Materials Science
Upcycling solar glass into Ce-doped oxyfluorides: spectroscopic and crystallization properties
Marcos Paulo Belançon, Rafaela Valcarenghi, Marcelo Sandrini et al. (+9 more)
Oxyfluorides containing up to 80 wt% recycled glass from end-of-life
solar panels have been investigated. Reduced processing temperature and high transparency have shown that the material has potential for optical applications. In this work, cerium-doped samples were investigated. Spectroscopic study reveals the presence of Ce$^{3+}$, and luminescence from these ions and oxygen-deficient centers was detected. Raman demonstrated that cerium affects the glass network by promoting polymerization. In turn, thermal analysis indicated some changes in the crystallization events between 500-800 $^o$ C, which were confirmed by in situ X-ray powder diffraction measurements. Crystallization of fluorite, xonotlite, and combeite was confirmed, while other phases give minor contributions to the XRD patterns. Cerium addition reduced the formation of xonotlite, mainly above 700 $^o$ C. The potential applications of the material and the further studies required are discussed.
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All authors Marcos Paulo Belançon, Rafaela Valcarenghi, Marcelo Sandrini, Brenno Greatti, Robson Ferrari Muniz, Vitor Santaella Zanuto, Sandra Ory, Aurélien Canizares, Maxence Vigier, Emmanuel Veron, Mathieu Allix, Michael Pitcher
Strongly Correlated Electrons
Structural and magnetic phases of topological kagome metal Fe$_3$Sn$_2$ under pressure
S. Chattopadhyay, L. Thomarat, C.S. Ong et al. (+8 more)
We investigate the pressure-induced
evolution of
crystal structure and magnetism in the kagome ferromagnet Fe$_3$Sn$_2$ by combining X-ray diffraction, X-ray Emission Spectroscopy, X-ray
Magnetic Circular Dichroism, and
spin-polarized density functional theory calculations. X-ray diffraction reveals a structural phase transition above $\sim$20~GPa, which coincides with a pronounced reduction of the local Fe
magnetic moment evidenced by X-ray emission spectroscopy, indicating a high-
spin to low-
spin transition. While XES probes the amplitude of the local moment, XMCD provides direct information on the orientation of the ordered
magnetic moments and uncovers a rich pressure–temperature
magnetic phase diagram. At room temperature, a collinear
ferromagnetic phase with moments aligned along the $c$ axis persists up to the structural transition. At low temperature, a tilted
magnetic configuration remains stable to significantly higher pressures, while at intermediate temperatures pressure stabilizes the low-temperature
magnetic phase at the expense of the high-temperature one.
Spin-polarized first-principles calculations show that, although isotropic
ferromagnetic exchange interactions remain robust under compression, pressure enhances
spin–orbit–driven
magnetic anisotropy and Dzyaloshinskii–Moriya interactions, favoring non-collinear
magnetic configurations. Our results demonstrate that pressure reshapes the
magnetic energy landscape of Fe$_3$Sn$_2$ by coupling
lattice,
spin state, and relativistic
magnetic interactions, establishing hydrostatic pressure as an effective control parameter to engineer
magnetic anisotropy and potentially topological phases in kagome materials.
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All authors S. Chattopadhyay, L. Thomarat, C.S. Ong, K. Kargeti, Lipika, J.-P. Rueff, L. Nataf, K. Manna, S. K. Panda, C. Shekhar, V. Balédent
Soft Condensed Matter
Jacopo Bilotto, Martin Trulsson and Jean-François Molinari
Athermal elongated particles are well-known to follow Jeffery orbits when sheared in viscous fluids. It is less clear if similar orbits appear in dense granular flows. We show that when sheared for long enough, sufficiently elongated frictionless granular rods, rather than following noisy Jeffery-like orbits, exist in a quasi-
equilibrium state, whose orientational statistics are quantitatively described by classical
liquid crystal theory, where the noise is provided by collisions due to shear. At the same time, we demonstrate a systematic breakdown of this
equilibrium analogy at two distinct limits: at low aspect ratios, where the
equilibrium theory incorrectly predicts an isotropic state, and as inter-particle friction is introduced, where the system moves from steric screening to frictional gearing. Even within this frictionally geared state, the rotational dynamics remain distinct from classical Jeffery orbits. We link this frictional breakdown directly to the system being driven far from
equilibrium, as quantified by an effective Ericksen number that compares non-
equilibrium rotational driving to steric ordering. Our results provide a quantitative map of the transition from a quasi-
equilibrium to a far-from-
equilibrium steady state in a dense, driven system, defining the limits of applicability for thermal
liquid crystal theory in athermal matter.
