CMP Journal 2026-08-10
Statistics
Nature: 1
Nature Nanotechnology: 1
Nature Physics: 1
arXiv: 65
Nature
Learning millisecond protein dynamics from what is missing in NMR spectra
Original Paper | Machine learning | 2026-08-09 20:00 EDT
Hannah K. Wayment-Steele, Gina El Nesr, Ramith Hettiarachchi, Adedolapo M. Ojoawo, Hasindu Kariyawasam, Sergey Ovchinnikov, Dorothee Kern
Many proteins’ biological functions rely on interconversions between multiple conformations occurring at micro- to millisecond (µs-ms) timescales. A lack of standardized, large-scale experimental data has hindered obtaining a more predictive understanding of these motions. After curating >100 Nuclear Magnetic Resonance (NMR) relaxation datasets, we realized an observable for µs-ms dynamics might be hiding in plain sight. Millisecond dynamics can cause NMR signals to broaden beyond detection, leaving some residues not assigned in the chemical shift datasets of ~10,000 proteins deposited in the Biological Magnetic Resonance Data Bank (BMRB) 1. We made the bold assumption that residues missing assignments are exchange-broadened due to µs-ms motions and trained various deep learning models to predict missing assignments. Strikingly, these models also predict exchange measured via NMR relaxation experiments, indicative of µs-ms dynamics. The best of these models, which we named Dyna-1, leverages an intermediate layer of the multimodal language model ESM-32. Notably, dynamics directly linked to biological function, including enzyme catalysis and ligand binding, are particularly well predicted by Dyna-1, which parallels our findings that residues experiencing µs-ms exchange are more conserved. We anticipate the datasets and models presented here will be transformative in unlocking the common language of dynamics and function.
Machine learning, NMR spectroscopy, Proteins
Nature Nanotechnology
Oral nano-delivery of a gut microbial metabolite enhances T cell stemness for cancer immunotherapy
Original Paper | Biomedical engineering | 2026-08-09 20:00 EDT
Kai Han, Young Seok Cho, Mariko Takahashi, Xingwu Zhou, Hannah E. Dobson, Kim Hutchings, Yuesong Wu, Youngseo Na, Fang Xie, Julia Crowther, Jinmei Wu, Jin Xu, Chuan Lee, Himani Jasewicz, Yujin Kim, Minal Nenwani, Olamide Animasahun, Fulei Wuchu, Anthony Andren, Harrison Wong, Emma Camp, Ziye Wan, Qi Wu, Li Zhang, Cheng Xu, Katherine Dong, Yao Xu, Anna Schwendeman, Grace Y. Chen, Yuying Xie, Costas A. Lyssiotis, Martin Clasby, Deepak Nagrath, Yu Leo Lei, James J. Moon
Gut microbial metabolites play crucial roles in regulating systemic immunity, but their mechanisms and limited drug-like properties remain unresolved. Here we report an oral nano-formulation that leverages gut microbial metabolites to modulate T cell metabolism and amplify antitumour immunity. Through an in vitro screening of gut microbial metabolites, we identified 3,4-dihydroxybenzoic acid that improved adoptive T cell therapy and enhanced CD8+ T cell stemness by suppressing glycolysis and regulating the Akt-mTORC1-Myc pathway. To harness the potency of 3,4-dihydroxybenzoic acid for systemic cancer immunotherapy, we engineered a 3,4-dihydroxybenzoic acid prodrug nano-emulsion, significantly increasing its oral absorption and half-life. In multiple murine tumour models, the oral nano-emulsion enhanced the expansion of antigen-specific, stem-like CD8+ T cells, sensitizing tumours to anti-PD-1 blockade and exerting robust antitumour efficacy. By integrating nanotechnology with microbial-metabolite-based immunotherapy, this study establishes a mechanistic link between the gut microbiota and T cell immunity, offering a promising approach for cancer immunotherapy.
Biomedical engineering, Drug delivery, Nanoparticles
Nature Physics
Time-resolved imaging of antiferromagnetic skyrmion interactions
Original Paper | Spintronics | 2026-08-09 20:00 EDT
Mona Bhukta, Takaaki Dohi, Kilian Leutner, Maria-Andromachi Syskaki, Fabian Kammerbauer, Duc Minh Tran, Sebastian Wintz, Markus Weigand, Simone Finizio, Jörg Raabe, Hendrik Ohldag, Thibaud Denneulin, Joseph Vimal Vas, Rafal E. Dunin-Borkowski, Robert Frömter, Mathias Kläui
Quantifying particle interactions is central to understanding and controlling collective dynamics in particle-based devices such as those comprising skyrmion ensembles. Here we directly visualize, in real time, the nanosecond current-driven dynamics of an antiferromagnetic skyrmion lattice. By tuning the spin-orbit torque relative to local pinning, we identify two regimes: an incoherent flow, where mobile skyrmions are driven toward pinned neighbours undergoing compression followed by a recoil, and a coherent flow regime, where the lattice translates uniformly. We use an inverse analysis method based on the Thiele equation to extract an exponentially decaying antiferromagnetic skyrmion interaction potential, which is in agreement with simulation results. At higher current densities, the lattice exhibits coherent motion free from detectable Hall and inertial effects or dynamical deformation, and this enables robust ultrafast operation. These findings establish a quantitative framework for antiferromagnetic skyrmion interactions and demonstrate deterministic control of their collective dynamics, even in the incoherent flow regime, thereby providing potential applications for multiskyrmion spintronic devices.
Spintronics, Topological defects
arXiv
Composite Fields and Tree Expansions: A Unified Framework for Renormalized Vertex Decompositions
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-08-10 20:00 EDT
Oleksandr Sulyma, Benedikt Schneider
One-particle irreducible vertices encode renormalized interactions in quantum field theories, but their practical treatment remains challenging due to their high dimensionality and nontrivial dependence on external variables such as momenta or frequencies. We develop a functional framework that algebraically reorganizes the diagrammatic content of the vertex functions into more efficient building blocks and reveals several established vertex decompositions, such as parquet, single-boson exchange, asymptotic classes and symmetric estimators, as different realizations of a common functional structure. Based on Legendre transforms of the effective action of composite fields, the formalism shows that different vertex representations arise from different choices of composite degrees of freedom. We demonstrate that in our framework higher-order vertices can be systematically obtained via tree expansions, thereby extending the aforementioned decompositions beyond the four-point level. Because our findings are independent of any specific physical setting, the framework applies broadly to quantum field theories in condensed matter physics, particle physics, and beyond.
Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Theory (hep-th)
28 pages, 11 figures, 1 table
Sublattice-resolved coherent phonon dynamics in charge density waves
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-10 20:00 EDT
Kyoung Hun Oh, Honglie Ning, Zongqi Shen, Yifan Su, Jack Maier, Gyeongbo Kang, Hyeongi Choi, Dong Wu, Qiaomei Liu, Hyun-Woo J. Kim, Seunghyeok Ha, Jaehwon Kim, Byungjune Lee, B. J. Kim, N. L. Wang, Yao Wang, Hoyoung Jang, Nuh Gedik
Phonons govern fundamental material properties and play a central role in various electronic phase transitions. Coherent driving of specific phonon modes enables on-demand phase control, motivating sublattice-resolved identification of real-space phonon motions. Yet experimentally resolving these motions remains challenging, limiting precise phonon-based control. Here, we introduce a dynamical protocol to track element-resolved phonon dynamics in the charge density wave material EuTe4, in which the dominant Te-sublattice charge order is accompanied by a previously unreported Eu-sublattice component. We leverage the elemental selectivity of time-resolved resonant X-ray scattering to reveal three coherent phonon modes with distinct sublattice character, thereby disentangling Eu- and Te-dominated lattice dynamics, in good agreement with theoretical calculations of the phonon eigenvectors. This time-domain approach, which surpasses the energy-resolution limits of conventional frequency-domain inelastic scattering, provides a broadly applicable framework for decomposing coherent phonons in multi-element materials, which is crucial for the targeted control of phases of matter.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
7 pages, 4 figures
Theory of spin-wave transport in ferromagnet-superconductor heterostructures: Negative refraction, perfect imaging and temperature-controlled spin-wave optics
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-10 20:00 EDT
Tomas T. Osterholt, Thijs van der Meer, Pim H. Vree, Merel A. Bouma, Michael Borst, Toeno van der Sar, Rembert A. Duine
We investigate spin-wave transport in ferromagnetic insulator-superconductor (FMI-SC) heterostructures and develop a general theoretical framework for spin-wave optics in these hybrid systems. We demonstrate that Meissner screening by the superconductor gives rise to a range of unconventional wave phenomena, including negative phase- and group-velocity refraction, and reflection and refraction laws that differ fundamentally from their optical counterparts. Within this framework, we derive the spin-wave Fresnel equations governing reflection and transmission at FMI-SC interfaces and show that the scattering properties exhibit a pronounced temperature dependence, enabling tunable spin-wave mirrors and refractive elements. Most strikingly, we find that superconducting screening can produce nearly straight isofrequency contours, far flatter than the kinked, intrinsically curved contours attainable in conventional dipolar spin-wave systems. We show that these straight contours enable functionalities such as perfect spin-wave imaging, efficient waveguiding, and interferometric elements, such as phase shifters and beam splitters, with unconventional properties. Our results establish FMI-SC heterostructures as a versatile platform for temperature-tunable spin-wave optics and interferometric magnonic devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
31 pages, 10 figures
Effectiveness of Some 0 dB Cryogenic Microwave Attenuators as Thermal Heatsinks
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-10 20:00 EDT
J.T. Klomp, Haoyun Huang, G.A. Csathy
Coaxial cables are widely used in radiofrequency and microwave cryogenic setups for condensed matter and quantum experiments. Since the inner conductor of coaxes is often in good thermal contact with the sample to be measured, it is desirable to know the phononic heat channeled by the inner conductor. Although cryogenic attenuators are widely used to thermalize the inner conductor of coaxes, to our knowledge, quantitative information is not available. We present data on the effectiveness of three commercially available 0 dB attenuators as thermal heatsinks. In particular, we measured the temperature of the inner pin of several 0 dB attenuators under a heat load. This information will aid in designing and carefully controlling the thermal environment of samples in high-frequency experiments mounted in dilution refrigerators and on nuclear demagnetization stages.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Journal of Low Temperature Physics 222, 117 (2026)
Excitonic Magnetism in Ruthenium Pyrochlores
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-08-10 20:00 EDT
Swetlana Swarup, Yang Yang, Natalia B. Perkins
Strong spin-orbit coupling in $ d^4$ systems is expected to stabilize a nonmagnetic $ J=0$ singlet ground state, yet many ruthenium pyrochlores exhibit robust long-range magnetic order. Motivated by this apparent contradiction, we develop a microscopic theory of Van Vleck excitonic magnetism on the pyrochlore lattice. Starting from a multi-orbital Hubbard model with spin-orbit coupling, we derive the effective superexchange interactions within the low-energy singlet–triplet manifold of Ru$ ^{4+}$ ions. We analyze the resulting excitonic Hamiltonian using both the spectrum of triplon excitations and a variational treatment of the condensed phase. We identify the instability of the nonmagnetic singlet state toward triplon condensation and determine the resulting magnetic phase diagram as a function of the microscopic hopping parameters. The phase diagram reproduces the magnetic orders known from conventional pyrochlore models while also predicting an additional magnetic phase unique to the singlet–triplet description. Finally, we apply the theory to the pyrochlore ruthenates, with particular emphasis on Nd$ _2$ Ru$ _2$ O$ _7$ , and show that it lies in close proximity to the excitonic quantum critical point. Our results establish a microscopic framework for understanding excitonic magnetism in pyrochlore ruthenates and their magnetic excitation spectrum, providing direct connections to spectroscopic probes, including Raman scattering.
