forms dense clusters, leading to spatial colocalization of the operons within the cell. Recent experimental evidence suggests that liquid-liquid phase separation contributes to the formation of RNAP clusters, with the antitermination factor NusA playing a key role. We present a simulation model to investigate the mechanisms underlying the formation of these biomolecular condensates. We propose that mutual attraction between NusA proteins, which exhibit a miscibility gap at higher concentrations, drives condensate formation via a polymer-assisted condensation pathway, and we demonstrate how these condensates promote the colocalization of rrn operons. Our results reconcile seemingly disparate experimental observations of chromosomal organization reported in fluorescence-based imaging and Hi-C experiments.
Soft Condensed Matter (cond-mat.soft)
High-energy electronic excitations in La3Ni2O7 by time-resolved optical spectroscopy
New Submission | Superconductivity (cond-mat.supr-con) | 2026-04-06 20:00 EDT
Junzhi Zhu, Mengwu Huo, Yubin Wang, Yuxin Zhai, Lili Hu, Haiyun Huang, Xiu Zhang, Baixu Xiang, Mengdi Zhang, Yusong Gan, Zhiyuan An, Meng Wang, Qihua Xiong, Haiyun Liu
Recently, high-temperature superconductivity has been established in bilayer La3Ni2O7, which exhibits a density-wave (DW) transition at ~ 150 K under ambient pressure. The DW order is believed to be linked to superconductivity, as it is suppressed upon the emergence of superconductivity at high pressures. Here, we explore the ultrafast dynamics of high-energy electronic excitations from 10 K to room temperature under ambient pressure using time-resolved optical spectroscopy. Two high-energy electronic excitations at ~1.8 and ~ 2.4 eV, arising from distinct interband transitions, are identified. They exhibit different DW gaps of approximately 54 and 67 meV, respectively, along with relaxation dynamics that can be well described by the Rothwarf-Taylor model. In addition, we observe four coherent Raman-active phonon modes that exhibit distinct coupling with different electronic excitations. The phonon softening with increasing temperature can be well described between ~100 K and room temperature by a semi-quantitative model, which includes thermal expansion and anharmonic phonon-phonon coupling. At cryogenic temperatures, deviations from the measured temperature-dependent phonon frequencies and the model fits suggest an additional contribution from electron-phonon coupling. Our study provides direct evidence of the complex gap structure and phonon dynamics in this material, offering critical insights into the DW mechanism and many-body effects.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
4 figures, 12 pages
Structure Functions and Intermittency for Coarsening Systems
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-04-06 20:00 EDT
Pradeep Kumar Yadav, Mahendra K. Verma, Sanjay Puri
In studies of turbulence, there has been extensive use of physical quantities such as {\it energy transfers} and {\it structure functions}. We examine whether these quantities can be useful in understanding problems of domain growth or coarsening, as modeled by the {\it time-dependent Ginzburg-Landau} (TDGL) equation and the {\it Cahn-Hilliard} (CH) equation. This paper has two major themes. First, we review our recent papers on energy transfers in domain growth. Second, we study structure functions and intermittency for coarsening systems. As a consequence of sharp interfaces, the structure functions scale as $ S_q \sim r^{\zeta_q}$ , where $ r$ is the distance between two points. For the TDGL and CH models, $ \zeta_q = 1$ , indicating {\it anomalous scaling}
Statistical Mechanics (cond-mat.stat-mech)
16 pages, 8 figures
Type-IV ‘t Hooft Anomalies on the Lattice: Emergent Higher-Categorical Symmetries and Applications to LSM Systems
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-04-06 20:00 EDT
‘t Hooft anomalies impose fundamental constraints on quantum matter and often lead to emergent symmetry structures upon gauging. We analyze a lattice model with four global symmetries realizing a mixed anomaly described by $ \sim a_1\wedge a_2\wedge a_3\wedge a_4$ , where the $ a_i$ denote background gauge fields for the global symmetries. Through explicit lattice gauging, we demonstrate the emergence of higher symmetry structures, including 2-group, non-invertible, and higher fusion categorical symmetries. We also provide a field-theoretical understanding of these results. Applying this framework to systems with Lieb-Schultz-Mattis anomalies, obtained by promoting part of the internal symmetries to translational symmetries, we demonstrate that modulated (dipole) symmetries arise as direct counterparts of those in systems with purely internal typeIV anomalies. Importantly, we uncover a qualitatively new feature absent in previously studied modulated symmetries: their realization can become intrinsically defect-dependent. In particular, the emergent symmetry structure changes depending on whether symmetry defects are present. This work establishes a concrete lattice realization of mixed anomalies and reveals a rich structure of emergent symmetries, thereby clarifying their role in constraining quantum phases of matter.
Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Theory (hep-th), Quantum Physics (quant-ph)
33 pages, 13 figures
Band Renormalization in Monolayer MoS2 Induced by Multipole Screening
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-04-06 20:00 EDT
Woojoo Lee, Seungwoo Yoo, Marios Zacharias, Junho Choi, Young-Kyun Kwon
Dielectric screening plays a crucial role in shaping the electronic structure of two-dimensional (2D) materials. In 2D semiconductors, screened Coulomb interactions arising from the surrounding dielectric environment are known to induce band renormalization, which is typically understood as a rigid shift of the electronic bands. Here, we experimentally demonstrate that dielectric screening can also give rise to non-rigid, momentum-dependent band renormalization. Using temperature-dependent angle-resolved photoemission spectroscopy (ARPES), we observe pronounced changes in the electronic band structure of monolayer MoS2 on a highly oriented pyrolytic graphite (HOPG) substrate. The results indicate that temperature-driven variations in the effective interlayer separation modulate the dielectric screening experienced by monolayer MoS2. At room temperature, the screening behavior is well described by a momentum-independent monopole approximation, whereas at liquid-helium temperatures the screening evolves into a multipole-like regime, leading to momentum-dependent band shifts.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Number fluctuations distinguish different self-propelling dynamics
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-04-06 20:00 EDT
Tristan Cerdin, Sophie Marbach, Carine Douarche
In nonequilibrium suspensions, static number fluctuations $ N$ in virtual observation boxes reveal remarkable structural properties, but the dynamic potential of $ N(t)$ signals remains unexplored. Here, we develop a theory to learn the dynamical parameters of self-propelled particle models from $ N(t)$ statistics. Unlike traditional trajectory analysis, $ N(t)$ statistics distinguish between models, by sensing subtle differences in reorientation dynamics that govern re-entrance events in boxes. This paves the way for quantifying advanced dynamic features in dense nonequilibrium suspensions.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
5 pages, 4 figures
Mesoscopic scattering dynamics under generic uniform SU(2) gauge fields: Spin-momentum relaxation and coherent backscattering
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-04-06 20:00 EDT
Masataka Kakoi, Christian Miniatura, Keith Slevin
We investigate the time- and momentum-resolved dynamics of matter waves undergoing elastic scattering from a disordered potential in the presence of spatially uniform SU(2) gauge fields. We derive the disorder-averaged density matrix as a function of time and momentum within the weak-localization regime. By accurately approximating the frequency dependence of the ladder and maximally crossed diagram series beyond the diffusive approximation, we describe short-time spin-momentum dynamics on timescales comparable to the scattering mean free time, for arbitrary strengths of the SU(2) gauge fields and disorder. We also present a cubic equation that determines the spin isotropization time, which gives accurate asymptotic forms in the limits where the spin-orbit length is much longer (Dyakonov-Perel spin relaxation regime) or much shorter than the scattering mean free path, as well as in the SU(2)-symmetric (persistent spin helix) limit. In comparison with numerical calculations, we reproduce both the relaxation of the momentum distribution and the transient backscattering peak with a momentum offset coexisting with the robust coherent backscattering dip, supporting the reliability of our calculations.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Gases (cond-mat.quant-gas)
18 pages, 4 figures
Microscopic NMR evidence for successive antiferroelectric and antiferromagnetic order in the van der Waals magnet CuCrP$_2$S$_6$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-04-06 20:00 EDT
C. S. Saramgi, L. F. Prager, S. Selter, Y. Shemerliuk, S. Aswartham, B. Büchner, H.-J. Grafe, K. M. Ranjith