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Strongly Correlated Electrons
Spinon Singlet Pairing: Microscopic nature of plaquettes in stripy LDOS
Ying Liang, Yi-Da Chu, Hao Ding et al. (+2 more)
Scanning tunneling microscopy (STM) is a powerful tool for visualizing the local density of states (LDOS) of individual stripes in cuprates. However, the microscopic nature of the observed exotic LDOS patterns and their connection to high-$T_c$ superconductivity remain open questions. Within the framework of the
quantum colored string model, we reveal that the ubiquitous $4a_0\times4a_0$ plaquettes originate from either the breaking of local spinon singlet pairs through hole insertion, or the formation of an unpaired spinon upon electron addition in a stripe. Moreover, by comparing our data with LDOS of cuprates, we identify an effect of particle-hole
symmetry breaking (PHSB): a $2a_0$ shift, which is predicted and confirmed in a longer stripe ($L=18$). At last, we establish and verify a general relation between hole density and plaquette size across multiple fillings. Our work offers a fresh wavefunction-based perspective on interpreting STM signals in cuprate experiments and demonstrates that their origin may arise from spinon singlet pairing in the ground state of fluctuating stripes, the same mechanism underlying the $d$-wave sign structure [Phys. Rev. Lett. 137, 086702 (2026)].
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All authors Ying Liang, Yi-Da Chu, Hao Ding, Shi-Jie Hu, Xue-Feng Zhang
Soft Condensed Matter · Cross-listed from physics.chem-ph
Deep learning of committor and explainable artificial intelligence analysis for identifying reaction coordinates
Toshifumi Mori, Kei-ichi Okazaki, Kang Kim et al. (+1 more)
In complex molecular systems, the reaction coordinate (RC) that characterizes transition pathways is essential to understand underlying molecular mechanisms. This review surveys a framework for identifying the RC by applying deep learning to the committor, which provides the most reliable measure of the progress along a transition path. The inputs to the neural network are collective variables (CVs) expressed as functions of atomic coordinates of the system, and the corresponding RC is predicted as the output by training the network on the committor as the learning target. Because deep learning models typically operate in a black-box manner, it is difficult to determine which input variables govern the predictions. The incorporation of eXplainable Artificial Intelligence (XAI) techniques enables quantitative assessment of the contributions of individual input variables to the predictions. This approach allows the identification of CVs that play dominant roles and demonstrates that the committor distribution on the surface using important CVs is separated by well-defined boundaries. The framework provides an explainable deep learning strategy for assigning a molecular mechanism from the RC and is applicable to a wide range of complex molecular systems.
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All authors Toshifumi Mori, Kei-ichi Okazaki, Kang Kim, Nobuyuki Matubayasi
Materials Science · Cross-listed from quant-ph
Epitaxial CeO2 Films as a Host for Quantum Applications
Pralay Paul, Kusal M. Abeywickrama, Nisha Geng et al. (+18 more)
In highly purified host, the coherence of
quantum emitters is ultimately limited by hyperfine interactions between the emitter and
lattice nuclei possessing non-zero
nuclear magnetic moments. This limitation can only be mitigated through isotopic purification. In this work, we investigate CeO2 as a host composed entirely of
nuclei with zero
nuclear moment. High-quality CeO2 thin films were grown by PLD and doped with Tm and Er ions. Structural characterization using X-ray diffraction, atomic force microscopy, and ion channeling confirms single-crystalline, atomically smooth films with dopants substitutionally incorporated at Ce
lattice sites. Photoluminescence lifetime measurements show significantly longer lifetimes for Er-doped CeO2 (2.9 - 5.3 ms) compared with Tm-doped films (14 - 68 {\mu}s). Moreover, the Er-doped PLD films exhibit longer lifetimes at ~1% dopant concentration than previously reported for MBE-grown films. Density functional theory calculations reveal a substantial overlap between unoccupied O 2p and Tm 4f states near the valence band maximum, whereas Er 4f states remain well isolated. This electronic interaction likely introduces non-radiative recombination pathways in Tm-doped CeO2, explaining the reduced lifetimes. These findings highlight the importance of selecting appropriate dopant-host combinations and optimized growth conditions to minimize non-radiative channels for
quantum applications.
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All authors Pralay Paul, Kusal M. Abeywickrama, Nisha Geng, Mritunjaya Parashar, Levi Brown, Mohin Sharma, Darshpreet Kaur Saini, Melissa Ayala Artola, Todd A. Byers, Bibhudutta Rout, Yiwei Ju, Xiaoqing Pan, Sumit Goswami, Sreehari Puthan Purayil, Casey Kerr, Dhiman Biswas, Ben Summers, Bin Wang, Horst Hahn, Alisa Javadi, T. Venkatesan
Materials Science
Pulsed Laser Template Engineering- PLATEN
Dhiman Biswas, Junyeob Song, Francisco Guzman et al. (+16 more)
Thin films of functional inorganic materials, particularly
oxides, play a vital role in optoelectronics, enabling applications that range from active optical components to MEMS-based architectures. Achieving high aspect ratio patterning of these functional materials remains a significant challenge, as many of their constituent elements do not readily form volatile compounds required for conventional reactive ion etch processes. We introduce a novel approach, Pulsed
Laser Template ENgineering (PLATEN), which offers a more accessible route for patterning materials that are typically difficult to etch. This technique involves depositing functional films using the Pulsed
Laser Deposition (PLD) process onto silicon substrates that have been pre-patterned using reactive ion etching to create high aspect ratio features. Due to the highly forward-directed nature of the PLD process, the deposited films replicate closely the topography of the patterned silicon, without coatings the sidewalls. This process remains effective even at feature sizes down to approximately 50 nm. The
oxide films replicate the underlying silicon pattern to a thickness of 80 nm. For thickness beyond 80 nm the patterns develop a waist at the midpoint which scales with film thickness and is not dependent on the feature size. In this paper, we present a detailed analysis of the PLATEN process, including deviations from ideal pattern replication in sub-micron features as a function of film thickness, and demonstrate near single crystalline growth of
oxides on the patterned silicon substrate, demonstrating the potential of PLATEN technique for active opto-electronic materials.