Strongly Correlated Electrons (cond-mat.str-el)
25 pages, 6 figures
Anderson Orthogonality as Measurement Backaction in Coupled Quantum Dots
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-10 20:00 EDT
Will Grant, Sarath Sankar, Elena Cornick, Vahid Movahed, Johann Drayne, Silvia Lüscher, Saeed Fallahi, Geoffrey C. Gardner, Michael J. Manfra, Eran Sela, Yigal Meir, Joshua Folk
Measurement perturbs a quantum system by coupling it to external degrees of freedom, but detector backaction depends on the physical mechanism of measurement itself. In solid-state devices, detectors driven far from equilibrium to enable faster measurements produce backaction that can often be understood as classical noise. However, a strong measurement can also induce backaction from quantum many-body correlations in the detector that are intrinsic to the measurement, even without shot noise. Here, we probe this near-equilibrium backaction through the effect of a quantum-dot charge sensor on tunnelling between a second quantum dot and its reservoirs. The measurement realizes the Anderson Orthogonality Catastrophe (AOC): electrons in the detector leads reorganize in response to an abrupt change in local scattering potential, suppressing resonant tunnelling while enabling inelastic processes that exchange energy with the detector. Changing the detector energy level tunes the AOC backaction from negligible to dominant in the tunnelling dynamics. More broadly, these results establish detector-induced many-body correlations as a controllable influence on quantum dynamics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Emergence of Bogoliubov Fermi Surfaces in hybrid Al/InAs heterostructures
New Submission | Superconductivity (cond-mat.supr-con) | 2026-08-10 20:00 EDT
S. Feyrer, V. Dimic, I. Lobato, A. Kirchner, P. Drexler, L. Rupp, D. Bougeard, T. Lindemann, S. Gronin, G. Gardner, M. J. Manfra, G. F. R. Ruiz, C. A. Balseiro, L. Arrachea, M. Aprili, N. Paradiso, C. Strunk, L. Tosi
We investigate the microwave electrodynamics of a proximitized two-dimensional electron gas in hybrid superconductor/semiconductor heterostructures. Using lumped-element resonators with inductor wires oriented relative to an in-plane magnetic field, we directly probe the superfluid stiffness via the kinetic inductance. As the field increases, the resonance frequency exhibits a non-monotonic and strongly anisotropic evolution that cannot be explained by orbital pair breaking alone. We show that this behavior is consistent with the emergence of Bogoliubov Fermi surfaces, which selectively suppress the supercurrent response depending on the direction of the magnetic field. Microscopic calculations of the stiffness tensor capture the observed anisotropy driven by the interplay of Zeeman and orbital Fulde-Ferrell effects. Our results establish microwave stiffness measurements as a sensitive probe of anisotropic gapless superconductivity in hybrid systems.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci)
8 pages, 4 figures and supplementary information
Temperature-tunable spin-wave refraction using superconducting control elements
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-10 20:00 EDT
Pim H. Vree (1), Merel A. Bouma (1), Michael Borst (1), Tomas T. Osterholt (2), Rembert A. Duine (2, 3), Toeno van der Sar (1) ((1) Department of Quantum Nanoscience, Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, The Netherlands, (2) Institute for Theoretical Physics, Utrecht University, 3584 CC Utrecht, The Netherlands, (3) Department of Applied Physics, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands)
Spin waves are promising signal carriers for microwave control at the micrometer scale. However, realizing low-damping, tunable control of spin-wave propagation remains a central challenge. Here we use magnetic shielding by superconducting control elements to tune the local spin-wave dispersion and realize temperature-controlled refraction of spin waves in a thin-film magnetic insulator. Using magnetic imaging based on spins in diamond, we characterize the refractive index and demonstrate both positive and negative refraction as well as wavefront shaping by the superconductors. The observed refraction is explained by a geometrical analysis of the superconductivity-induced modification of the hyperbolic spin-wave dispersion. Our results demonstrate that superconductors enable tunable spin-wave optical elements, opening new opportunities for microwave control in classical or quantum information devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con), Quantum Physics (quant-ph)
29 pages, 26 figures, 1 table
Nonreciprocity reversal of magnetoacoustic attenuation in NiFe alloy thin films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-10 20:00 EDT
Mingran Xu, Kei Yamamoto, Kouta Kondou, Zheng Zhu, Liyang Liao, Kiyohiro Adachi, Tomoka Kikitsu, Daisuke Hashizume, Dirk Grundler, Sadamichi Maekawa, Yoshichika Otani
Nonreciprocity, the asymmetry of transport, underlies technologies from the diode to the microwave isolator. In a ferromagnet, a surface acoustic wave generates an elliptical effective field with propagation-locked handedness, breaking the reciprocity of its propagation. Despite decades of study on this phenomenon, a method for controlling the sign of the nonreciprocity has remained elusive. Here we observe a sign reversal in Ni$ _x$ Fe$ _{100-x}$ films. A 0.8 at.% change across Permalloy’s zero-magnetostriction composition, where the magnetoelastic coefficient $ b$ changes sign, reverses the handedness of the elliptical effective field and thereby the nonreciprocity, from 78.6% to -61.8%. Angle-dependent measurements and spin-wave-ellipticity modelling show that reversing the sign of $ b$ reverses the handedness of the elliptically polarized effective field. Aided by cubic frequency scaling, we resolve the sign of $ b$ down to -0.05 MPa in a 10-nm film, establishing nonreciprocity as a nanoscale probe of magnetoelastic coupling.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
13 pages, 4 figures
Observation of metastable chiral domain walls in a topological magnet
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-10 20:00 EDT
Richen Xiong, Chenxin Qin, Zhaoyu Han, Nisarg Chadha, Qiang Gao, William Holtzmann, Weijie Li, Jiaqi Cai, Yi Guo, Weihanzhang Guo, Qi Chen, Samuel L. Brantly, Sam Bonkowsky, Chen Huang, Kenji Watanabe, Takashi Taniguchi, Andrea F. Young, Xiaodong Xu, Eslam Khalaf, Chenhao Jin
The interplay between topology and correlation can give rise to exotic collective excitations. The integer and fractional quantum anomalous Hall (QAH) magnets recently discovered in two-dimensional (2D) flatband systems are predicted to host spin excitations distinct from those in conventional magnets. Experimentally, nevertheless, these new excitations remain largely unexplored. Here we investigate spin-valley excitations in a twisted MoTe2 moiré superlattice using resonant ultrafast pump-probe spectroscopy. We observe a metastable spin-valley excitation in the QAH magnet below T ~ 3.7 K that survives reverse magnetic field several times larger than the saturation field. The behavior of this excitation is sharply distinct from ordinary domain walls and magnons, indicating a new type of spin-valley textures unique to topological magnets. We propose that these textures are chiral domain walls with an in-plane winding of the pseudospin order parameter along the domain wall. Their metastability arises from the interplay between the topological winding in real space and the quantum geometry of the parent bands in momentum space through a universal mechanism. These chiral domain walls govern the nonequilibrium dynamics of QAH magnets and may play a central role in their stability. Our study highlights intrinsic quantum geometry effects on spin excitations in topological magnets; and provides key insights into the fundamental mechanism limiting stability of topological protection.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
4+10 figures
The structural relaxation time of a polymer glass during deformation
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-08-10 20:00 EDT
Pradip K. Bera, Grigori A. Medvedev, James M. Caruthers, Mark D. Ediger
In order to determine the structural relaxation time of a polymer glass during deformation, a strain rate switching experiment is performed in the steady-state plastic flow regime. A lightly cross-linked poly (methyl methacrylate) (PMMA) glass was utilized, and simultaneously the segmental motion in the glass was quantified using an optical probe reorientation method. After the strain rate switch, a non-monotonic stress response is observed, consistent with previous work. The correlation time for segmental motion, in contrast, monotonically evolves towards a new steady-state, providing an unambiguous measurement of the structural relaxation time during deformation, which is found to be approximately equal to the segmental correlation time. The Chen-Schweizer model qualitatively predicts the changes in the segmental correlation time and the observed non-monotonic stress response. In addition, our experiments are reasonably consistent with the material time assumption used in polymer deformation modeling; in this approach, the response of a polymer glass to a large deformation is described by combining a linear-response model with a time-dependent segmental correlation time.
Soft Condensed Matter (cond-mat.soft)
Pradip K. Bera, Grigori A. Medvedev, James M. Caruthers, and Mark D. Ediger. “Structural Relaxation Time of a Polymer Glass during Deformation”. PRL (2024). 132(20):208101
Cascading Through the Hierarchy: Regularizer-Induced Feature Detection as Phase Transitions in Deep Linear Neural Networks
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-08-10 20:00 EDT
Björn Ladewig, Ibrahim Talha Ersoy, Karoline Wiesner
A scientific theory of deep learning, comprising learning dynamics and statistical properties of learned models, is rapidly gaining attention. One of the corner stones of this development are analytically solvable toy models, allowing for the fully tractable analysis of the learning dynamics. Here we analytically investigate such a toy model using the regularization strength as a tunable external parameter - akin to external fields in statistical physics. In previous studies, (i) an onset of learning transition was predicted analytically and (ii) it was phenomenologically/numerically established that tuning the regularization strength can result in a cascade of phase transitions. The number of those transitions was linked to the geometry of the loss landscape determined by the model complexity. Setting up a rigorous framework underpinning the previous numerical observations, our investigation reveals a precise connection between those cascades of phase transitions, learnable features and the underlying geometry. We provide analytic predictions of these phase transitions as well as tractable order parameters related to learned features. At the level of the minimal model, we connect this macroscopic perspective (that can be condensed into an effective description) to the microscopic perspective in terms of the geometry of the loss landscape characterized by the Hessian spectrum. Thus, the presented model provides a platform to explore and sharpen advances made in the scientific theory of deep learning rooted in statistical physics concepts.
Statistical Mechanics (cond-mat.stat-mech), Disordered Systems and Neural Networks (cond-mat.dis-nn), Machine Learning (cs.LG)
39 pages, 9 figures
Determination of the properties of a superconducting single crystal FeSe using an EPR spectroscopy
New Submission | Superconductivity (cond-mat.supr-con) | 2026-08-10 20:00 EDT
S.I. Bondarenko, A.A. Prokhorov, N.N. Galtsov, V.P. Timofeev, V.P. Koverya, A.V. Krevsun
Using an EPR spectrometer, the properties of single-crystal FeSe were studied in a magnetic field up to 6000 Oe at temperatures from 3.5 K to 8 K in the superconducting state and at temperatures above 8K and up to 25K in the normal state. It was shown that by measuring non-resonant spectrometer signals in zero and weak magnetic fields up to 30 Oe, it is possible to determine critical temperature Tc, the superconducting transition width, and the value of the first critical magnetic field Hc1 in FeSe single-crystal. Resonant EPR signals are observed in fields at 1400 Oe and 3400 Oe, which corresponds to the paramagnetism of doubly ionized iron atoms (Fe2+) in the FeSe crystal. Non-resonant EPR signals in a magnetic field up to 6000 Oe at temperatures from 3.5K to 8K are a nonlinear function of the field, and correspond to the superconducting mixed state of the FeSe, but at temperatures above 8K (up to 25K) they are field independent.