We present a comprehensive $ ^{31}$ P and $ ^{65}$ Cu nuclear magnetic resonance (NMR) study of the layered van der Waals magnet CuCrP$ _2$ S$ 6$ . The compound exhibits a sequence of structural and magnetic phase transitions: a high-temperature paraelectric state, followed by a quasi-antiferroelectric (QAFE) state near 185 K, a long-range antiferroelectric (AFE) phase below 150 K, and finally, antiferromagnetic (AFM) order below $ T\mathrm{N}$ = 30 K. The evolution of the NMR spectra, NMR shift, and spin-lattice ($ T_1^{-1}$ ) and spin-spin ($ T_2^{-1}$ ) relaxation rates provide direct microscopic fingerprints of these transitions. The splitting of both the NMR line and $ T_1^{-1}$ below the AFE transition demonstrates the emergence of two inequivalent P sites. From $ K - \chi$ analysis, we extract nearly isotropic transferred hyperfine couplings and show that the NMR shift anisotropy originates primarily from the dipolar contribution, in contrast to Mn$ _2$ P$ _2$ S$ _6$ and Ni$ _2$ P$ 2$ S$ 6$ . We determine the ferromagnetic intralayer exchange $ J{intra}\approx$ -4.9 K from the Curie Weiss temperature, consistent with ferromagnetic layers antiferromagnetically stacked along the $ c$ axis, and evaluate the Moriya high temperature relaxation rate including cross correlation effects of the P P dimer. Critical divergence of $ T_1^{-1}$ near $ T\mathrm{N}$ yields a critical exponent $ \gamma\simeq$ 0.45(4), placing CuCrP$ _2$ S$ _6$ in a three dimensional Heisenberg universality regime.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
14 pages, 12 figures
The Countoscope for self-propelled particles
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-04-06 20:00 EDT
Tristan Cerdin, Talia Calazans, Carine Douarche, Sophie Marbach
Particle number fluctuations $ N(t)$ , measured in virtual observation boxes of an image or a simulation, offer a way to quantify particle dynamics when particle tracking is impractical, such as in high-density systems. While traditionally limited to equilibrium diffusive systems, we extend this approach – named ``Countoscope’’ – to out-of-equilibrium self-propelled particles: Active Brownian (ABPs), Run and Tumble (RTPs), and Active Ornstein-Uhlenbeck Particles (AOUPs). For AOUPs, we leverage their Gaussian statistics to derive a general formula applicable to any Gaussian system. For ABPs and RTPs, we derive the intermediate scattering function (ISF) – and thus the correlations of $ N(t)$ – using an exact perturbative expansion over the probability density fields, revealing key physical features of the ISF and of the number correlations. Our theoretical predictions for the mean-squared number difference $ \langle \Delta N^2(t) \rangle = \langle (N(t) - N(0))^2 \rangle$ match stochastic simulations and exhibit three time-dependent scaling regimes: diffusive, advective, and long-time enhanced diffusive, reflecting the regimes of the mean squared particle displacement. We further uncover limiting laws in each of these regimes that are useful to quantify self-propulsion properties.
Soft Condensed Matter (cond-mat.soft)
17 pages, 10 figures
Hamiltonian flocks: Time-Reversal Symmetry and its consequences
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-04-06 20:00 EDT
Mathias Casiulis, Leticia F. Cugliandolo
The fluctuation-dissipation theorem is a hallmark of equilibrium system that stem from their time-reversal symmetry. In many non-equilibrium systems, in particular active ones, extensions and explicit violations of this theorem are used to assess their ‘’distance’’ to equilibrium. In Hamiltonian flocks, conservative yet non-Galilean models of polar liquids, previous work reported collective motion without the activity that usually underlies it. In this paper, we show that this model obeys a generalized time-reversal symmetry that yields a fluctuation-dissipation theorem that mixes position and polarity degrees of freedom. Due to the oddness of spin under time reversal, the system also obeys Onsager-Casimir reciprocity rather than standard Onsager relations. The coupling also induces rich spin orientation dynamics, including a non-trivial diffusion constant at long times. Finally, we show that considering the naïve time-reversal operation rather than the generalized one that leaves the system invariant leads to a spurious entropy production rate, that could be wrongly interpreted as a distance to equilibrium. Our findings suggest looking for possible extensions of time-reversal symmetry in active-looking systems, which may lead to yet unknown generalizations of the fluctuation-dissipation theorem.