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All authors Dhiman Biswas, Junyeob Song, Francisco Guzman, Levi Brown, Yiwei Ju, Nisha Geng, Pralay Paul, Sumit Goswami, Casey Kerr, Sreehari Puthan Purayil, Ben Summers, Preston Larson, Binbin Weng, Bin Wang, Horst Hahn, Xiaoxing Pan, Alisa Javadi, Henri Lezec, Thirumalai Venkatesan
Soft Condensed Matter
Classification of interfacial water governed by water-polymer interactions in hydrated polymers: A molecular dynamics simulation study of ethylene-based and acrylate polymers
Atsuki Hashimoto, Kokoro Shikata, Kang Kim et al. (+1 more)
We perform molecular dynamics simulations to investigate hydration structures and dynamics in seven water-containing
polymers: PVA, PHEA, PHEMA, PBA, PMEMA, PEG, and PMEA. The analysis integrates four perspectives: the water-content dependence of the glass transition temperature $T_g$,
polymer chain fluctuations characterized by dihedral angle distributions, hydrogen-bond lifetimes $\tau_{\mathrm{HB}}$ between water and
polymer functional groups, and the localization and exchange dynamics of confined water quantified by the distinct part of van Hove correlation function. Hydroxyl-containing
polymers (PVA, PHEA, and PHEMA) exhibit relatively high dry-state $T_g$ values and its pronounced depression upon hydration. Chain fluctuations are limited, and $\tau_{\mathrm{HB}}$ follows Arrhenius behavior, forming localized hydration shells. In contrast, PMEMA and PBA show low
equilibrium water contents and hydrophobic character; although their dry-state $T_g$ values are moderately lower and less sensitive to water content, chain fluctuations remain small, and $\tau_{\mathrm{HB}}$ also obeys Arrhenius behavior, with hydrophobic aggregation promoting water localization. PEG and PMEA display low dry-state $T_g$ values and weak water-content dependence. Greater rotational freedom around ether or methoxy oxygen atoms leads to larger chain fluctuations and loosely bound water. Below $T_g$, $\tau_{\mathrm{HB}}$ between water and ether or methoxy oxygen atoms exhibits super-Arrhenius behavior. These results clarify three hydration types: highly hydrated (PVA, PHEA, and PHEMA), hydrophobic (PMEMA and PBA), and flexibly hydrated (PEG and PMEA), and provide a molecular-level framework for interpreting interfacial water governed by water-
polymer interactions.
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All authors Atsuki Hashimoto, Kokoro Shikata, Kang Kim, Nobuyuki Matubayasi
Disordered Systems and Neural Networks · Cross-listed from q-bio.NC
Quantifying plasticity: a network-based framework linking structure to dynamical regimes
Igor Branchi
Plasticity is a fundamental property of complex systems, such as the
brain or an organism. Yet it typically remains a descriptive concept inferred retrospectively from observed outcomes, such as modifications in activity or morphology. Here, the network-based operationalization of plasticity is further formalized as the ratio between system size and connectivity strength among system elements. Within this framework, system size determines the dimensionality of the accessible state space, while connectivity strength tunes the system's regime. An optimal range of plasticity – balancing capacity for change and capacity to maintain coherence – emerges at intermediate connectivity strength. Notably, this balance coincides with the critical regime, which provides a theoretically motivated
benchmark that enables a normalized unit of measure, termed effective plasticity, and comparisons of adaptive efficacy across diverse systems. Plasticity is thus transformed into a predictive tool that quantifies a system's capacity for change before it occurs. Its validity is supported across disciplines and, in particular, by evidence from psychopathology where it anticipates transitions between mental states. At a mechanistic level, plasticity acts as a structural tuning parameter for criticality, reframing their relationship as causal, with plasticity driving criticality rather than merely accompanying it. Furthermore, this network-based operationalization explains how larger systems can more robustly maintain critical dynamics. Crucially, the proposed perspective distinguishes functional regime shifts from thermodynamic phase changes, identifying plasticity as the system-level regulator that shapes and constrains the dynamic repertoire. This framework is applicable across domains, including ecology, economics, and social systems, and may foster cross-disciplinary integration within complexity science.
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Materials Science
Decoding the Electronic and Structural Fingerprints of Single-Atom Catalysts via DFT-Assisted XANES Analysis
Petr Lazar and Michal Otyepka
Single-atom catalysts (SACs), composed of isolated metal atoms dispersed on solid supports, represent the ultimate expression of atomic efficiency in catalysis. Their remarkable activity and selectivity arise from local coordination environments and adjustable oxidation states, yet precise determination of these features remains an enduring challenge. Among modern characterization techniques, X-ray absorption near-edge structure (XANES) spectroscopy stands out for its sensitivity to both electronic and
geometric structure, though its interpretation is often constrained by empirical comparison with bulk references. Here we introduce a density functional theory (DFT) based computational spectroscopy framework for the quantitative interpretation of Cu K-edge XANES spectra. We then employ this framework to reveal the oxidation state, coordination geometry, and hydration environment of Cu single atoms supported on cyanographene, demonstrating direct correspondence between spectral signatures and atomic-scale structure. This methodology establishes a robust and transferable route for connecting XANES features with the underlying electronic and structural characteristics of SACs, thereby advancing the rational design of atomically precise catalysts.
