CMP Journal 2025-07-03
Statistics
Nature Materials: 1
Physical Review Letters: 25
Physical Review X: 2
arXiv: 70
Nature Materials
Accelerated data-driven materials science with the Materials Project
Review Paper | Condensed-matter physics | 2025-07-02 20:00 EDT
Matthew K. Horton, Patrick Huck, Ruo Xi Yang, Jason M. Munro, Shyam Dwaraknath, Alex M. Ganose, Ryan S. Kingsbury, Mingjian Wen, Jimmy X. Shen, Tyler S. Mathis, Aaron D. Kaplan, Karlo Berket, Janosh Riebesell, Janine George, Andrew S. Rosen, Evan W. C. Spotte-Smith, Matthew J. McDermott, Orion A. Cohen, Alex Dunn, Matthew C. Kuner, Gian-Marco Rignanese, Guido Petretto, David Waroquiers, Sinead M. Griffin, Jeffrey B. Neaton, Daryl C. Chrzan, Mark Asta, Geoffroy Hautier, Shreyas Cholia, Gerbrand Ceder, Shyue Ping Ong, Anubhav Jain, Kristin A. Persson
The Materials Project was launched formally in 2011 to drive materials discovery forwards through high-throughput computation and open data. More than a decade later, the Materials Project has become an indispensable tool used by more than 600,000 materials researchers around the world. This Perspective describes how the Materials Project, as a data platform and a software ecosystem, has helped to shape research in data-driven materials science. We cover how sustainable software and computational methods have accelerated materials design while becoming more open source and collaborative in nature. Next, we present cases where the Materials Project was used to understand and discover functional materials. We then describe our efforts to meet the needs of an expanding user base, through technical infrastructure updates ranging from data architecture and cloud resources to interactive web applications. Finally, we discuss opportunities to better aid the research community, with the vision that more accessible and easy-to-understand materials data will result in democratized materials knowledge and an increasingly collaborative community.
Condensed-matter physics, Materials chemistry, Materials for energy and catalysis, Theory and computation
Physical Review Letters
Second Law of Entanglement Manipulation with an Entanglement Battery
Research article | Quantum entanglement | 2025-07-02 06:00 EDT
Ray Ganardi, Tulja Varun Kondra, Nelly H. Y. Ng, and Alexander Streltsov
A central question since the beginning of quantum information science is how two distant parties can convert one entangled state into another. It has been conjectured that such conversions could be executed reversibly in an asymptotic regime, mirroring the reversible nature of Carnot cycles in classical thermodynamics. While a conclusive proof of this conjecture has been missing so far, earlier studies have excluded reversible entanglement manipulation in various settings. In this Letter, we show that arbitrary mixed state entanglement transformations can be made reversible under local operations and classical communication, when assisted by an entanglement battery—an auxiliary quantum system that stores and supplies entanglement in a way that ensures no net entanglement is lost. In particular, the rate of transformation in the asymptotic limit can be quantitatively expressed as a ratio of entanglement present within the quantum states involved. Our setting allows us to consider different entanglement quantifiers which give rise to unique principles governing state transformations, effectively constituting diverse manifestations of a ‘’second law’’ of entanglement manipulation. These findings resolve a long-standing open question on the reversible manipulation of entangled states and are also applicable to multipartite entanglement and other quantum resource theories, including quantum thermodynamics.
Phys. Rev. Lett. 135, 010202 (2025)
Quantum entanglement, Quantum information theory, Quantum thermodynamics
Magic Monotone for Faithful Detection of Nonstabilizerness in Mixed States
Research article | Quantum correlations, foundations & formalism | 2025-07-02 06:00 EDT
Krzysztof Warmuz, Ernest Dokudowiec, Chandrashekar Radhakrishnan, and Tim Byrnes
We introduce a monotone to quantify the amount of nonstabilizerness in mixed quantum states. The monotone gives a necessary and sufficient criterion for detecting the presence of nonstabilizerness for both pure and mixed states. The monotone is based on determining the boundaries of the stabilizer polytope in the space of Pauli string expectation values. The boundaries can be described by a set of hyperplane inequations, where violation of any one of these gives a necessary and sufficient condition for nonstabilizerness. The monotone is constructed by finding the hyperplane with the maximum violation and is a type of Minkowski functional. We also introduce a faithful witness based on similar methods. The approach is more computationally efficient than existing faithful mixed state monotones such as robustness of magic due to the smaller number and discrete nature of the parameters to be optimized.
Phys. Rev. Lett. 135, 010203 (2025)
Quantum correlations, foundations & formalism, Quantum formalism, Quantum information theory
Quantum Dynamics with Stochastic Non-Hermitian Hamiltonians
Research article | Open quantum systems & decoherence | 2025-07-02 06:00 EDT
Pablo Martinez-Azcona, Aritra Kundu, Avadh Saxena, Adolfo del Campo, and Aurélia Chenu
We study the quantum dynamics generated by a non-Hermitian Hamiltonian subject to stochastic perturbations in its anti-Hermitian part, describing fluctuating gains and losses. The dynamics averaged over the noise is described by an ‘’antidephasing’’ master equation. We characterize the resulting state evolution and analyze its purity. The properties of such dynamics are illustrated in a stochastic dissipative qubit. Our analytical results show that adding noise allows for a rich control of the dynamics, stabilizing the lossy state and making state purification possible to a greater variety of steady states.
Phys. Rev. Lett. 135, 010402 (2025)
Open quantum systems & decoherence, PT-symmetric quantum mechanics, Quantum correlations, foundations & formalism, Qubits
Estimate of Equilibration Times of Quantum Correlation Functions in the Thermodynamic Limit Based on Lanczos Coefficients
Research article | Nonequilibrium & irreversible thermodynamics | 2025-07-02 06:00 EDT
Jiaozi Wang, Merlin Füllgraf, and Jochen Gemmer
We study the equilibration times ${T}{\mathrm{eq}}$ of local observables in quantum chaotic systems by considering their autocorrelation functions. Based on the recursion method, we suggest a scheme to estimate ${T}{\mathrm{eq}}$ from the corresponding Lanczos coefficients that is expected to hold in the thermodynamic limit. We numerically find that, if the observable eventually shows smoothly growing Lanczos coefficients, a finite number of the former is sufficient for a reasonable estimate of the equilibration time. This implies that equilibration occurs on a realistic time scale much shorter than the life of the Universe. The numerical findings are further supported by analytical arguments.
Phys. Rev. Lett. 135, 010403 (2025)
Nonequilibrium & irreversible thermodynamics, Nonequilibrium statistical mechanics, Quantum statistical mechanics, Quantum thermodynamics, 1-dimensional spin chains, Many-body techniques, Spin lattice models
Quantum Algorithms for Representation-Theoretic Multiplicities
Research article | Quantum algorithms & computation | 2025-07-02 06:00 EDT
Martín Larocca and Vojtech Havlicek
Kostka, Littlewood-Richardson, Plethysm, and Kronecker coefficients are the multiplicities of irreducible representations in the decomposition of representations of the symmetric group that play an important role in representation theory, geometric complexity, and algebraic combinatorics. We give quantum algorithms for computing these coefficients whenever the ratio of dimensions of the representations is polynomial. We show that there is an efficient classical algorithm for computing the Kostka numbers under this restriction and conjecture the existence of an analogous algorithm for the Littlewood-Richardson coefficients. We argue why such classical algorithm does not straightforwardly work for the Plethysm and Kronecker coefficients and conjecture that our quantum algorithms lead to superpolynomial speedups. The conjecture about Kronecker coefficients was disproved by Panova [Polynomial time classical versus quantum algorithms for representation theoretic multiplicities, arXiv:2502.20253] with a classical algorithm which, if optimal, points to a $\mathcal{O}({n}^{4+2k})$ vs $\stackrel{\texttildelow{}}{\mathrm{\Omega }}({n}^{4{k}^{2}+1})$ polynomial gap in quantum vs classical computational complexity for an integer parameter $k$.
Phys. Rev. Lett. 135, 010602 (2025)
Quantum algorithms & computation, Quantum circuits, Quantum computation
Time-Optimal Transfer of the Quantum State in Long Qubit Arrays
Research article | Quantum communication | 2025-07-02 06:00 EDT
Andrei A. Stepanenko, Kseniia S. Chernova, and Maxim A. Gorlach
Recent technological advances have allowed the fabrication of large arrays of coupled qubits, serving as prototypes for quantum processors. However, the optimal control of such systems remains notoriously challenging, limiting the potential of large-scale quantum systems. Here, we investigate a model problem of quantum state transfer in a large nearest-neighbor-coupled qubit array. We derive an optimal control strategy that simultaneously achieves maximal fidelity and minimal transfer time, reaching the quantum speed limit in a lattice with time-varying couplings.
Phys. Rev. Lett. 135, 010803 (2025)
Quantum communication, Quantum control, Quantum optics
Quantum Teleportation from Telecom Photons to Erbium-Ion Ensembles
Research article | Quantum communication | 2025-07-02 06:00 EDT
Yu-Yang An, Qian He, Wenyi Xue, Ming-Hao Jiang, Chengdong Yang, Yan-Qing Lu, Shining Zhu, and Xiao-Song Ma
To realize a quantum internet, the distribution of quantum states via quantum teleportation with quantum memories is a key ingredient. Being compatible with existing fiber networks, entangled photons and quantum memories at telecom wavelength are of central interest for such a scalable quantum network. Here, we demonstrate quantum teleportation from a telecom-wavelength photonic qubit to a solid-state quantum memory based on erbium-ion ensembles, which have a native optical transition at $1.5\text{ }\text{ }\mathrm{\mu }\mathrm{m}$ telecom C band. To accomplish this, we use chip-scale silicon nitride microresonators to generate entangled photons with narrow linewidth, compatible with the quantum memory. We confirm the quality of the quantum teleportation procedure using quantum state and process tomography techniques, in which both the quantum state and process fidelities exceeds the classical limit. These results pave the way for the realization of scalable quantum networks based on solid-state devices.
Phys. Rev. Lett. 135, 010804 (2025)
Quantum communication, Quantum communication, protocols & technology, Quantum memories, Quantum networks, Quantum repeaters, Quantum teleportation
Enhancing DUNE’s Solar Neutrino Capabilities with Neutral-Current Detection
Research article | Neutrino interactions | 2025-07-02 06:00 EDT
Stephan A. Meighen-Berger, Jayden L. Newstead, John F. Beacom, Nicole F. Bell, and Matthew J. Dolan
We show that the Deep Underground Neutrino Experiment (DUNE) has the potential to make a precise measurement of the total active flux of $^{8}\mathrm{B}$ solar neutrinos via neutral-current (NC) interactions with argon. This would complement proposed precise measurements of solar-neutrino fluxes in DUNE via charged-current (CC) interactions with argon and mixed $\mathrm{CC}/\mathrm{NC}$ interactions with electrons. Together, these would enable DUNE to make a Sudbury Neutrino Observatory (SNO)-like comparison of rates and thus to make the most precise measurements of ${\mathrm{sin}}^{2}{\theta }{12}$ and $\mathrm{\Delta }{m}{21}^{2}$ using solar neutrinos. Realizing this potential requires dedicated but realistic efforts to improve DUNE’s low-energy capabilities and separately to reduce neutrino-argon cross-section uncertainties. Comparison of mixing-parameter results obtained using solar neutrinos in DUNE and reactor antineutrinos in the Jiangmen Underground Neutrino Observatory (JUNO) would allow for unprecedented tests of new physics.