Statistical Mechanics (cond-mat.stat-mech)
62 pages (20 pages of main text and 42 of appendices), 8 figures
Mott-Derived Local Moments and Kondo Hybridization in a d-electron Kagome lattice
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-04-06 20:00 EDT
Xing Zhang, Xintong Li, Boqin Song, Yuyang Xie, Qinghong Wang, Taimin Miao, Shusen Ye, Junhao Liu, Bo Liang, Neng Cai, Hao Chen, Wenpei Zhu, Mingkai Xu, Wei-Jian Li, Shun-Li Yu, Shenjin Zhang, Fengfeng Zhang, Feng Yang, Zhimin Wang, Qinjun Peng, Hanqing Mao, Zhihai Zhu, Guodong Liu, Zuyan Xu, Yi-feng Yang, Tianping Ying, Lin Zhao, X. J. Zhou
Unlike canonical Kondo lattices in f-electron systems, where localized f orbitalsnaturally provide local moments, d-electron Kondo lattices require a distinct mechanism for local-moment formation. However, the study of d-electron Kondo lattices in bulk materials remains far from settled, particularly with regard to the microscopic origin of the local moments. Here, we report a microscopic mechanism for this process in the bilayer kagome metal CsCr6Sb6, where strong correlations drive a Mott splitting of the kagome flat band to supply the requisite local moments. By combining STM/STS and ARPES, we resolve a spectroscopic hierarchy between high-energy correlation effects and low temperature hybridization. Low-temperature STS reveals a robust asymmetric suppression of the density of states near EF that is well captured phenomenologically by a Fano-type lineshape, while ARPES detects a sharp quasiparticlepeak near EF. These low-energy signatures evolveon the same temperature scale and disappear upon warming, consistent with the onset of Kondo hybridization. At the same time, STS resolves symmetric humps at approximately +-50 mV and ARPES identifies a weakly dispersive feature around 50 meV below EF; unlike the near-EF hybridization signatures, these features persist to substantially higher temperatures. This separation of energy and temperature scales supports a two-stage picture in which a kagome flat band first undergoes correlation-driven splitting into lower and upper Hubbard bands, and the occupied lower Hubbard band supplies the local moments that later hybridize with itinerant electrons at lower temperature. Our results therefore move beyond the phenomenology of a kagome Kondo lattice candidate and instead provide a microscopic spectroscopic picture linking Mottness to Kondo hybridization in a frustrated d-electron system.
Strongly Correlated Electrons (cond-mat.str-el)
Resetting dynamics in a system with quenched disorder
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-04-06 20:00 EDT
Riya Verma, Binayak Banerjee, Shamik Gupta, Saroj Kumar Nandi
Although resetting has widespread applicability, applying it to the dynamics in the presence of spatial quenched disorder, which is essential in many physical problems, is challenging. In this study, we consider a well-known one-dimensional model of particle hopping on a lattice with quenched disorder in the form of site-dependent hopping probabilities, drawn from a power-law distribution, and apply the resetting formalism. As a physical example, we recast the growth dynamics of microtubules with sudden catastrophic disassembly events as a resetting dynamics. We consider two distinct regimes for growth dynamics: a strongly biased case and a less biased case. Motivated by experimental results, we take a Gamma distribution for the resetting time. Our results show that occasional disassembly events are crucial for the experimentally observed distribution of reset (or catastrophe) lengths. We also analyze steady-state distributions under different resetting protocols-resetting to the initial position versus a random site. We also investigate the distribution of first-passage times to a fixed distance following reset. Finally, by considering other resetting probability distributions, we identify a regime where the mean displacement grows as slowly as $ \log^2 t$ . We also elucidate the role of disorder in the system properties under the resetting dynamics. Our study paves the way to treat the dynamics of complex physical systems using resetting.