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Mesoscale and Nanoscale Physics
Fluctuation response of a minimal Kitaev chain in nonequilibrium states
Sergey Smirnov
Minimal Kitaev chains provide a unique platform to engineer Majorana states in
quantum dots interacting via normal tunneling and crossed Andreev reflection specified by their amplitudes $|\eta_{n,a}|$. Here we analyze fluctuations of electric currents in a double
quantum dot Kitaev chain using the differential effective charge $q$, that is the ratio of the differential shot noise and conductance. At low bias voltages $V$ we find that $q=e/2$ in a very narrow vicinity of the point $|\eta_n|=|\eta_a|$ whereas $q=3e/2$ almost in the whole sweet spot region and marks the range where the poor man's Majorana states largely govern the fluctuations. At high $V$ we show that the sweet spot region is still characterized by $q=3e/2$ uniquely identifying the poor man's Majorana states using the high voltage tails. For $|\eta_n|=0$ or $|\eta_a|=0$ we obtain $q=e$ at any $V$. Remarkably, before the asymptotic value $q=e$ is reached for very high $V$, the maximal value $q=2e$ is formed at $|eV|=2\sqrt{|\eta_n|^2+|\eta_a|^2}$. The unique nature and potentially rich fluctuation behavior revealed in this work provide a stimulating ground for the next generation experiments on nonequilibrium shot noise in minimal Kitaev chains.
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Superconductivity
Vortex-driven superconducting diode effect in asymmetric multilayer heterostructures
Jiong Li, Ji Jiang and Qing-Hu Chen
The superconducting diode effect (SDE), characterized by nonreciprocal critical currents, has attracted growing
attention due to its potential applications in
quantum technologies and energy-efficient devices. In this work, we explore the microscopic mechanism of the SDE by simulating asymmetric multilayer
heterostructures within time-dependent Ginzburg-Landau theory. We systematically vary the layer thickness, external
magnetic field and stacking order in a trilayer structure composed of niobium, vanadium, and tantalum, which share a similar structure to that in the pioneering experimental work, to clarify the role of
vortex dynamics. Our simulations reveal a pronounced SDE originating from the interplay of Lorentz forces and asymmetric
vortex dynamics, which strongly depend on layer stacking order. Besides, by simply changing the stacking order of the constituent layers, the SDE can be entirely suppressed. These findings offer insights into the microscopic mechanisms of the SDE and provide a feasible approach for controlling and eliminating the SDE in practical superconducting devices.
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Quantum Gases
Dynamically Stable Vortices in Exciton-Polariton Condensates Engineered by Repulsive Interactions
Palanivel Raman, Ramaswamy Radha, Pankaj Kumar Mishra et al. (+1 more)
We present an analytical and numerical study of the dynamics and stability of
exciton-polariton condensates described by the open-dissipative Gross-Pitaevskii equation, incorporating both binary and short-range three-body interactions. Using an asymptotic description, we identify the parameter regime and derive equations for the instability amplitude, providing insights into
vortex formation via the snake instability of dark
solitons. We find that a repulsive three-body interaction, when combined with a binary interaction, supports stable
vortex-antivortex pair formation. On the other hand, the reinforcement of attractive three-body interactions with binary interaction triggers the emergence of snake instability, leading to boundary-driven
vortex disintegration. The time
evolution of the instability under the influence of reservoir effects indicates that the boundary effects are more pronounced, to the extent of destabilizing the
vortices with attractive three-body interactions compared to repulsive three-body interactions, thereby underscoring the stable nature of
vortices in the repulsive domain.
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All authors Palanivel Raman, Ramaswamy Radha, Pankaj Kumar Mishra, Paulsamy Muruganandam
Materials Science
Distinguishing apparent and hidden altermagnetism via uniaxial strain in $\mathrm{CsV_2Te_2O}$-family
San-Dong Guo and Yang Liu
The hidden altermagnetism has been theoretically proposed and then experimentally confirmed in metal $\mathrm{Cs_{1-\delta}V_2Te_2O}$, which exhibits two nearly degenerate ground-state
magnetic configurations (C-type and G-type) corresponding respectively to apparent and hidden altermagnetism. Here, we propose that in-plane uniaxial strain can be utilized to distinguish apparent and hidden altermagnetism. Under uniaxial strain, apparent altermagnetism exhibits an obvious net
magnetic moment, whereas hidden altermagnetism maintains zero net
magnetic moment. The
magnetic moment induced by uniaxial strain here, namely the piezomagnetic effect, differs from that in
semiconductors, where strain must be applied first followed by carrier doping to generate net magnetism. First-principles calculations verify our proposal, revealing that the
magnetic moment induced by uniaxial strain in C-type
antiferromagnetic $\mathrm{CsV_2Te_2O}$ is much larger than that in the previously studied altermagnetic
semiconductors. Furthermore, we also investigate the electronic state transitions of
semiconductors featuring a
crystal structure analogous to $\mathrm{CsV_2Te_2O}$ under uniaxial strain, and verify our proposal in specific material via first-principles calculations. Our work provides an experimentally feasible strategy to distinguish apparent and hidden altermagnetism in material $\mathrm{Cs_{1-\delta}V_2Te_2O}$, and extends the physical implication of the piezomagnetic effect, which can be directly verified in experimentally synthesizable $\mathrm{KV_2Se_2O}$ and $\mathrm{Rb_{1-\delta}V_2Te_2O}$.
