Statistical Mechanics
Critical Dynamics of Non-Reciprocally Coupled Conserved Systems
Emir Sezik and Gunnar Pruessner
Non-reciprocal systems have been shown to sustain time-dependent patterns, most prominently travelling waves. The transition into these time-dependent states generally breaks time-translational invariance, representing a clear deviation from
equilibrium dynamics. Though common implementations of non-reciprocity lead to such phenomenology, these spatio-temporal patterns are absent in other models. In the same vein, the ensuing scaling behaviour also depends on the precise way non-reciprocity is implemented. To better understand the effects of different non-reciprocal interactions, we study the critical conserved dynamics of non-reciprocally coupled
spin systems. Specifically, we consider the dynamics of two $n$-component order parameter fields $\boldsymbol{\phi}_i$ with $i \in\{1,2\}$. Unlike the common implementations of non-reciprocal interactions, we introduce the non-reciprocity solely through the non-linear interaction between the distinct species. Using the field-theoretic renormalisation group (RG) procedure, we perform a one-loop analysis and show that at one-loop level, the critical behaviour depends on the microscopic value of certain quantities. Using the flow functions, we elucidate the behaviour of the fixed points for different bare microscopic values. We also show that for $n \geq 4$, there is a fixed point where the ensuing critical dynamics asymptotically obey detailed-balance, implying the emergent dynamics are agnostic to the microscopic non-reciprocity on large scales. Finally, we show that the conserved dynamics reduces the number of independent scaling exponents, mimicking the effect of a standard fluctuation-dissipation relation.
Read the full abstract ▾
Quantum Gases
Observation of sine-Gordon-like solitons in a spinor Bose-Einstein condensate
Yannick Deller, Alexander Schmutz, Raphael Schäfer et al. (+7 more)
We experimentally generate sine-Gordon-like
solitons in a
spin-1 spinor Bose-Einstein condensate (BEC) utilizing a robust and reproducible local phase-imprinting scheme. We find that the
soliton velocity can be tuned by the effective quadratic Zeeman shift. This enables the investigation of controlled
soliton interactions, in which we observe the characteristic elastic collision behavior of the integrable sine-Gordon model. The spatial displacement – the so-called phase shift – between incoming and outgoing
solitons, the signature of their pairwise interaction, is found to be in quantitative agreement with numerical
spin-1 simulations within the error bars. These results establish spinor BECs as a highly controllable experimental platform for studying aspects of the dynamics of sine-Gordon-like models.
Read the full abstract ▾
All authors Yannick Deller, Alexander Schmutz, Raphael Schäfer, Alexander Flamm, Florian Schmitt, Ido Siovitz, Thomas Gasenzer, Panayotis G. Kevrekidis, Helmut Strobel, Markus K. Oberthaler
Materials Science
Universality of magnetic susceptibility in the conical state of kagome ferromagnet Fe$_3$Sn$_2$
Lilian Prodan, Donald M. Evans, Lukas Puntigam et al. (+2 more)
We report universal behavior of the differential
magnetic susceptibility (DMS) in the conical phase that mediates the
spin-reorientation (SR) transition of the kagome ferromagnet Fe$_3$Sn$_2$. Within the SR temperature range, the DMS isotherms exhibit extremely narrow crossing regions, forming isosbestic points. Using an isosbestic-invariance analysis, we show that the isotherms collapse onto a single temperature-independent curve, revealing quadratic-in-temperature corrections to the susceptibility. Complementary field-dependent
magnetic-force-microscopy measurements uncover
evolution of
spin textures from stripe-like domains at low fields to isolated bubble-like domains near the isosbestic field ($\sim 0.6$~T), a behavior not previously reported in bulk Fe$_3$Sn$_2$ within the conical state. These findings point to a universal mechanism for the emergence of complex
magnetic textures near isosbestic points, driven by the competition between magnetocrystalline anisotropy, dipolar interactions, and external
magnetic field.
Read the full abstract ▾
All authors Lilian Prodan, Donald M. Evans, Lukas Puntigam, 1 István Kézsmárki, Vladimir Tsurkan
Strongly Correlated Electrons
Relationship between doping-induced in-gap states and spin excitations in Kitaev-Hubbard models
Si-Qi Hou, Shun-Li Yu, Zhao-Yang Dong et al. (+1 more)
We investigate the connection between doping-induced in-gap states and underlying
spin excitations in Mott
insulators by employing cluster perturbation theory on one-dimensional (1D) and quasi-1D Kitaev-Hubbard models. By manipulating Kitaev-like hopping terms ($t^{\prime}$) that selectively control
spin anisotropies in the strong-coupling limit, we establish a direct correspondence between the kinetic dispersion of the in-gap states and the
spin excitation spectra. Specifically, in the Z chain, in-gap states evolve from a gapless dispersion to a gapped flat band as the system transitions from the Heisenberg to the Ising model, exhibiting a gap scaling of $2t^{\prime 2}/U$ that matches the Ising
spin gap. In the XY chain, the in-gap states split into a dispersive and a flat branch at the Kitaev limit, perfectly mirroring the Jordan-Wigner fermionic spectrum. For the two-leg ladder, we observe an emergent broad continuum of in-gap states that reflects the fractionalization of
spin excitations, accompanied by a gap manifesting the presence of topological $Z_2$ visons. Our results establish a robust correspondence between charge and
spin dynamics in doped Mott
insulators and demonstrate that in-gap states can serve as a probe of exotic
quantum spin phenomena, including fractionalization and topological excitations, offering a new pathway to investigate
spin liquids via spectroscopic probes of charge excitations.