Superconductivity (cond-mat.supr-con)
9 pages, 6 figures
Extracting the full conductivity tensor in a rectangular sample
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-10 20:00 EDT
Electrical transport measurements reveal that many 2D materials exhibit anisotropic conductivity. However, current methodologies for rectangular geometries can only extract a partial conductivity tensor or are difficult to execute experimentally. Here, we propose a simple experimental procedure to extract the full conductivity tensor (or the resistivity tensor by inversion) including the principal axes angle. Our procedure is developed by using a conformal mapping approach to obtain an analytical expression for the potential with a point source and drain on the perimeter. Our solution agrees very well with numerical simulations using COMSOL and the known limiting case where the principal axes angle vanishes. Finite source/drains can be modeled using superposition.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
13 pages, 5 figures
Tunable g-Factors of Hybridized Orbitals in a Quantum Dot Molecule
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-10 20:00 EDT
Michelle Lienhart, Krzysztof Gawarecki, Pavel Daskalov, Christopher Thalacker, Nadeem Akhlaq, Irina Ivanova, Johannes Schall, Sven Rodt, Stephan Reitzenstein, Arne Ludwig, Dirk Reuter, Kai Müller, Jonathan J. Finley
The ability to control the $ g$ -factors of orbital spin states in optically active quantum dot molecules (QDMs) is a prerequisite for the high-fidelity generation of multi-photonic cluster states with higher-dimensional entanglement structure. Protocols that rely on two coupled spins require knowledge of the $ g$ -factor and its dependence on external control parameters. Mismatches in the $ g$ -factor between tunnel-coupled dots introduce unwanted dephasing of coupled spin-states, making precise characterization and voltage control essential. Here, we measure the gate voltage dependence of the electron and hole $ g$ -factors of negatively charged trions $ X^{-}$ in a single InGaAs QDM using polarization-resolved magneto-photoluminescence spectroscopy. The electron $ g$ -factor exhibits a pronounced step-like change at the tunneling resonance, shifting from $ g_\mathrm{e} = -0.336\pm 0.008$ to $ g_\mathrm{e} = -0.389\pm 0.003$ , providing a direct spectroscopic fingerprint of molecular orbital formation and a shift of the wavefunction localization from the lower to the upper dot. In contrast, the hole $ g$ -factor remains nearly constant at $ g_\mathrm{h} \approx 0.094 \pm 0.007$ , exhibiting a weak modulation near the anticrossing voltages attributed to Coulomb-mediated deformation of the wavefunction by the tunneling electron. Our results are quantitatively reproduced by an eight-band $ \mathbf{k}{\cdot}\mathbf{p}$ model, establishing electric-field control of the trion $ g$ -factors as a practical tool for independently tuning the Zeeman splitting of individual dots and opening new pathways towards the deterministic generation of two-dimensional photonic cluster states.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Cross-Geometry Transferability Assessment of Universal Machine Learning Interatomic Potentials: From Bulk Materials to Atomic Nanowires
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-10 20:00 EDT
Pedro H. M. Zanineli, Bruno Focassio, Gabriel R. Schleder
Foundation machine-learning interatomic potentials (MLIPs) enable atomistic simulations at substantially lower computational cost than first-principles methods, but their reliability across structural geometries remains insufficiently understood. Here, we construct a density-functional-theory dataset of ZrO2 configurations spanning bulk, slab, particle, neck, and atomically thin wire environments motivated by an experimentally observed ZrO2 desintering process involving neck thinning and atomic wire formation. We first benchmark 26 pretrained MLIPs and observe pronounced geometry-dependent degradation in zero-shot predictions. Without any training, after only reference-energy alignment, the best zero-shot model (ORB-V3) reaches energy and force root-mean-square errors of 6 meV/atom and 197.3 meV/Å, respectively, with the largest force errors in neck and wire configurations. We then compare zero-shot inference, fine-tuning, and training from scratch strategies. Fine-tuning yields lower energy and force errors than training from scratch, while both require comparable wall-clock time. Geometry-specific fine-tuning improves in-domain accuracy but frequently produces negative transfer to other structural classes, whereas mixed-geometry fine-tuning reduces cross-geometry errors. Evaluations of elastic and vibrational properties, surface energies, and neck dynamics further show that rankings based on average energy and force errors do not universally predict property-level behavior. These results demonstrate that geometry-diverse target data and independent physical validations are necessary when adapting foundation MLIPs to low-coordination (ionic) nanostructures.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Computational Physics (physics.comp-ph)
Non-uniqueness of restitution coefficients in oblique impacts of discs, even in cases of unique normal restitution
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-08-10 20:00 EDT
We investigate the different coefficients of restitution $ e$ of a dissipative, frictional disc as a function of the impact angle $ \theta$ and the friction coefficient $ \mu$ . We observe a non-monotonic, non-linear behaviour of $ e_{\mathrm{T}}$ and $ e_{\mathrm{kin}}$ with a clear minimum at $ \mu$ -dependent values of $ \theta$ and a convergence for all $ \mu$ at large $ \theta$ , bounded by the cases of pure rolling and pure sliding. Changing the dissipative normal interaction affects the $ \mu$ convergence at large $ \theta$ and leads to a convergence at low $ \theta$ . The presence of initial angular velocity $ \omega$ can significantly alter the functional behaviour of $ e_{\mathrm{T}}$ at steep impacts and slightly change the magnitude of $ e_{\mathrm{kin}}$ , with friction playing only a minor role. Overall, our results indicate, that any value of $ e_{\mathrm{T},\mathrm{kin}}$ is highly situational and can describe entirely different configurations.
Soft Condensed Matter (cond-mat.soft)
5 pages, 5 figures
Universal Magnetoresistance Scaling in Layered Pd-based Multiband Metals Beyond Compensated Semimetal Regime
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-10 20:00 EDT
We systematically investigated the magnetoresistance ratio (MR) of single-crystalline, nonmagnetic layered Pd-based metals, including centrosymmetric PdTe2, PdPb2, and beta-PdBi2 and noncentrosymmetric alpha-PdBi. Our study identifies a distinct class of large MR in multiband, high-carrier-density systems. Unlike well-studied extremely large MR materials, such as Dirac and Weyl semimetals described by simple compensated-carrier models, these compounds possess complex Fermi surfaces, as validated by our first-principles calculations. Nevertheless, they exhibit a remarkably simple MR scaling governed by carrier mobility, manifested in systematic dependencies on magnetic field, temperature, and the residual resistivity ratio (RRR). The validity of Kohler’s rule in high-RRR crystals indicates that MR is governed by a single effective scattering time, even in these multiband systems. The field and RRR dependences of MR follow an intermediate power-law behavior between linear and quadratic, attributable to imperfect carrier compensation and a distribution of carrier mobilities. Among the studied compounds, alpha-PdBi exhibits the largest MR, reaching 1500% (2 K, 7 T), owing to its exceptionally high RRR (approximately 660). However, when compared on an equal-RRR basis, its MR is smaller than that of its centrosymmetric counterparts. This trend suggests that additional scattering channels arising from spin-orbit-induced band splitting in noncentrosymmetric systems reduce the effective carrier mobility. Our results establish a new class of large MR in clean multiband metals where complex electronic structures give rise to emergent single-parameter scaling, highlighting the interplay between disorder, mobility, and symmetry.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
11 pages, 5 figures
Electron Temperature and Electron-Electron Scattering Length in GaAs/AlGaAs Using Mesoscopic Multiparallel Aperture Geometries
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-10 20:00 EDT
Arati Thapa, Rishav Khatiwada, Prakash Sharma, Jean J. Heremans, Adbhut Gupta, Kirk W. Baldwin, Loren N. Pfeiffer, Mansour Shayegan
Quantifying electron temperatures and electron-electron scattering lengths is essential for understanding electron transport regimes in two-dimensional systems. To that end, this work experimentally investigates low-temperature ballistic transport using semiclassical cyclotron orbits in a multiparallel aperture geometry. The mesoscopic geometry is fabricated on a GaAs/AlGaAs heterostructure of very high electron mobility. The amplitudes of maxima in magnetoresistance due to ballistic transport are observed to decay exponentially with temperature, allowing determination of the electron-electron scattering length from the data. A quantitative relation between electron temperature and an applied dc bias heating current is established by comparing magnetoresistance peak amplitudes measured as a function of temperature and dc bias, reflecting bias-induced Joule heating. In addition, the resistance measured near zero magnetic field decreases with increasing temperature, providing signatures of superballistic conductance.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
15 pages, 4 figures
Giant-exchange-driven Vectorial Control of a Minimal Topological Magnet in Eu3In2As4
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-10 20:00 EDT
Haonan Chen, Xunkai Duan, Guangyi Wang, Yuhan Du, Huayao Li, Jiayu Wang, Wenbin Wu, Zixuan Xu, Yingchao Xia, Jiaming Gu, Pengliang Leng, Lin Miao, Fengfeng Zhu, Xiang Yuan, Tong Zhou, Cheng Zhang
The interplay between magnetism and band topology provides a route to controlling quantum states of matter, yet its realization in materials is often constrained by weak exchange coupling and complex electronic structures. Here, a giant exchange coupling is identified in the newly predicted topological magnet Eu3In2As4, giving rise to magnetization-dependent band shifts of up to 300 meV. Together with its intrinsically soft magnetic response, this strong cou-pling enables systematic tuning of topological phases by both the magnitude and orientation of applied magnetic fields. The magneto-topological phase diagram is mapped out in which an antiferromagnetic topological insulator ground state evolves, under modest fields, into a pro-posed intermediate 2/3-ferrimagnetic phase, and further into fully polarized ferromagnetic states predicted to host either Weyl or nodal-ring semimetals. Notably, the Weyl phase corresponds to a minimal model hosting a single pair of Weyl nodes. Quantum oscillations, anomalous Hall transport and magneto-infrared spectroscopy consistently reveal exchange-driven band recon-struction across these transitions. Rotation of the magnetization theoretically provides an effi-cient means to tune the momentum-space positions and separations of the Weyl nodes. These results establish Eu3In2As4 as a model system for exploring how strong exchange coupling can be used to control topological band structures with minimal complexity.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
26 pages, 5 figures
Advanced Materials (2026): e74504
Suppression of orbital ordering and emergence of a glassy magnetic state in a high-entropy spinel vanadate
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-08-10 20:00 EDT
Shun Ito, Sota Nakakuki, Satoshi Demura, Tadataka Watanabe
High-entropy oxides provide a unique platform for exploring the interplay between configurational disorder and correlated electronic states. We report on structural, thermodynamic, and magnetic properties of the high-entropy spinel vanadate (Li$ _{0.2}$ Mg$ _{0.2}$ Mn$ _{0.2}$ Co$ _{0.2}$ Zn$ _{0.2}$ )V$ _2$ O$ _4$ , in which orbital-active V ions occupy the pyrochlore sublattice. X-ray diffraction measurements reveal that the cubic spinel structure is preserved at temperatures down to 5 K without any detectable symmetry lowering. Unlike conventional spinel vanadates exhibiting a symmetry-lowering structural transition driven by orbital ordering, the compound that we study exhibits a suppression of long-range orbital ordering in the high-entropy state. Magnetic susceptibility measurements show glassy magnetic freezing at temperatures below $ \sim$ 20 K, while specific-heat measurements reveal no anomaly associated with long-range ordering down to 3 K. Frequency-dependent ac susceptibility reveals pronounced glassy dynamics. Analyses based on the Mydosh parameter, dynamic scaling law, and Vogel–Fulcher law suggest an intermediate dynamical regime between canonical spin-glass and cluster-glass behavior. Furthermore, Cole–Cole analyses reveal systematic deviations from a single Debye relaxation process, indicating the presence of heterogeneous magnetic relaxation dynamics near the freezing regime. Our results demonstrate that, in a frustrated spinel vanadate, high configurational entropy suppresses long-range orbital ordering and stabilizes a heterogeneous glassy magnetic state, highlighting the combined roles of geometrical frustration, orbital degrees of freedom, and configurational disorder in high-entropy magnets.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
11 pages, 8 figures
Optical Anisotropy and Phase Matching in Non-Centrosymmetric Perovskite Oxides from DFT+U and DFT+U+V Functionals
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-10 20:00 EDT
Mohamed S.M.M. Ali, Ismaila Dabo (Department of Materials Science and Engineering, and Wilton E. Scott Institute for Energy Innovation, Carnegie Mellon University)
Optical anisotropy underpins the operation and performance of a broad range of photonic and quantum technologies. In this work, we critically examine the accuracy of density functional theory approximations with onsite and intersite Hubbard corrections (the DFT+$ U$ and DFT+$ U$ +$ V$ functionals) in predicting the anisotropic optical response of the non-centrosymmetric perovskite oxides, such as BaTiO$ _3$ , LiNbO$ _3$ , KNbO$ _3$ , and PbTiO$ _3$ . It is found that correcting self-interaction errors using DFT+$ U$ alone does not capture the optoelectronic response of these materials, often leading to a suppression of their optical anisotropy. While intersite Hubbard interactions restore this anisotropy, the choice of the (inter)atomic orbital manifold that defines the Hubbard correction remains critical to its accuracy. The predictive performance of the resulting, systematically validated DFT+$ U$ +$ V$ functional is achieved at a fraction of the computational cost of hybrid functionals and many-body perturbation theory calculations. As benchmarks, we investigate Zn- and (Bi,Mn)-substituted BaTiO$ _3$ solid solutions; the latter exhibit polarization-dependent bandgap narrowing from mid-gap states, substantially enhancing the dichroic ratio and birefringence with promising implications for polarization-sensitive photodetectors and integrated photonics.