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Mesoscale and Nanoscale Physics · Cross-listed from quant-ph
Optimal measurement-based quantum thermal machines in a finite-size system
Chinonso Onah, Obinna Uzoh and Obinna Abah
We present a measurement-based
quantum thermal machine that extracts work from the back-action of generalized
quantum measurements whose working medium is a coupled two-level
quantum system. Specifically, we derive universal optimization criteria for a three-stroke measurement-based engine cycle with coupled two-level system of Ising-like interaction as a working medium. Furthermore, we present two numerical
algorithms to optimize the engine work extraction and enhance its performance. Our numerical results demonstrate: (i) efficiency peaks in the projective-measurement limit; (ii)
symmetry breaking (detuning or weak coupling) enlarges the exploitable energy gap; and (iii) performance remains robust ($>50\%$ of optimum) under $\sim\!10^\circ$ feedback-pulse errors. The framework is platform-agnostic and directly implementable with current superconducting, trapped-ion, or NMR technologies, providing a concrete route to scalable, measurement-powered
quantum thermal machines.
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Materials Science
Effect of Pb doping on the crystallization process and thermoelectric properties of Ge2Sb2Te5 phase change material
M. Zhezhu, A. Vasil'ev, M. Yaprintsev et al. (+3 more)
Phase change materials based on Ge-Sb-Te
alloys are widely explored for their potential in both
memory devices and thermoelectric applications. In this study, films of Ge2Sb2Te5 (GST) doped with varying concentrations of Pb were prepared and systematically investigated to trace the effect of Pb doping on crystallization-induced phase transformations and thermoelectric properties. Via X-ray diffraction and Raman spectroscopy, the impact of Pb doping on the crystallization behavior was revealed and examined. According to the specific electrical resistivity measurements, the Pb doping resulted in decreasing both the amorphous-to-cubic and cubic-to-hexagonal transition temperatures, thereby facilitating the formation of the hexagonal phase at a lower thermal regime. Furthermore, Seebeck coefficient and electrical resistivity data of hexagonal Pb-doped GST were used to calculate the power factor, PF. A PF maximum equal to 1.3 was found for 2.5 at. Pb-GST at 633 K, with the highest carrier mobility also observed for this composition. Controlled Pb doping effectively modulates both structural transitions and thermoelectric performance, highlighting the potential of Pb-GST for applications that combine phase-change
memory and thermoelectric functionality, such as opto-thermoelectric devices and non-volatile thermoelectric sensors.
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All authors M. Zhezhu, A. Vasil'ev, M. Yaprintsev, A. Musayelyan, E. Pilyuk, O. Ivanov
Superconductivity
Polar, checkerboard charge order in bilayer nickelate La3Ni2O7
Ryo Misawa, Shunsuke Kitou, Jian-Ping Sun et al. (+6 more)
Competing charge and
spin orders are central to uncovering the nature of unconventional superconductivity. Here we utilize synchrotron X-ray diffraction on a high-quality single
crystal to reveal the charge order of La$_3$Ni$_2$O$_7$ at ambient pressure, which competes with the high-temperature superconducting phase under pressure. Enabled by the high synchrotron
photon flux and a large dynamic range, we resolve faint reflections – nearly four orders of magnitude weaker than the main Bragg reflections – that were overlooked in prior diffraction studies. This observation evidences a broken glide-mirror
symmetry, leading to a polar
crystal structure, rather than the widely used centrosymmetric structure model. The polarity is induced by checkerboard charge order on nickel sites in combination with octahedral tilting, reminiscent of
bilayer manganese
oxides. Our results provide a foundation for understanding phase competition and the mechanism of pressure-induced superconductivity in
bilayer nickelates.