Read the full abstract ▾
All authors Si-Qi Hou, Shun-Li Yu, Zhao-Yang Dong, Jian-Xin Li
Strongly Correlated Electrons
Exciton-roton mode in moiré fractional Chern insulators
Xiaoyang Shen, Zijian Zhou, Ruiping Guo et al. (+4 more)
Moiré fractional Chern
insulators (FCIs) are a novel class of
quantum matter that realizes fractional
quantum Hall (FQH) physics in zero
magnetic field and provides a platform for exploring unconventional collective excitations. Here we show that hybridization between the magneto-roton and moiré interband excitations gives rise to an
exciton-roton mode absent in continuum FQH systems in the long-wavelength limit. Using exact diagonalization and a variational Bethe-Salpeter equation for twisted MoTe$_2$, we demonstrate that this hybridization is controlled by the
quantum geometry and yields a mode that combines excitonic optical response with the characteristic FCI roton minimum. The resulting
exciton-roton remains low-lying, with excitation energy below the interband transition, and acquires optical activity, leading to a double-peak spectroscopic signature. These results identify optical spectroscopy as a direct probe of collective excitations in moiré FCIs.
Read the full abstract ▾
All authors Xiaoyang Shen, Zijian Zhou, Ruiping Guo, Renqi Wang, Wenhui Duan, Chong Wang, Yong Xu
Strongly Correlated Electrons
CERTIFY-ED: A Multi-Layer Verification Framework for Exact Diagonalization of Quantum Many-Body Systems
Sarang Vehale and Ritu Goel
Exact diagonalization (ED) is a workhorse technique in computational
quantum many-body physics, but published ED results are rarely accompanied by machine-checkable evidence of their numerical correctness. The community typically relies on the implicit trust chain LAPACK $\to$ user code $\to$ result, with at most informal agreement against another package treated as confirmation. We argue that this practice is inadequate for a method whose output frequently underpins theoretical claims, and we present certify-ed, a verification framework designed to be used alongside existing ED packages (QuSpin, XDiag, ALPS) rather than as a replacement for them. The framework consists of (i) a multi-oracle eigensolver that runs three independent LAPACK paths and reports their pairwise disagreement, (ii) thirteen logically independent validation layers covering algebraic invariants, analytic limits, alternative
algorithms, arbitrary-precision reference computation, conservation laws, dynamical consistency, and finite-size scaling, and (iii) tamper-evident SHA-256 hashed certificates that downstream consumers can verify. The framework also ships an error-injection layer that confirms the entire pipeline detects six injected error classes. Running on sixteen physics models from one-dimensional
spin chains to two-dimensional Kitaev honeycomb clusters, our reference implementation passes 53 of 53 unit tests and 81 of 81 individual validation tests in under thirty seconds, with maximum disagreement against QuSpin of $1.6\times 10^{-14}$ across 320
eigenvalue comparisons, and agreement with 50-digit mpmath reference values to $1.6\times 10^{-15}$. The package is released under the MIT license on Zenodo and Github
Read the full abstract ▾
Materials Science · Cross-listed from physics.optics
Theory of Supercritical Coupling And Generalized Bound States in the Continuum
Sergio Balestrieri, Bruno Miranda, Silvia Romano et al. (+1 more)
Bound states in the continuum (BICs) arise from destructive interference suppressing radiation despite spectral overlap with the continuum. Here we show that Friedrich–Wintgen interference naturally emerges from a bright–dark supermode decomposition of resonances coupled through a shared radiation channel. In this basis, any finite leakage of a quasi-BIC induces a causality-driven reactive coupling enabling non-Hermitian pumping of the dark sector. We derive the optimal condition for this process and show that it corresponds to the supercritical coupling regime previously identified in [Nature 626, 765 (2024)], while naturally recovering universal quasi-BIC asymmetry scaling. Extending the theory to Dirac-like dispersions in photonic
crystal slabs, we identify an open-Dirac singularity where the Dirac gap matches the supercritical regime. A four-wave
Hamiltonian quantitatively reproduces rigorous coupled-wave analysis, revealing the breakdown of conventional critical coupling. Near this regime, absorptive cross-coupling induces coherent absorption interference and enables suppression of effective dissipative losses beyond conventional material limits. These results motivate the concept of a generalized bound state in the continuum (gBIC) as a limiting non-Hermitian state where radiative and effective gain compensate, producing a true divergence of the total quality factor. Overall, this work establishes a unified framework connecting BIC interference, Dirac
topology, and non-Hermitian physics for ultra-high-Q enhancement and loss engineering in open photonic systems.