Phys. Rev. Lett. 135, 011803 (2025)
Neutrino interactions, Neutrino mixing, Nucleus-neutrino interactions, Solar neutrinos, Neutrinos, Neutrino detection
Dark Matter Internal Pair Production: A Novel Direct Detection Mechanism
Research article | Form factors | 2025-07-02 06:00 EDT
Bhaskar Dutta, Aparajitha Karthikeyan, Mudit Rai, and Hyunyong Kim
We introduce a new dark matter detection mechanism, dark matter internal pair production (DIPP), to detect dark matter candidates at beam dump facilities. When energetic dark matter scatters in a material, it can create a lepton-antilepton pair by exchanging a virtual photon with the nucleus, akin to the neutrino trident process. We demonstrate this process for dark matter coupled to dark photons in experiments such as DarkQuest, SBND, and DUNE ND. Since the lepton-antilepton pair carries a significant fraction of dark matter energy, it can be clearly distinguished from backgrounds. Utilizing the above features, we show that DIPP is highly effective at probing various dark matter models, particularly at DUNE ND and DarkQuest, by searching for electron-positron and muon-antimuon signatures. At DUNE ND, we find that the sensitivity of DIPP extends over a larger parameter space than the existing limits from electron and nuclear recoil. Additionally, we explore a scenario where dark sector couplings involve quarks and muons only, demonstrating that DIPP can probe a wide variety of dark matter models with different final states.
Phys. Rev. Lett. 135, 011804 (2025)
Form factors, Particle dark matter, Particle decays, Particle detection signatures, Particle interactions, Particle production, Phenomenology, Total cross sections
Bell Inequality Violation of Light Quarks in Dihadron Pair Production at Lepton Colliders
Research article | Fragmentation functions | 2025-07-02 06:00 EDT
Kun Cheng and Bin Yan
Spin correlations between particles produced at colliders provide valuable insights for quantum information studies. While traditional studies of quantum information at colliders are typically limited to massive particles with perturbative decay, we propose an innovative method to explore the Bell inequality in massless quark pair systems by analyzing the azimuthal correlations in ${\pi }^{+}{\pi }^{- }$ dihadron pair production at lepton colliders. Revisiting the Belle data, we have shown the potential to detect Bell inequality violation of light quarks by introducing an additional angular cut, achieving a significance of $2.5\sigma $ even in the worst-case scenario of 100% correlated systematic uncertainties in each bin. The significance substantially exceeds $5\sigma $ when considering uncorrelated systematic uncertainties. Our approach opens avenues for exploring spin quantum information with nonperturbative processes as spin analyzer and leverages existing data for quantum information research.
Phys. Rev. Lett. 135, 011902 (2025)
Fragmentation functions, QCD phenomenology, Quantum entanglement, Light quarks, Spin
Effective-Range Expansion with a Long-Range Force
Research article | Hadron-hadron interactions | 2025-07-02 06:00 EDT
Meng-Lin Du, Feng-Kun Guo, and Bing Wu
The validity range of the time-honored effective range expansion can be very limited due to the presence of a left-hand cut close to the two-particle threshold. Such a left-hand cut arises in the two-particle interaction involving a light particle exchange with a small mass or a mass slightly heavier than the mass difference of the two particles, identified as a long-range force, a scenario encountered in a broad range of systems. This can hinder a precise extraction of low-energy scattering observables and resonance poles. To address this issue, we propose a new parametrization for the low-energy scattering amplitude that accounts for the left-hand cut. The parametrization is like a Pad'e approximation but with nonanalytic terms from the left-hand cut and can be regarded as an extension of the effective range expansion. This parametrization is versatile and applicable to a broad range of systems with Yukawa-type interactions, including particle, hadronic, nuclear, cold atom, and quantum gas systems. In particular, it should be invaluable in understanding various near-threshold hadron resonances. As byproducts, we also show that the parametrization can be used to extract the couplings of the exchanged particle to the scattering particles, and derive expressions for amplitude zeros caused by the interplay between the short- and long-range interactions.
Phys. Rev. Lett. 135, 011903 (2025)
Hadron-hadron interactions, Particle interactions, Phase shift, Scattering amplitudes
Exploiting $^{20}\mathrm{Ne}$ Isotopes for Precision Characterizations of Collectivity in Small Systems
Research article | Collective flow | 2025-07-02 06:00 EDT
Giuliano Giacalone, Benjamin Bally, Govert Nijs, Shihang Shen, Thomas Duguet, Jean-Paul Ebran, Serdar Elhatisari, Mikael Frosini, Timo A. Lähde, Dean Lee, Bing-Nan Lu, Yuan-Zhuo Ma, Ulf-G. Meißner, Jacquelyn Noronha-Hostler, Christopher Plumberg, Tomás R. Rodríguez, Robert Roth, Wilke van der Schee, and Vittorio Somà
Whether or not femto-scale droplets of quark-gluon plasma (QGP) are formed in so-called small systems at high-energy colliders is a pressing question in the phenomenology of the strong interaction. For proton-proton or proton-nucleus collisions the answer is inconclusive due to the large theoretical uncertainties plaguing the description of these processes. While upcoming data on collisions of $^{16}\mathrm{O}$ nuclei may mitigate these uncertainties in the near future, here we demonstrate the unique possibilities offered by complementing $^{16}\mathrm{O}+^{16}\mathrm{O}$ data with collisions of $^{20}\mathrm{Ne}$ ions. We couple both nuclear lattice effective field theory (NLEFT) and projected generator coordinate method (PGCM) ab initio descriptions of the structure of $^{20}\mathrm{Ne}$ and $^{16}\mathrm{O}$ to hydrodynamic simulations of $^{16}\mathrm{O}+^{16}\mathrm{O}$ and $^{20}\mathrm{Ne}+^{20}\mathrm{Ne}$ collisions at high energy. We isolate the imprints of the bowling-pin shape of $^{20}\mathrm{Ne}$ on the collective flow of hadrons, which can be used to perform quantitative tests of the hydrodynamic QGP paradigm. In particular, we predict that the elliptic flow of $^{20}\mathrm{Ne}+^{20}\mathrm{Ne}$ collisions is enhanced by as much as $1.174(8{)}{\mathrm{stat}}(31{)}{\mathrm{syst}}$ for NLEFT and $1.139(6{)}{\mathrm{stat}}(39{)}{\mathrm{syst}}$ for PGCM relative to $^{16}\mathrm{O}+^{16}\mathrm{O}$ collisions for the 1% most central events. At the same time, theoretical uncertainties largely cancel when studying relative variations of observables between two systems. This demonstrates a method based on experiments with two light-ion species for precision characterizations of the collective dynamics and its emergence in a small system.
Phys. Rev. Lett. 135, 012302 (2025)
Collective flow, Hydrodynamic models, Nuclear structure & decays, Quark-gluon plasma, Relativistic heavy-ion collisions, 20 ≤ A ≤ 38, 6 ≤ A ≤ 19, Ab initio calculations
$Z=14$ Magicity Revealed by the Mass of the Proton Dripline Nucleus $^{22}\mathrm{Si}$
Research article | Nuclear structure & decays | 2025-07-02 06:00 EDT
Y. M. Xing et al.
Using the $B\rho $-defined isochronous mass spectrometry technique, we conducted the first mass measurement of the proton dripline nucleus $^{22}\mathrm{Si}$. We confirm that $^{22}\mathrm{Si}$ is bound against particle emission with ${S}{p}/{S}{2p}=+1412(114)/+229(54)\text{ }\text{ }\mathrm{keV}$, fixing the proton dripline location for the Si element. By analyzing the mass differences of the neighboring $sd$-shell nuclei, we find that $^{22}\mathrm{Si}$ exhibits a doubly magic character similar to its mirror partner $^{22}\mathrm{O}$, and that the mirror energy difference of $^{22}\mathrm{Si}\text{- }^{22}\mathrm{O}$ deviates from the predictions assuming mirror symmetry. Gamow shell-model calculations reveal that the average occupations of valence protons in $^{22}\mathrm{Si}$ are nearly identical to those of valence neutrons in $^{22}\mathrm{O}$, supporting the $Z=14$ magicity in $^{22}\mathrm{Si}$. The observed mirror-symmetry breaking is attributed to the extended proton distribution in $^{22}\mathrm{Si}$ arising from a small contribution of the unbound $\pi 2{s}_{1/2}$ orbital.
Phys. Rev. Lett. 135, 012501 (2025)
Nuclear structure & decays
Observation of Non-Markovian Radiative Phenomena in Structured Photonic Lattices
Research article | Integrated optics | 2025-07-02 06:00 EDT
Rodrigo A. Vicencio, Fabiola G. L. Cárcamo-Macaya, Diego Román-Cortés, and Pablo Solano
The spectral structure of a photonic reservoir shapes radiation phenomena for embedded quantum emitters. We implement an all-optical analog to study such an effect, particularly to observe the non-Markovian radiation dynamics of an emitter coupled to two-dimensional structured reservoirs. Its dynamics is simulated by light propagating through a photonic lattice, acting as a reservoir for an adjacent waveguide that mimics a coupled quantum emitter. We study radiation dynamics in square and Lieb lattices under different coupling regimes and observe how the flat band properties of the Lieb lattice significantly enhances light-matter coupling and non-Markovianity. Our platform opens a path for the experimental exploration of single-photon quantum optical phenomena in structured reservoirs to enhance light-matter interactions.
Phys. Rev. Lett. 135, 013601 (2025)
Integrated optics, Quantum optics with artificial atoms, Superradiance & subradiance
Thermal Effects in the Casimir Torque between Birefringent Plates
Research article | Casimir effect & related phenomena | 2025-07-02 06:00 EDT
Benjamin Spreng and Jeremy N. Munday
The Casimir effect, originating from quantum and thermal fluctuations, is well known for inducing forces between closely spaced surfaces. When these surfaces are optically anisotropic, these interactions can produce a Casimir torque that rotates the surfaces relative to each other. We investigate, for the first time, the influence of thermal fluctuations on the Casimir torque between birefringent plates. Our results reveal that thermal modes significantly diminish the torque, with reductions up to 2 orders of magnitude for highly birefringent materials. Temperature is also shown to alter the angular dependence of the torque, significantly deviating from the typical sinusoidal behavior, and becomes particularly important at large separations that exceed the thermal wavelength. Finally, we demonstrate that systems of dissimilar birefringent plates that exhibit a distance-dependent reversal in the torque’s directions can enable precise control of the torque’s magnitude and sign through temperature manipulation. These findings advance our understanding of quantum and thermal fluctuation interplay and provide a framework for designing innovative nanoscale sensors and devices leveraging Casimir torque phenomena.