Materials Science (cond-mat.mtrl-sci)
13 pages, 7 figures + 1-page Supplementary Information (1 figure)
Prominent Intrinsic Orbital Hall Effect in the 135 Kagome Metal Family and Orbital Responses in the Loop-Current Phase
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-08-10 20:00 EDT
Jianxin Huang, Rina Tazai, Youichi Yamakawa, Hiroshi Kontani
The study of electronic orbital degrees of freedom, including the generation and control of orbital currents and orbital angular momentum, has emerged as a vibrant research field. Here, we study the orbital Hall effect (OHE), one of the key mechanisms for orbital current generation, in transition-metal kagome-lattice metals. We propose a large positive OHE in CsTi$ _3$ Bi$ _5$ and negative OHEs in CsV$ _3$ Sb$ _5$ and CsCr$ _3$ Sb$ _5$ models. Orbital-sector decomposition shows that the $ \vert l^z_d \vert=2$ $ d$ -orbital channel gives a positive contribution, whereas the $ \vert l^z \vert=1$ $ d$ - and $ p$ -orbital channels can give negative contributions. Control calculations suggest a persistent orbital-sector sign tendency near the actual filling, while strong $ p$ -$ d$ hybridization modulates the quantitative balance and total OHE sign. Thus, the compound and filling dependence of the OHE reflects both the sign tendency of each orbital sector and the hybridization-controlled balance among them. Furthermore, we investigate the loop-current phase of CsV$ _3$ Sb$ _5$ and show that it induces finite local atomic orbital angular momentum. We also show that loop-current-related symmetry lowering allows finite symmetric components of the orbital conductivity tensor. This study provides a basis for exploring orbital currents and local orbital-angular-momentum responses in strongly correlated kagome metals.
Strongly Correlated Electrons (cond-mat.str-el)
15 pages, 12 figures
Floquet spintronics: tuning the current-induced spin polarization of topological surface states with light
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-10 20:00 EDT
Youngjae Kim, Aayushi Agrawal, Kwon Park
Topological surface states are a promising platform for spintronics due to spin-momentum locking. Spin-momentum locking can induce a net spin polarization in topological surface states via an electric current, a phenomenon known as the Edelstein effect. In this work, using Floquet theory, we show that the current-induced spin polarization of topological surface states can be tuned by illuminating them with light, thereby modifying their spin texture in momentum space. Specifically, the electric spin susceptibility of topological surface states can be controlled and even reversed by varying the electric-field strength of high-frequency, circularly polarized light.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
8 pages, 4 figures
Symmetry Classification of Non-Relativistic Hidden Spin Polarization in Noncollinear Magnets
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-10 20:00 EDT
Yuzhong Hu, Pan Zhou, Baoru Pan, PengBo Lyu, Lizhong Sun
Hidden spin polarization (HSP), in which spin-polarized states exist locally while the total spin polarization are hidden in momentum space, has been extensively studied in nonmagnetic and collinear magnetic systems, but remains largely unexplored in noncollinear magnets. Here we establish a unified symmetry framework for HSP in noncollinear magnetic materials based on spin-group theory. We show that spin symmetries systematically constrain nonrelativistic spin polarization, giving rise to four distinct split spin-texture (SST) types for each local sector, denoted as SST-1, SST-2, SST-3, and SST-4. Based on these splitting forms, together with the dimensionality of the associated local spin textures and the symmetry relations between different local sectors, we further classify HSP into three categories: HSP-1, HSP-2, and HSP-3. We illustrate these categories using tight-binding models and representative material examples, including SrFe$ _2$ Se$ _2$ O, USb, Sr$ _2$ Mn$ _3$ Sb$ _2$ O$ _2$ , PrFeAsO, and GdMn$ _2$ Si$ _2$ . A survey of the MAGNDATA database further identifies 133, 7, and 139 candidate noncollinear magnetic materials hosting HSP-1, HSP-2, and HSP-3, respectively. In addition, our symmetry analysis and first-principles calculation show that many of these materials can exhibit nonzero spin-related response tensors. These results establish a general framework for understanding HSP in noncollinear magnets and highlight their potential for spin-dependent functionalities.
Materials Science (cond-mat.mtrl-sci)
Phys. Rev. Lett. (2026)
Ultralow p-type contact resistance for ultra-nanoscaled 2D-materials transistors
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-10 20:00 EDT
Ying Xiong, Tong Su, Qiang Li, Yee Sin Ang, Lain-Jong Li, L. K. Ang
High contact resistance is one of the main bottlenecks for practical two-dimensional (2D) materials transistors, especially for p-type transistors and future 2D ultra-nanoscaled (sub-10 nm) FETs (PMOS + CMOS). We develop self-consistent contact resistance models for metal-2D semiconductor-metal devices to capture the essential interface physics for both vertical and edge configurations. Our calculations have been verified with various recent experiments of p-type and n-type contacts. For a given set of materials, the model determines the scaling of contact resistance over a wide range of device parameters including channel length (100s nm down to sub-10 nm), doping and mobility of the 2D materials, contact length of the electrodes, and applied voltages. These results identify the key factors in order to reduce the contact resistance for p-type 2D semiconductor WSe$ _2$ towards the sub-10 nm channel length scale that are readily to be realized by future experiments. It is found that the effect of source-limited current saturation is the key challenge for down scaling 2D FET to sub-10 nm channel length. Two topological semi-metals as potential electrodes are proposed for 2D p-type semiconducting WSe$ _2$ with our predicted contact resistance $ R_c<$ 100 $ \Omega ; {\rm \mu m}$ approaching the quantum limit. Our model is also verified with the computational expensive full quantum atomistic model that is currently limited to a few nm scale.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Particle Contacts Generate Fractional Density Relaxation
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-08-10 20:00 EDT
Dense-liquid relaxation evolves from local particle collisions to cooperative structural rearrangements. While hard-sphere kinetics determines an early $ t^{3/2}$ fractional decay in density correlation functions, collective theories describe the subsequent structural relaxation. A central open question has been how short-time contact physics supplies an exact starting point for the memory kernel governing later times without being modified by subsequent many-body rearrangements. Here we resolve this problem for a broad class of reversible Brownian systems. We prove that hard particle contacts act as reflecting boundaries in configuration space, uniquely dictating the amplitude of the leading $ t^{3/2}$ density relaxation. Mechanistically, diffusion samples a contact boundary layer of thickness $ O(\sqrt{t})$ , which combines with the local density response to produce the fractional signal. We derive an explicit surface formula expressing this amplitude in terms of equilibrium contact probability, normal mobility, and density sensitivity. For monodisperse hard spheres, this yields an exact, fit-free prediction determined entirely by static structure $ S(k)$ , radial contact value $ g(\sigma^+)$ , and short-time diffusion $ D_0$ . Extending the construction, we determine the corresponding normalization for soft interfaces and prove via a Gram–Schur projection hierarchy that regular collective variables leave the leading contact amplitude strictly invariant. The resulting formulation connects microscopic collision kinetics directly to caging and glass-like structural relaxation, providing an exact microscopic boundary condition for scattering experiments, molecular simulations, and memory-kernel reconstructions.
Soft Condensed Matter (cond-mat.soft), Optics (physics.optics)
9 pages, 4 figures
Acoustic fluctuations of two-dimensional dipolar supersolids
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-08-10 20:00 EDT
We investigate the microscopic structure of the long-wavelength acoustic excitations of two-dimensional dipolar supersolids with triangular and honeycomb crystal order. Using Bogoliubov–de Gennes calculations, we determine the density, phase, current, and lattice-displacement fluctuations associated with the three acoustic modes. We develop a procedure to extract the lattice displacement directly from the microscopic density perturbation, allowing the modes to be identified as one transverse and two longitudinal branches. The displacement field further separates the density fluctuations into contributions from crystal strain and particle transport relative to the lattice. This reveals that the lower longitudinal mode can have large strain and defect-density fluctuations that substantially cancel in the total density response. We show that the long-wavelength fluctuation amplitudes agree with hydrodynamic theory, which is specified entirely by the elastic coefficients of the supersolid. Our analysis provides a microscopic connection between Bogoliubov excitations and the crystalline and superfluid degrees of freedom of two-dimensional supersolids, and identifies their signatures in density- and current-sensitive probes.
Quantum Gases (cond-mat.quant-gas)
12 pages, 6 figures
Spin Qubits in Photon-Coupled Microwave Cavities
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-10 20:00 EDT
Electron spin qubits in microwave cavities provide a promising platform for scalable quantum computing hardware, leveraging long coherence times, charge-noise robustness and cavity mediated qubit-qubit interactions. While the strong spin-photon coupling regime is accessible via on-chip micromagnets, scaling conventional architectures by placing multiple qubits within a single shared resonator degrades transmission amplitudes, hence limiting large-scale efficiency. To overcome this limitation, we analyze a modular architecture where individual cavities containing a limited number of qubits are coupled via single-photon-exchange waveguides. Using input/output theory, we compute the transmission amplitudes for networks of two and three coupled cavities in various configurations. We map out the distinct physical regimes accessible by tuning key system parameters, offering a viable pathway for scalable cavity-based quantum spin qubit networks.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
12 figures
Autonomous Optimization of Complex Oxides for Thermochemical Fuel Production
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-10 20:00 EDT
Shuiping Gong, Mingcheng Li, Han Hao, Zhenhao Zhou, Yi Li, Xiaobo Liao, Cheng Fang, Jian Deng, Jiangang He, Wenpei Gao, Yakun Yuan, Chris Wolverton, Tao Deng, Chaochao Dun, Runxia Cai, Zhenpeng Yao
Two-step thermochemical fuel production, including H2O and CO2 splitting, offers a promising route to sustainable fuel manufacturing, with performance governed by redox-active oxides that enable cyclic reduction-oxidation reactions. Maximizing thermal-to-fuel conversion efficiency demands materials that simultaneously satisfy multiple stringent thermodynamic and kinetic targets. Addressing these requirements has increasingly driven materials design toward complex, multi-cation oxides, such as mixed-cation fluorites, perovskites, and high-entropy oxides, wherein composition, defect chemistry, phase stability, and morphology should be co-optimized. This creates a challenging materials optimization problem that is poorly suited to traditional trial-and-error approaches. In this review, we argue that thermochemical fuel production provides a compelling frontier for autonomous materials design and optimization. We first examine why redox-active complex oxides are difficult to develop, owing to multidimensional phase spaces, harsh operating conditions, and competing functional targets. We then discuss how high-throughput computation, automated synthesis, characterization and testing, and machine learning can be integrated into closed-loop workflows to address these challenges. Building on broader oxide materials research, we organize recent progress into a capability roadmap for complex-oxide optimization, spanning compositionally diverse synthesis, operando characterization, robotic testing, operation-condition computation, and multi-objective optimization. Finally, we outline key experimental, computational, and data challenges for building self-improving materials development platforms for materials development in thermochemical fuel production.
Materials Science (cond-mat.mtrl-sci)
31 pages, 3 figures, 1 table
Extracting the pairing gap from van Hove singularities in rf spectra of the Fermi Hubbard model
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-08-10 20:00 EDT
Chuping Li, Kaichao Zhang, Junru Wu, Yuxuan Wu, Dingli Yuan, Pengyi Chen, Lin Sun, Qijin Chen
We show that van Hove singularities in rf spectra of the 3D attractive Fermi Hubbard model provide a robust route to extracting the pairing gap. Four types of singularities are classified, and their spectral positions are shown to depend solely on the pairing gap $ \Delta$ and chemical potential $ \mu$ through simple algebraic relations. Measuring two well-resolved singularities therefore determines both parameters without requiring full spectral fitting. Numerical simulations incorporating phenomenological lifetime and scattering broadenings confirm that these features remain visible in both momentum-integrated and $ k_z$ -integrated spectra, and become more pronounced at stronger coupling where conventional back-bending methods lose sensitivity. At half filling, particle-hole symmetry fixes $ \mu$ , reducing the extraction to a single singularity measurement. These results establish vHS analysis as a practical spectroscopic diagnostic for pairing in quantum-simulated 3D Fermi Hubbard systems.