Read the full abstract ▾
All authors Sergio Balestrieri, Bruno Miranda, Silvia Romano, Gianluigi Zito
Mesoscale and Nanoscale Physics
Laser-assisted tunneling in a static tungsten diselenide WSe$_2$ barrier
Rachid El Aitouni, Mohammed El Azar, Clarence Cortes et al. (+3 more)
We study the tunneling effect of Dirac
fermions in a monolayer WSe$_2$ subjected to a static electrostatic barrier and irradiated by a linearly polarized
laser field. Within the Floquet formalism, the time-periodic driving is incorporated to derive analytical wave functions across the three regions of the system. By enforcing continuity conditions at the interfaces, we obtain the transmission and reflection coefficients, which are then used to evaluate the conductance via the Büttiker approach. Our results reveal that the
laser field induces a rich Floquet sideband structure, whose number and strength increase with the driving parameter $\alpha$. This leads to a significant suppression of transmission and provides an efficient mechanism to overcome Klein tunneling. Moreover, increasing the width of the irradiated region enhances the interaction between
fermions and the external field, resulting in energy renormalization and the formation of Stark-like confined states. The interaction between several Floquet channels creates strong interference effects, which reduce the transmitted current even further. The results demonstrate that light-matter interaction allows for the dynamic control of
quantum transport in WSe$_2$ materials. This technology allows for the development of new optoelectronic devices, including tunable
quantum filters and light-controlled nanoscale transistors.
Read the full abstract ▾
All authors Rachid El Aitouni, Mohammed El Azar, Clarence Cortes, Pablo Díaz, David Laroze, Ahmed Jellal
Materials Science
Synergistic improvement of specific strength and plasticity achieved in Ti-based metallic glass designed based on quasicrystal structure
Zhengqing Cai, Zijing Li, Shidong Feng et al. (+2 more)
Achieving a balance between low density, high strength, and good ductility remains a major challenge in the development of structural materials. Ti-based bulk metallic glasses (BMGs) have attracted considerable
attention due to their exceptionally high specific strength. However, the intrinsic strength-plasticity trade-off has hindered their practical applications. Based on a quasicrystal-derived structural heredity and minor-element microalloying, this work realizes a synergistic enhancement of specific strength and plasticity in Ti-based BMGs. The resulting ((Ti_{40}Zr_{40}Ni_{20})_{72}Be_{28})_{97}Al_{3} BMGs demonstrate an ultrahigh specific strength of 5.34 \times 10^5 \text{ N}\cdot\text{m}\cdot\text{kg}^{-1}, establishing a new record for Ti-based BMGs, along with a plastic strain of 13%, breaking through the traditional strength-plasticity limitation of BMGs. Structural analyses show that Al microalloying effectively inherits and modulates the short-range order derived from quasicrystalline structures, thereby achieving an observed synergistic enhancement in both strength and plasticity. This work provides new insights into composition design and lightweight structural applications of Ti-based BMGs.
Read the full abstract ▾
All authors Zhengqing Cai, Zijing Li, Shidong Feng, Limin Wang, Riping Liu
Materials Science
Theory and Discovery of Electrides
Chengcheng Xiao, Nicholas Bristowe and Arash A. Mostofi
Electrides are materials with electrons localized at interstitial regions of the
crystal lattice and have been identified as promising candidates for a variety of applications, including catalysis, electron emission, and superconductivity. We present a theoretical framework for the origin of interstitial electrons in electrides. We demonstrate that this theory can explain electride-like behavior in prototypical electrides, and we use it to develop descriptors for the high-throughput discovery of new inorganic electride candidates from first principles. We also show that the same concepts can explain electride-like behavior in other classes of material, including high-pressure electrides and organic electrides and, more broadly, provide an alternative understanding of F-center defects and solvated electrons.
Read the full abstract ▾
Soft Condensed Matter
Nanostructure of PEGDA-PEG hydrogel membranes and how it controls their permeability
Sixtine de Chateauneuf-Randon, Malak Alaa Eddine, Bruno Bresson et al. (+7 more)
The spacial heterogeneity of hydrogels composed of PEGDA and added
polymer chains is expected to play a crucial role on their transport properties which can be exploited in filtration or tissue engineering. However little is known about the arrangement of the
polymer chains in the
matrix and the length scales of these heterogeneities. Here we combine solid-state NMR and Small Angle
Neutron Scattering to unravel the structure and dynamics of PEGDA hydrogels containing added PEG chains of various concentrations. Our results show that the samples present heterogeneities in both the PEGDA and PEG concentrations and suggest that the PEG chains entangle with the PEGDA network. When plotting the sample permeability, K, as a function the specific surface of the PEGDA heterogeneities we obtain a master curve, showing that the heterogeneity of the PEGDA
matrix controls the permeability of the sample. Moreover the scaling K ___ V/S suggests a structure composed of facetted PEGDA/PEG heterogeneities separated by a network of aqueous thin and flattened films in which the water can permeate.
Read the full abstract ▾
All authors Sixtine de Chateauneuf-Randon, Malak Alaa Eddine, Bruno Bresson, Thomas Salez, Sylvain Prévost, S. Belbekhouche, Théo Merland, Cédric Lorthioir, Clémence Le Coeur, C. Monteux
Statistical Mechanics · Cross-listed from nlin.AO
The role of asymmetric time delay and its structure in 1D swarmalators
Rommel Tchinda Djeudjo, Gourab Kumar Sar and Timoteo Carletti
Swarmalators are a class of coupled oscillators that simultaneously synchronize in both space and phase, providing a minimal model for systems ranging from biological microswimmers to robotic swarms. Time delay is ubiquitous in such systems, arising from finite signal propagation speeds and sensory processing lags, yet its structural form, whether symmetric or asymmetric, has received little
attention. Here, we study a one-dimensional swarmalator model with asymmetric time delay, in which the delay enters only the self-interaction terms of the spatial and phase dynamics, breaking the
symmetry assumed in prior work. We identify various collective states such as async, static phase wave, static {\pi}, and active {\pi}, and derive analytical stability boundaries for each as a function of the coupling parameters and delay. Our analysis reveals that the asymmetric delay structure fundamentally reshapes the collective phase diagram: in particular, for the asymmetric delay models, increasing the delay systematically expands the active {\pi} state at the expense of other ordered states, in contrast to the symmetric delay model, which more strongly promotes the presence of unsteady states that are generally not well ordered. By providing closed-form stability conditions validated against numerical simulations, our work establishes that the internal structure of the delay, not merely its magnitude, is a decisive factor in determining the emergent collective behavior of swarmalator populations.