Phys. Rev. Lett. 135, 013602 (2025)
Casimir effect & related phenomena
Structured Squeezed Light Allows for High-Harmonic Generation in Classical Forbidden Geometries
Research article | High-order harmonic generation | 2025-07-02 06:00 EDT
J. Rivera-Dean, P. Stammer, M. F. Ciappina, and M. Lewenstein
High-harmonic generation (HHG) is a nonlinear process in which a strong driving field interacts with a material, resulting in the frequency up-conversion of the driver into its high-order harmonics. This process is highly sensitive to the field’s polarization: circular polarization, for instance, inhibits HHG. In this Letter, we demonstrate that the use of nonclassical structured light enables HHG in this otherwise prohibitive configuration for classical drivers. We consider circularly polarized light with nonclassical fluctuations, introduced via squeezing along one polarization direction, and show that these nonclassical features prompt the HHG process. We find that the spectral properties of the emitted harmonics depend on the type of squeezing applied and, by analyzing the inner electron dynamics, we relate the observed differences to modifications of the HHG three-step mechanism induced by the specific squeezing type. This approach opens new pathways for integrating quantum optics in HHG, providing novel means of controlling the light-matter interaction dynamics.
Phys. Rev. Lett. 135, 013801 (2025)
High-order harmonic generation, Multiphoton or tunneling ionization & excitation, Quantum optics, Quantum states of light
Particle Acceleration in Collisionless Magnetically Arrested Disks
Research article | Space & astrophysical plasma | 2025-07-02 06:00 EDT
Jesse Vos, Benoît Cerutti, Monika Mościbrodzka, and Kyle Parfrey
We present the first collisionless realization of two-dimensional axisymmetric black hole accretion consistent with a persistent magnetically arrested disk state. The accretion flow, consisting of an ion-electron disk plasma combined with magnetospheric pair creation effects, is simulated using first-principles general-relativistic particle-in-cell methods. The simulation is evolved over significant dynamical timescales during which a quasisteady accretion state is reached with several magnetic flux eruption cycles. We include a realistic treatment of inverse Compton scattering and pair production, which allows for studying the interaction between the collisionless accretion flow and pair-loaded jet. Our findings indicate that magnetic flux eruptions associated with equatorial magnetic reconnection within the black hole magnetosphere and the formation of spark gaps are locations of maximal particle acceleration. Flux eruptions, starting near the central black hole, can trigger Kelvin-Helmholtz-like vortices at the jet-disk interface that facilitate efficient mixing between disk and jet plasma in this region. Transient periods of increased pair production following magnetic flux eruptions and reconnection events are responsible for most of the highly accelerated particles.
Phys. Rev. Lett. 135, 015201 (2025)
Space & astrophysical plasma, Accretion disk & black-hole plasma, Astronomical black holes, Relativistic plasmas, Particle-in-cell methods
Quantum Phases and Transitions of Bosons on a Comb Lattice
Research article | Bose-Einstein condensates | 2025-07-02 06:00 EDT
Leo Radzihovsky and Emil Pellett
Motivated to elucidate the nature of quantum phases and their criticality when entangled with a correlated quantum bath, we study interacting bosons on a ‘’comb lattice’’—a one-dimensional backbone (system) coupled at its sites to otherwise independent one-dimensional ‘’teeth’’ chains (bath). We map out the corresponding phase diagram, detailing the nature of the phases and phase transitions. Controlled by the backbone and teeth hopping amplitudes, short-range interactions, and chemical potential, phases include a Mott insulator, backbone, and teeth Luttinger liquids and the long-range ordered incoherent superfluid. We explore their properties and potential realizations in condensed matter and cold-atom experiments and simulations.
Phys. Rev. Lett. 135, 016001 (2025)
Bose-Einstein condensates, Bosons, Cold atoms & matter waves, Cold gases in optical lattices, Critical phenomena, Quantum phase transitions, Quantum statistical mechanics
Toward Numerically Exact Computation of Conductivity in the Thermodynamic Limit of Interacting Lattice Models
Research article | Electrical conductivity | 2025-07-02 06:00 EDT
Jeremija Kovačević, Michel Ferrero, and Jakša Vučičević
Computing dynamical response functions in interacting lattice models is a long-standing challenge in condensed matter physics. In view of recent results, the dc resistivity ${\rho }{\mathrm{dc}}$ in the weak-coupling regime of the Hubbard model is of great interest, yet it is not fully understood. The challenge lies in having to work with large lattices while avoiding analytical continuation. The weak-coupling ${\rho }{\mathrm{dc}}$ results were so far computed at the level of the Boltzmann theory and at the level of the Kubo bubble approximation, which neglects vertex corrections. Neither theory was so far rigorously proven to give exact results even at infinitesimal coupling, and the respective dc resistivity results differ greatly. In this Letter we develop, cross-check and apply two state-of-the-art methods for obtaining dynamical response functions. We compute the optical conductivity at weak coupling in the Hubbard model in a fully controlled way, in the thermodynamic limit, and without analytical continuation. We show that vertex corrections persist to infinitesimal coupling, with a constant ratio to the Kubo bubble. We connect our methods with the Boltzmann theory, and show that the latter applies additional approximations that lead to quantitatively incorrect scaling of ${\rho }_{\mathrm{dc}}$ with respect to the coupling constant.
Phys. Rev. Lett. 135, 016502 (2025)
Electrical conductivity, Optical conductivity, Strongly correlated systems, Boltzmann theory, Diagrammatic methods, Hubbard model, Monte Carlo methods, Nonequilibrium Green’s function, Perturbation theory
Strong Nonlinear Response of Strange Metals
Research article | Third order nonlinear optical processes | 2025-07-02 06:00 EDT
Serhii Kryhin, Subir Sachdev, and Pavel A. Volkov
We show that nonlinear transport responses in strange metals are strong, larger by a factor of ${E}_{F}/T$ than in Fermi liquids. Within the two-dimensional Yukawa-Sachdev-Ye-Kitaev model of a Fermi surface with a spatially random coupling to a critical scalar, the third order conductivity is found to diverge as $1/T$ at low $T$, indicating the existence of a voltage-temperature scaling regime in the conductance. Its frequency and orientation dependence contains information on relaxation times of heat and electron distribution deformations, providing a new set of tools to characterize strange metals.
Phys. Rev. Lett. 135, 016503 (2025)
Third order nonlinear optical processes, Metals, Strongly correlated systems, Nonequilibrium Green’s function, Sachdev-Ye-Kitaev model
Quantum Orbital-State Control of a Neutral Nitrogen-Vacancy Center at Millikelvin Temperatures
Research article | Coherent control | 2025-07-02 06:00 EDT
Hodaka Kurokawa, Shintaro Nakazato, Toshiharu Makino, Hiromitsu Kato, Shinobu Onoda, Yuhei Sekiguchi, and Hideo Kosaka
A neutral nitrogen-vacancy center (${\mathrm{NV}}^{0}$) is promising for realizing strong coupling with a single microwave photon due to its large electric field sensitivity, although it is susceptible to environmental phonon noise at 5 K. Decreasing the temperature to 15 mK results in a tenfold increase in orbital relaxation time compared to that at 5 K. Dynamical decoupling pulses significantly increase the orbital coherence time to more than $1.6\text{ }\text{ }\mathrm{\mu }\mathrm{s}$, representing a 30-fold improvement compared to that without decoupling pulses. Based on these results, a single ${\mathrm{NV}}^{0}$ can reach the strong coupling regime when coupled with a high-impedance microwave resonator, thus opening up the possibility of microwave quantum electrodynamics using a single optically active defect center in diamond.
Phys. Rev. Lett. 135, 016902 (2025)
Coherent control, Quantum control, Nitrogen vacancy centers in diamond, Confocal imaging, Dilution refrigerator, Photoemission
Photonic Bilayer Chern Insulator with Corner States
Research article | Photonics | 2025-07-02 06:00 EDT
Subhaskar Mandal, Ziyao Wang, Rimi Banerjee, Hau Tian Teo, Minggui Wei, Peiheng Zhou, Xiang Xi, Zhen Gao, Gui-Geng Liu, and Baile Zhang
Photonic Chern insulators can be implemented in gyromagnetic photonic crystals with broken time-reversal (TR) symmetry. They exhibit gapless chiral edge states (CESs), enabling unidirectional propagation and demonstrating exceptional resilience to localization even in the presence of defects or disorders. However, when two Chern insulators with opposite Chern numbers are stacked together, this one-way nature can be nullified, causing the originally gapless CESs to become gapped. Recent theoretical works have proposed achieving such a topological phase transition in condensed matter systems using antiferromagnetic thin films such as ${\mathrm{MnBi}}{2}{\mathrm{Te}}{4}$ or by coupling two quantum spin/anomalous Hall insulators, but these approaches have yet to be realized experimentally. In a bilayer gyromagnetic photonic crystal arranged in an antiferromagnetic layer configuration, our experimental observations reveal that interlayer coupling initiates a transition from a Chern insulating phase to a higher-order topological phase. This transition results in the gapping of CESs and triggers the emergence of corner states within the band gap. The corner mode energy within this gap originates from CES interactions, forming a Jackiw-Rebbi-type topological domain wall mode at the corner, which is expected to remain within the bulk band gap without relying on local symmetries such as chiral or particle-hole symmetry. These states exhibit heightened resilience against defects, distinguishing them from their TR-symmetric counterparts.
Phys. Rev. Lett. 135, 016903 (2025)
Photonics, Topological effects in photonic systems, Layered crystals, Topological materials
Near-Infrared Spectroscopic Sensing of Hydrogen Order in Ice XIII
Research article | Chemical Physics & Physical Chemistry | 2025-07-02 06:00 EDT
Christina M. Tonauer, Eva-Maria Köck, Raphael Henn, Christoph Kappacher, Christian W. Huck, and Thomas Loerting
Infrared spectroscopy performed on high-pressure ice phases demonstrates a possible technique for studying ice on other planets or moons.
Phys. Rev. Lett. 135, 018002 (2025)
Chemical Physics & Physical Chemistry, Crystal phenomena, Hydrogen bonds, Laboratory studies of space & astrophysical plasmas, Optical, UV, & IR astronomy, Phase diagrams, Solid-state chemistry, Ice, Water, Infrared spectroscopy, Spectroscopy
Machine Learning Potential for Electrochemical Interfaces with Hybrid Representation of Dielectric Response
Research article | Dielectric properties | 2025-07-02 06:00 EDT
Jia-Xin Zhu and Jun Cheng
Understanding electrochemical interfaces at a microscopic level is essential for elucidating important electrochemical processes in electrocatalysis, batteries, and corrosion. While ab initio simulations have provided valuable insights into model systems, the high computational cost limits their use in tackling complex systems of relevance to practical applications. Machine learning potentials offer a solution, but their application in electrochemistry remains challenging due to the difficulty in treating the dielectric response of electronic conductors and insulators simultaneously. In this Letter, we propose a hybrid framework of machine learning potentials that is capable of simulating metal-electrolyte interfaces by unifying the interfacial dielectric response accounting for local electronic polarization in electrolytes and nonlocal charge transfer in metal electrodes. We validate our method by reproducing the bell-shaped differential Helmholtz capacitance at the Pt(111)-electrolyte interface. Furthermore, we apply the machine learning potential to calculate the dielectric profile at the interface, providing new insights into electronic polarization effects. Our Letter lays the foundation for atomistic modeling of complex, realistic electrochemical interfaces using machine learning potential at ab initio accuracy.
