Strongly Correlated Electrons
Uniform-Charge-Density $d$-Wave Superconductivity in the Pure $t$-$J$ Model at $1/8$ Doping on an Infinite Cylinder
Guangyu Yu and Zheng Zhu
The ground state of the square-
lattice $t$-$J$ model at $1/8$ hole doping has been the subject of a long-standing controversy, with conflicting numerical reports of stripe order versus superconductivity. Here, we address this debate using the variational uniform
matrix product state (VUMPS) method, which optimizes the wave function directly in the thermodynamic limit along the cylinder axis and eliminates the boundary pinning effects that can arise in finite-cylinder calculations. On an infinite cylinder of circumference $L_y = 8$, we find a uniform-charge-density $d$-wave superconducting ground state with quasi-long-range pairing correlations. The dominant pairing occurs at zero center-of-mass momentum, while no sizable finite-momentum pairing component is detected. Twisted-boundary-condition calculations reveal a finite superconducting phase stiffness, with the order-parameter phase winding smoothly to follow the applied flux, providing an independent probe of the robustness of the superconductivity. Moreover, both charge and
spin correlations decay rapidly, with no signatures of long-range stripe or
magnetic order, in contrast to an $L_y=6$ cylinder at $1/6$ doping where the same method readily identifies stripe order. Our results provide methodologically distinct evidence in the long-standing stripe–superconductivity debate in the pure $t$-$J$ model and reveal uniform $d$-wave superconductivity in a minimal model of doped Mott
insulators.
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Mesoscale and Nanoscale Physics
Jie-Cheng Feng, Xinle Cheng, Itai Keren et al. (+5 more)
Vacuum fluctuations can be engineered using optical cavities, resonators, and surface-polaritonic modes, but extending such control deep inside a material remains challenging. Here we show that the
vacuum field inside a
hyperbolic material can be reshaped by a much thinner overlayer with opposite hyperbolicity. This effect requires overlap between the
hyperbolic bands of the two materials and modifies the coupling between the
vacuum field and matter excitations within the bottom material, without changing its intrinsic dielectric properties. As an application, we use Eliashberg theory to study a two-dimensional superconducting layer inside the bottom material, showing that the overlayer can remotely change its critical temperature. Our results may shed light on recent experiments reporting changes in superconductivity arising from a frequency-matched
hyperbolic overlayer, and suggest an on-chip route to long-range control of matter excitations and collective material properties.
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All authors Jie-Cheng Feng, Xinle Cheng, Itai Keren, Dante M. Kennes, Abhay N. Pasupathy, Dmitri N. Basov, Emil Vinas Bostrom, Angel Rubio
Statistical Mechanics
Accurate ground-state entropies from population Monte Carlo: The antiferromagnetic Ising model on the Shastry-Sutherland lattice
Denis Gessert, Wolfhard Janke and Martin Weigel
We demonstrate how the population annealing Monte Carlo simulation method can be used to compute the ground-state
entropy to high precision. This approach is tested for the classical antiferromagnetic Ising model on the Shastry-Sutherland
lattice with diagonal couplings chosen twice as strong as the nearest-neighbor interactions. In the absence of an external
magnetic field, the model is known to be disordered at all temperatures, with a macroscopically degenerate ground state. We find the ground-state
entropy to be $0.458\,777\,78(10)$ per site, which is in good agreement with the estimate of a recent study using the corner transfer
matrix renormalization group method. The sampled ground-state configurations are analyzed by considering the bond configurations, the local-energy configurations, and the
spin-
spin correlations. While all observations are consistent with the disordered nature of the ground state, the numerical data suggest a power-law decay of the size distribution of clusters of sites with local energies different from the ground-state level.
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Mesoscale and Nanoscale Physics · Cross-listed from physics.optics
Optically-Induced Modulation and Programming of Diamond Photonic Cavities
Yuchun Zhu, Amirali Arabmoheghi, Nicolas Le Thomas et al. (+3 more)
Single-
crystal diamond combines exceptional optical, thermal, and mechanical properties while hosting optically addressable and
spin-coherent colour centres, making it a promising platform for integrated
quantum and nonlinear photonics. However, practical post-fabrication mechanisms for dynamically controlling and tuning monolithic diamond photonic
circuits remain limited. Here, we demonstrate all-optical modulation and long-lived tuning of suspended diamond Fabry–Perot nanobeam cavities containing nitrogen-vacancy centres. Under 532~nm illumination, the infrared (1000 to 1100~nm) cavity response is governed by two competing contributions: a well-understood thermo-optic red-shift, and a novel charge-mediated blue-shift that we attribute to the free-carrier
plasma dispersion effect. With 10~mW of 20~kHz-modulated green light, we achieve an infrared modulation depth of approximately 45% of the available reflection contrast. Green illumination also produces quasi-permanent photo-refractive resonance blue-shifts, with a maximum observed tuning of 3.15~nm (0.87~THz), without measurable degradation of the cavity linewidth or contrast. Achieving the same cavity shift in a lithium-niobate Pockels modulator would require 200 to 500~V across a \(5~\mu\mathrm{m}\) electrode gap. These results establish a monolithic diamond nanophotonic platform combining agile and reversible modulation with long-lived optical reconfiguration, two key ingredients in photonic technologies.