Read the full abstract ▾
Soft Condensed Matter
Tensional wrinkling of thin elastic sheets with two circular holes
Yang Liu, Sepideh Razavi, Pietro Cicuta et al. (+2 more)
A paradigm for the study of wrinkling in elastic sheet is the Lamé configuration, in which azimuthal wrinkles form in an annular sheet subjected to tensile loads at both edges. Since wrinkles are spatially extended, this instability provides a mechanism for stress transmission over long distances. A natural extension of this problem is wrinkling in sheets with multiple holes or broken
symmetry. Here, we investigate tension-induced wrinkling in thin elastic sheets containing two identical circular holes by combining analytical modeling and experiments. The pre-buckled state is solved analytically using bipolar coordinates within the framework of linear elasticity, enabling the identification of the wrinkling threshold as a function of the distance between the two holes. Near-threshold wrinkling and interactions between wrinkles are analyzed, and we validate our theoretical predictions against experimental observations obtained through
video imaging of
spin-coated polystyrene sheets floating on
liquid surfaces with controlled surface tension. Our results demonstrate that
geometric symmetry breaking, such as the presence of a second hole, strongly influences wrinkle nucleation, orientation, and spatial extent. Beyond mechanics, these findings further support the idea that mechanical cues can be amplified by instabilities, providing a mechanical analogue for long-range cellular mechanosensing.
Read the full abstract ▾
All authors Yang Liu, Sepideh Razavi, Pietro Cicuta, Dominic Vella, Alain Goriely
Quantum Gases
Barnett effect in rotating spinor dipolar quantum droplets
Donghao Yan, Shaoxiong Li and Hiroki Saito
We propose releasing the
spin degree of freedom to stabilize the
vortex state in self-bound droplets of dipolar Bose-Einstein condensates. When a
vortex is embedded into the droplet, spontaneous magnetization arises in the axial direction via a mechanism similar to the Barnett effect; that is, the orbital angular momentum is transferred to the
spin angular momentum. When an external
magnetic field is applied to the spontaneously magnetized droplet, the entire atomic cloud starts to rotate without changing its shape, which can be regarded as mechanical Larmor precession of a macroscopic object. A chirally different pair of droplets can form a stable bound state because of the attractive interaction between the spontaneously magnetized droplets.
Read the full abstract ▾
Strongly Correlated Electrons
Altermagnons at the metal-insulator transition
Jonas Issing, Matteo Dürrnagel, Sarbajit Mazumdar et al. (+7 more)
By means of slave-
boson theory for the Hubbard model on the checkerboard
lattice, we calculate dynamical altermagnetic
spin susceptibilities from the metallic to the Mott-insulating regime. We track
magnon dispersion and lifetime renormalization, allowing us to uncover a crossover from a chirality-selective dissipation of
magnon modes to coherent yet strongly deformed
chiral magnon branches across the metal
insulator transition. Our formalism lends itself to a quantitative description of collective
spin dynamics in correlated altermagnets.
Read the full abstract ▾
All authors Jonas Issing, Matteo Dürrnagel, Sarbajit Mazumdar, Alena Lorenz, Niklas Witt, Giorgio Sangiovanni, Michael Klett, Lennart Klebl, Ronny Thomale, Jannis Seufert
Soft Condensed Matter
Tracer-free Contactless Acoustic Microrheometry Quantifies Viscoelastic Spectrum of Phase-separated Condensates
Kichitaro Nakajima, Taichi Yoshikawa, Yuta Suzuki et al. (+13 more)
The rheology of phase-separated condensates plays a central role in applications spanning advanced materials design and cellular processes, yet quantitative characterization of their viscoelasticity remains challenging due to the limitations of existing microrheological methods that require tracer particles or mechanical contact. Here, we establish tracer-free and contactless acoustic microrheometry as a versatile platform for quantifying the frequency-dependent complex shear modulus of single microscale condensates over 0.01-10 Hz. Using spatiotemporally controlled acoustic radiation force generated within a micro-acoustic resonator, this method deforms condensates for creep-recovery and oscillatory viscoelastic measurements. Quantitative validation using dextran condensates in a polyethylene-glycol continuous phase successfully captures their size- and frequency-dependent mechanical responses, while application to nucleic-acid condensates reveals salt-dependent internal viscoelastic changes at single-condensate resolution. By enabling quantitative dissection of condensate mechanics without invasive probes, acoustic microrheometry provides a broadly applicable framework for investigating phase-separated condensates across materials science, soft matter physics, biology, and beyond.