Phys. Rev. Lett. 135, 018003 (2025)
Dielectric properties, Electrochemistry, Interface & surface thermodynamics, Liquid-solid interfaces
Twisting-Induced Instabilities in Double-Helix Chiral Rods
Research article | Bifurcations | 2025-07-02 06:00 EDT
G. Risso, M. Isbled, D. Melancon, and K. Bertoldi
Elastic rods exhibit complex, nonlinear mechanical behaviors, especially under combined axial tension and twisting. Our study focuses on the nonlinear response of double-helix chiral rods, structures that combine a cylindrical core with helically coiled reinforcements. Through experiments, analytical modeling, and finite element simulations, we reveal that twisting induces mechanical instabilities, leading to complex deformation patterns. These instabilities are heavily influenced by the interplay between the core and the helical reinforcements, with the resulting deformations showing strong sensitivity to geometric and material characteristics. The findings enhance our understanding of chiral rods, with potential applications in soft robotics and tunable optical devices.
Phys. Rev. Lett. 135, 018202 (2025)
Bifurcations, Continuum mechanics, Finite-element method
Physical Review X
Charge Pickup Reaction Cross Section for Neutron-Rich $p$-Shell Isotopes at $900A\text{ }\text{ }\mathrm{MeV}$
Research article | Charge-exchange reactions | 2025-07-02 06:00 EDT
J.-C. Zhang et al.
*et al.*Experiments reveal that neutron-to-proton conversion in light nuclear reactions at relativistic energies rises exponentially with neutron number, challenging prior models and allowing for refined nuclear reaction and astrophysics predictions.
Phys. Rev. X 15, 031004 (2025)
Charge-exchange reactions, Nuclear reactions, Unstable nuclei induced nuclear reactions, Radioactive beams
Spin-Forbidden Excitations in the Magneto-optical Spectra of ${\mathrm{CrI}}_{3}$ Tuned by Covalency
Research article | Excitons | 2025-07-02 06:00 EDT
Connor A. Occhialini, Luca Nessi, Luiz G. P. Martins, Ahmet Kemal Demir, Qian Song, Vicky Hasse, Chandra Shekhar, Claudia Felser, Kenji Watanabe, Takashi Taniguchi, Valentina Bisogni, Jonathan Pelliciari, and Riccardo Comin
Strong optical signals in the van der Waals magnet CrI3 arise from spin-forbidden chromium ion transitions enhanced by orbital hybridization with iodine atoms, offering new ways to detect and control magnetism in ultrathin materials.
Phys. Rev. X 15, 031005 (2025)
Excitons, Magnetism, Magneto-optics, Magnetic insulators, Van der Waals systems, Reflectivity, Resonant inelastic x-ray scattering
arXiv
Pedagogical approach to anomalous position and velocity
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-03 20:00 EDT
Younsik Kim, Suk Bum Chung, Changyoung Kim
In this work, we discuss a pedagogical method in deriving the expressions for anomalous position and velocity. While we follow the steps used in optics in the derivation of the group velocity, we use Bloch wave functions instead of plane wave states. In comparison to the plane wave case, application of Bloch wave functions results in two additional terms in the expression of the group velocity: the Berry phase factor and anomalous position contributions. These two new terms with distinct origins eventually lead to the known anomalous velocity. Aiming for an intuitive understanding, we simulate the situation under an electric field using linear-combination-of-atomic-orbital states and visually demonstrate that the envelope function exhibits the transverse motion expected from an anomalous velocity.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
In situ Study of Phase Transitions in La$2$NiO${4+δ}$ using Raman Spectroscopy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-03 20:00 EDT
Adeel Riaz, Alexander Stangl, Mónica Burriel, Michel Mermoux
La$ _2$ NiO$ _{4+\delta}$ has attracted increasing interest in recent years, both as oxygen electrode in solid oxide fuel cells and electrolysers due to its high electrochemical activity at intermediate to high temperatures, and as key component of memristive devices for neuromorphic computing, owing to its variable oxygen stoichiometry. The integration of La$ _2$ NiO$ _{4+\delta}$ into devices operating at different temperatures and oxygen partial pressures requires knowledge of the effects of hyper-stoichiometry ($ \delta$ ) on its crystalline structure. La$ _2$ NiO$ _{4+\delta}$ is known to accommodate oxygen at interstitial sites allowing for large delta values, up to ~ 0.16. In addition, the O-doping - temperature phase diagram is known to be complex, exhibiting several phase transitions with increasing delta. Herein, we use Raman spectroscopy to monitor the effects of O-doping in the phase diagram and the various structures it contains. Throughout this work, we studied this material in its usual ceramic form, as well as in the form of thin films. Results are discussed in terms of phase transitions, chemical expansion, and some of the possible consequences of the low mean grain size inherent to such thin films.
Materials Science (cond-mat.mtrl-sci)
Dynamic Models for Two Nonreciprocally Coupled Fields: A Microscopic Derivation for Zero, One, and Two Conservation Laws
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-03 20:00 EDT
Kristian Blom, Uwe Thiele, Aljaž Godec
We construct the dynamic models governing two nonreciprocally coupled fields for cases with zero, one, and two conservation laws. Starting from two microscopic nonreciprocally coupled Ising models, and using the mean-field approximation, we obtain closed-form evolution equations for the spatially resolved magnetization in each lattice. For single spin-flip dynamics, the macroscopic equations in the thermodynamic limit are closely related to the nonreciprocal Allen-Cahn equations, i.e. conservation laws are absent. Likewise, for spin-exchange dynamics within each lattice, the thermodynamic limit yields equations similar to the nonreciprocal Cahn-Hilliard model, i.e. with two conservation laws. In the case of spin-exchange dynamics within and between the two lattices, we obtain two nonreciprocally coupled equations that add up to one conservation law. For each of these cases, we systematically map out the linear instabilities that can arise. Our results provide a microscopic foundation for a broad class of nonreciprocal field theories, establishing a direct link between non-equilibrium statistical mechanics and macroscopic continuum descriptions.
Statistical Mechanics (cond-mat.stat-mech), Soft Condensed Matter (cond-mat.soft), Pattern Formation and Solitons (nlin.PS)
Weyl-Superconductivity revealed by Edge Mode mediated Nonlocal Transport
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-03 20:00 EDT
Wenyao Liu, Gabriel Natale, Camron Farhang, Michael Geiwitz, Kewen Huang, Qishuo Tan, Xingyao Guo, Mason Gray, Vincent Lamberti, Jazzmin Victorin, Huairuo Zhang, James L. Hart, Vsevolod Belosevich, Xi Ling, Qiong Ma, Wan Kyu Park, Kenji Watanabe, Takashi Taniguchi, Judy J. Cha, Albert V. Davydov, Kin Chung Fong, Ethan Arnault, Genda Gu, Rui-Xing Zhang, Enrico Rossi, Jing Xia, Kenneth S. Burch
Topological superconductivity (TSC) hosts exotic modes enabling error-free quantum computation and low-temperature spintronics. Despite preliminary evidence of edge modes, unambiguous signatures remain undetected. Here, we report the first observation of protected, non-local transport from the edge modes of the potential Weyl-superconductor \ch{FeTe_{0.55}Se_{0.45}}. Namely resonant charge injection, ballistic transport, and extraction via edge modes. An anomalous conductance plateau emerges only when topological, superconducting, and magnetic phases coexist, with source-drain contacts coupled via the edge. Moving the drain to the bulk switches the non-local transport process to a local Andreev process, generating a zero-bias conductance peak (ZBCP). The edge mode’s topological protection is confirmed by its insensitivity to external magnetic fields and increasing temperatures until the spontaneous magnetization is substantially suppressed. Our findings provide a new methodology to demonstrate TSC edge states in \ch{FeTe_{0.55}Se_{0.45}} via topologically protected non-local transport.
Superconductivity (cond-mat.supr-con)
30 pages, 4 figures
Trade-Offs in EuBa2Cu3Oy Films containing Artificial Pinning Centers: Higher Critical Currents yet Faster Vortex Creep
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-03 20:00 EDT
Jiangteng Liu, Masashi Miura, Daisaku Yokoe, Takeharu Kato, Akira Ibi, Teruo Izumi, Serena Eley
The electromagnetic properties of type-II superconductors depend on vortices-magnetic flux lines whose motion introduces dissipation that can be mitigated by pinning from material defects. The material disorder landscape is tuned by the choice of materials growth technique and incorporation of impurities that serve as vortex pinning centers. For example, metal organic deposition (MOD) and pulsed laser deposition (PLD) produce high-quality superconducting films with uncorrelated versus correlated disorder, respectively. Here, we study vortex dynamics in PLD-grown EuBa2Cu3Oy films containing varying concentrations of BaHfO3 inclusions and compare our results with those of MOD-grown (Y,Gd)Ba2Cu3Oy films. Despite both systems exhibiting behavior consistent with strong pinning theory, which predicts the critical current density J_c based on vortex trapping by randomly distributed spherical inclusions, we find striking differences in the vortex dynamics owing to the correlated versus uncorrelated disorder. Specifically, we find that the EuBa2Cu3Oy films grown without inclusions exhibit surprisingly slow vortex creep, comparable to the slowest creep rates achieved in (Y,Gd)Ba2Cu3Oy films containing high concentrations of BaHfO3. Whereas adding inclusions to (Y,Gd)Ba2Cu3Oy is effective in slowing creep, BaHfO3 increases creep in EuBa2Cu3Oy even while concomitantly improving J_c. Lastly, we find evidence of variable range hopping and that J_c is maximized at the BaHfO3 concentration that hosts a vortex or Bose glass state.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci)
Magnetocrystalline anisotropy of FeNi and FeCo along the Bain path
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-03 20:00 EDT
Nica Jane B. Ferrer, Gregory A. Fiete
We theoretically investigate magnetic anisotropy in materials with non-critical elements to determine which symmetry conditions and atomic shell filling favor enhanced magnetic anisotropy. We study the magnetocrystalline anisotropies (MCA) of the equiatomic ferrous compounds FeCo and FeNi using ab initio calculations and analytical approaches via the diatomic pair model. We find that when these materials undergo a Bain transformation, that is, the variation of the a and c lattice parameters adjust to interpolate between the B2 and L10 structural phases while keeping the unit cell volume constant, the MCA versus r = c/a ratio varies differently for FeCo and FeNi despite Co and Ni differing only by one valence electron. To uncover the physics governing these trends, we use a diatomic pair model to perform a theoretical analysis of the ab initio results. We find that the MCA variation along the Bain path is correlated with the structural phase of the material as well as the occupation of (l, m)-resolved states for each equiatomic ferrous compound. Accordingly, the MCA was found to differ depending on the element paired with Fe to form the Fe-X compound (X = Co, Ni). Our work could help guide the scientific community in solving the supply crisis of hard/strong permanent magnets that are crucial for various technological applications such as those depending on motors and generators for energy conversion and clean energy applications.