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All authors Yuchun Zhu, Amirali Arabmoheghi, Nicolas Le Thomas, Niels Quack, Valentin Goblot, Christophe Galland
Materials Science · Cross-listed from cs.LG
GLASS: Global Latent Aggregation with Slot-based Set Decoding for Scalable All-Atom Crystal Generation
Hendrik Kraß, Seyed Mohamad Moosavi and Mathias Niepert
Generative models for
crystals enable the discovery of novel structures, but scaling all-atom generation to larger systems such as metal–organic frameworks remains challenging. We connect this difficulty to the correspondence problem of particle-space generation. Even on a single fixed target set, index-free permutation-equivariant particle flows require substantially more training for reliable generation as set size and density increase, under both independent and optimal-transport couplings. To resolve this challenge, we introduce GLASS—Global Latent Aggregation with Slot-based Set Decoding, which encodes structures in a permutation-invariant global latent space and learns their distribution via flow matching. A learned-slot decoder constructs all atoms in parallel, removing atom-wise correspondence from generative transport. On MP20, GLASS is competitive with particle-space models, and flow training can reach the validity of the training data at every structure size. On a QMOF subset, GLASS generates MOFs with up to 150 atoms per unit
cell without conditioning on building blocks,
topology, or composition, and approaches the structural validity of the training data. On both
datasets, flow training exposes a validity–novelty tradeoff, and MOF novelty remains limited by autoencoder generalization on the available data. These results show that separating correspondence assignment from generative transport provides a simple route toward high-validity generation of larger atomistic systems.
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Quantum Gases
Second-order coherence properties of ultrafast polariton dynamics in plasmonic lattices
Evgeny A. Mamonov, Lukas Freter, Sioneh Eyvazi et al. (+2 more)
The first-order coherence properties of strongly coupled systems supporting polariton lasing and Bose-Einstein condensation (BEC) have been thoroughly studied and show consistent results. In contrast, second-order coherence properties have been found to vary for different systems, and the second-order coherence function can deviate from the value of one, typical for atomic BEC, revealing super-Poissonian fluctuations even above the BEC/polariton lasing threshold. This calls for a deeper understanding of the emission statistics and dynamics in light-based condensates, especially in the non-
equilibrium regime. Here we demonstrate a coherent state of polariton emission from a plasmonic
lattice measured as the second-order coherence function value separately for $\mathrm{\Gamma}$- and non-$\mathrm{\Gamma}$-point radiation (ground state and high-energy tail). We observe a high degree of coherence with the value $g^{(2)}(\tau=0)-1<10^{-4}$. We also demonstrate the ultrafast ($>$1 THz) nature of the dynamics. The process can be interpreted as a BEC with ultrafast, sub-50-fs thermalization, but we also suggest an alternative explanation as superradiance in a system where the emitters have vibrational degrees of freedom.
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All authors Evgeny A. Mamonov, Lukas Freter, Sioneh Eyvazi, Elliot W. Lloyd, Päivi Törmä
Strongly Correlated Electrons
Evolution of Magnetism in Ce$_4$Ge$_7$ under Magnetic Field and Pressure
Kaixin Ye, Qihe Yu, Yongjian Li et al. (+8 more)
We report the
magnetic and transport properties of single-crystalline Ce$_4$Ge$_7$, which crystallizes in a non-centrosymmetric orthorhombic structure (space group C222$_1$). It undergoes an antiferromagnetic transition at $T_N$ = 7.3 K. When a
magnetic field is applied along the $b$-axis, a metamagnetic transition occurs at 1.3 T (at 2 K). Correspondingly, this transition gives rise to an anomalous Hall effect, which is dominated by the intrinsic Karplus-Luttinger mechanism. Under hydrostatic pressure, $T_N$ of Ce$_4$Ge$_7$ initially increases slightly and is then gradually suppressed. For pressures above $P_c$ = 10.2 GPa, no
magnetic order is observed. The divergence of the $A$ coefficient, the maximum of the residual resistivity, and the non-Fermi
liquid behavior around $P_c$ indicate the possible existence of an antiferromagnetic
quantum critical point in Ce$_4$Ge$_7$.