Read the full abstract ▾
All authors Kichitaro Nakajima, Taichi Yoshikawa, Yuta Suzuki, Shuta Nakatani, Kanta Adachi, Nobutomo Nakamura, Sanae Murayama, Hiroki Sakuta, Naoya Yangisawa, Nadia A. Erkamp, Tomas Sneideris, Mao Fukuyama, Masateru Taniguchi, Miho Yanagisawa, Hirotsugu Ogi, Tuomas P.J. Knowles
Mesoscale and Nanoscale Physics
Tian Yuan and Yang Qi
Research on topological phases of matter is a core field in modern condensed matter physics. Free
fermion systems, such as topological
insulators and
superconductors, have been studied using the "Tenfold Way" and K-theory. Building on Kitaev's idea of $\Omega$-spectrum and classifying space, as well as Freed-Moore's K-theory, this work demonstrates that free fermionic systems form a genuine $G$-$\Omega$-spectrum and clarifies its connection to several distinct classification schemes appearing in the physical literature. By introducing the $\mathbb{Z}_2$-graded
algebra $A_{\mathrm{sym}}^V$, the classification problem for systems with general
symmetries, including antilinear
symmetries, antisymmetries, projective representations, and point group
symmetries, is turned into an extension problem in representation theory. To solve this, a computational method for the $\mathbb{Z}_2$-graded Wedderburn-Artin decomposition of $A_{\mathrm{sym}}^V$ is developed. This decomposition not only yields a classification but also enables the explicit construction of the corresponding Dirac
Hamiltonian. Furthermore, a GAP programming package has been developed to automate these calculations.
Read the full abstract ▾
Disordered Systems and Neural Networks · Cross-listed from physics.med-ph
Computed Tomography Reconstruction Algorithm Using Markov Random Field Model
Taiga Shimomiya, Taichi Kusumi, Masayuki Uesugi et al. (+4 more)
X-ray computed
tomography (CT) reveals the materials' internal structures non-destructively from a tilt series of projected images. Filtered back projection (FBP) is a widely-adopted reconstruction
algorithm in CT owing to its small computational cost. Under low-dose or sparse-view conditions, however, FBP often amplifies noise, severely degrading the reconstructed images. In this study, we evaluated the performance of a
Bayesian CT reconstruction
algorithm based on the Markov random field model under such adverse conditions. Through simulations, we demonstrated that the proposed
algorithm shows higher reconstruction performance than FBP under both low-dose and sparse-view conditions. The hyperparameters are estimated by minimizing the
Bayesian free energy, enabling adaptive reconstruction that reflects the noise characteristics of the observed projection data. These results suggest that the proposed
algorithm can broaden the applicability of CT to dose-sensitive applications and time-constrained measurements, where only limited observed projection data are available.
Read the full abstract ▾
All authors Taiga Shimomiya, Taichi Kusumi, Masayuki Uesugi, Akihisa Takeuchi, Yuki Sada, Hayaru Shouno, Masato Okada
Materials Science
Fast and Accurate Prediction of Lattice Thermal Conductivity via Machine Learning Surrogates
Zeyu Wang, Shuya Yamazaki, Martin Hoffmann Petersen et al. (+11 more)
The appearance of generative models has opened vast chemical spaces in the design of functional materials. Although machine learning interatomic potentials (MLIPs) have substantially accelerated
phonon calculations, high-fidelity prediction of
lattice thermal conductivity ąppa}lat still requires accurate treatment of anharmonic interactions, which remains a key challenge for existing potentials across novel chemical spaces. To address this challenge, we present a comprehensive
benchmark of 15 surrogate models for predicting ąppa}lat using the Phonix database, which contains 6,966 entries with anharmonic
phonon properties derived from first-principles calculations. Firstly, We categorize these surrogate models into three distinct groups: Physical-informed feature descriptors combined with ML models, end-to-end deep neural networks, and pre-trained MLIP-
embeddings combined with ML models. By evaluating model performance across random, space-group disjoint (testing generalization to unseen
crystal symmetries), and Out-Of-Distribution splits (OOD
dataset that testing extrapolation to property regimes beyond the training range) based on ąppa}lat, we probe both interpolation and exploration capabilities. Our results reveal that MLIP-embedded models excel in interpolation within well-sampled regions, deep neural network models especially ALiEGNN demonstrate superior robustness in OOD regimes critical for discovering novel low-ąppa}lat. Additionally, we find a systematic degradation in performance when the structural representation is reduced. Although surrogate models exhibit lower accuracy than direct simulations using first-principles calculation, they reduce computational costs by orders of magnitude, enabling efficient high-throughput screening of thermoelectric materials with minimal loss in generative design workflows.