Materials Science (cond-mat.mtrl-sci)
9 pages, 7 figures
Localized and quasi-localized energy levels in the electron spectrum of graphene with isolated boron and nitrogen substitutions
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-03 20:00 EDT
S.B. Feodosyev, V.A. Sirenko, E.S. Syrkin, E.V. Manzhelii, I.S. Bondar, K.A. Minakova
Based on the calculation and analysis of local Green functions of impurity atoms of low concentration in a two-dimensional graphene lattice, the conditions for the formation and characteristics of local discrete levels with energies lying outside the band of the quasi-continuous spectrum and quasi-localized states with energies near the Fermi one are determined. Specific calculations were performed for boron and nitrogen impurity atoms, which can actually replace carbon in graphite and graphene nanostructures. For a boron impurity that forms local discrete levels outside the band of the quasi-continuous spectrum, sufficiently simple analytical expressions for the conditions for their formation, energy, intensity at the impurity atom, and damping parameter are obtained. An analysis of the formation of states quasi-localized on nitrogen impurities with energy near the Fermi level in graphene nanostructures was carried out.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Other Condensed Matter (cond-mat.other)
15 pages 6 figures
Fiz. Nizk. Temp.49, 34 (2023) [Low Temp. Phys. 49, 30 (2023)]
Searching for evidence of strengthening by short-range order in the CrCoNi medium entropy alloy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-03 20:00 EDT
The coupling of strength to short-range order (SRO) in the CrCoNi medium entropy alloy remains hotly debated, with conflicting reports supporting and opposing SRO-induced strengthening continuing to emerge. A direct understanding of this effect remains elusive, due to difficulties in the quantification of SRO. Here, we deliver a structurally agnostic analysis that searches for unusual patterns in crystal size effects as evidence of SRO-induced strengthening. For this purpose, we assemble a large dataset of strengthening measurements drawn from a range of thermomechanical processing conditions known to produce SRO. Based on a comparative analysis with pure metal benchmarks, we find no evidence for significant coupling of SRO to strengthening in CrCoNi, and that patterns interpreted as a positive finding are likely explained by cross-study measurement scatter. Nevertheless, we leverage our analysis to provide an upper bound estimate of SRO-induced strengthening in the unlikely scenario where other sources of scatter are negligible.
Materials Science (cond-mat.mtrl-sci)
Tensor network methods for the Gross-Pitaevskii equation on fine grids
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-07-03 20:00 EDT
Ryan J. J. Connor, Callum W. Duncan, Andrew J. Daley
The Gross-Pitaevskii equation and its generalisations to dissipative and dipolar gases have been very useful in describing dynamics of cold atomic gases, as well as polaritons and other nonlinear systems. For some of these applications the numerically accessible grid spacing can become a limiting factor, especially in describing turbulent dynamics and short-range effects of dipole-dipole interactions. We explore the application of tensor networks to these systems, where (in analogy to related work in fluid and plasma dynamics), they allow for physically motivated data compression that makes simulations possible on large spatial grids which would be unfeasible with direct numerical simulations. Analysing different non-equilibrium cases involving vortex formation, we find that these methods are particularly efficient, especially in combination with a matrix product operator representation of the quantum Fourier transform, which enables a spectral approach to calculation of both equilibrium states and time-dependent dynamics. The efficiency of these methods has interesting physical implications for the structure in the states that are generated by these dynamics, and provides a path to describe cold gas experiments that are challenging for existing methods.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
Dynamics of a dark soliton in a curved 1D Bose-Einstein condensate
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-07-03 20:00 EDT
Jorge A. G. Attie, Emanuel A. L. Henn
We investigate the nonlinear dynamics of dark solitons in a one-dimensional Bose-Einstein condensate confined to a curved geometry. Using the Gross-Pitaevskii equation in curvilinear coordinates and a perturbative expansion in the local curvature, we derive a set of coupled evolution equations for the soliton velocity and the curvature. For the case of constant curvature, such as circular geometries, the soliton dynamics is governed solely by the initial velocity and curvature. Remarkably, the soliton travels a nearly constant angular trajectory across two orders of magnitude in curvature, suggesting an emergent conserved quantity, independent of its initial velocity. We extend our analysis to elliptical trajectories with spatially varying curvature and show that soliton dynamics remain determined by the local curvature profile. In these cases, the model of effective constant curvature describes accurately the dynamics given the local curvature has smooth variation. When the soliton crosses regions of rapid curvature variation and/or non-monotonic behavior, the model fails to describe to soliton dynamics, although the overall behavior can still be fully mapped to the curvature profile. Our results provide a quantitative framework for understanding the role of geometry in soliton dynamics and pave the way for future studies of nonlinear excitations in curved quantum systems.
Quantum Gases (cond-mat.quant-gas), Pattern Formation and Solitons (nlin.PS)
25 pages with Appendix, 6 figures
Helical spin dynamics in Cu$_2$OSeO$_3$ as measured with small-angle neutron scattering
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-03 20:00 EDT
Victor Ukleev, Priya R. Baral, Robert Cubitt, Nina-Juliane Steinke, Arnaud Magrez, Oleg I. Utesov
The insulating chiral magnet Cu$ _2$ OSeO$ _3$ exhibits a rich array of low-temperature magnetic phenomena, making it a prime candidate for the study of its spin dynamics. Using spin wave small-angle neutron scattering (SWSANS), we systematically investigated the temperature-dependent behavior of the helimagnon excitations in the field-polarized phase of Cu$ _2$ OSeO$ _3$ . Our measurements, spanning 5-55 K, reveal the temperature evolution of spin-wave stiffness and damping constant with unprecedented resolution, facilitated by the insulating nature of Cu$ _2$ OSeO$ _3$ . These findings align with theoretical predictions and resolve discrepancies observed in previous studies, emphasizing the enhanced sensitivity of the SWSANS method. The results provide deeper insights into the fundamental magnetic properties of Cu$ _2$ OSeO$ _3$ , contributing to a broader understanding of chiral magnets.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
About the Strain-Coupled Molecular Dynamics in the Ferroelastic Phase Transition of TMACd(N$_3$)$_3$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-03 20:00 EDT
A. Nonato, R. X. Silva, C.C. Santos, A. P. Ayala, C.W.A. Paschoal
Tetramethylammonium (TMA) cadmium azide, is a new perovskite-like compound which undergoes a series of first-order phase transitions, including a ferroelastic transition above room temperature. Understanding the order-disorder structural phase transition (SPT) mechanism in hybrid organic–inorganic perovskites (HOIPs) is crucial for designing new compounds with enhanced barocaloric efficiency, as well as unlocking other multifunctional properties. In this paper, we employed the energy fluctuation (EF) model to investigate the experimental linewidth of Raman modes in TMACd(N$ _3$ )$ _3$ near the critical phase transition temperature ($ T_C = {322}{K}$ ), aiming to gain insights into the molecular dynamics around the SPT. The temperature dependence of the strain, used as an order parameter, was obtained using the appropriate thermodynamic potential for the first-order phase transition in TMACd(N$ _3$ )$ _3$ , expressed through a Landau expansion, which can be successfully employed to model first-order ferroelastic phase transitions. We show that the EF model suitably captures the behavior of the Raman linewidths in the vicinity of the structural phase transition in TMACd(N$ _3$ )$ _3$ . The activation energies obtained for TMACd(N$ _3$ )$ _3$ are comparable to those of DMACd(N$ _3$ )$ _3$ , as well as to $ k_B T_C$ . Additionally, the temperature dependence of the relaxation reveals that the torsional and librational modes require longer to renormalize after the phase transition in TMACd(N$ _3$ )$ _3$ when compared with DMACd(N$ _3$ )$ _3$ . The discussion based on these new parameters provides a new perspective for understanding molecular dynamics in systems undergoing order-disorder phase transitions, particularly in ferroelastic transitions, where order-disorder mechanisms are coupled to symmetry-breaking lattice distortions.
Materials Science (cond-mat.mtrl-sci)
Fractional Shapiro steps in a Cavity-Coupled Josephson ring condensate
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-07-03 20:00 EDT
Nalinikanta Pradhan, Rina Kanamoto, M. Bhattacharya, Pankaj Kumar Mishra
The Josephson effect presents a fundamental example of macroscopic quantum coherence as well as a crucial enabler for metrology (e.g. voltage standard), sensing (e.g. Superconducting Quantum Interference Device) and quantum information processing (Josephson qubits). Recently, there has been a major renewal of interest in the effect, following its observation in Bose, Fermi, and dipolar atomic condensates, in exciton-polariton condensates, and in momentum space. We present theoretically a nondestructive, \textit{in situ} and real time protocol for observing the AC and DC Josephson effects including integer (recently observed in cold atoms) and fractional (hitherto unobserved in cold atoms) Shapiro steps, using a ring condensate coupled to an optical cavity. Our analysis presents a metrology standard that does not require measurmement of atomic number and that challenges the conventional wisdom that quantum computations cannot be observed without being destroyed. Our results have implications for the fields of atomtronics, sensing, metrology and quantum information processing.
Quantum Gases (cond-mat.quant-gas)
7 pages, 4 figures
Autonomous Fabrication of Tailored Defect Structures in 2D Materials using Machine Learning-enabled Scanning Transmission Electron Microscopy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-03 20:00 EDT
Zijie Wu, Kevin M. Roccapriore, Ayana Ghosh, Kai Xiao, Raymond R. Unocic, Stephen Jesse, Rama Vasudevan, Matthew G. Boebinger
Materials with tailored quantum properties can be engineered from atomic scale assembly techniques, but existing methods often lack the agility and accuracy to precisely and intelligently control the manufacturing process. Here we demonstrate a fully autonomous approach for fabricating atomic-level defects using electron beams in scanning transmission electron microscopy (STEM) that combines advanced machine learning and automated beam control. As a proof of concept, we achieved controlled fabrication of MoS-nanowire (MoS-NW) edge structures by iterative and targeted exposure of $ MoS_2$ monolayer to a focused electron beam to selectively eject sulfur atoms, utilizing high-angle annular dark-field (HAADF) imaging for feedback-controlled monitoring structural evolution of defects. A machine learning framework combining a random forest model and convolutional neural networks (CNN) was developed to decode the HAADF image and accurately identify atomic positions and species. This atomic-level information was then integrated into an autonomous decision-making platform, which applied predefined fabrication strategies to instruct beam control about atomic sites to be ejected. The selected sites were subsequently exposed to localized electron beam using an FPGA-controlled scan routine with precise control over beam positioning and duration. While the MoS-NW edge structures produced exhibit promising mechanical and electronic properties, the proposed autonomous fabrication framework is material-agnostic and can be extended to other 2D materials for the creation of diverse defect structures and heterostructures beyond $ MoS_2$ .