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All authors Kaixin Ye, Qihe Yu, Yongjian Li, Yanan Zhang, Ye Chen, Rui Li, Lin Jiao, M. Smidman, Yongjun Zhang, Yu Liu, Huiqiu Yuan
Statistical Mechanics
Weakly interacting Bose-Einstein condensate with stochastic resetting
Nikhil Mesquita, Manas Kulkarni, Satya N. Majumdar et al. (+1 more)
Stochastic resetting can generate strong correlations in many-body systems through a shared fluctuating environment. Here, we investigate how such dynamically emergent correlations (DEC) coexist with intrinsic (direct) interactions in a weakly repulsive Bose-Einstein condensate described within the Gross-Pitaevskii framework. The condensate undergoes free expansion from an initial Thomas-Fermi state and is stochastically reset to this initial state at a constant rate. We show that the resetting protocol drives the system into a unique nonequilibrium steady state and obtain its density profile, edge statistics, and full counting statistics analytically. The steady-state density retains an inverted-parabolic form within the core, while developing exponentially decaying tails outside it. We further show that resetting induces nontrivial fluctuations of the condensate edge and particle number, yielding exact scaling forms for the edge distribution and the full counting statistics. Our results provide a tractable setting for exploring the interplay between intrinsic repulsive interactions and attractive DEC generated by a common
stochastic environment in
quantum many-body systems.
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All authors Nikhil Mesquita, Manas Kulkarni, Satya N. Majumdar, Sanjib Sabhapandit
Mesoscale and Nanoscale Physics
Symmetry-enforced topological parity: revisiting $2\mathbb{Z}$ classifications beyond cellwise symmetry actions
Ken Shiozaki
Momentum-dependent
symmetry actions can turn the even-integer constraint of a $2\mathbb{Z}$ classification of topological
insulators and
superconductors into an odd-integer constraint without changing the
symmetry algebra. For internal and order-two crystalline
symmetries in up to four spatial dimensions, we derive parity relations between the Chern or winding number of a gapped
Hamiltonian and topological invariants of its momentum-dependent antiunitary
symmetry matrices. Whenever the
symmetry action enforces odd parity, any
symmetry-preserving gapped phase must be topologically nontrivial. Using cellwise actions, which are represented by momentum-independent
matrices in a fixed unit-
cell basis, as a reference, we determine how locality constrains the realization of odd topological numbers. Explicit model constructions and no-go
theorems distinguish three cases: odd values can be realized by finite-range
symmetry actions, can be realized by exponentially decaying quasilocal actions but not by finite-range actions, or are impossible in finite-dimensional Bloch systems.
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Statistical Mechanics
Thermodynamics of the space of trajectories governed by a combination of two additive boundary functionals
V. V. Ryazanov
This paper extends the formalism of
stochastic path-space thermodynamics by systematically expanding the space of thermodynamic variables with a spectrum of boundary and relative functionals of random processes. Generalizing the approaches introduced in preprints arXiv:2607.24078 and arXiv:2609.08477, we investigate the fluctuation statistics of a one-dimensional Ornstein-Uhlenbeck process with an asymmetric linear drift and a step penalty potential at the origin, which models the waiting phase of a molecular Brownian motor. Utilizing the Feynman-Kac formalism and the parabolic cylinder theory, a numerical scheme based on matching logarithmic derivatives via the secant method is constructed. A high-precision
eigenvalues of the effective
Hamiltonian is obtained, which define the cumulant generating function. We formulate a modified path-space fluctuation
theorem of the Gallavotti-Cohen type for the conjugate drift current at a fixed integral occupation time of the system in the dissipative half-plane. The physical and thermodynamic significance of the new variables is elucidated. A combination of "residence time" and "integral current" functionals is applied to describe an ion channel sensitive to mechanical or electrical stimuli.
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Materials Science
Defect-controlled electrical and optical properties of CrN thin films: experiment and first-principles study
J. Bulíř, U. D. Wdowik, J. More-Chevalier et al. (+7 more)
Thin chromium nitride (CrN) films were deposited by RF magnetron sputtering in a reactive atmosphere of Ar-N$_2$ on fused silica and MgO (001) substrates at temperatures between 400 $^o$C and 800 $^o$C. The influence of nitrogen content and substrate temperature on structural, electrical, and optical properties was systematically investigated. The overstoichiometric CrN films exhibited a reduced resistivity below 6 m$\Omega \cdot$cm with stable p-type behavior, while increasing the substrate temperature above 600 $^o$C induced a transition to n-type conductivity. Spectroscopic ellipsometry in the UV-Vis-NIR and infrared spectral ranges revealed a strong dependence of the dielectric function and the absorption edge on film stoichiometry and deposition conditions. Structural characterization using X-ray diffraction and atomic force microscopy confirmed substrate-dependent crystallinity and grain growth. Density functional theory calculations showed that cation and anion vacancies strongly modify the electronic structure and optical response, explaining the experimentally observed conductivity transitions. The results demonstrate that the deposition parameters provide an effective means to tailor CrN thin films via defect engineering.