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All authors Ryo Misawa, Shunsuke Kitou, Jian-Ping Sun, Yingpeng Yu, Chihaya Koyama, Yuiga Nakamura, Taka-hisa Arima, Jin-Guang Cheng, Max Hirschberger
Quantum Gases · Cross-listed from quant-ph
Neural Operator Quantum State: A Foundation Model for Quantum Dynamics
Zihao Qi, Christopher Earls and Yang Peng
Capturing the dynamics of
quantum many-body systems under time-dependent driving protocols is a central challenge for numerical simulations. Existing methods such as tensor networks and time-dependent neural
quantum states, however, must be re-run for every protocol. In this work, we introduce the Neural Operator
Quantum State (NOQS) as a foundation model for
quantum dynamics. Rather than solving the Schrödinger equation for individual trajectories, our approach aims to learn the solution operator that maps entire driving protocols to time-evolved
quantum states. Once trained, the NOQS predicts time
evolution under unseen protocols in a single forward pass, requiring no additional optimization. We validate NOQS on the two-dimensional Ising model with time-dependent longitudinal and transverse fields, demonstrating accurate prediction not only for unseen in-distribution protocols, but also for qualitatively different, out-of-distribution functional forms of driving. Further, a single NOQS model can be transferred between different temporal resolutions, and can be efficiently fine-tuned with sparse experimental measurements to improve predictions across all observables at negligible cost. Our work introduces a new paradigm for
quantum dynamics simulation and provides a practical computational-experimental interface for driven
quantum systems.
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Mesoscale and Nanoscale Physics · Cross-listed from physics.optics
Robust topological BIC nanocavities for upconversion directional emission
Yongqi Chen, Ming Zhu, Qingfeng Bian et al. (+4 more)
Photonic bound states in the continuum (BICs) provide a revolutionary paradigm for boosting light-matter interactions in integrated nanocavity systems. Nevertheless, precise manipulation of open cavity-emitter architectures still faces critical challenges, especially in realizing deterministic directional radiation and suppressing the perturbation of intrinsic cavity modes induced by emitters as local
impurities. Conventional investigations on cavity-emitter coupling are predominantly based on ensemble measurements, which inevitably mask the intrinsic physics underlying individual light-matter interactions. Here, we propose a robust strategy to control the upconversion and emission of a single-particle emitter using a topological plasmonic cavity with broken {\sigma}h mirror
symmetry. This structured design enables the transition from
symmetry-protected BICs to a multi-BIC regime with finite but ultrahigh confinement, where nontrivial phase
evolution and hybridization of transverse electric and
magnetic modes open a well-defined far-field radiation channel for directional emission. Leveraging this scheme, we experimentally demonstrate dramatically enhanced radiation intensity from a single point-like emitter, together with uniform and deterministic directional emission, while achieving excellent structural robustness against local perturbations. This work establishes a general framework for engineering coherent directional light emission at the nanoscale, which lays a solid foundation for high-performance chip-scale integrated nanophotonic applications.
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All authors Yongqi Chen, Ming Zhu, Qingfeng Bian, Xiumei Yin, Wenxin Wang, Bin Dong, Yurui Fang
Quantum Gases
Dynamics of two particles with quasiperiodic long-range interactions
Yun Zou
We investigate the dynamics of two identical spinless
fermions on a one-dimensional
lattice with open boundary conditions (OBC), subject to quasiperiodic long-range interactions. Using numerical exact diagonalization (ED), we study this non-integrable system as a continuous-time
quantum walk and uncover a robust correlated dynamical regime. This regime, characterized by an approximately constant inter-particle distance, emerges under sufficiently strong quasiperiodic modulation of the long-range interactions. Further, the study shows that the behavior is determined by the nature of the interaction and the choice of boundary condition. Notably, by tuning the phase of the quasiperiodic modulation, we observe three distinct manifestations of this phenomenon: localization, nearest-neighbor separation oscillations, and next-nearest-neighbor separation transitions – each arising for specific initial separations. Furthermore, we identify the suppression of
entanglement entropy in the system, including instances of oscillatory behavior. Our results highlight how quasiperiodic long-range interactions shape few-body
quantum dynamics.
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Other Condensed Matter · Cross-listed from quant-ph
Explicit States with Two-sided Long-Range Magic
Zhi Li
Nonstabilizerness, or magic, is a necessary resource for
quantum advantage beyond the classically simulatable Clifford framework. Recent works have begun to chart the structure of magic in many-body states, introducing the concepts of long-range magic – nonstabilizerness that cannot be removed by finite-depth local
unitary (FDU)
circuits – and the magic hierarchy, which classifies
quantum circuits by alternating layers of Clifford and FDUs. In this work, we construct explicit states that provably possess two-sided long-range magic, a stronger form of magic meaning that they cannot be prepared by a Clifford
circuit and a FDU in either order, thus placing them provably outside the first level of the magic hierarchy. Our examples include the “magical cat" state, $|\psi\rangle \propto |0^n\rangle + |+^n\rangle$, and ground states of certain nonabelian topological orders. These results provide new examples and proof techniques for
circuit complexity, and in doing so, reveal the connection between long-range magic, the structure of many-body phases, and the principles of
quantum error correction.
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Other Condensed Matter
Origin of Giant Phonon Magnetic Moment in Orbital Seebeck Effect: a Heisenberg-type L-L Coupling
Hong Sun, Jinxin Zhong, Yimin Yao et al. (+2 more)
Inspired by the recent observation of the orbital Seebeck effect in alpha-quartz, we identify an intrinsic amplification mechanism for thermally generated
phonon angular momentum and
phonon magnetic moment in
chiral insulators. We propose a Heisenberg-type long-range coupling between
phonon angular momenta, referred to here as L-L coupling, which opens a self-consistent feedback channel and strongly enhances the bare thermal response within linear response. Our calculations reveal a pronounced temperature- and size-dependent amplification, dominated by the off-diagonal channel, with the total
phonon angular momentum enhanced by up to nearly two orders of magnitude as the system approaches the threshold from below. These findings suggest that L-L coupling may provide a microscopic origin of
giant phonon magnetic moment the recently observed orbital Seebeck effect in alpha-quartz.