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
19 pages, 5 figures
Thermodynamic bound on current fluctuations in coherent conductors
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-03 20:00 EDT
We derive a universal bound on the large-deviation functions of particle currents in coherent conductors. This bound depends only on the mean value of the relevant current and the total rate of entropy production required to maintain a non-equilibrium steady state, thus showing that both typical and rare current fluctuations are ultimately constrained by dissipation. Our analysis relies on the scattering approach to quantum transport and applies to any multi-terminal setup with arbitrary chemical potential and temperature gradients, provided the transmission coefficients between reservoirs are symmetric. This condition is satisfied for any two-terminal system and, more generally, when the dynamics of particles within the conductor are symmetric under time-reversal. For typical current fluctuations, we recover a recently derived thermodynamic uncertainty relation for coherent transport. To illustrate our theory, we analyze a specific model comprising two reservoirs connected by a chain of quantum dots, which shows that our bound can be saturated asymptotically.
Statistical Mechanics (cond-mat.stat-mech), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
20 pages, 2 figures
Ultralow-loss diamond nanomechanics enabled by van der Waals self-assembly
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-03 20:00 EDT
Guanhao Huang, Chang Jin, Sophie Weiyi Ding, Marko Lončar
Nanomechanical systems are critical platforms for precision measurement, sensing, macroscopic quantum physics, and emerging quantum-information technologies. In these applications, high mechanical quality factors, often achieved using dissipation dilution, are important since they directly enhance measurement sensitivity and quantum coherence. However, surface stiction intrinsic to nanoscale structures severely limits their performance. Here, we transform this longstanding obstacle into a solution for tension-enabled dissipation dilution, via a novel van der Waals (vdW) self-assembly method. Leveraging intrinsic nanoscale surface interactions, we achieve controlled tensile stresses up to 1.3GPa in single-crystal diamond–an ideal but notoriously difficult material to strain-engineer–without introducing additional interface losses. We demonstrate mechanical quality factors exceeding 100 million at 5K, surpassing state-of-the-art systems at comparable aspect ratios. This versatile approach, applicable to other crystalline materials, opens up avenues using cryogenic nanomechanical systems for ultra-precise quantum sensing, tests of quantum gravity, and hybrid quantum systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Quantum Physics (quant-ph)
14 pages, 11 figures
LOMS.cz: A computational platform for high-throughput Classical and Combinatorial Judd-Ofelt analysis and rare-earth spectroscopy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-03 20:00 EDT
Jan Hrabovský, Petr Vařák, Robin Kryštůfek
We present this http URL (Luminescence, Optical and Magneto-optical Software), an open-source computational platform that addresses the long-standing challenge of standardizing Judd-Ofelt (JO) calculations in rare-earth spectroscopy. Despite JO theory’s six-decade history as the fundamental framework for understanding $ 4f\leftrightarrow4f$ transitions, the field lacks standardized computational methodologies for precise and reproducible parameter determination. LOMS integrates three key innovations: (1) automated computation of JO parameters, transition probabilities, branching ratios, and theoretical radiative lifetimes, (2) a dynamically expanding database of experimentally validated parameters enabling direct comparison between computed and empirical results, and (3) a novel Combinatorial JO (C-JO) analysis algorithm that systematically identifies optimal absorption band combinations to ensure reliable parameter extraction. As a proof-of-concept, we demonstrate how this computational framework enables rapid screening of spectroscopic parameters, allowing researchers to predict optical properties with enhanced reliability. By combining automated analysis with experimental validation through its integrated database, this http URL establishes a standardized platform for accelerating the discovery and optimization of rare-earth-based photonic and optoelectronic materials.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph), Computational Physics (physics.comp-ph), Data Analysis, Statistics and Probability (physics.data-an), Optics (physics.optics)
New interactive software for Classical and Combinatorial Judd-Ofelt analysis
Type-1.5 SNSPD: Interacting vortex theory of two bandgap superconducting single photon detectors
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-03 20:00 EDT
Leif Bauer, Daien He, Sathwik Bharadwaj, Shunshun Liu, Prasanna V. Balachandran, Zubin Jacob
Photon detectors based on type-2 superconductors have found widespread applications from on-chip quantum computing to quantum remote sensing. Here, we develop the theory for a new class of type-1.5 superconducting nanowire single photon detectors (SNSPDs) based on two bandgap superconductors with high transition temperatures such as MgB2 (Tc ~38.6K). We show that vortex-vortex interactions in two component condensates lead to a unique operating regime where single photons can seed multiple vortices within a hotspot. We also show that dark counts are suppressed in the type-1.5 regime compared to the widely studied type-2 SNSPDs. Our work opens the door for exploring the unique vortex physics of two-gap superconductors for quantum device applications.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Instrumentation and Detectors (physics.ins-det)
12 pages, 4 figures
Hydrogen-based direct reduction of multicomponent oxides: Insights from powder and pre-sintered precursors toward sustainable alloy design
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-03 20:00 EDT
Shiv Shankar, Barak Ratzker, Yan Ma, Dierk Raabe
The co-reduction of metal oxide mixtures using hydrogen as a reductant in conjunction with compaction and sintering of the evolving metallic blends offers a promising alternative toward sustainable alloy production through a single, integrated, and synergistic process. Herein, we provide fundamental insights into hydrogen-based direct reduction (HyDR) of distinct oxide precursors that differ by phase composition and morphology. Specifically, we investigate the co-reduction of multicomponent metal oxides targeting a 25Co-25Fe-25Mn-25Ni (at.%) alloy, by using either a compacted powder (mechanically mixed oxides) comprising Co3O4-Fe2O3-Mn2O3-NiO or a pre-sintered compound (chemically mixed oxides) comprising a Co,Ni-rich halite and a Fe,Mn-rich spinel. Thermogravimetric analysis (TGA) at a heating rate of 10 °C/min reveals that the reduction onset temperature for the compacted powder was 175 °C, whereas it was significantly delayed to ~525 °C for the pre-sintered sample. Nevertheless, both sample types attained a similar reduction degree (80%) after isothermal holding for 1 h at 700 °C. Phase analysis and microstructural characterization of reduced samples confirmed the presence of metallic Co, Fe, and Ni alongside MnO. A minor fraction of Fe remains unreduced, stabilized in the (Fe,Mn)O halite phase, in accord with thermodynamic calculations. Furthermore, ~1 wt.% of BCC phase was found only in the reduced pre-sintered sample, owing to the different reduction pathways. The kinetics and thermodynamics effects were decoupled by performing HyDR experiments on pulverized pre-sintered samples. These findings demonstrate that initial precursor states influence both the reduction behavior and the microstructural evolution, providing critical insights for the sustainable production of multicomponent alloys.
Materials Science (cond-mat.mtrl-sci)
Scaling particle-size segregation in wide-ranging sheared granular flows
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-03 20:00 EDT
Tianxiong Zhao, Daisuke Noto, Xia Li, Tomás Trewhela, Hugo N. Ulloa
Scaling relationships have been proposed to describe shear-driven size segregation based on intruder experiments and simulations. While these models have shown agreement with experimental and numerical results under uniform shear rate, their validity across varying shear-rate conditions remains uncertain. Here, we employ Discrete Element Method (DEM) simulations to investigate particle size segregation in sheared granular flows under wide-ranging shear-rate conditions. We find that the scaling between segregation velocity and local rheological conditions holds only within a moderate inertial number range ($ 0.01 < I < 0.1$ ), and breaks down in both quasi-static and collisional regimes. Furthermore, we show that this discrepancy leads continuum models to mispredict segregation rates in bidisperse mixtures. These findings emphasize the need for more generalized scaling laws capable of capturing segregation dynamics across a broader spectrum of shear-rate conditions and regimes.
Soft Condensed Matter (cond-mat.soft), Fluid Dynamics (physics.flu-dyn), Geophysics (physics.geo-ph)
14 pages, 11 figures
Forbidden p-d Orbital Coupling Accelerates High-Power-Factor Materials Discovery
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-03 20:00 EDT
Wu Xiong, Zhongjuan Han, Zhonghao Xia, Zhilong Yang, Jiangang He
The intrinsic entanglement between electrical conductivity ($ \sigma$ ) and the Seebeck coefficient ($ S$ ) significantly constrains power factor (PF) enhancement in thermoelectric (TE) materials. While high valley degeneracy ($ N_{\mathrm{vk}}$ ) effectively balances $ \sigma$ and $ S$ to improve PF, identifying compounds with high $ N_{\mathrm{vk}}$ remains challenging. In this study, we develop an effective approach to rapid discover $ p$ -type semiconductors with high $ N_{\mathrm{vk}}$ through manipulating anion-$ p$ and cation-$ d$ orbital coupling. By prohibiting $ p$ -$ d$ orbital coupling at the $ \Gamma$ point, the valence band maximum shifts away from the $ \Gamma$ point (where $ N_{\mathrm{vk}}$ =1), thereby increasing $ N_{\mathrm{vk}}$ . Through the examination of the common irreducible representations of anion-$ p$ and cation-$ d$ orbitals at the $ \Gamma$ point, we identify 7 compounds with $ N_{\mathrm{vk}}$ $ \ge$ 6 from 921 binary and ternary semiconductors. First-principles calculations with electron-phonon coupling demonstrate that PtP$ _2$ , PtAs$ _2$ , and PtS$ 2$ exhibit exceptionally high PFs of 130, 127, and 82 $ \mu$ Wcm$ ^{-1}$ K$ ^{-2}$ at 300K, respectively, which are three to five times higher than those of the well-studied TE materials. This work not only elucidates the underlying mechanism of high $ N{\mathrm{vk}}$ formation through group theory, but also establishes an efficient high-PF material discovery paradigm, extended to more complex systems.
Materials Science (cond-mat.mtrl-sci)
11 pages, 5 figures
TeO2-BaO-Bi2O3 tellurite optical glasses II. – Linear and non-linear optical and magneto-optical properties
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-03 20:00 EDT
Jan Hrabovský, Jaden R. Love, Lukáš Střižík, Takayuki Ishibashi, Stefan Zollner, Martin Veis
The present study investigates the linear and non-linear optical and magneto-optical properties of TeO$ _2$ -BaO-Bi$ _2$ O$ _3$ (TeBaBi) glasses prepared by the conventional melt-quenching technique at 900 °C. Prepared glass composition ranges across the whole glass-forming-ability (GFA) region focusing on mutual substitution trends of constituent oxides, where TeO$ _2$ : 55-85 mol.%, BaO: 10-35 mol.%, Bi$ 2$ O$ 3$ : 5-15 mol.%. Studied glasses exhibit high values of linear ($ n{632} \approx$ 1.922-2.084) and non-linear refractive index ($ n_2\approx$ 1.63-3.45$ \times10^{-11}$ esu), Verdet constant ($ V{632} \approx$ 26.7-45.3 radT$ ^{-1}$ m$ ^{-1}$ ) and optical band gap energy ($ E_g \approx$ 3.1-3.6 eV). The introduction of TeO$ _2$ and Bi$ _2$ O$ _3$ results in increase of both linear/non-linear refractive index and Verdet constant, with a more pronounced influence of Bi$ _2$ O$ _3$ . Measured spectral dispersion of refractive index and Verdet constant were used for estimation of magneto-optic anomaly parameter ($ \gamma \approx$ 0.71-0.92), which may be used for theoretical modelling of magneto-optic response in diamagnetic TeBaBi glasses. Additionally, the properties of the prepared TeBaBi glasses were directly compared to those of the TeO$ _2$ -ZnO-BaO glass system, which was prepared and characterized under similar experimental conditions. The compositional dependence of the refractive index in both glass systems was described using multilinear regression analysis, demonstrating high correlation and uniformity of estimation across the entire GFA region. This makes them highly promising for precise dispersion engineering and construction of optical devices operating from visible to mid-infrared spectral region.
Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other), Applied Physics (physics.app-ph), Chemical Physics (physics.chem-ph), Optics (physics.optics)
D-wave condensates and the landscape of the 2D Hubbard model
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-03 20:00 EDT
Kazue Matsuyama, Jeff Greensite
We consider BCS-like states in the 2D Hubbard model which, starting from some arbitrary point in field space in the neighborhood of a Hartree-Fock ground state, are relaxed within that BCS ansatz to local minima of the energy. As in the Hartree-Fock approximation there are a vast number of local minima. What is new, and unlike the conventional Hartree-Fock states, is that there is a region in parameter (coupling-density) space, where these local minima are associated with d-wave condensates.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
7 pages, 6 figures
Structure and flow of low-dimensional water
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-03 20:00 EDT
Maxim Trushin, Daria V. Andreeva, Francois M. Peeters, Kostya S. Novoselov
Water, a subject of human fascination for millennia, is likely the most studied substance on Earth, with an entire scientific field – hydrodynamics – dedicated to understanding water in motion. However, when water flows through one-dimensional or two-dimensional channels, its behavior deviates substantially from the principles of hydrodynamics. This is because reducing the dimensionality of any interacting physical system amplifies interaction effects that are beyond the reach of traditional hydrodynamic equations. In low-dimensional water, hydrogen bonds can become stable enough to arrange water molecules into an ordered state, causing water to behave not only like a liquid but also like a solid in certain respects. In this review, we explore the relationship between water’s ordering and its ability to flow in low-dimensional channels, using viscosities of bulk water, vapor, and ice as benchmarks. We also provide a brief overview of the key theoretical approaches available for such analyses and discuss ionic transport, which is heavily influenced by the molecular structure of water.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci), Fluid Dynamics (physics.flu-dyn)
This a draft of the manuscript accepted for publication in Nature Reviews Physics. 13 pages incl. 160 references
Floquet spin textures in optically pumped non-Hermitian surface states
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-03 20:00 EDT
Xiao-Xiao Zhang, Naoto Nagaosa
Optical effects of quantum matter with interaction are key to physics and technology. The class of non-Hermitian (NH) phenomena is mostly explored in cold atoms, photonics, and metamaterials out of equilibrium. Effective NH systems due to interaction in equilibrium solids, however, provide a unique opportunity for realizing light-NH matter hybrids via periodic irradiation. Given NH topological surface states with magnetic disorder, here we reveal spectroscopically observable Floquet spin textures for this hybrid quantum matter: merged meron strings, dichroic skyrmions, and domain structure accompanying vortices in energy planes; Bloch lines and topologically twisted vortex rings distinct from Hopfions in energy-momentum space; topological selectiveness of linear polarization occurs besides circular dichroism. Spectroscopic energy evolution and chemical potential dependence are key ingredients of this open hybrid system. With spin-resolved photoemission spectroscopy, this scenario bears prime physical interest by reaching the crossroad between solid-state interaction effects, non-Hermiticity, and light-matter coupling.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
Communications Physics 8, 151 (2025)
Conformal Operator Flows of the Deconfined Quantum Criticality from $\mathrm{SO}(5)$ to $\mathrm{O}(4)$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-03 20:00 EDT
Shuai Yang, Liang-dong Hu, Chao Han, W. Zhu, Yan Chen
The deconfined quantum critical point (DQCP), which separates two distinct symmetry-broken phases, was conjectured to be an example of (2+1)D criticality beyond the standard Landau-Ginzburg-Wilson paradigm. However, this hypothesis has been met with challenges and remains elusive. Here, we perform a systematic study of a microscopic model realizing the DQCP with a global symmetry tunable from $ \mathrm{SO}(5)$ to $ \mathrm{O}(4)$ . Through the lens of fuzzy sphere regularization, we uncover the key information on the renormalization group flow of conformal operators. We reveal O(4) primaries decomposed from original SO(5) primaries by tracing conformal operator content and identifying the ``avoided level crossing’’ in the operator flows. In particular, we find that the existence of a scalar operator, in support of the nature of pseudo-criticality, remains relevant, persisting from $ \mathrm{SO}(5)$ to $ \mathrm{O}(4)$ DQCP. This work not only uncovers the nature of O(4) DQCP but also demonstrates that the fuzzy sphere scheme offers a unique perspective on the renormalization group flow of operators in the study of critical phenomena.
Strongly Correlated Electrons (cond-mat.str-el)
Realization of a Kondo Insulator in a Multilayer Moire Superlattice
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-03 20:00 EDT
Qiran Wu, Jingyuan Cui, Ang-Kun Wu, Yuze Meng, Dongxue Chen, Li Yan, Lei Ma, Takashi Taniguchi, Kenji Watanabe, Shi-Zeng Lin, Su-Fei Shi, Yong-Tao Cui
Kondo insulators are a paradigmatic strongly correlated electron system, arising from the hybridization between itinerary conduction electrons and localized magnetic moments, which opens a gap in the band of conduction electrons. Traditionally, the known Kondo insulators are found in materials with f-electrons. Recent developments in two-dimensional (2D) moire systems provide a new approach to generate flat bands with strong electron correlation, which host localized moments at half filling. In this work, we demonstrate the realization of a Kondo insulator phase in a moire superlattice of monolayer WS2 / bilayer WSe2 which hosts a set of moire flat bands in the WSe2 layer interfacing the WS2 layer and dispersive bands in the other WSe2 layer. When both WSe2 layers are partially doped but with a total density of two holes per moire unit cell, an insulating state appears when the density of the moire band is below one hole per moire unit cell. The insulating state disappears above a certain threshold magnetic field and the system becomes metallic, which is a telltale signature of the Kondo insulator. The physics can be well explained by a periodic Anderson lattice model that includes both the on-site Coulomb repulsion in the moire flat band and the hybridization between moire flat and non-moire dispersive bands. Our results suggest that multilayer moire structures of transition metal dichalcogenides provide a tunable platform to simulate the Kondo insulator, which holds promise to tackle many critical open questions in the Kondo insulators.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Electronic structure and defect properties of Bi-doped GaN: origins of photoluminescence and optical absorption
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-03 20:00 EDT
Yujie Liu, Ishtiaque Ahmed Navid, Zetian Mi, Emmanouil Kioupakis
Extreme lattice-mismatched III-V nitrides, such as Bi-incorporated GaN, have been realized experimentally thanks to recent advances in epitaxial growth and characterization techniques. However, theoretical insights into defect-related optical absorption and emission phenomena in these materials remain scarce. Here, we apply hybrid density functional theory to systematically explore the role of substitutional bismuth atoms on both cationic $ \mathrm{Bi_{Ga}}$ and anionic $ \mathrm{Bi_{N}}$ sites in Bi-incorporated GaN, as well as their complexes with native vacancies. Our calculations reveal that the charge-compensated defect complexes $ (\mathrm{Bi_{N}} + \mathrm{V_{Ga}})^{3-}$ and $ (\mathrm{Bi_{N}} + \mathrm{V_{Ga}})^{3+}$ stabilize anionic bismuth incorporation, accounting for the experimentally observed absorption peaks at ~1.11 eV and ~3.17 eV. We further uncover the origins of the reported band-edge emissions near 2.0 eV and 2.5 eV by examining various charge states of $ \mathrm{Bi_{Ga}}$ and $ \mathrm{Bi_{N}}$ centers. Our findings elucidate the defect-level physics of Bi-doped GaN and provide practical guidelines for controlling the incorporation of Bi into GaN.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
4 pages, 3 figures
Reliable Magnetometry for Antiferromagnets and Thin Films: Correcting Substrate Artifacts in Mn3Sn/MgO Systems
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-03 20:00 EDT
The rapid progress in antiferromagnetic and altermagnetic spintronics has led to increased interest in magnetic materials with vanishing net magnetization but strong spin-dependent transport properties. As thin films of such materials become central to device concepts, precise magnetic characterization is essential, for quantify intrinsic moments, and interpret transport signatures such as the anomalous Hall effect. In this work, we show that commercial MgO substrates, commonly used in epitaxial growth, often produce substantial parasitic magnetic signals that can match or exceed the response of weakly magnetic films. We identify two major components: a low-field ferromagnetic-like contribution originating from epi-ready surface, and a temperature-dependent paramagnetic background associated with dilute bulk impurities. These artifacts vary between samples and cannot be corrected using standard linear background subtraction or a measured reference substrate. To address this, we develop and put forward a compensation scheme which combines two complementary, non-destructive measurement protocols. We demonstrate up to 97% efficacy without requiring prior measurements of the bare substrate. The proposed framework enables reliable extraction of intrinsic magnetic signals and provides a general strategy for high-fidelity magnetometry in weakly magnetic thin-film systems, including emerging classes of materials such as topological phases and two-dimensional magnets. We also report the diamagnetic susceptibility of crystalline MgO, chi_MgO = -4.0 x 10^-7 emu/g/Oe.
Materials Science (cond-mat.mtrl-sci)
18 pages, 12 figures
Two-Dimensional Superconductivity at the CaZrO3/KTaO3 (001) Heterointerfaces
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-03 20:00 EDT
Lu Chen, Siyi Zhou, Daming Tian, Yinan Xiao, Qixuan Gao, Yongchao Wang, Yuansha Chen, Fengxia Hu, Baogen Shen, Jirong Sun, Weisheng Zhao, Jinsong Zhang, Hui Zhang
We investigated the superconducting transport properties of two-dimensional electron gases (2DEGs) at (001)-oriented CaZrO3/KTaO3 (CZO/KTO) heterointerfaces. Our results unambiguously demonstrate the emergence of two-dimensional superconductivity, with a superconducting transition TC up to ~0.25 K. The two-dimensional nature of the superconducting state is corroborated by the Berezinskii-Kosterlitz-Thouless (BKT) transition and pronounced anisotropy of the upper critical field. The estimated superconducting layer thickness and coherence length are 10.1 nm and 146.4 nm, respectively, for the sample with nS=7.7\ast10^13 cm^-2. Furthermore, we demonstrate that the two-dimensional superconductivity at the CZO/KTO(001) interface can be effectively tuned by applying a back gate voltage. These findings conclusively establish two-dimensional superconductivity at the CZO/KTO(001) interfaces, providing a new platform for exploring emergent superconductivity in complex oxide heterostructures.