Read the full abstract ▾
All authors Zeyu Wang, Shuya Yamazaki, Martin Hoffmann Petersen, Masato Ohnishi, Tomiya Yamamoto, Wei Nong, Jianghai Wang, Ruiming Zhu, Masatoshi Hanai, Michimasa Morita, Toyotaro Suzumura, Zekun Ren, Junichiro Shiomi, Kedar Hippalgaonkar
Materials Science · Cross-listed from physics.chem-ph
Gel-Chemistry-Controlled Heavy-Metal Transport and Retention in Cementitious Gel Nanopores: A Molecular Dynamics Study
Weiqiang Chen, Qiyao He and Kai Gong
Cementitious materials are widely used for hazardous-waste encapsulation, yet molecular mechanisms governing heavy-metal ion retention across gel chemistries remain insufficiently resolved. Previous MD studies have focused on individual gel systems and pore-averaged metrics, limiting direct comparison across gel chemistries. Here, classical molecular dynamics simulations were used to investigate adsorption-controlled mobility of Pb2+, Ba2+, and Cs+ in nanopores of C-S-H, C-(N)-A-S-H, and N-A-S-H gels. Combining pore-averaged and spatially resolved diffusivity, residence-time analysis, ion-density profiles, 2D adsorption maps, radial distribution functions, coordination analysis, and interfacial binding-strength descriptors establishes a framework linking gel surface chemistry to mobility suppression while distinguishing local mobility from spatial ion partitioning effects on pore-averaged transport. Ion mobility is reduced in all gel nanopores relative to bulk, but the extent and mechanism vary strongly with gel chemistry. C-(N)-A-S-H with higher interfacial Al/Si substitution exhibits the strongest retention, driven by ion accumulation around Al-linked oxygen species via an ion-exchange-like mechanism with charge-balancing Na+. C-S-H immobilizes ions primarily through surface hydroxyl oxygens and Ca-mediated linkages, whereas N-A-S-H exhibits more distributed binding environments. Pb2+ and Ba2+ show broadly similar immobilization mechanisms, whereas Cs+ exhibits more gel-dependent interactions with silicate and aluminosilicate oxygen sites. A relative total binding strength (rTBS) descriptor shows a strong positive correlation with ion immobilization across gel types, ion species, and pore sizes. These results clarify gel- and ion-specific retention mechanisms and link interfacial binding strength to pore-averaged mobility suppression in idealized cementitious nanopores.
Read the full abstract ▾
Quantum Gases
Interband Berry connection measurement in the optical honeycomb lattice
Shao-Wen Chang, Malte N. Schwarz, Erin G. Moloney et al. (+2 more)
The geometry of Bloch bands affects many physical properties of crystalline solids and other spatially periodic systems. Direct experimental determination of such geometry is an active area of research. In this work, we focus on the fundamental connection between optical excitations and the relative geometry of pairs of Bloch bands, as characterized by the interband Berry connection. We simulate the response of electrons in solids to optical excitation by the response of ultracold fermionic atoms in optical
lattices to periodic modulation of the
lattice position. The strength of resonant excitation between bands, measured at each quasimomentum and for various
lattice-shaking polarizations, directly maps out the interband Berry connection. We apply this method to the optical honeycomb
lattice, driving excitations between the ground $n=1$ band and the excited $n'=\{2,3,4\}$ bands. We observe transparency lines of quasimomenta at which the response to excitation of specific polarization is zero. Further, the interband Berry connection between bands 1 and 3 shows irreducible Dirac strings connecting the $K$ and $K'$ points in the Brillouin zone, lines along which the interband Berry connection abruptly changes orientation. Our work establishes optical response as a powerful tool for characterizing geometrical and topological properties of band structure.
Read the full abstract ▾
All authors Shao-Wen Chang, Malte N. Schwarz, Erin G. Moloney, Ke Lin, Dan M. Stamper-Kurn
Strongly Correlated Electrons
Outstanding TC Enhancement in 5d-3d Y2NiIrO6 by Compression
Zheng Deng, Yao Zhang, Sijia Zhang et al. (+16 more)
Understanding and predicting the properties of 5d compounds critically depend on the identification of the superexchange interactions from which their magnetism emerges. The study of pressure effects on double perovskite Y2NiIrO6 (YNIO) provides deep insight toward this goal. At ambient pressure, YNIO is a ferrimagnetic
insulator with the Ir4+-5d Jeff = 1/2 Mott-insulating state. Under physical pressure up to 17 GPa, the compound exhibits concurrent compression on Ni/Ir-O bond lengths and Ni-O-Ir bond angles, leading to an increase of the Curie temperature from 192 to 243 K. On the contrary, external pressure increases distanced Ir-Ir interaction and in turn induces
magnetic frustration in Sr2IrO4/Sr3Ir2O7 due to the extended 5d orbitals. In YNIO, the rock-salt ordered Ni-Ir naturally blocks extended superexchange beyond the nearest neighbor, and in turn suppresses such
magnetic frustration. Moreover, the orthogonal Ni eg-Ir t2g pathway in YNIO is robust under
lattice distortion, while the superexchange is weakened by bond bending in La2NiMnO6 with a similar half-filed eg-t2g configuration. Our findings establish a framework for elucidating the mechanism of 5d-3d superexchange and guide bond-engineered magnetism in iridate-related systems.
Read the full abstract ▾
All authors Zheng Deng, Yao Zhang, Sijia Zhang, Jing Song, Wanli He, Yuanzhe Li, Meilin Jin, Xiang Li, Guanghua Liu, Zhen Dong, Jinkai Bi, Wenmin Li, Jianfa Zhao, Jun Zhang, Yi Peng, Luchuan Shi, Junling Meng, Xiancheng Wang, Changqing Jin
Superconductivity
Euler Topology in Superconducting Honeycomb Lattices
Rasoul Ghadimi, Chiranjit Mondal and Bohm-Jung Yang
Electronic bands in systems with space-time inversion (IST)
symmetry can host nontrivial Euler
topology. Here, we investigate the band
topology of IST-symmetric superconducting honeycomb
lattices and demonstrate that s-wave
spin-singlet (SWSS) and f-wave
spin-triplet (FWST) superconducting pairings give rise to valley-Euler and Euler
superconductors, respectively. We find that Euler
topology in both pairing states gives rise to mirror-
symmetry-protected helical domain-wall modes. Furthermore, we show that Euler
topology in the FWST state induces non-Abelian braiding of Dirac nodes in momentum space when anisotropic hopping is introduced. Our work establishes superconducting electronic instabilities as a natural route to realizing nontrivial Euler band
topology in Dirac materials.