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All authors Hong Sun, Jinxin Zhong, Yimin Yao, Jun Zhou, Lifa Zhang
Materials Science
Dual migration modes of unfaulted disconnections on curved twin boundaries
Hongrui He, Hao Lyu and Xueting Si
Grain boundary migration governs microstructural
evolution in crystalline materials, directly influencing mechanical properties such as strength and thermal stability. Disconnections, which are line defects formed at grain boundaries in response to local
curvature, have been identified as critical carriers of boundary migration. Here, we investigate the glide of unfaulted disconnections (UFDs) on a coherent twin boundary in aluminum at elevated temperatures using molecular dynamics simulations combined with the Nudged Elastic Band (NEB) method. Our results reveal a striking bifurcation in migration behavior depending on the disconnection core structure. UFDs with a pure edge Burgers vector migrate via a thermally activated double-kink mechanism, exhibiting a migration velocity that increases monotonically with temperature. In contrast, UFDs containing a screw dipole component possess an energy barrier approximately eight times lower, and their core structure undergoes a continuous transformation during glide, giving rise to
stochastic, bidirectional motion with no systematic temperature dependence. These findings demonstrate that the disconnection core structure fundamentally dictates the migration mode and kinetics of twin boundaries, offering new mechanistic insights into disconnection-mediated grain boundary migration.
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Superconductivity
Tracking unconventional superconductivity in the presence of strongly correlated Fermi arcs
Xianliang Zhou, Fei Yang, Miao Liu et al. (+2 more)
One of the primary reasons that superconductivity in underdoped cuprates is enigmatic is that it emerges from an incoherent
Fermi-arc state, so the applicability of the Bardeen-Cooper-Schrieffer (BCS) theory is questionable. Here we approach this problem by investigating unconventional $d$-wave superconductivity in a recently proposed solvable model for strongly correlated
Fermi arcs. We show analytically that the exact incorporation of
Fermi arcs fundamentally modifies the BCS equations, which enables us to isolate a many-body effect that suppresses the superconducting transition temperature $T_c$ beyond the simple reduction expected from a shrinking
Fermi surface. The theory unambiguously produces: (i) a $T_c$ tracing out a dome as a function of hole doping, (ii) a new low-energy mode upon entering superconductivity, (iii) a suppressed superfluid stiffness in the underdoped regime, and (iv) a gap-to-$T_c$ ratio far exceeding the BCS limit, all consistent with experimental observations in cuprate
superconductors. These findings provide an analytic
benchmark for understanding how superconductivity emerges from a correlated
Fermi-arc state in high-$T_c$
superconductors.
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All authors Xianliang Zhou, Fei Yang, Miao Liu, Yin Shi, Sheng Meng
Mesoscale and Nanoscale Physics
Amarnath Chakraborty, Aleksandr Rodin, Shaffique Adam et al. (+1 more)
We investigate the interplay of in-plane
magnetic and transverse electric fields in AB-stacked
bilayer graphene. In prior work neglecting trigonal warping, we demonstrated that this configuration induces an
insulator-metal transition purely via orbital effects, albeit requiring impractically large
magnetic fields ($>100$ T). Here, we extend the analysis to the ultra-low-energy regime by incorporating interlayer skew couplings. In a restricted region of momentum space, trigonal warping produces a fine splitting of Dirac cones leading to a compensated semimetallic state at zero external field. Application of a transverse electric field above a small threshold ($V_c\sim0.6$ meV) reinstates an insulating gap. When an in-plane
magnetic field is applied, the orbital gauge vector immediately breaks the $C_3$ spatial
symmetry of the
lattice, and we uncover two sequential, field-driven transitions separated by an order of magnitude in scale. First, at fields ($B \approx 1$ T), the Zeeman effect drives an indirect
insulator-to-semimetal transition at the ungated charge neutrality point; the cross-
spin gap closes, generating distinct electron and hole pockets separated in momentum space. Second, as the field increases to $B \approx 10$–$25$ T, the orbital coupling closes the same-
spin gap at an energy well away from the charge-neutral
Fermi level. By electrostatically tuning the
Fermi level to this specific gap-closing energy, we reveal the emergence of $C_3$-broken same-
spin Fermi pockets, accompanied by a distinct step-like onset in the density of states. This dual-transition regime provides a highly sensitive platform for tunable,
spin-selective transport.