Statistical Mechanics (cond-mat.stat-mech), Soft Condensed Matter (cond-mat.soft), Applied Physics (physics.app-ph), Biological Physics (physics.bio-ph), Computational Physics (physics.comp-ph)
Total 12 pages including the appendix
Engineering Electrochromism in Ni-Deficient NiO through Defect, Dopant, and Strain Coupling
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-06 20:00 EDT
Katarina Jakovljević (1), Ana S. Dobrota (2), Igor A. Pašti (2 and 3), Natalia V. Skorodumova (4) ((1) 5th Belgrade Gymnasium, Belgrade, Serbia, (2) University of Belgrade - Faculty of Physical Chemistry, Belgrade, Serbia, (3) Serbian Academy of Sciences and Arts, Belgrade, Serbia, (4) Applied Physics, Division of Materials Science, Department of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå, Sweden)
The electrochromic response of Ni-deficient NiO is governed by vacancy-mediated electronic processes that can be strongly influenced by dopant chemistry and lattice deformation. Using density functional theory, we systematically investigated Cu-, Sn-, and V-doped Ni-deficient NiO(001) surfaces and examined alkali-ion insertion at surface Ni vacancies. Li insertion proceeds as nearly complete ionic electron donation (~+0.9 e), but the fate of the injected electron depends on dopant identity. V-doping preserves framework-dominated charge compensation and leads to conventional bleaching through filling of vacancy-associated hole states. In contrast, Sn actively traps the injected charge, generating dopant-assisted optical transitions and reversing the electrochromic response, while Cu produces an intermediate spectral redistribution without significant dopant reduction. Substitution of Li by Na or K in the V-doped system does not alter the switching mechanism, confirming that vacancy-state filling governs the optical behavior. Biaxial tensile strain enhances the energetics of Li insertion but reduces optical contrast by altering the defect electronic structure. These results establish dopant activity, vacancy stabilization, and lattice strain as key parameters controlling electrochromism in NiO-based materials.
Materials Science (cond-mat.mtrl-sci)
15 pages, 6 figures, 2 tables, 23 references
Hamiltonian learning for spin-spiral moiré magnets from electronic magnetotransport
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-04-06 20:00 EDT
Fedor Nigmatulin, Greta Lupi, Jose L. Lado, Zhipei Sun
Two-dimensional noncollinear magnetic states, such as spin-spiral magnets, offer an excellent platform for investigating fundamental phenomena, with potential for advancing stray-field-free spintronics. However, detection and characterization of noncollinear magnetic states in two-dimensional systems remain challenging, motivating the development of alternative probing methods. Here, we present a methodology for extracting the spin-spiral $ \mathbf{q}$ vector from lateral electronic transport measurements. Our approach leverages the magnetic field and bias dependence of the conductance to train a supervised machine learning algorithm, which enables us to extract the $ \mathbf{q}$ vectors of arbitrary spin-spiral magnets. We demonstrate that this methodology is robust to the presence of impurities in the system and noise in the conductance data. Our findings show that the conductance pattern reveals a complex dependence on the $ \mathbf{q}$ vector of the spin spiral, providing a new strategy to learn magnetic structures directly from transport experiments.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
7 pages, 6 figures
Nanomechanical detection of vortices in an electron fluid
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-04-06 20:00 EDT
Andrey A. Shevyrin, Askhat K. Bakarov, Arthur G. Pogosov
Electron vortices are the quintessential signature of a viscous electron fluid. For decades, their detection relied on indirect transport measurements with persistently debated interpretations. Recently, scanning magnetometry enabled direct visualization, yet these techniques demand considerable sophistication. Here we introduce a conceptually different and inherently simpler paradigm based on nanomechanics. By integrating a circular cavity into a suspended resonator, we create a vortex whose circulating current generates a magnetic moment. In an in-plane magnetic field, this moment experiences a torque, driving vibrations that directly reveal the vortex’s presence and nature. We detect ballistic and hydrodynamic vortices and trace their temperature-driven crossover. Our work establishes nanomechanics as a platform for electron hydrodynamics, showing that viscosity - subtle in transport - is one of the dominant factors shaping nanoelectromechanical response.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Fluid Dynamics (physics.flu-dyn)