Quantum Gases (cond-mat.quant-gas)
9 pages, 8 figures
Local Structure Dictates Ionic Transport and Mechanical Properties in Glassy Solid Electrolytes for Lithium Batteries
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-10 20:00 EDT
Yong Li, Tao Du, Rasmus Christensen, Timothée Jamin, Zhencai Li, Qi Zhang, Xiaoyi Xu, Kasper Tolborg, Yuanzheng Yue, Morten M. Smedskjaer
Electrolytes composed of sulfide and halide glasses are promising candidates for all-solid-state lithium batteries owing to their processability, lack of grain boundaries, and relatively high ionic conductivity. Nevertheless, their ionic conductivity and mechanical properties are still not satisfying for the real-world applications. Significant advances in solid electrolytes require a thorough understanding of their microstructures. Here, we reveal the connections among structure, ionic transport properties, and mechanical stability in a series of glassy solid electrolytes by employing molecular dynamics simulations based on a machine learning interatomic potential. Specifically, we explore how the interplay between B-S and P-S networks in glassy Li-S-P-B-I (LSPBI) governs ionic conductivity and deformation behavior. The introduction of P2S5 into a B2S3-based glass induces a critical structural transformation, through which both ionic conductivity and mechanical nano-ductility can be enhanced. For a moderate P2S5 content, incorporated PS4 units depolymerize the rigid boron framework, creating percolative diffusion pathways for fast ionic transport. Concurrently, the flexible P-S-P configurations enable energy dissipation through bond bending, leading to the brittle-to-ductile transition. However, excessive P2S5 increases the fraction of polyphosphates (e.g., P2S6 and P2S7), thereby polymerizing the structural network and ultimately impeding Li+ mobility. Our work thus provides atomistic principles for engineering glass electrolytes with balanced ionic conductivity and mechanical robustness.
Materials Science (cond-mat.mtrl-sci)
Fast Isotropic Li-Ion Diffusion in Zeolitic Imidazolate Framework Glass Electrolytes for Batteries
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-10 20:00 EDT
Yong Li, Tao Du, Timothée Jamin, Zhencai Li, Kasper Tolborg, Yuanzheng Yue, Morten M. Smedskjaer
All-solid-state lithium batteries require solid electrolytes that combine rapid room-temperature ion transport with mechanical robustness and interfacial compatibility. Zeolitic imidazolate framework (ZIF) glasses, with ZIFs being a sub-set of metal-organic frameworks, offer an attractive yet relatively underexplored platform because they combine an grainboundary-free and amorphous topology with chemically tunable frameworks. Here, we reveal that structural disorder unlocks fast and isotropic lithium diffusion in ZIF glasses. This is realized by using a machine learning interatomic potential to simulate Li+ transport in crystalline and glassy ZIF-4 and ZIF-62. Structural disorder reduces the activation energy for Li+ migration from ~0.35 eV to 0.16 eV and increases the extrapolated room-temperature diffusion coefficient by more than one order of magnitude for ZIF-4 and nearly sevenfold for ZIF-62. Analyses of non-Gaussian dynamics and van Hove correlation functions reveal that Li+ diffusion in crystalline ZIFs occurs via rare, dynamically heterogeneous hopping events among well-defined cages, whereas Li+ diffusion in glassy ZIFs is more homogeneous, continuous, and Fickian-like, benefiting from a wide distribution of coordination geometries and migration barriers. Li+ diffusion in crystalline ZIFs is strongly anisotropic, reflecting that ordered orientations of imidazolate and benzimidazolate rings impose distinct energy barriers along different crystallographic directions. Upon vitrification, these ring orientations become randomized, and hence, the diffusion of Li+ becomes isotropic or near-isotropic. These findings imply that well-designed metal-organic framework glasses are a promising candidate as high-performance solid-state electrolytes.
Materials Science (cond-mat.mtrl-sci)
Spin-group theory on Edelstein effect and spin-orbit torque in Collinear Ferromagnets
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-10 20:00 EDT
Yizhuo Song, Qing Zhang, Jiahao Shentu, Jie Li, Jia Zhang
Current-induced spin-orbit torques (SOTs) are central to the electrical manipulation of magnetic order in spintronic devices. In transition-metal/collinear ferromagnet bilayers, field-like and damping-like torques have been described only phenomenologically via the spin or orbital Hall effect, lacking a rigorous symmetry-based foundation. The precise role of spin-orbit coupling (SOC) in both the Edelstein effect and SOTs has remained unresolved. Here we develop a spin-group symmetry theory for the Edelstein effect and SOTs in collinear ferromagnets, treating SOC as a symmetry-breaking perturbation. For 4mm (C4v) point group symmetry, we derive the full forms of field-like and damping-like torques, which arise predominantly from first- and second-order SOC. We further show that SOTs in both orbital-Hall-dominated Ti/Ni and spin-Hall-dominated Pt/CoFe bilayers originate at first-order SOC. Taking the 3m (C3v) torque as a paradigmatic example, we elucidate the role of second- and higher-order SOC torques in field-free switching of perpendicular magnetic anisotropy. Remarkably, in PtMnSb, we demonstrate that SOTs under certain point group symmetries deviate from the conventional form: zeroth- and first-order SOC contributions vanish identically, with the leading SOT emerging at second order. All symmetry-based predictions from spin-group theory are in excellent quantitative agreement with first-principles calculations. Our work establishes a unified symmetry framework for the microscopic understanding of the Edelstein effect and current-induced spin torques in ferromagnetic systems.
Materials Science (cond-mat.mtrl-sci)
23 pages, 8 figures
Local magnetic properties of the rare-earth intermetallics $R$Mn$_2$Ge$_2$ ($R$=Ce, Pr, Nd)
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-08-10 20:00 EDT
N. P. Bentley, T. L. Breeze, A. Hernández-Melián, M. J. Pearce, T. J. Hicken, M. T. F. Telling, B. M. Huddart, D. A. Mayoh, G. Balakrishnan, S. J. Clark, T. Lancaster
We present an investigation of the rare-earth intermetallic materials, $ R$ Mn$ _2$ Ge$ _2$ ($ R$ =Ce, Pr, Nd), reported to host a lattice of skyrmionic bubbles at room temperature. The magnetism of all three materials is characterised by the onset of local fluctuations as the magnetic state changes from a conical magnetic structure to a collinear antiferromagnetic one as temperature $ T$ is increased. In this $ T$ regime, where skyrmion-bubble textures have been reported, we see dynamics similar to those observed in other skyrmion-hosting materials. The level of disorder above this transition increases across the series from $ R$ =Ce to Nd. At low temperatures the magnetism is affected by the ordering of the rare-earth ions, resulting in distinct behaviour for the different members of the series.
Strongly Correlated Electrons (cond-mat.str-el)
23 pages, 11 figures, submitted to PRB
Out-of-equilibrium spin-valley dynamics of ferromagnets in topological Chern bands
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-10 20:00 EDT
J. James, I. Krastilevskiy, F. Pichler, L. Wang, A. Iafarova, F. Menzel, K. Watanabe, T. Taniguchi, C. Kuhlenkamp, M. Knap, T. Smoleński
Understanding quantum matter far from equilibrium is a central goal of modern physics. Twisted MoTe2 bilayers constitute a promising platform for exploring this frontier by combining strong Coulomb interactions, nontrivial band geometry, and optical control. Here, we exploit this setting to investigate the role of topology and many-body correlations in the out-of-equilibrium dynamics of ferromagnets in Chern bands. Using a focused circularly polarized light pulse, we create a local magnetic domain oriented opposite to an external magnetic field and directly image its subsequent spin-valley relaxation in spatially and time-resolved low-temperature experiments. We demonstrate that in the vicinity of both integer and fractional Chern insulating states, the dynamics is governed by qualitatively different mechanisms than in ferromagnetic metals. Whereas metallic domains collapse by shrinking, Chern domains melt via thermal activation, resulting in drastically different temporal spin evolution and orders-of-magnitude longer relaxation times. These findings demonstrate the influence of topology and strong correlations on far-from-equilibrium collective spin phases, opening new opportunities for dynamical control of ferromagnets in the quantum Hall regime.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
Main text: 6 pages, 4 figures; Methods: 8 pages (+ 14 extended data figures)
Magneto-optical signal from $\mathrm{Co_2Mn}$-based Heusler thin films in MOKE and BLS
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-10 20:00 EDT
Anna Maria Friedel, Nicolas Fermon, Tobias Böttcher, Sébastien Petit-Watelot, Stéphane Andrieu, Philipp Pirro
$ \mathrm{Co_2Mn}$ -based Heusler compounds offer a versatile, composition-tunable platform for magnonics and spintronics. Among them, the half-metallic $ \mathrm{Co_2MnSi}$ is of particular interest for magnonics owing to its ultralow Gilbert damping, yet its weak magneto-optical response in the visible challenges optical probing such as Brillouin light scattering (BLS). We study the magneto-optical response of epitaxial $ \mathrm{Co_2Mn}X$ films ($ X = {\mathrm{Al}x\mathrm{Si}{1-x}, \mathrm{Ga}x\mathrm{Ge}{1-x}, \mathrm{Sn}}$ ) by magneto-optical Kerr effect (MOKE) spectroscopy and BLS. Angle-resolved MOKE resolves a significant, wavelength-dependent quadratic MOKE (QMOKE) only for $ \mathrm{Co_2MnSi}$ , whereas $ \mathrm{Co_2MnAl}$ , $ \mathrm{Co_2MnGa}$ and $ \mathrm{Co_2MnSn}$ respond dominantly linearly. Comparing BLS intensities of thermal magnons at two wavelengths, $ \mathrm{Co_2MnSi}$ gives the weakest signal at $ 532,\mathrm{nm}$ yet among the strongest at $ 457,\mathrm{nm}$ , tracking the spectral dependence of its Kerr angle. These results emphasise the relation between the two magneto-optical techniques, guiding the choice of probing wavelength for $ \mathrm{Co_2Mn}$ -based Heusler compounds.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
18 pages, 4 figures. Data available at this https URL
Active Brownian motion in a single-relaxation viscoelastic fluid
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-08-10 20:00 EDT
Active Brownian particles (ABPs) in viscoelastic (VE) media exhibit fascinating dynamical phenomena set by self-propulsion, thermal fluctuations, and fluid viscoelasticity. We extend our model, in which the Brownian dynamics within a slowly diffusing harmonic well emulates that in a single-relaxation VE fluid, to study active Brownian motion in such media. Consequently, the resultant dynamics is governed by the interplay of the characteristic timescales of the systems: the crossover and equilibration times of the VE fluid, $ \tau_k$ and $ \lambda$ , respectively, and the persistence time of the ABP, $ \tau_{\mathrm{R}}$ . Following analytical predictions and simulations, we study two practically relevant regimes where the dynamics is dominated by the persistence of active motion and the elastic confinement of the VE fluid, with a phoretically active Pt-coated Janus colloid in a dynamic optical trap, and show quantitative agreement with the simulations. This approach provides a VE environment with tunable VE properties that remain unaffected by the strength of self-propulsion, allowing us to systematically investigate active Brownian motion in VE media in ways that are not otherwise possible with physical VE fluids.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
7 pages, 4 figures, 2 supplementary movies
Local lattice dynamics of hcp zinc from EXAFS and machine-learning interatomic potentials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-10 20:00 EDT
Vitalijs Dimitrijevs, Pjotrs Žguns, Inga Pudza, Aleksandr Kalinko, Alexei Kuzmin
The lattice dynamics of hexagonal close-packed (hcp) zinc, a prototypical anisotropic metal, is studied using temperature-dependent Zn K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy combined with atomistic simulations. The reverse Monte Carlo method enable the extraction of mean-square relative displacements (MSRDs) for eight coordination shells, providing a shell-resolved description of thermal motion. The MSRD temperature dependence, analysed using the correlated Einstein model, yields effective interatomic force constants and reveals pronounced anisotropy between in-plane and out-of-plane interactions. This anisotropy is further quantified by the ratio of MSRDs for the first and second coordination shells, which closely matches the anisotropic displacement parameters from diffraction experiments. Molecular dynamics simulations using the CHGNet universal machine-learning interatomic potential show that the original model overestimates thermal disorder, while a fine-tuned version substantially improves agreement with experimental EXAFS spectrum and radial distribution function. Overall, EXAFS-informed analysis is effective for validating and refining machine-learning interatomic potentials.