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All authors J. Bulíř, U. D. Wdowik, J. More-Chevalier, P. Hubík, E. de Prado, M. Vondráček, L. Fekete, M. Novotný, J. Lančok, D. Legut
Quantum Gases
Quantum Simulation of Detuning-Controlled Proximity-Induced Localization and Reentrant Delocalization in a Quasiperiodic Ladder
Mrinal Kanti Giri, Shih Tai-Ming, Pinaki Sengupta et al. (+1 more)
We demonstrate proximity-induced localization and re-entrant delocalization in a detuned quasiperiodic ladder. In the weak-quasiperiodic regime, where uncoupled Aubry-André chains are extended, a staggered detuning applied to only one leg induces localization in the neighboring leg through inter-leg hybridization. With further increasing detuning, the pure chain re-enters a delocalized regime, producing a delocalized-localized-delocalized sequence without directly modifying its quasiperiodic potential. We identify these regimes using static localization diagnostics and demonstrate experimentally accessible dynamical signatures on IBM
Quantum hardware: strongly suppressed wavefunction spreading in the proximity-localized regime and its re-entrant recovery at larger detuning. These results establish leg-selective detuning as a programmable control knob for inducing and reversing localization in coupled quasiperiodic systems.
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All authors Mrinal Kanti Giri, Shih Tai-Ming, Pinaki Sengupta, Pochung Chen
Materials Science
Linear-Scaling Quantum Transport from Machine-Learning Density Functional Theory Hamiltonians
Bang Liu, Yang Zhong, Zhi-Xin Guo et al. (+2 more)
Quantum transport simulations that combine density functional theory (DFT) with the nonequilibrium Green's function formalism (DFT-NEGF) are important to modern technology, yet their unfavorable scaling has long confined predictive simulations to small, idealized systems far below the ten-thousand-atom scale of realistic devices. Here, we introduce HamGNN-NEGF, a linear-scaling framework with DFT-level fidelity. An E(3)-equivariant graph neural network trained on conventional DFT
Hamiltonians of small structures predicts
Hamiltonians for large devices, avoiding costly DFT-NEGF training data. The predicted
Hamiltonians are integrated with DFT-derived electrode self-energies, a nonorthogonal kernel
polynomial method for Fermi-level determination, and a recursive Green's function
algorithm, yielding a computational cost that scales linearly with device length at fixed cross section. Even for devices containing fewer than 500 atoms, HamGNN-NEGF achieves speedups exceeding three orders of magnitude over fully self-consistent DFT-NEGF, with the advantage increasing further with system size.
Benchmarks on pristine Pt-Si-Pt, doped Pt-Si:P-Pt, and Pt-molecule-Pt junctions demonstrate meV-level
Hamiltonian accuracy, faithful transmission spectra, and predictive simulations beyond 10,000 atoms. Eliminating transport self-consistency also enables hybrid functionals such as HSE06 without additional NEGF overhead, while a zero-bias
Hamiltonian approximation extends the framework to finite-bias transport in weakly nonlinear regimes. HamGNN-NEGF thus bridges first-principles accuracy and device-scale simulation, providing a practical route toward predictive modeling of realistic nanoelectronic and
quantum devices.
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All authors Bang Liu, Yang Zhong, Zhi-Xin Guo, Xin-Gao Gong, Hongjun Xiang
Materials Science
HyTopo A High-Performance Hierarchical Algorithm for Mapping the Structural Evolution and Transition Networks of Gas Hydrates
Zherui Chen, Shuquan Huang, Ke Xu et al. (+6 more)
Resolving the formation and dissociation mechanisms of hydrate requires identifying not only hydrate-like water, but also the specific cage
topologies by which disordered
liquid water reorganizes into, or escapes from, crystalline hydrate networks. Here we introduce HyTopo, a cage-
topology-centered analysis framework that combines a hydrate order parameter, hierarchical ring and cage recognition, and cage-transition network analysis. Based on local orientational correlations, HyTopo classifies water molecules into
liquid-like, precursor-like, hydrate-like, and ice-like environments, and uses this information to guide efficient topological searches for crystalline hydrate cages and defective intermediates. Applications to methane hydrate growth, homogeneous nucleation, and depressurization-induced dissociation reveal that hydrate
evolution is governed by heterogeneous and pathway-dependent cage dynamics. During hydrate growth, EA-WPU suppresses the overall proliferation of cage-like structures while altering the balance between defective cages and crystalline sI cages. During nucleation, incomplete cage motifs dominate the early pathway and provide a structural reservoir from which a small fraction of stable 512 and 51262 cages. Hydrate dissociation proceeds through interfacial collapse, bulk decomposition, and dissolved-gas exsolution, with cage lifetimes and transition pathways strongly dependent on cage
topology. These results show that HyTopo provides a physically interpretable and
topology-resolved route to connect local water ordering, cage formation, structural defects, and hydrate phase transitions in complex molecular simulations.