Spatially inhomogeneous delithiation in LiNiO2 positive electrode: the effect of X-rays dose
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-06 20:00 EDT
Francesco La Porta, Laurent Barthe, Anthony Beauvois, Gilles Wittmann, Valérie Briois, Antonella Iadecola, Stéphanie Belin
Operando synchrotron X-ray techniques have become essential tools for investigating rechargeable batteries as they provide real-time insights into electrochemical processes. However, the high brilliance of synchrotron radiation can alter the electrochemical mechanisms within the battery, thereby compromising the reliability and reproducibility of operando measurements. In this study, we introduce a novel methodology that directly correlates the local X-ray dose with the Ni4+/Ni3+ redox activity in a LiNiO2 positive electrode. Full-field transmission X-ray absorption spectroscopy imaging (FFI-XAS) is employed to probe the charge-compensation mechanism during lithium extraction at the micrometre scale, using two beam configurations with different focal distances (far-focus and near-focus). While the spatially averaged XAS spectra exhibit sluggish reaction, regions exposed to lower dose rates exhibit the expected electrochemical evolution. This contrast enables the identification of a dose threshold for reliable operando measurements. This approach establishes a practical dose limit and provides spatially resolved insight into beam-induced effects, offering both a diagnostic framework and a pathway toward more reliable operando experiments.
Materials Science (cond-mat.mtrl-sci)
Maximizing the magnetic anisotropy of Dy complexes by fine tuning organic ligands: A systematic multireference high-throughput exploration of over 30k molecules
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-06 20:00 EDT
Lion Frangoulis, Lorenzo A. Mariano. Vu Ha Anh Nguyen, Zahra Khatibi, Alessandro Lunghi
The design of the coordination environment of magnetic ions is key to achieving properties such as large magnetic anisotropy and slow magnetic relaxation, but a systematic exploration of the relevant chemical space for these compounds is missing. Here, we automatically extract all entries of mononuclear Dy coordination complexes from crystallographic databases and use multireference ab initio methods to compute their magnetic anisotropy. In addition, we generate and simulate magnetic anisotropy for 25k new molecules with the general formula [Dy(H$ _2$ O)$ _5$ L$ _2$ ]$ ^{n-}$ and pentagonal bipyramidal coordination geometry, a motif selected as very promising. While no molecule with record magnetic anisotropy is serendipitously identified in crystallography databases, molecules with crystal field splittings over 1600 cm$ ^{-1}$ are identified by systematically exploring new organic ligands. This corresponds to a ~100% increase of magnetic anisotropy over the reference compound, ~30% over any known pentagonal bipyramidal Dy complex, and approaching record values of pseudo bi-coordinated Dy ions. This study demonstrates that the fine-tuning of Dy’s second coordination sphere by organic ligands design can significantly improve magnetic anisotropy and that automated computational screening is key to accelerating this chemically non-intuitive process.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
Hilbert space fragmentation in quantum Ising systems induced by side coupling
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-04-06 20:00 EDT
We study Hilbert space fragmentation and quantum scars in quantum spin systems with Ising interactions. The system consists of two sets of quantum spins, A and B. As the parent system, set A is an Ising model on arbitrary lattices with a transverse field, while set B comprises free spins that are coupled to set A. We show that the Hilbert space is fragmented into exponentially many decoupled sectors when the transverse field and the side coupling strength are at resonance. As examples, several typical systems with quantum scars are studied analytically. Numerical simulations of probability distribution of entanglement entropy for finite-size chains, square and triangular lattices are performed using the Monte Carlo method. The results show that Hilbert space fragmentation and the corresponding quantum scars become pronounced when the system approaches resonance.