Materials Science (cond-mat.mtrl-sci)
Physica B 739 (2026) 418945
Many-Body Mobility Edge and Non-Hermitian Skin Effect in an Interacting Quasi-Periodic Spin Chain
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-08-10 20:00 EDT
Lavoisier Wah, Ayan Banerjee, Flore K. Kunst
Non-Hermitian many-body physics reveals a rich interplay between topology, localization, and boundary effects, yet their collective behavior in interacting disordered systems remains largely unexplored. In this work, we study an interacting non-Hermitian spin chain subject to a quasi-periodic longitudinal field, providing a unified and controlled setting, where non-Hermitian dynamics, interactions, and localization mechanisms intertwine. Remarkably, we discover a “D-shaped” many-body mobility edge that separates extended and localized eigenstates, while simultaneously delineating regimes of many-body localization and the many-body skin effect (where many-body eigenstates acquire an anomalous drift towards a boundary under open boundaries) emerging from the combined action of interactions, non-Hermiticity, and driving amplitude. We demonstrate that the skin effect induces multifractal scaling in the non-Hermitian eigenstates, providing a clear signature of the many-body skin effect. Employing diagnostics such as the fractal dimension, complex eigenvalue fractions, and many-body inverse participation ratios, we map out a unified phase diagram in which all measures consistently identify the “D-shaped” mobility edge. Finally, we probe this interplay using both complex level-spacing statistics and dynamical observables such as density imbalance, entanglement growth, and wave-packet evolution, culminating in a rich many-body mobility phase diagram that captures both the many-body skin effect and localization transitions. Our results identify a clear, defining signature of the “D-shaped” many-body mobility edge, and underscore its pivotal role in shaping the physics of open quantum many-body systems.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
16 pages, 11 figures
Net and Hidden Spin-Valley Locking Enable Ultrahigh Hole Mobility in Covalent Bulk WN$_2$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-10 20:00 EDT
Rong-Tian Pang, Zhongjuan Han, Jiayi Gong, Jiangang He, Jin-Jian Zhou, Yugui Yao
High carrier mobility at room temperature underpins high-performance electronics, yet high hole mobility remains rare in bulk semiconductors. Spin-valley locking can suppress intervalley scattering and enhance mobility, but it is limited to materials with broken inversion symmetry. Hidden spin polarization offers a possible route beyond this constraint, although whether its compensated spin textures could protect charge transport remains unclear. Using ab initio electron-phonon and transport calculations, we show that the two hexagonal phases of bulk WN$ _2$ realize net and hidden spin-valley locking and exhibit ultrahigh room-temperature hole mobilities. In non-centrosymmetric $ \alpha$ -WN$ _2$ , a large valley spin splitting produces net spin-valley locking that nearly eliminates phonon-mediated intervalley scattering. In centrosymmetric $ \beta$ -WN$ _2$ , hidden Zeeman-type spin polarization yields a compensated, sector-resolved spin texture that reverses between valleys and suppresses intervalley scattering as effectively as the net locking does. The stiff W-N/N-N covalent network further keeps the remaining intravalley scattering weak. Our results establish hidden spin polarization as an effective transport-protection mechanism and extend spin-valley engineering to centrosymmetric bulk semiconductors.
Materials Science (cond-mat.mtrl-sci)
7 pages, 4 figures
Topological surface altermagnets in SSH-stacked magnetic layers
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-10 20:00 EDT
Rui Chen, Bin Zhou, Dong-Hui Xu
Surface altermagnetism opens new avenues in spintronics by unlocking altermagnetic spin-splitting at the boundaries of conventional antiferromagnets, bypassing the strict symmetry requirements of bulk altermagnets. In this work, we propose creating topological surface altermagnet by stacking magnetic layers in a Su-Schrieffer-Heeger pattern. We show that while the bulk of the system is a standard antiferromagnet with degenerate bands protected by $ PT$ symmetry, breaking the local symmetry at the boundary gives rise to a topologically protected surface altermagnetic state residing within the topological gap. Furthermore, we propose that this effect can be experimentally detected by applying a perpendicular electric field. Besides, this approach can be readily generalized to surface altermagnetism of different types. Our work establishes topological boundaries as a natural platform for surface altermagnetism, offering a distinct route for realizing and manipulating topological surface altermagnets.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Origin of the superconductor-insulator transition in disordered two-dimensional films
New Submission | Superconductivity (cond-mat.supr-con) | 2026-08-10 20:00 EDT
Alexander Weitzel, Lea Pfaffinger, Animesh Panda, Arpan Das, Ilaria Maccari, Simon Reinhardt, Sven Linzen, Evgenii Il’ichev, Nicola Paradiso, Ferdinand Evers, Christoph Strunk
Theory predicts the superconductor-to-insulator transition (SIT) to emerge from the competition between Anderson localization, which tends to localize single-particle wavefunctions, and superconductivity, which establishes long-range correlations in the superconducting order parameter. In two-dimensional (2D) superconducting films, the transition temperature $ T_\text{c}$ at which resistance vanishes, $ R_\Box(T_\text{BKT}){=}0$ , is set by the Berezinskii-Kosterlitz-Thouless (BKT) mechanism and satisfies $ T_\text{BKT}< T_{c0}$ , where $ T_{c0}$ is the mean-field transition temperature. In weakly disordered samples $ T_\text{BKT}\lesssim T_{c0}$ , whereas increasing disorder drives $ T_\text{BKT}\ll T_{c0}$ near the SIT. Whether the finite-temperature transition retains its BKT character throughout this crossover remains an open question. Here, we investigate the evolution of both sheet resistance $ R_\Box(T)$ and superfluid stiffness $ J_s(T)$ over a wide range of disorder strength $ W$ . We establish that even near the SIT, the finite-temperature transition from the superconducting to the resistive state remains of BKT type. However, as disorder approaches the critical value, the zero temperature superfluid phase stiffness, $ J_s(0)$ , is found to vanish rapidly while $ T_{c0}$ remains finite, which we attribute to quantum phase fluctuations as the drive for the zero-temperature transition. Three decades after its experimental discovery by Haviland, Liu, and Goldman, our measurements clarify the origin of the SIT in 2D films.
Superconductivity (cond-mat.supr-con)
Morphology Engineering of Mixed Ionic Electronic Conductors through Aqueous Phase Separation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-10 20:00 EDT
Siqi Wang, Maria Restrepo, John Linkhorst, Matthias Wessling
The performance of organic electrochemical transistors (OECTs) is fundamentally governed by the interplay between ionic accessibility and electronic transport within organic mixed ionic-electronic conductors. Although increasing channel thickness enhances transconductance, it also prolongs ion transport, resulting in the well-known gain-speed trade-off. Here, we demonstrate that engineering the internal morphology of PEDOT:PSS:PEI films through pH-induced aqueous phase separation provides an effective route to mitigate this limitation. The resulting interconnected pore network promotes electrolyte penetration and increases the electrochemically addressable volume, while DMSO treatment and annealing enhance the continuity and ordering of the PEDOT-rich electronic phase. Consequently, porous OECT channels achieve a transconductance of 30 mS and a response time of 13 ms at an ultralow gate voltage of 0.05 V despite channel thicknesses exceeding 100 um. Comparison of films with comparable electronic conductivity but different pore architectures identifies morphology as the dominant factor governing device performance, supporting a transition from predominantly surface-limited modulation toward spatially distributed mixed ionic-electronic transport. Beyond demonstrating a scalable water-based fabrication strategy, this work establishes internal morphology as a design parameter that complements molecular structure and device geometry in organic mixed conductors, providing a general framework for the development of high-performance OECTs, soft bioelectronics, and future neuromorphic materials.
Materials Science (cond-mat.mtrl-sci)
conducting polymer, PEDOT:PSS, porous films, organic electrochemical transistors (OECTs), ion sensing
Statistical stability of random potentials to thermal and quantum activation
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-08-10 20:00 EDT
In numerous physical, chemical, and biological systems the dynamics can be reduced to the motion of state variables in a complex potential landscape. In case the manifold is known, the motion and response of the embedded object can be described deterministically up to stochastic effects usually associated with a noise. In contrast, if the manifold is unknown, the static and dynamic response of the state variable may be used as a spectroscopic tool to characterize the potential landscape. Inspired by a seminal work of L.\ Embon and co-workers, [Sci.\ Rep.\ \textbf{5}, 7598 (2015)] we investigate the statistical properties of potential minima, in particular, their stability to thermal and quantum activation. For Gaussian random manifolds, we derive an algebraic expression to evaluate the statistical probability of the potential character (value, slope, curvature, …). With this tool, we compute the expectation value for the rate of thermal and quantum activation and link these findings to the principal characteristics of the Gaussian potential, i.e., its Green’s function. This link provides the opportunity to access information on the potential’s Green’s function by studying the activation behavior of an object in this manifold.
Statistical Mechanics (cond-mat.stat-mech), Superconductivity (cond-mat.supr-con), Applications (stat.AP)
7 pages, 3 figures
Distribution of the Radius of Gyration for an ISAW
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-08-10 20:00 EDT
Antony Lesage, Vincent Dahirel, Jean-Marc Victor, Maria Barbi
We aim at calculating an explicit expression for the finite-size probability distribution of the radius of gyration $ R$ of an Interacting Self-Avoiding Walk (ISAW), as a function of chain length $ N$ and monomer-monomer interaction energy $ \varepsilon$ . We first derive the explicit free energy expression for a non-interacting Self-Avoiding Walk, introducing a new natural scale variable $ t = \rho^g$ expressed as a power of the density $ \rho$ . Then, thanks to a cumulant expansion approach introduced by Lhuillier, Victor and coworkers, we extend it to the interacting case, capturing both the coil-globule transition and finite-size corrections to scaling, including entropic and surface-energy contributions. The radius of gyration distribution determined by the new free energy expression is then compared, using Bayesian inference to estimate the model parameters, to results from extensive Monte Carlo simulations of three-dimensional ISAWs, showing excellent agreement except very close to the $ \Theta$ -point, where finite chain lengths limit the accessible scaling regime. This validates our resulting free energy expression and allows us, as an application, to construct a phase diagram of the coil-globule transition.
Statistical Mechanics (cond-mat.stat-mech), Soft Condensed Matter (cond-mat.soft)
15 pages, 5 figures
Observation of far-from-equilibrium scaling in the transient dynamics of 2D quantum magnets
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-08-10 20:00 EDT
Fabio Bensch, Umberto Borla, Federico Balducci, Philip Osterholz, Shuanghong Tang, Silpa Baburaj Sheela, Anushya Chandran, Roderich Moessner, Jad C. Halimeh, Christian Groß
The transient regime of far-from-equilibrium quantum many-body dynamics lacks the established organizing principles that universality and scaling provide in equilibrium. It is least understood for two-dimensional short-range interacting systems, where mean-field arguments are not expected to hold, controlled theoretical descriptions are few, and fluctuations are strong. Here we investigate the quench dynamics of the transverse-field Ising model using programmable Rydberg-atom arrays realizing honeycomb, square, kagome, and triangular lattices. Starting from a fully magnetized state, we observe a pronounced softening of the dominant collective magnetization oscillation accompanied by a maximum in the damping rate, signaling a crossover between interaction- and field-dominated transient dynamics. Even though the microscopic lattice geometries are different, both the oscillation frequencies and the damping rates collapse onto common curves after being rescaled by the coordination-number-weighted interaction strength. Our findings show that a mean-field description effectively reproduces the magnetization oscillations. The importance of correlated quantum fluctuations is underlined by the failure of the discrete truncated Wigner approximation to predict the damping for strong interactions, while tree-tensor-network simulations reproduce the dynamics accurately. These results reveal a robust scaling regime governing the transient dynamics of short-range interacting two-dimensional quantum magnets. They reveal that the dominant transient dynamics is governed by a simple collective description despite the presence of strong quantum fluctuations — an important insight in the quest to uncover organizing principles in far-from-equilibrium quantum matter.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
Perfect absorption by metal-contacted two-dimensional systems with ultra-proximate reflectors
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-10 20:00 EDT
Kirill Kapralov, Vladislav Atlasov, Alina Khisameeva, Viacheslav Muravev, Dmitry Svintsov
Electromagnetic absorbance by most two-dimensional electron systems is typically well below unity, which hinders both practical applications in photodetection and fundamental studies of their optical properties. Here, we show that a periodic structure comprised of narrow two-dimensional sections connected with wide perfectly conducting metal sections enables large absorbance. It reaches 50 % provided the filling factor by the two-dimensional system $ f$ equals its dimensionless conductivity $ \eta=\sigma Z_0/2$ , where $ Z_0$ is the free-space impedance. The absorbance is further raised to 100 % if the periodic structure is placed above a perfectly conducting electromagnetic reflector, and provided $ f=2\eta$ . Surprisingly, the optimal distance between two-dimensional system and reflector may fall well below the quarter of incident wavelength $ \lambda_0/4$ , which was assumed as conventional absorption enhancement condition in optics. For low filling factors $ f\ll1$ , large dielectric constants of the substrate, and grating periods comparable with $ \lambda_0$ , the optimal distance to reflector tends to zero. Above the critical values of the grating geometrical parameters, the absorbance maximum ceases to exist. The critical behavior manifests as a large-amplitude resonance in ‘dirty’ two-dimensional system with purely real conductivity, while enhancement of carrier momentum relaxation time lowers the resonant peak. Such resonance mimics the plasmonic one, but does not rely on high electron mobility.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics)
JETP Letters vol. 124 iss. 4 p. 290 (2026)
Emergent magnetic pseudogap from phase fluctuations and hierarchy of scales in two-dimensional superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2026-08-10 20:00 EDT
Preformed pairs and phase fluctuations are believed to play a vital role in predicting the charge pseudogap in the normal state of two-dimensional superconductors. In this work, we extend this idea and further identify the emergent magnetic pseudogap from pure phase fluctuations without invoking any competing order. We examine the NMR relaxation rate $ 1/T_1T$ by evaluating the bubble contribution and leading-order vertex correction within perturbation theory. It is found that the magnetic pseudogap, manifesting as a smooth suppression of $ 1/T_1T$ in the normal state, is characterized by a temperature scale $ T_\text{mPG}$ distinct from the superconducting gap $ \Delta_\text{SC}$ and transition temperature $ T_c$ . The onset scales of both charge and magnetic pseudogap are dominated by the competition of BKT correlation length $ \xi(T)$ and BCS coherence length $ \xi_\text{BCS}$ . Moreover, the vertex correction is shown to be irrelevant for $ d$ -wave pairing, while it becomes prominent in $ s$ -wave systems and drives a coherent enhancement of $ 1/T_1T$ at lower temperatures just above $ T_c$ . We attribute this normal-state enhancement of $ 1/T_1T$ to the diverging coherence peak at the $ s$ -wave superconducting gap edge, which shares the same spirit as the celebrated Hebel-Slichter peak in the BCS theory. Analogous to the coherent Hebel-Slichter peak, regularization by Fermi-liquid-like scatterings is important and is characterized by a scattering length $ \ell$ . The normal-state coherent enhancement of $ 1/T_1T$ is hence described by the competition of $ \xi(T)$ and $ \ell$ , through which the coherence scale $ T_\text{coh}$ is determined. As a result, the complete evolution of $ 1/T_1T$ is understood quantitatively in a unified picture as the interplay among hierarchy of scales $ \xi(T)$ , $ \xi_\text{BCS}$ and $ \ell$ .