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All authors Zherui Chen, Shuquan Huang, Ke Xu, Zhanbo Li, Xinyu Song, Haijun Wang, Dingyuan Tang, Qingxia Liu, Yajun Deng
Mesoscale and Nanoscale Physics
Cavity-QED enhancement of quantum entanglement and battery performance in double quantum dots
Hamid Arian Zad, Usama Shoukat, Michal Jaščur et al. (+2 more)
We theoretically investigate
quantum correlations and energy storage in a single-electron silicon double
quantum dot (eDQD) coupled to a single-mode microwave cavity. The charge and
spin degrees of freedom are hybridized by Rashba
spin-orbit coupling (SOC), while the cavity interacts with the eDQD through
spin-
photon and charge-
photon couplings. Using the reduced thermal density
matrix, we characterize
spin-charge
entanglement by concurrence and
quantum coherence by the $l_1$ norm. At low temperature, the cavity strongly modifies the
spin-charge correlations, producing distinct regimes of enhanced and suppressed
entanglement. We identify a nonlinear crossover between an eDQD-dominated regime and a
photon-dressed regime. This crossover is revealed independently by two signatures: a rapid change in the concurrence and the onset of finite
photon occupation in the cavity. Its boundary exhibits a dominant $G_{\rm c}\propto\sqrt{\Omega}$ dependence and is robust against cavity
Hilbert-space truncation. Beyond the Rashba coupling studied in [Ferreira et al., Phys. Rev. A 107, 052408 (2023)], we show that the cavity provides an additional tunable means of controlling
quantum correlations and energy storage. We further characterize the eDQD as a
quantum battery under coherent charging and evaluate its stored energy and ergotropy. The ergotropy varies markedly across a cavity-dressing crossover resembling that identified from
entanglement, connecting cavity-induced modification of the dressed states to extractable work. Optimization over the charge-
photon coupling reveals parameter-dependent optimal charging regimes and enhanced maximum ergotropy with increasing Rashba coupling. Our results establish cavity coupling and SOC as complementary controls of
quantum correlations and extractable energy in
semiconductor eDQD-cavity systems.
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All authors Hamid Arian Zad, Usama Shoukat, Michal Jaščur, Hazrat Ali, Saeed Haddadi
Quantum Gases
Finite-momentum trimers and Cooper quartets in a one-dimensional Fermi gas with coexistent $s$- and $p$-wave interactions
Yixin Guo
We study finite-momentum trimers and Cooper quartets in a one-dimensional two-component Fermi gas with coexistent $s$- and $p$-wave interactions, regularized in the relative momentum of each pair so that they remain Galilean invariant. Pauli blocking alone then makes the trimer dispersion deviate from free center-of-mass motion, so the trimer energy can be lowest at finite total momentum. Allowing this motion expands the $abb$ region among pairs and trimers and removes the region where an odd-wave pair is lowest. The $aabb$ quartet lies below all these branches at every sampled coupling, and in a strip starting on the crossing of the two dimer-pair channels its lowest breakup channel is a moving $abb$ trimer and an atom. At weak interspecies attraction, a variational bound shows that two odd-wave Cooper pairs bind into a quartet, whose binding exceeds that of the coexisting trimer by orders of magnitude as the attraction weakens. At stronger interspecies attraction, the quartet binding relative to two unlike-species dimers disappears when the odd-wave interaction is switched off, although the even-wave interaction dominates the interaction energy. Relative to the in-
vacuum case, the Fermi sea enhances the weak-coupling quartet binding, and at fixed scattering lengths the quartet binding grows with density while the coexisting trimer becomes much shallower. These results show that neither the most strongly bound pair nor the dominant interaction energy alone determines whether the quartet binds.
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Mesoscale and Nanoscale Physics
Spin separation of Dirac electrons by twisted and vector optical beams
A. A. Gunyaga, M. V. Durnev and S. A. Tarasenko
We demonstrate that twisted and vector optical beams can spatially separate two-dimensional electrons with opposite
spin projections.
Spin accumulation arises from diverging
spin currents induced by structured light together with
spin relaxation and
diffusion. We derive analytical expressions for the resulting
spin density in the quasi-local and
diffusion-controlled regimes and numerically calculate the
spin textures for the parameters relevant to transition metal dichalcogenide monolayers. Our results suggest a mechanism by which the twist and vector pattern of optical beams can be imprinted onto the electron
spin degree of freedom.
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Soft Condensed Matter
Polar Phase of an Egg-Yolk Particle in a Rotating Magnetic Field
Roberts Treize and Janis Cimurs
The orbit selected by a
magnetic particle in a viscous
liquid under a rotating field is commonly described in the instantaneous Stoner–Wohlfarth limit, in which the
magnetic moment always occupies a minimum of the anisotropy energy. In this limit, precession out of the field plane exists only for reduced fields $B_0/B_a<1/\sqrt2$, and stronger fields admit only planar synchronous rotation or libration. We study a macroscopic egg-yolk particle, a printed shell containing two freely rotating permanent magnets in fluid-filled cavities, driven by a compensated rotating field and tracked optically. In addition to synchronous rotation, precession, and libration, the particle exhibits a polar phase: above the instantaneous bound and at high frequency, the shell axis leaves the field plane and locks onto a narrow cone about the rotation axis. We extend the model by a finite viscous friction between the magnets and the shell. The extension introduces a single dimensionless parameter, the ratio $\kappa$ of inner to outer rotational friction, and reduces to the instantaneous theory as $\kappa\to0$. Numerical phase diagrams show that increasing $\kappa$ tilts the bistable band to higher fields at higher frequencies and extends stable precession above $B_0/B_a=1/\sqrt2$, whereas for large $\kappa$ planar libration returns at high frequency. With a calibrated anisotropy field, relaxation rate, and $\kappa$ of order unity, the model reproduces the terminal state of all measured records and their tilt angles, including the polar cone. In the model the polar state is maintained by a steady rotation of the magnets relative to the shell, driven by the field and anisotropy torques and dissipated by the inner friction; it therefore exists only for intermediate $\kappa$.