Strongly Correlated Electrons (cond-mat.str-el)
Escape dynamics and implicit bias of one-pass SGD in overparameterized quadratic networks
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-04-06 20:00 EDT
Dario Bocchi, Theotime Regimbeau, Carlo Lucibello, Luca Saglietti, Chiara Cammarota
We analyze the one-pass stochastic gradient descent dynamics of a two-layer neural network with quadratic activations in a teacher–student framework. In the high-dimensional regime, where the input dimension $ N$ and the number of samples $ M$ diverge at fixed ratio $ \alpha = M/N$ , and for finite hidden widths $ (p,p^\ast)$ of the student and teacher, respectively, we study the low-dimensional ordinary differential equations that govern the evolution of the student–teacher and student–student overlap matrices. We show that overparameterization ($ p>p^\ast$ ) only modestly accelerates escape from a plateau of poor generalization by modifying the prefactor of the exponential decay of the loss. We then examine how unconstrained weight norms introduce a continuous rotational symmetry that results in a nontrivial manifold of zero-loss solutions for $ p>1$ . From this manifold the dynamics consistently selects the closest solution to the random initialization, as enforced by a conserved quantity in the ODEs governing the evolution of the overlaps. Finally, a Hessian analysis of the population-loss landscape confirms that the plateau and the solution manifold correspond to saddles with at least one negative eigenvalue and to marginal minima in the population-loss geometry, respectively.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech), Machine Learning (stat.ML)
30 pages, 6 figures
Proximate quantum spin liquids and Majorana continua in magnetically ordered Kitaev magnets
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-04-06 20:00 EDT
Peng Rao, Johannes Knolle, Roderich Moessner
We study the spin excitation spectra in magnetically ordered phases proximate to the Kitaev quantum spin liquid (KQSL). Although the low-energy universal features should be governed by the magnetic orders, the $ \textit{non-universal}$ high-energy features of the KQSL and adjacent phases can be remarkably similar. Therefore, we study the extended Kitaev model within a Stoner-like theory using Majorana partons, and compute the inelastic neutron scattering (INS) intensities in the random phase approximation. First, we benchmark against the antiferromagnetic (AFM) Heisenberg model and recover the AFM order with linear Goldstone modes. We then explore the phase diagram which agrees qualitatively with previous numerical results. In particular, the Majorana parton theory accurately captures Order-by-Disorder effects in the Kitaev-Heisenberg limit. We also find large INS intensities near the associated high-symmetry Brillouin zone (BZ) points of the magnetic orders. At intermediate and high energies, broad multi-spinon continua emerge across the BZ, providing a distinct mechanism for magnon decay and spectral broadening beyond the conventional multi-magnon decay scenario. Finally, we study the model Hamiltonian of candidate Kitaev material $ \alpha$ -RuCl$ _3$ . The zigzag ground state agrees qualitatively with experiments, its stability under external magnetic field also exhibits strong anisotropy in the field directions, and broad scattering continua are recovered similar to those observed experimentally.
Strongly Correlated Electrons (cond-mat.str-el)
main text: 9 pages, 6 figures; supplemental information: 3 pages, 1 figure
Testing the Role of Diagonal Interactions in High-Order Hopfield Models via Dynamical Mean-Field Theory
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-04-06 20:00 EDT
Yuto Sumikawa, Yoshiyuki Kabashima
High-order extensions of the Hopfield model are known to exhibit dramatically enhanced storage capacity at equilibrium, while their dynamical retrieval properties remain less well understood. In our previous work, we carried out a dynamical mean-field theory (DMFT) analysis of the Krotov–Hopfield-type dense associative memory and found that the transition between successful and failed retrieval is accompanied by pronounced slow dynamics. As a consequence, the effective basin of attraction observed in numerical simulations extends well beyond that predicted by equilibrium statistical mechanics. A natural hypothesis is that this discrepancy originates from diagonal (self-interaction) contributions in the Krotov–Hopfield model, which generate a large number of lower-order interaction terms and may induce glassy relaxation near the retrieval boundary. To test this hypothesis, we analyze an alternative high-order associative memory model, namely the Abbott–Arian-type $ p$ -body Hopfield model, in which such diagonal contributions are absent by construction. Using dynamical mean-field theory, we derive an effective single-site process together with closed macroscopic equations governing the retrieval dynamics. Our analysis reveals that both slow dynamics and a substantial enlargement of the apparent basin of attraction persist even in this model. These results indicate that the dynamical slowdown near the retrieval boundary cannot be attributed primarily to diagonal self-interaction effects, but instead originates from intrinsic properties of high-order interactions.