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
12 pages and 8 figures
Crossing over universal scaling laws in two-dimensional driven dissipative condensates
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-08-10 20:00 EDT
Q. Fontaine, F. Helluin, M. Escalera, D. Pinto Dias, A. Lemaître, M. Morassi, M. Wouters, A. Minguzzi, L. Canet, S. Ravets, J. Bloch
In low dimensional systems, fluctuations are enhanced and prevent the spontaneous breaking of continuous symmetries. As a result, spatial and temporal correlation functions decay at large distances and long times. A well established example is given by two-dimensional bosonic condensates at equilibrium, which do not display long-range order of the coherence but algebraic decay belonging to the Berezinski-Kosterlitz-Thouless universality class. In contrast, the universal behaviors of non-equilibrium bosonic condensates are more diverse and many open questions remain. Here, we explore the spatio-temporal coherence properties of two-dimensional driven-dissipative polariton condensates in semiconductor optical microcavities. By tuning microscopic parameters, we observe a cross-over between two scaling laws that we attribute to the Edwards-Wilkinson (EW) and the Kardar-Parisi-Zhang (KPZ) universality classes. We demonstrate the collapse of the measured first-order correlations onto the EW and KPZ universal scaling functions and obtain critical exponents, well matching the values predicted theoretically. Our results highlight the intrinsic non-equilibrium nature of polariton condensates and establish them as a platform of choice for controlled exploration of the two-dimensional KPZ universality class.
Quantum Gases (cond-mat.quant-gas), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Statistical Mechanics (cond-mat.stat-mech), Optics (physics.optics)
Homojunction-induced thermopower enhancement in polymer films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-10 20:00 EDT
Zhen Xu, Hui Li, Guangzheng Zuo, Xiaojuan Dai, Jincheng Liao, Guofeng Cheng, Jian Song, Wenqing Zhang, Martijn Kemerink, Lidong Chen
It has been more than twenty years since conductive polymers began to receive attention as an emerging thermoelectric material. However, the trade-off between electrical conductivity ({\sigma}) and thermopower (S) has proven to be a major challenge that has obstructed their use in actual devices. Here we report the discovery that the thermopower of the p- and n-type legs of organic thermogenerators can be substantially enhanced, without significant deterioration of {\sigma}, by constructing an in-plane segmented structure consisting of a homojunction with different doping levels on either side. In such segmented layers, the S is abnormally higher than the average value of the constituent parts when applying a forward temperature gradient (heating the heavily doped counterpart), while it is lower upon a reverse temperature gradient. Typically, for a two-stage segmented film of p-type PDPP-Se, an abnormally large S of 210 uV K-1 and {\sigma} of 2.5\ast10^4 S m-1 are obtained, resulting in a large power factor (PF) of 1100 uW m-1 K-2 and a record ZT of 1.36 at room temperature. The enhanced thermopower is attributed to an additional voltage developed at the homojunction under heating as explained by kinetic Monte Carlo simulations. This finding provides a breakthrough approach to the modulation of thermoelectric transport properties of conductive polymers.
Materials Science (cond-mat.mtrl-sci), Soft Condensed Matter (cond-mat.soft), Chemical Physics (physics.chem-ph)
75 pages, 45 figures
Fractional Spin Ferroelectric and Sliding Spin Current in Magnetic Sliding Ferroelectrics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-10 20:00 EDT
Yilin Han, Lei Li, Chaoxi Cui, Run-Wu Zhang, Zhi-Ming Yu, Yugui Yao
We investigate the fractional spin ferroelectric (FSFE) in magnetic sliding ferroelectrics (SFEs), where ferroelectric switching is characterized not only by the reversal of the out-of-plane electric polarization but also by a variation of fractional in-plane spin electronic polarization. We show that interlayer sliding in FSFEs can naturally lead to a symmetry-protected pure spin current, termed the sliding spin current here. The underlying mechanism is that, during switching, the contributions of valence electrons and ions to the in-plane charge transfer cancel each other, whereas the in-plane spin transfer, which stems solely from valence electrons, persists, leading to a pure spin current. We demonstrate our ideas in various material candidates, including $ H$ -stacked bilayer CrI$ _3$ , whose few-layer form has been experimentally confirmed to be a magnetic SFE, and $ R$ -stacked bilayers $ 2H$ -V$ X_2$ ($ X=$ S, Se, Te), which have been experimentally synthesised. For a typical switching time of about $ 1$ ns, the estimated spin-current densities for bilayer CrI$ _3$ and V$ X_2$ reach $ 10^9 (\hbar/2e)\mathrm{A/m^2}$ and $ 10^8 (\hbar/2e)\mathrm{A/m^2}$ , respectively. This means that by applying a periodic out-of-plane electric field, a significant alternating spin current can be generated in magnetic SFEs. Thus, our findings propose a compelling new mechanism for the all-electrical generation of pure spin current, and predict concrete realistic materials for experimental verification.
Materials Science (cond-mat.mtrl-sci)
Overaging with stress in polymer glasses? Faster segmental dynamics despite larger yield stress!
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-08-10 20:00 EDT
Masoud Razavi, Enran Xing, M.D. Ediger
It is well known that physical aging of polymer glasses increases their yield stress and affects their failure behavior. Studies indicate that application of moderate levels of stress during aging results in higher yield stress compared to aging in the absence of stress (quiescent aging). This has been interpreted to indicate that stress accelerates physical aging, and has been described as overaging. In this study, we age PMMA glasses under stress, and carry out direct measurement of segmental dynamics during and after aging by using a probe reorientation technique. We observe that samples aged under stress, despite having higher yield stress, have faster segmental dynamics after stress release than quiescently aged samples. This contradicts the overaging interpretation, for the range of conditions explored here. Our results indicate that yield stress is not a simple function of structural relaxation time and theoretical models based on this understanding need to be revised.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
23 pages, 5 figures, 1 table, 71 references
Macromolecules 2022, 55, 10043-10051
Surface Equilibration Mechanism Controls the Stability of a Model Co-deposited Glass Mixture of Organic Semiconductors
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-10 20:00 EDT
Shinian Cheng, Yejung Lee, Junguang Yu, Lian Yu, M. D. Ediger
While previous work has identified the conditions for preparing ultrastable single-component organic glasses by physical vapor deposition (PVD), little is known about the stability of co-deposited mixtures. Here, we prepared binary PVD glasses of organic semiconductors, TPD (N,N-Bis(3-methylphenyl)-N,N-diphenylbenzidine) and m-MTDATA (4,4,4-Tris[phenyl(m-tolyl)amino]triphenylamine), with 50:50 mass concentration over a wide range of substrate temperatures (Tsub). The enthalpy and kinetic stability are evaluated with differential scanning calorimetry and spectroscopic ellipsometry. Binary organic semiconductor glasses with exceptional thermodynamic and kinetic stability comparable to the most stable single-component organic glasses are obtained when deposited at Tsub=0.78-0.90Tg (where Tg is the conventional glass transition temperature). When deposited at 0.94Tg, the enthalpy of m-MTDATA/TPD glass equals that expected for the equilibrium liquid at that temperature. Thus, the surface equilibration mechanism previously advanced for single-component PVD glasses is also applicable for these co-deposited glasses. These results provide an avenue for designing high-performance organic electronic devices.
Materials Science (cond-mat.mtrl-sci), Soft Condensed Matter (cond-mat.soft)
23 pages, 5 figures, 47 references, Supporting information including 5 figures
J. Phys. Chem. Lett. 2023, 14, 4297-4303
Entwined lattice of atoms and anionic electrons in layered electride LaCl
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-08-10 20:00 EDT
Songyuan Geng, Xin Wang, Jianqi Zhong, Risi Guo, Fangjie Chen, Qun Wang, Kangjie Li, Keyu An, Teng-Fei Ying, Chen Qiu, Hanpu Liang, Zhengtai Liu, Mao Ye, Sungsoo Hahn, Balasubramanian Thiagarajan, Benjamin T. Zhou, Haoxiang Li
Controlling the lattice geometry that governs electronic structure is a central theme in condensed-matter physics, yet in crystalline solids this geometry is usually fixed by the atomic framework. Electrides offer an alternative route to electronic structure design in which their excess electrons can organize into anionic electron lattice (AEL) and provide a lattice-like degree of freedom. Recent work has highlighted the standalone limit, where the AEL in YCl yields bands well described by the dice-lattice model. Here, using angle-resolved photoemission spectroscopy (ARPES), we show that LaCl, although isostructural to YCl, realizes a qualitatively different regime where the AEL is entwined with the La cation framework, producing a fully reconstructed electronic structure. Combining the ARPES result with tight-binding model analysis, we demonstrate that this radical divergence stems from the activation of direct hopping channels between the AEL and the La atomic lattice. This coupling reshapes the effective lattice geometry, reconstructs the electronic states, and modifies the associated Chern band topology, transforming the bipartite dice-lattice network in YCl into a tripartite structure in LaCl. Our findings demonstrate that the coupling between the AEL and the atomic lattice can actively shape the effective lattice geometry that governs the electronic structure. This coupling can act as a powerful tuning knob for electronic structure design that is inaccessible in conventional materials.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Onset of the transitional flux-avalanche regime in bulk NbTi controlled by the thermal boundary conductance
New Submission | Superconductivity (cond-mat.supr-con) | 2026-08-10 20:00 EDT
Irina Abaloszewa, Victor V. Chabanenko, Aleksander Abaloszew
Thermomagnetic avalanches in type-II superconductors occur in two qualitatively different regimes, electromagnetically controlled in thin films and thermally limited in bulk samples, distinguished by the sign of the temperature derivative of the threshold field $ H_\text{th}(T)$ . The two regimes are separated by a critical thermal boundary conductance $ h_c$ , and a non-monotonic $ H_\text{th}(T)$ has been predicted in the transitional region where the interface conductance $ h$ approaches $ h_c$ . We approach this region in a bulk NbTi disk by raising the interface coupling above the pure-nonadecane baseline with a silver-filled interface layer. Whereas the pure interface gives a monotonically decreasing $ H_\text{th}(T)$ , the silver-filled interface produces a non-monotonic dependence not previously realized in a bulk superconductor: a temperature interval of positive slope, $ dH_\text{th}/dT > 0$ , terminating in a maximum at $ T^\ast \approx 6.1$ –$ 6.4$ ~K. The effect is reproduced for two independent silver-filled compositions; in a third, with the highest loading, the low-temperature decrease is absent altogether and $ H_\text{th}(T)$ is flat up to the same $ T^\ast$ , the evolution expected for stronger coupling. The position of the maximum is set by the intrinsic properties of NbTi, independent of the silver content. The onset of the positive-slope interval coincides in temperature with a change of the avalanche morphology from narrow channeled fingers to broad fronts. The reversal of the sign of $ dH_\text{th}/dT$ is a direct experimental signature of the onset of the transitional regime, in which heat removal during the instability becomes dynamically relevant.