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Quantum Gases
Topological Pseudo-Goldstone Modes from Weakly Broken Dipole Conservation
Yan-Guang Yue, Jie Lou and Yan Chen
Weakly breaking a continuous
symmetry in an ordered phase can convert its Goldstone modes into topological collective bands. We establish this mechanism in a neutral dipole condensate whose conserving parent supports two independent Goldstone phase modes. Weak real flavor mixing pins the phases and selects a chiral condensate. The resulting gyroscopic coupling acts on their winding polarization texture, producing a pseudo-Goldstone sector containing a topological lowest band. Restoring dipole conservation forces the two modes to meet at zero frequency, where their separate band Chern numbers cease to be defined. The same parent dipole charges define a tensor current whose circular response permits model-assisted reconstruction of low-energy embedded local Berry
curvature in the
benchmark regime. Analytical stability bounds and a large-occupation limit provide a controlled realization of this mechanism.
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Materials Science
24-hr Solid-State Power Generation with Self-Adaptive Tunable Radiative Coatings
Ken Araki and Liping Wang
Day-night solid-state power generation is experimentally demonstrated with thermoelectric generators integrated with a tunable radiative coating, which switches between a selective solar absorber during daytime and a radiative cooler during nighttime by temperature without any external control. The self-adaptive radiative coating is carefully designed with thermochromic VO2 thin film on heavily doped silicon substrate along with a phase-shifting silicon spacer in between, whose physical mechanism is elucidated. The fabricated coating exhibits a high solar absorptivity of 0.90 and a low infrared emissivity of 0.23 during daytime, and a high emissivity of 0.85 at night, resulting in large emissivity change of 0.62 within the atmospheric transparency window upon metal-to-
insulator phase transition. From outdoor tests in a high
vacuum apparatus, the tunable radiative coating in 35-mm squared size achieves 1.64 W/m2 power generation around noon time from a stack of commercial thermoelectric modules of 15 mm squared, which is 32% more from that with a black absorber. At night, it produces 26 mW/m2 power, outperforming the black emitter by 63%. Even exposed the ambient with convective loss, the 2-inch-round tunable coating generates power of 0.48 W/m2 at noon time, 14% more than the black absorber of the same size. The tunable radiative coating covered thermoelectric modules produces open
circuit voltages from 433 mV to -62 mV in
vacuum and from 300 mV to -51 mV in ambient through 24-hr continuous outdoor tests.
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Disordered Systems and Neural Networks · Cross-listed from physics.comp-ph
From Bellissard's gap labeling to atomistic quasiperiodic bilayers
Thomas D. Kühne, Vladislav Efremkin and Emil Prodan
Bellissard's framework uses covariant observables to describe aperiodic solids. We examine how butterfly-like spectra in twisted bilayers can be related to bulk gap labels and topological response. A bulk gap permits a spectral projector and an integrated density of states. A topological response requires an additional pairing of that projector. In an illustrative finite honeycomb bilayer, an exact second-moment identity isolates the interlayer contribution to spectral variance. Angle-resolved spectra, finite state counts, an uncoupled reference, and size and broadening checks show how coupling redistributes spectral weight without assigning a bulk gap label. We then examine the requirements for atomistic electronic-structure calculations, including nonorthogonal orbitals, projected densities of states, and basis functions that move during relative sliding. The resulting framework specifies the steps needed to connect atomistic spectra with bulk state counting and topological response.
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Mesoscale and Nanoscale Physics
Deep Learning GW Quasiparticle Hamiltonians for Many-Body Excited-State Electronic Structure at Scale
Xiaoxun Gong, Zechen Tang, Woochang Kim et al. (+4 more)
Accurate quasiparticle electronic structures are the foundation for understanding excited-state properties of materials and explaining optoelectronic,
quantum, and transport phenomena. First-principles GW calculations nevertheless remain computationally intensive for large or configurationally complex systems. Here we introduce DeepH-GW, a deep-learning framework that predicts an effective GW quasiparticle
Hamiltonian directly from atomic structure. Building on the local, equivariant message-passing architecture of DeepH, DeepH-GW is trained on high-fidelity plane-wave GW calculations through a real-space
Hamiltonian-reconstruction interface. This approach combines the systematic accuracy and broad chemical applicability of plane-wave methods with linear-scaling neural-network inference. Across the systems examined, DeepH-GW reproduces quasiparticle band structures with errors on the order of a few meV. Moreover, we show that, despite the intrinsic nonlocality of many-body interactions, DeepH-GW exhibits strong cross-scale transferability from relatively small training structures to substantially larger supercells. We demonstrate that the framework can accurately capture GW-level electron-
phonon band-gap renormalization through predictions in supercells with thermal displacements, illustrating the power of the approach. DeepH-GW therefore provides a practical route toward large-scale many-body simulations and foundation models for excited-state electronic structure.