Statistical Mechanics (cond-mat.stat-mech)
24 pages and 17 figures
Determination of the ground state polarizability of $^{162}$Dy near 530 nm
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-04-06 20:00 EDT
Alexandre Journeaux, Maxime Lecomte, Julie Veschambre, Maxence Lepers, Jean Dalibard, Raphael Lopes
Open-shell lanthanide atoms, and dysprosium in particular, combine a large ground-state angular momentum with dense electronic spectra, making their dynamical polarizability strongly dependent on wavelength and internal state and therefore particularly challenging to characterize accurately. This issue has become especially relevant with the recent development of single-atom trapping of dysprosium in optical-tweezer arrays, where precise knowledge of the polarizability is needed to design optimized trapping architectures. Here, we exploit the strong spin-dependent light shift near the $ J’=J-1$ intercombination line at 530.306 nm to determine the background scalar and vector polarizabilities of $ ^{162}$ Dy in its ground state near this wavelength. Our measurements quantitatively agree with atomic-structure calculations and provide new insight into the contributions of nearby transitions in a spectral region relevant to emerging dysprosium tweezer platforms.
Quantum Gases (cond-mat.quant-gas), Atomic Physics (physics.atom-ph)
Observation of anomalous thermal Hall effect in altermagnets
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-04-06 20:00 EDT
Wenbo Wan, Xu Zhang, Yixuan Luo, Yanfeng Guo, Shiyan Li
Altermagnets, recently proposed as a third category of collinear magnets, combine the features of zero net magnetization in antiferromagnets and the spin splitting in ferromagnets. While abundant spectroscopic evidence for altermagnetism has been reported, experimental observation of the anomalous Hall effect, a hallmark of ferromagnetism, remains scarce. Here, we present systematic measurements of the thermal Hall effect in two representative altermagnet candidates, MnTe and CrSb. In both materials, we observe a pronounced anomalous phonon thermal Hall signal, with no electrical counterpart observed, attributed to the coupling of this distinctive magnetic structure with phonons. Our findings establish the anomalous phonon thermal Hall effect as an intrinsic feature of altermagnets, and provide a sensitive probe to identify this new kind of quantum magnets.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
Vibrationally-mediated Dzyaloshinskii-Moriya interaction as the origin of Chirality-Induced Spin Selectivity in donor-acceptor molecules
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-04-06 20:00 EDT
Alessandro Chiesa, D. K. Andrea Phan Huu, Arianna Cantarella, Leonardo Celada, Michael R. Wasielewski, Paolo Santini, Stefano Carretta
Chirality-induced spin selectivity (CISS) was recently observed in photo-excited donor-chiral bridge-acceptor molecules, but a predictive theory able to explain available experiments is still lacking. Here we show that low-energy torsional modes modulating hopping and spin-orbit coupling give rise to a Dzyaloshinskii-Moriya interaction between the transferred electron and the one sitting on the donor, producing high spin polarization for perfectly realistic parameters. Our model introduces a low energy scale in the spin dynamics which explains the magnetic field dependence observed in EPR measurements and predicts a non-trivial temperature dependence, as demonstrated by numerical simulations. The present theory lays the foundations for future test-bed experiments and for the design of applications in spintronics and quantum technologies.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)