Superconductivity (cond-mat.supr-con)
10 pages, 3 figures
Segmental Dynamics in the Strain-hardening Regime for Poly(methyl methacrylate) Glasses with and without Melt-stretching
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-08-10 20:00 EDT
Enran Xing, Trevor Bennin, Masoud Razavi, M. D. Ediger
Strain-hardening is a feature of polymer glasses during large deformation, which helps to stabilize the glasses against breakage. Experimentally, little is known about the segmental dynamics during strain-hardening, and such data is important for building a molecular-level theory of polymer glasses deformed in this regime. Here, using a photobleaching technique, we measured the segmental dynamics of lightly-crosslinked poly(methyl methacrylate) (PMMA) glasses with and without melt-stretching, which were deformed into the strain-hardening regime with local engineering strain rates from 10^-4.6 s^-1 to 10^-4 s^-1 at Tg-23K and Tg-33K. We find that melt-stretched PMMA glasses show a more prominent strain-hardening feature and faster segmental dynamics by a factor of about 15% compared to PMMA without melt-stretching. At a given true strain rate, the segmental dynamics of PMMA without melt-stretching are accelerated in the deep strain-hardening regime from the value just beyond yield, by up to 40% at 0.8 true strain. Our observations are in agreement with previously published simulation results.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
28 pages, 5 figures, 39 references, Supplemental Information with 5 figures
Macromolecules 2022, 55, 8067-8073
Exciton Alchemy: Chern Excitons from Trivial Bands
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-10 20:00 EDT
Yoonseok Hwang, Henry Davenport, Frank Schindler
Exciton topology is commonly inherited from the topology of the underlying electronic bands. Recent theoretical work, however, has shown that the exciton Chern number can in general receive an additional contribution from the topology of the exciton envelope wave function, allowing, in principle, interaction-induced topological excitons even when the constituent electronic bands are topologically trivial. Here, we provide an explicit realization of this case by constructing a two-dimensional exciton model with topologically trivial conduction and valence bands that nevertheless hosts a Chern exciton diagnosed by inversion symmetry. Starting from a real-space limit of exponentially localized Wannier states for the conduction and valence bands, we identify the essential ingredients responsible for the emergent exciton topology and formulate a simple construction recipe. Our work demonstrates that interactions alone can generate nontrivial exciton topology, independent of the topology of the underlying electronic bands, and establishes a general framework for designing interaction-induced topological excitons.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
6+14 pages, 2+1 figures
Type-II Mirror Chern Insulator in Altermagnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-08-10 20:00 EDT
Amrita Mukherjee, Pritesh Srivastava, Rahul Verma, Bahadur Singh
Altermagnets with momentum-dependent spin splitting despite zero net magnetization can support unique topological states under broken time-reversal symmetry. We predict a mirror-symmetry-protected topological crystalline insulator with momentum-separated edge modes in a two-dimensional altermagnet. Using a square-octagon lattice model, we show that altermagnetic order generates symmetry-related valley-polarized Dirac nodes, which are gapped by spin-orbit coupling to yield a mirror Chern insulator with $ C_{\mathcal{M}}=2$ . In contrast to conventional mirror Chern insulators, where the two mirror-protected edge modes cross at the same momentum to form a Dirac cone, altermagnetic spin splitting and valley-selective band inversion separate these edge modes in momentum. We refer to this phase as a type-II mirror Chern insulator. We further propose a PbSe/$ \mathrm{V_2Se_2O}$ heterobilayer as a candidate material for realizing this phase through the altermagnetic proximity effect. Our results establish altermagnetism as a route to mirror-protected topological phases with momentum-separated edge modes.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
6 pages, 4 figures
DynaCrys: Crystal Generation with Dynamic Space-Group Diffusion
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-10 20:00 EDT
Zhuotao Jin, Xiaoyun Wang, Nicholas Brawand, Roman Zubatyuk, Atul Thakur, Eric Qu, Boris Kozinsky, Justin Smith
The search for new crystalline materials spans an enormous compositional and structural space. Generating candidates in this space requires jointly modeling discrete crystallographic symmetry, elemental composition, and continuous geometry. We introduce DynaCrys, a generative model for crystals in which the space group co-evolves with Wyckoff occupations and elements through a coupled symbolic diffusion process. The structured space-group transitions follow crystallographic group-subgroup relations. As the space group changes, a shared, pretrained symmetry codebook provides both the legality-constrained stochastic decoder and the symmetry-constrained crystal-geometry model with a common representation of the corresponding Wyckoff vocabulary. Across large-scale evaluations using two independent relaxation-and-evaluation engines, DynaCrys achieves best-in-class performance in symmetry-aware discovery of stable, unique, and novel crystals, both overall and under the additional requirement of nontrivial post-relaxation symmetry. It also enables fast sampling while generating structures with consistently low relaxation-induced structural displacements.
Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG)
Phase-Noise-Induced Heating in Optical Lattices
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-08-10 20:00 EDT
Jean Paul Nohra, Cyprien Daix, Joris Verstraten, Maxime Dixmerias, Tim de Jongh, Bruno Peaudecerf, Fabrice Gerbier, Tarik Yefsah
We experimentally and theoretically study the origin of heating in optical lattices by disentangling the respective roles of intensity and phase noise depending on the lattice parameters. While intensity noise is widely identified as a major limiting factor, we show that phase noise can become the dominant heating source, especially for light atoms and deep optical lattices. We provide a simple theoretical framework to predict the phase-noise-induced heating from the power spectral density of the laser phase noise, which can be measured experimentally. We show that such predictions can accurately reproduce the measured heating rates of lithium-6 atoms in a triangular lattice. Our approach is readily generalized to other lattice geometries and atomic species.
Quantum Gases (cond-mat.quant-gas), Atomic Physics (physics.atom-ph), Quantum Physics (quant-ph)
A quantum geometric mechanism for chiral domain wall metastability: Application to twisted transition-metal dichalcogenides
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-08-10 20:00 EDT
Nisarg Chadha, Qiang Gao, Eslam Khalaf, Zhaoyu Han
Band topology can have an imprint on the excitations of a ferromagnet. A known example is quantum Hall ferromagnets and their lattice analogs; when both flavors have the same Chern number $ C$ , a smooth skyrmion texture binds charge $ -eC$ per unit winding. Here, we consider instead the case of conjugate Chern bands related by time-reversal. We show that, despite the vanishing net charge response, a smooth texture can be associated with a dipole response—a domain wall (DW) with an in-plane winding along its length can bind a nonzero dipole density transverse to the wall. The strength of this dipole density is controlled by a dimensionless coefficient $ c_G$ . Although not quantized, the geometric dipole coefficient $ c_G$ is a moment of the second Chern form of the occupied projector in mixed (momentum and order-parameter) space and is generally nonzero. The dipole-decorated DW can thus become metastable at a finite radius due to the competition between dipolar repulsion and the usual surface tension, even at a finite Zeeman field. In a realistic model of twisted MoTe$ _2$ , we find that $ c_G$ drops sharply across a transition within the valley-polarized (VP) phase from a $ C=1$ to a $ C=0$ ferromagnet. This naturally explains recent pump-probe experiments~\cite{exp} at hole filling $ \nu=1$ , in which a long-lived excitation survives reverse fields far exceeding the saturation field but disappears at an intermediate displacement field despite only weak changes in conventional magnetic diagnostics. Metastable spin textures thus serve as a sensitive probe of band quantum geometry, and as an intrinsic bottleneck for fast optical control of moiré ferromagnets in Chern-conjugate bands.
Strongly Correlated Electrons (cond-mat.str-el)
Permutation invariant neural network prediction of vacancy formation under deformation and varying chemical environment in FCC high entropy alloys
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-08-10 20:00 EDT
Vacancy formation energies govern diffusion, irradiation damage, phase stability, and dynamic failure in high-entropy alloys (HEAs), yet their strong dependence on local chemical environments and mechanical deformation makes atomistic calculations prohibitively expensive for large-scale studies. Here, we develop an atomistically informed permutation invariant machine learning framework for predicting strain dependent vacancy formation energies in FCC HEAs from local atomic environments. The model employs a vacancy-centered representation constructed from objective geometric descriptors together with invariants of the local deformation gradient, enabling the coupled effects of chemical disorder and finite deformation to be learned within a unified framework. Atomistic simulations reveal that volumetric deformation is the dominant factor controlling the average variation in vacancy formation energy, whereas shear deformation has a comparatively minor influence. At the same time, substantial site to site variability persists under identical macroscopic loading, demonstrating that local chemical environments govern the statistical distribution of vacancy energetics beyond species-averaged trends. The proposed framework accurately predicts vacancy formation energies across diverse deformation states while providing orders-of-magnitude faster evaluation than direct atomistic simulations. These results establish an efficient route for incorporating stress-dependent defect energetics into multiscale models of diffusion, irradiation damage, and dynamic failure in chemically complex alloys.
Materials Science (cond-mat.mtrl-sci), Disordered Systems and Neural Networks (cond-mat.dis-nn), Computational Physics (physics.comp-ph)
Active movement of foraging sea turtles generates anomalous looping
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-08-10 20:00 EDT
Vijay Kumar, Vladimir V. Palyulin, Perla Roman-Torres, Christophe Eizaguirre, Rainer Klages
Animals inhabiting diverse environments by moving across different spatial scales, from insects to birds, marine predators, mammals and even humans, often display apparently random movement paths. Over the past decade, novel biologging technologies have recorded these patterns in increasing detail, generating a wealth of experimental data. A central challenge is to understand such complex patterns by constructing data-driven mathematical models. Many animal movements depart from Brownian motion, as described by correlated random walks, Lévy walks, or active particle dynamics. Yet, these movement models do not incorporate long-term non-Markovian memory extracted from experimental trajectories. Here, we construct a stochastic generalised Langevin equation from satellite tracking data for loggerhead sea turtles (Caretta caretta) foraging off the coast of West Africa. We find that these turtles exhibit active movement characterised by large-scale loops that are not explained by ocean currents or chirality. These loops maintain movement within a specific foraging region and, over intermediate timescales, generate superdiffusion similar to Lévy walks. We thus identify a loop-based form of active anomalous search related to foraging patterns observed across a wide range of animal species, which may inspire robotic search strategies and AI-based metaheuristic optimisation algorithms.
Statistical Mechanics (cond-mat.stat-mech)
11 pages, 4 figures (accompanied by 38 pages of supplementary information with 40 figures and 1 table)
Entanglement Mpemba Effect
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-08-10 20:00 EDT
Generating entanglement rapidly and reliably is essential for quantum information processing, communication, and metrology. Dissipative preparation is attractive because engineered reservoirs robustly drive a system toward an entangled target, yet relaxation can carry a substantial time cost. Here we formulate the entanglement Mpemba effect, whereby an initially less entangled state overtakes a more entangled state under the same open-system dynamics. This effect turns initial-state engineering into a route for faster preparation without altering the dissipative protocol. We derive a general criterion for the reversal from the relaxation spectrum, applicable even when entanglement evolves nonmonotonically. A reversal of deterministic local operations and classical communication (LOCC)-reachability preorder provides a measure-independent certificate of reversed entanglement order. Exactly solvable models show that initial-state selection can substantially shorten the time required to reach high entanglement. We further propose an experimentally relevant trapped-ion protocol that can realize the entanglement Mpemba effect.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
6 pages, 3 figures