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All authors Amarnath Chakraborty, Aleksandr Rodin, Shaffique Adam, Giovanni Vignale
Materials Science
Forster energy transfer boosts indirect anisotropic interlayer excitons in 2L-MoSe2/perovskite heterostructures
Yingying Chen, Zihao Jiao, Haizhen Wang et al. (+1 more)
Interlayer
excitons (IXs) in two-dimensional (2D) van der Waals
heterostructures have attracted considerable
attention due to their unique optical and electronic properties. Owing to the spatially indirect nature, the radiative emission efficiency highly sensitive to interlayer twist angles. Further considering that their uniformly oriented out-of-plane dipole moments limit directional emission, strategies to simultaneously improve emission efficiency and induce optical anisotropy warrant in-depth investigation. In this work, we report significant photoluminescence (PL) enhancement and optical anisotropy of IXs in 2L-MoSe2/perovskite
heterostructures mediated by energy transfer from ReS2. We attribute this enhancement to Forster resonance energy transfer (FRET), which increases the 2L-MoSe2 emission by approximately eight-fold at room temperature, and nearly doubles the emission intensity of momentum-indirect IXs in 2L-MoSe2/perovskite
heterostructures at 78 K. Importantly, the optical anisotropy of ReS2 can be effectively imprinted onto 2L-MoSe2 and associated indirect IXs during the energy transfer process, yielding a linear dichroism of approximately 1.1 for both intralayer
excitons and IXs with identical polarization directions. These findings expand the scope of IX study beyond direct bandgap materials with strong intrinsic emission to include systems with indirect bandgaps, offering new avenues for realizing high-performance polarization-sensitive optoelectronic devices.
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All authors Yingying Chen, Zihao Jiao, Haizhen Wang, Dehui Li
Strongly Correlated Electrons
Dynamical Response of the Kitaev Spin Liquid under Third-Nearest-Neighbor Heisenberg Interaction
Chuan Chen and Jiucai Wang
Motivated by growing evidence for the significance of the third-nearest-neighbor Heisenberg ($J_3$) interaction in candidate Kitaev materials, we investigate the dynamical properties of the Kitaev
spin liquid (KSL) under a $J_3$ perturbation, focusing on its
spin dynamical structure factor (DSF) and Raman scattering. Within a self-consistent parton mean-field plus random-phase approximation framework, we find that $J_3$ induces coherent, paramagnon-like collective modes that coexist with a high-energy Majorana continuum in the
spin DSF. The softening of these modes with increasing $|J_3|$ signals a
quantum phase transition to
magnetic order. Remarkably,
magnetic ordering sets in at a common critical $J_3$ for both
ferromagnetic ($K<0$) and
antiferromagnetic ($K>0$) Kitaev models, with the resulting ordered states forming exact dual pairs under a four-sublattice duality transformation that maps $(K,J_3) \rightarrow (-K,J_3)$. An external
magnetic field further softens the preexisting paramagnon modes, thereby enhancing
magnetic order. Perturbative Raman calculations show that while the Kitaev-like Raman vertex probes only itinerant matter Majorana
fermions, the response from the $J_3$-like vertex features both matter Majoranas and visons. Four-vison excitations produce a sharp peak accompanied by a two-
fermion continuum, whereas two-vison excitations yield a continuum closely resembling the single-matter-
fermion density of states. These results provide a unified perspective on the dynamical signatures of $J_3$-perturbed KSL and are helpful for interpreting experimental spectra in candidate Kitaev materials with sizable $J_3$ interactions.
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Materials Science
The ground state of CuInP$_2$S$_6$ thin films: A study of the deep potential method
Shengxian Li, Jiaren Yuan, Tao Ouyang et al. (+2 more)
The two-dimensional ferroelectric (FE) material CuInP$_2$S$_6$ (CIPS) has garnered considerable interest due to its out-of-plane ferroelectricity at room temperature. However, a notable discrepancy exists between experiments and density functional theory (DFT) calculations regarding the ground state of CIPS thin films: experiments suggest a state with net polarization, while DFT predicts an antiferroelectric (AFE) state as the lowest-energy state. Here, we investigate the stability of polarization states in CIPS thin films by combining first-principles calculations with the deep potential (DP) method. Our results reveal that for films thicker than the
bilayer, an AFE state that has intralayer AFE ordering in the inner layers and intralayer FE ordering in the two surface layers has the lowest electronic energy. This state is significantly lower than the uniform FE state. In addition, we find that a ferrielectric (FiE) state with pure intralayer FE ordering is very close to the AFE state in energy. By using the DP model, we calculated the
phonon free energy of CIPS thin films. For the monolayer, the intralayer FE ordering possesses a lower
phonon free energy than the intralayer AFE ordering. This energetic preference for the intralayer FE ordering maintains as the thickness grows. Consequently, when the
phonon-free energy is incorporated, the FiE state becomes energetically favorable over the AFE state for multilayers CIPS. Our findings demonstrate that the inclusion of vibrational
entropy stabilizes the FiE state as the ground state in multilayers CIPS at finite temperatures, reconciling the previous discrepancy between experimental observations and DFT predictions. This insight is vital for understanding the FE properties of CIPS and its potential applications in devices.
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All authors Shengxian Li, Jiaren Yuan, Tao Ouyang, Anlian Pan, Mingxing Chen
Soft Condensed Matter
Electrically controlled propulsion of skyrmions in chiral nematic
Oleg D. Lavrentovich
Design of soft matter capable of controllable microscale dynamics is a frontier of modern science. Jiahao Chen et al. demonstrate that an electric field can drive particle-like
solitons-skyrmions in a
chiral nematic along a preprogrammed trajectory with a variable speed within a two-dimensional plane. The effect is rooted in flexoelectric polarization of a deformed director field.
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