Read the full abstract ▾
Superconductivity
Experimental Progress in Ambient-Pressure Superconducting Bilayer Nickelate Films
Meng Zhang and Xi Yan
Bilayer Ruddlesden-Popper nickelates display superconductivity near 80 K under high pressure, establishing a new nickelate platform for studying unconventional high-temperature superconductivity. The recent stabilization of superconducting RA3Ni2O7 (RA = rare earth or alkaline earth) films at ambient pressure has changed the experimental landscape: epitaxial strain can reproduce key structural ingredients of the high-pressure phase while making transport, spectroscopy, microscopy, and device-oriented measurements directly accessible. This Review summarizes the experimental progress on ambient-pressure superconducting
bilayer nickelate films, with emphasis on synthesis routes, oxygen stoichiometry, substrate-induced strain, normal-state transport, superconducting properties, doping phase diagrams, and momentum-resolved electronic structure. We highlight several issues that remain unsettled, including the reproducibility of phase-pure ultrathin films, the microscopic origin of the two-step superconducting transition, the role of oxygen defects and substrate-derived doping, the position of the Ni 3dz2-derived {\gamma} band, and the pairing
symmetry. We close by outlining experimental directions that could establish a more quantitative link among
crystal structure, orbital reconstruction, and superconductivity in
bilayer nickelate films.
Read the full abstract ▾
Statistical Mechanics · Cross-listed from hep-th
A Monte Carlo Study of the Dipolar Universality Class in Three Dimensions
Akira Matsumoto, Yu Nakayama, Toshiki Onagi et al. (+1 more)
The dipolar universality class describes the phase transition in 3D ferromagnets with strong dipolar interactions, as first discussed by Aharony and Fisher in the 1970s. While this universality class has been studied theoretically using renormalization group methods, as well as experimentally, little is known about it from Monte Carlo simulations. In this paper, we aim to bridge this gap. We introduce a
lattice model that faithfully implements the transverse constraint on the order parameter. We introduce a Markov Chain Monte Carlo
algorithm which involves a combination of local Metropolis updates preserving the constraint, and a global update of the zero mode. We perform simulations on cubic
lattices up to volume $48\times 48 \times 48$. We observe a continuous phase transition between the disordered and ordered phases. We obtain estimates of the critical exponent $\nu$ and the critical Binder ratio, and compare them with results from other techniques. We also study whether rotational invariance emerges at the critical point, and discuss the influence of the toroidal geometry on this question.
Read the full abstract ▾
All authors Akira Matsumoto, Yu Nakayama, Toshiki Onagi, Slava Rychkov
Materials Science
$G^0W^0$ implementation based on the pseudopotential and numerical-atomic-orbital basis-set framework: Algorithms and benchmarks
Huanjing Gong, Min-Ye Zhang, Peize Lin et al. (+4 more)
The $GW$ method delivers substantially improved accuracy in electronic band structure calculations over conventional Kohn-Sham density functional theory (KS-DFT) by explicitly incorporating the electron self-energy effect beyond mean-field approximations. Despite many existing implementations, a periodic $GW$ implementation within the framework of numerical atomic orbitals (NAO) combined with the pseudopotential (PP) scheme has not been reported. This is urgently needed given the increasing popularity of the NAO-PP framework in KS-DFT calculations and its importance for the development of machine-learning electronic-structure approaches. In this work, we present an efficient NAO-PP-based $G^0W^0$ computational framework by interfacing the first-principles software package ABACUS with LibRPA – a library for performing low-scaling random-phase approximation and $GW$ calculations based on NAOs. Our approach employs the localized resolution of identity (LRI) technique with a novel compression scheme, significantly improving both computational efficiency and numerical stability. In addition, an analytic treatment of the small-q limit of the microscopic dielectric function reduces the need for dense q-point sampling. Furthermore, we propose a practical strategy to select a suitable KS-DFT pseudopotential prior to $G^0W^0$ calculations by examining the frequency-dependent macroscopic dielectric function. Systematic
benchmarks validate the effectiveness of our compression scheme and real-space tensor filtering strategies, demonstrating both high accuracy and significant computational efficiency gains. Comparisons with established $G^0W^0$ implementations show excellent agreement in band structures and band gaps, confirming ABACUS+LibRPA as a reliable and efficient platform for large-scale $G^0W^0$ simulations.