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All authors Xiaoxun Gong, Zechen Tang, Woochang Kim, Yang Li, Wenhui Duan, Yong Xu, Steven G. Louie
Mesoscale and Nanoscale Physics
Ohm's law for information revealed by a skyrmion Maxwell's demon
Soma Miki, Yoshishige Suzuki, Ryo Ishikawa et al. (+10 more)
Reducing the energy cost of computation-a pressing issue in the age of AI-requires a framework for
circuit design based on information thermodynamics. By extending non-
equilibrium statistical mechanics to information thermodynamics, it has been shown that a probability flow carrying information-hereinafter referred to as an 'information current'-is driven by its conjugate thermodynamic force, namely 'information affinity'. Since information affinity plays a role analogous to that of voltage in an electrical
circuit, it is suggested that information transport also follows a linear response relationship analogous to Ohm's law. However, despite this theoretical prediction, experimentally establishing an Ohm-like constitutive relation for information transport remains an important unsolved problem. Here, we realise an information engine consisting of two
magnetic skyrmions undergoing Brownian motion at room temperature. We demonstrate that the resulting information current is proportional to the information affinity generated by Maxwell's demon over a relatively wide range, establishing Ohm's law for information. Furthermore, we clarify that, in real information
circuits, both Ohm's law for information and Kirchhoff's voltage law must be slightly modified to account for interactions between information carriers and the scattering of the information current.
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All authors Soma Miki, Yoshishige Suzuki, Ryo Ishikawa, Yuki Hibino, Shunya Morishita, Hiroto Imanishi, Keigo Adachi, Yoichi Shiota, Takayuki Nozaki, Minori Goto, Hikaru Nomura, Shigemi Mizukami, Eiiti Tamura
Strongly Correlated Electrons
Ergodicity in a hole-doped Anderson spin insulator
M. S. Bahovadinov, A. A. Markov and G. V. Shlyapnikov
An interacting many-body system being localized in the presence of disorder can fail to serve as its own bath. In an electronic system, the charge and
spin degrees of freedom can act as thermal baths for each other. In this paper, we study the stability of an Anderson
insulator in the
spin sector with respect to charge doping. We consider one-dimensional two-component
fermions in a
lattice with large onsite repulsion ($t-J_{XX}$ model) and with a single hole in a random
magnetic field. In the absence of the hole the
spin sector is localized in arbitrarily weak random
magnetic fields. We argue that a single hole thermalizes the
spin chain in the weak disorder limit. In this regime our numerical results indicate ergodicity of the system as a whole and delocalization of the hole. At larger
magnetic fields the hole eventually localizes with a finite localization length, and the Anderson
spin insulator is restored.
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Materials Science
Tuning the secondary electron yield and electronic conductivity of MgZnO multilayers synthesized by Atomic layer deposition
Mathieu Lafarie, Sarah Dadouch, Fréderic Miserque et al. (+4 more)
Secondary electron emission (SEE), arising from the interaction of energetic electrons with material surfaces, can induce deleterious effects in
vacuum radio-frequency (RF) systems, notably multipacting, thereby degrading performance and threatening device integrity. Despite extensive efforts, effective and widely adopted mitigation strategies remain limited. Here, we report an approach to simultaneously tailor SEE and electrical conductivity using nanometric multi-element multilayers deposited by atomic layer deposition (ALD). The design and fabrication of these
heterostructures are presented, and a range of films is systematically characterized to establish correlations between emission properties, electrical conductivity, chemical and structural features. We demonstrate that such
heterostructures enable combinations of total electron emission yield (TEEY) and conductivity unattainable in single-phase materials, including regimes combining high TEEY with relatively high conductivity and low TEEY with low conductivities. These results open new avenues for the rational design of functional surfaces for
vacuum electronic applications.
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All authors Mathieu Lafarie, Sarah Dadouch, Fréderic Miserque, Yunlin Zheng, Jocelyne Leroy, Mohamed Belhaj, Thomas Proslier
Statistical Mechanics
Static versus dynamic universality in the site-diluted kagome Ising model
Alexandros Vasilopoulos, Zeynep Demir Vatansever, Erol Vatansever et al. (+2 more)
We study the site-diluted Ising model on the kagome
lattice using the Wolff single-cluster
algorithm, focusing on both
equilibrium and dynamic critical properties. The
equilibrium critical exponents $\nu = 1$ and $\gamma/\nu = 7/4$ retain their exact pure Ising values for all
spin concentrations $p$ considered, consistent with the marginal irrelevance of disorder at $\alpha = 0$, with the specific heat crossing over from logarithmic to double-logarithmic growth upon dilution. These static results are shared between the kagome and square
lattices. On the dynamic side, $z$ decreases upon dilution on both
lattice, opposite to what is observed under local dynamics, with evidence of saturation to a $p$-independent value at strong dilution, suggesting a diluted dynamic fixed point. While $z$ is consistent between the two
lattices in the pure case, it differs in the diluted regime, an effect we attribute to the two
lattices sitting at different positions along the renormalization-group flow between the Ising and percolation fixed points, rather than to a true asymptotic breakdown of dynamic universality.