Read the full abstract ▾
All authors Huanjing Gong, Min-Ye Zhang, Peize Lin, Bohan Jia, Ziqing Guan, Lixin He, Xinguo Ren
Soft Condensed Matter
Defect screening and load transfer in minimal hard-soft double networks
Fucheng Tian, Feixue Lu, Katsuhiko Sato et al. (+3 more)
Double network (DN) materials exhibit anomalous strength and toughness that far exceed the sum of their constituents. While widely exploited, the fundamental physical mechanisms underlying this synergy remain elusive. Here, we show that a minimal three-dimensional model of two coupled, disordered linear-elastic networks is sufficient to capture the essential physics of DN nonlinear mechanics. The model reproduces the full suite of unique mechanical behaviors, including yielding, necking, strain hardening, and the brittle-to-ductile transition. Mechanical contrast between the hard and soft networks drives inter-network load transfer, which screens defects and suppresses stress concentrations in the hard network. By defining a stress-concentration factor, K_sc, we find that the hard-network failure strain scales universally as 1/K_sc, directly bridging microscopic defect screening to macroscopic yielding. We further show that complete defect screening triggers the shift from localized necking to delocalized damage. Furthermore, the stable necking plateau is identified as an energetic selection governed by the balance between potential energy release and irreversible dissipation. These findings reveal that a simple linear-elastic framework can account for the rich nonlinear landscape of DN materials, providing a general principle for designing next-generation tough solids.
Read the full abstract ▾
All authors Fucheng Tian, Feixue Lu, Katsuhiko Sato, Liangbin Li, Bin Li, Jian Ping Gong
Soft Condensed Matter
Thermoviscoelasticity of polydomain liquid crystal elastomers regulated by soft elasticity
Zhengxuan Wei, Beijun Shen, Zumrat Usmanova et al. (+2 more)
Liquid crystal elastomers (LCEs) are elastomeric networks with rod-like mesogens that reorient under load. In polydomain LCEs, this reorientation drives a polydomain-to-monodomain transition that produces a soft-elastic plateau. Coupling between this soft elasticity and
polymer-network viscoelasticity yields a path-dependent thermoviscoelastic response, central to applications in damping, impact protection, and tough adhesives. However, the physics governing this response under complex thermomechanical histories remains insufficiently studied. We present a combined experimental and theoretical study of polydomain LCEs under three uniaxial protocols: single-cycle loading-unloading, stress-free recovery from various pre-stretches, and multi-cycle loading with progressively increasing amplitude. We develop a finite-deformation constitutive model combining two parallel mechanisms: rate-independent, temperature-dependent soft elasticity from mesogen reorientation, and time- and temperature-dependent viscoelasticity. With a single parameter set, the model quantitatively reproduces all three protocols and resolves each mechanism's contribution. A temperature-dependent soft-elastic limit governs the low-rate response and the long-time recovered stretch, while viscoelasticity controls the rate-dependent deviation and the cycle-wise accumulation of residual stretch away from this limit. A thermal recovery test above the nematic-isotropic transition confirms that all hysteresis and residual deformation are reversible, ruling out irreversible damage. The framework provides mechanistic understanding and a predictive basis for designing polydomain LCE components under complex thermomechanical histories.
Read the full abstract ▾
All authors Zhengxuan Wei, Beijun Shen, Zumrat Usmanova, Umme Hani Bootwala, Ruobing Bai
Soft Condensed Matter
Landau theory applied to antiferroelectric ordering in ferroelectric nematic liquid crystals
Manisha Badu, Arjun Ghimire, Milon et al. (+6 more)
The polarization and mass density modulation associated with antiferroelectric ordering in two ferroelectric nematic
liquid crystals, a prototypical single compound (referred to as DIO) and a commercial mixture (FNLC919), are studied experimentally as a function of temperature. The wavenumber of the polarization modulation, qA, is determined by small angle X-ray diffraction from the weak, accompanying density wave (wavenumber qS = 2qA) using a conventional laboratory source. Combined results for qS and the saturated value of the polarization are analyzed in terms of Landau theory previously developed to describe the para-/antiferro-/ferroelectric sequence of phase transitions in solid ferroelectrics. The analysis of qS indicates that the polarization modulation can be reasonably well approximated by a simple sinusoid in DIO, whereas in FNLC919 a sharp decrease in qS close to the antiferro- to ferroelectric transition indicates development of a
soliton-like profile.
Read the full abstract ▾
All authors Manisha Badu, Arjun Ghimire, Milon, Priyanka Kumari, Hari Krishna Bisoyi, Oleg D. Lavrentovich, James Gleeson, Antal Jakli, Samuel Sprunt
Superconductivity
Superconductivity Reinforces Charge-Density-Wave Phase Coherence across Cuprates
H. Lee, C.-T. Kuo, M. Fujita et al. (+2 more)
For decades, superconductivity in high-Tc cuprates has been viewed as a competitor that suppresses charge-density-wave (CDW) order by reducing its amplitude and spatial extent. Here, we show that this picture is incomplete, as superconductivity is accompanied by a systematic enhancement of CDW phase coherence across multiple cuprate families. Using resonant soft x-ray scattering combined with a coherence-sensitive momentum-profile analysis, we uncover a BCS-like growth of phase coherence below Tc, which phenomenologically manifests as the absence of CDW peak broadening and near-perfect wave-vector locking. This enhancement remains visible even in a disorder-dominated regime created by long-term
crystal aging and follows a common trend when compared with published data on Bi-, Hg-, Y-, and Nd-based cuprates. These results indicate that superconductivity reshapes CDW order in two distinct ways, suppressing its amplitude while strengthening its phase coherence, and reveal an additional phase-level interplay with
lattice coupling in high-Tc cuprates.
Read the full abstract ▾
All authors H. Lee, C.-T. Kuo, M. Fujita, C.-C. Kao, J.-S. Lee