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All authors Alexandros Vasilopoulos, Zeynep Demir Vatansever, Erol Vatansever, Gerard T. Barkema, Nikolaos G. Fytas
Materials Science
Orientation engineering is a universal strategy for ferroelectric trans-switching
Cameron Scott and Jorge Íñiguez-González
About two decades ago, “strain engineering” emerged as a powerful strategy to tune epitaxial thin films. Here we contend that ”orientation engineering” - that is, controlling the film's growth direction - constitutes a complementary design route that opens unprecedented opportunities and deserves greater
attention. Specifically, we show that orientation engineering can endow standard ferroelectric compounds with exotic and useful behaviors that may be difficult or impossible to obtain otherwise. Critically, we predict it readily enables ”trans-switching,” where polarization components switch perpendicularly to the applied electric field, paving the way for novel 3D device architectures. We also show that, by controlling the electric screening provided by electrodes in contact with the film, ferrielectric behavior can be obtained. Notably, one can even design an operational mode where the switching is, in effect, fully transversal to the applied field. Supported by phenomenological calculations for representative compounds LiNbO$_3$ and BaTiO$_3$, we thus propose orientation engineering as a powerful and general method to unlock unprecedented functionalities in common ferroelectrics.
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Strongly Correlated Electrons
Quantized Hyperfine Field at an Implanted $\mu^+$ Site in PrPb$_3$: Interplay between Localized $f$ Electrons and an Interstitial Charged Particle
T. U. Ito, W. Higemoto, K. Ohishi et al. (+6 more)
The local effect of an interstitial hydrogen-like particle on localized $f$ electrons was studied in PrPb$_3$ by means of $\mu^+$
spin rotation and relaxation. Spontaneous $\mu^+$
spin precession with harmonic frequencies was observed for the first time in $f$ electron compounds. We demonstrate that the signal is derived from a coupling between the $\mu^+$
spin and the hyperfine-enhanced nuclear
spin of nearest neighbor (nn) $^{141}$Pr with Ising-like anisotropy. The signal also suggests a marked suppression of
spin dynamics of the nn $^{141}$Pr in comparison with that of the bulk $^{141}$Pr. These facts strongly indicate modification of the $f$ electronic state due to the interstitial charged particle.
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All authors T. U. Ito, W. Higemoto, K. Ohishi, N. Nishida, R. H. Heffner, Y. Aoki, A. Amato, T. Onimaru, H. S. Suzuki
Disordered Systems and Neural Networks
Locking transition in coupled disordered systems
Guy Bunin
When a system of many interacting constituents is extended across space, every region carries the same disordered landscape, and it is unclear whether distant regions settle into the same state. We study copies of the Random Energy Model (REM), sharing one disorder realization, coupled along a chain. A first-order transition separates a phase with short-range correlations, from a locked phase in which the entire chain occupies the lowest-energy state with probability one, even at positive temperature. No intermediate ordering lengths occur. In the Generalized REM the chain locks either to the lowest-energy state or to the lowest free-energy valley.
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Materials Science
Evidence for Distributed Fault Energetics and Their Impact on Deformation in a Chemically Complex Alloy
Kaijun Yin, Jun-Ping Du, Peijun Yu et al. (+7 more)
Chemically complex
alloys feature intrinsically heterogeneous local chemical environments and, consequently, fluctuations in local fault energetics. However, experimentally quantifying their relationship remains challenging, leaving the role of this distributed energy landscape in deformation mechanisms incompletely resolved. Here, we develop a distribution based framework linking experimentally measured stacking fault widths to deformation relevant apparent fault energy, revealing a distributed local fault-energy landscape in CrCoNi. The framework reveals the stabilizing role of energy fluctuations and captures an upward shift in the apparent fault energetics, from negative values toward zero following heat treatment, which atomistic simulations associate with the emergence of L12 type chemical short-range order. Using one-dimensional kinetic Monte Carlo simulations, supported by electron microscopy observations, we further show that history-dependent changes in the local fault-energy landscape bias the competition among stacking faulting, nano-twinning and HCP transformation in CrCoNi. Our results provide an experimentally anchored, distribution-based framework for understanding deformation in chemically complex
alloys as it evolves within a distributed fault-energy landscape shaped by local chemical order.
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All authors Kaijun Yin, Jun-Ping Du, Peijun Yu, Rui Feng, Hanyu Hou, Haw-Wen Hsiao, Ke An, Peter K. Liaw, Shigenobu Ogata, Jian-Min Zuo