Superconductivity (cond-mat.supr-con)
7 Pages,4 figures
Magnetic Ground State and Spin Excitations in the 2D Trimerized Collinear-II Lattice Antiferromagnet Li2Ni3P4O14
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-03 20:00 EDT
K. S. Chikara, A. K. Bera, A. Kumar, S. M. Yusuf, F. Orlandi, C. Balz
We report the magnetic ground state, spin excitations, and spin Hamiltonian of the 2D spin-1 trimerized Heisenberg antiferromagnet Li2Ni3P4O14. Below the magnetic ordering temperature TN = 14.5 K, the compound exhibits a canted long-range antiferromagnetic order with a propagation vector k = (0 0 0), consistent with the magnetic space group P21/c.1 (No. 14.75). The ground state magnetic structure consists of ferromagnetic spin-trimers of Ni2+ ions. The spin-trimers are coupled antiferromagnetically along the c-axis and ferromagnetically along the a-axis. Inelastic neutron scattering (INS) reveals gapped and dispersive magnon excitations below the TN, and gapless quasi-elastic scatterings at higher temperature. The linear spin-wave theory simulations reveal the essential features of the excitation spectrum; by a spin Hamiltonian composed of ferromagnetic intra-trimer exchange interaction J1 and inter-trimer exchange interactions J2 (FM) and J3(AFM) within the bc plane. The J2 and J3 along the b-axis and c-axis, respectively, with strengths of J2/J1=0.79 and J3/J1=-0.91. In addition, a weak inter planer ferromagnetic exchange interaction J4 (|J4/J1|~0.12) is found along the a-axis. The determined exchange constants reveal a 2D trimerized Collinear-II spin lattice within the bc-plane. The analysis of INS spectra by linear spin-wave theory also yields a moderate single-ion anisotropy (D/J1=0.48) which accounts for the observed spin gap below TN as well as the metamagnetic transition near 44 kOe in dc magnetization (M vs H) curves. These findings identify Li2Ni3P4O14 as a rare realization of a two-dimensional trimerized spin system and offer the direct experimental confirmation of theoretically predicted magnon excitations, unveiling the fundamental characteristics of the expected excitation spectrum.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
22 pages, 10 figures, 4 tables
Interaction-induced magnetoconductivity, magnetoresistivity, and the Hall effect in massive-massless fermion mixtures
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-03 20:00 EDT
Yuping Huang, D. S. Eliseev, V. M. Kovalev, O. V. Kibis, Yu. Yu. Illarionov, I. G. Savenko
The presence of two types of holes, namely the Dirac holes and the heavy holes, in a two-dimensional sample exposed to a weak external permanent magnetic field leads to the emergence of the temperature and magnetic field-dependent contribution to the resistivity due to their interactions. Taking a HgTe-based two-dimensional semimetal as a testbed, we develop a theoretical model describing the role of interactions between the degenerate massive and Dirac particles for the resistivity in the presence of a classical magnetic field. If only the Dirac holes are present in the system, the magnetoconductivity acquires a finite interaction-induced contribution which would be vanishing for the parabolic spectrum. It demonstrates $ T^4 \ln(1/T)$ behavior at low temperatures for screened Coulomb interhole interaction potential, asymptotically reaching $ T^2$ with increasing temperature. However, the magnetoresistivity and the Hall effect are not affected by the Dirac holes interparticle correlations. Instead, the presence of two types of holes provides a finite contribution to the magnetoconductivity, magnetoresistivity, and the classical Hall effect resistivity. The temperature behavior of the magnetoconductivity here is $ T^2$ in the case of the short-range constant interparticle interaciton potential and $ T^2 \ln(1/T)$ for the bare unscreened Coulomb interaction.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Quantum Anharmonic Effects in Hydrogen-Bond Symmetrization of High-Pressure Ice
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-03 20:00 EDT
The nuclear quantum effects of hydrogen play a significant role in determining the phase stability of water ice. Hydrogen-bond symmetrization occurs as hydrogen atoms tunnel in a double-well potential, ultimately occupying the midpoint between oxygen atoms and transforming ice VIII into ice X under high pressure. Quantum fluctuations lower this transition from classical predictions of over 100 GPa to 60 GPa. We reveal that the Perdew-Burke-Ernzerhof functional underestimates the hydrogen double-well barrier, thus resulting in a transition pressure over 10 GPa lower than the strongly constrained and appropriately normed functional, which is validated against quantum Monte Carlo calculations. Nuclear quantum anharmonicity, treated via neural canonical transformation (NCT), reveals that this transition pressure is temperature-independent and observes a 2 GPa reduction when comparing the non-Gaussian flow models based wavefunction compared to the self-consistent harmonic approximation. Despite increasing pressure typically shortens chemical bonds and hardens phonon modes, NCT calculations reveal that hydrogen bond softens hydrogen-oxygen stretching in ice VIII upon pressure.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
6+2 pages, 4+2 figures
The principle of least action for random graphs
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-07-03 20:00 EDT
Ioannis Kleftogiannis, Ilias Amanatidis
We study the statistical properties of the physical action $ S$ for random graphs, by treating the number of neighbors at each vertex of the graph (degree), as a scalar field. For each configuration (run) of the graph we calculate the Lagrangian of the degree field by using a lattice quantum field theory(LQFT) approach. Then the corresponding action is calculated by integrating the Lagrangian over all the vertices of the graph. We implement an evolution mechanism for the graph by removing one edge per a fundamental quantum of time, resulting in different evolution paths based on the run that is chosen at each evolution step. We calculate the action along each of these evolution paths, which allows us to calculate the probability distribution of $ S$ . We find that the distribution approaches the normal(Gaussian) form as the graph becomes denser, by adding more edges between its vertices. The maximum of the probability distribution of the action corresponds to graph configurations whose spacing between the values of $ S$ becomes zero $ \Delta S=0$ , corresponding to the least-action (Hamilton) principle, which gives the path that the physical system follows classically. In addition, we calculate the fluctuations(variance) of the degree field showing that the graph configurations corresponding to the maximum probability of $ S$ , which follow the Hamilton’s principle, have a balanced structure between regular and irregular graphs.
Disordered Systems and Neural Networks (cond-mat.dis-nn), General Relativity and Quantum Cosmology (gr-qc), High Energy Physics - Lattice (hep-lat), Quantum Physics (quant-ph)
5 pages, 3 figures
Spin Systems Coupled to Photons: A Case study of Phase Transition in a One-Dimensional Classical Ferromagnetic Ising Spin Chain at Finite Temperature
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-03 20:00 EDT
Although one-dimensional classical spin chains do not exhibit phase transitions, we found that a phase transition does occur when they are coupled to a cavity photon mode. This provides one of the simplest examples demonstrating that finite-temperature superradiant phase transitions can emerge from long-range fully connected interactions mediated by photons and interactions within the material.
Statistical Mechanics (cond-mat.stat-mech)
8 pages
Levy-driven temporally quenched dynamic critical behavior in directed percolation
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-03 20:00 EDT
Yanyang Wang, Yuxiang Yang, Wei Li
Quenched disorder in absorbing phase transitions can disrupt the structure and symmetry of reaction-diffusion processes, affecting their phase transition characteristics and offering a more accurate mapping to real physical systems. In the directed percolation (DP) universality class, time quenching is implemented through the dynamic setting of transition probabilities. We developed a non-uniform distribution time quenching method in the (1+1)-dimensional DP model, where the random quenching follows a Lévy distribution. We use Monte Carlo (MC) simulations to study its phase structure and universality class. The critical point measurements show that this model has a critical region controlling the transition between the absorbing and active states, which changes as the parameter $ \beta $ , influencing the distribution properties varies. Guided by dynamic scaling laws, we measured the continuous variation of critical exponents: particle density decay exponent $ \alpha$ , total particle number change exponent $ \theta $ , and dynamic exponent $ z$ . This evidence establishes that the universality class of Lévy-quenched DP systems evolves with distribution properties. The Lévy-distributed quenching mechanism we introduced has broad potential applications in the theory and experiments of various absorbing phase transitions.
Statistical Mechanics (cond-mat.stat-mech)
The effect of doping layers position on the heterojunction sharpness in (In,Al)As/AlAs quantum dots
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-03 20:00 EDT
T. S. Shamirzaev, D. R. Yakovlev, M. Bayer
Effect of doped layer placed in structures with indirect band-gap (In,Al)As/AlAs quantum dots (QDs) on heterointerface sharpness is investigated. We demonstrate that growth of n (p) doped layer below QDs sheet leads to pronounced deceleration (acceleration) for dynamics of exciton recombination (which is very sensitive to heterointeface structure in these QDs) in compare with the undoped structure. Opposite, the placing of the same doped layers above the QDs sheet does not effect on the exciton recombination dynamic at all. The experimental data are explained by increase (decrease) charged vacancy formation rate in the cation sublattice, that result in QD/matrix interface bluring (sharping), with the increases in the electron (hole) concentration at this heterointerface formation. The thicknesses of the diffuse layer on QD/matrix heterointerface estimated is in range from 0 up to 5 in the lattice constant depending on doped layer placing.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Other Condensed Matter (cond-mat.other)
Looking Back: Field theory of transiently chiral active particles
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-03 20:00 EDT
Callum Britton, Gunnar Pruessner, Thibault Bertrand
We derive a Doi-Peliti Field Theory for transiently chiral active particles in two dimensions, that is, active Brownian particles that undergo tumbles via a diffusing reorientation angle. Using this framework, we compute the mean squared displacement for both uniformly distributed and fixed initial reorientations. We also calculate an array of orientation-based observables, to quantify the transiently chiral behaviour observed.
Statistical Mechanics (cond-mat.stat-mech)
26 pages, 7 figures
Defects Potentials for Two-Dimensional Topological Materials
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-03 20:00 EDT
Yuval Abulafia, Amit Goft, Nadav Orion, Eric Akkermans
For non-topological quantum materials, introducing defects can significantly alter their properties by modifying symmetry and generating a nonzero analytical index, thus transforming the material into a topological one. We present a method to construct the potential matrix configuration with the purpose of obtaining a non-zero analytical index, akin to a topological invariant like a winding or Chern number. We establish systematic connections between these potentials, expressed in the continuum limit, and their initial tight-binding model description. We apply our method to graphene with an adatom, a vacancy, and both as key examples illustrating our comprehensive description. This method enables analytical differentiation between topological and non-topological zero-energy modes and allows for the construction of defects that induce topology.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
A reentrancy of motility-induced phase separation in overdamped active Brownian particles
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-03 20:00 EDT
In a system of Self-Propelled Particles (SPPs), the combination of self-propulsion and excluded volume effects can result in a phase separation called Motility-Induced Phase Separation (MIPS). Previous studies reported that MIPS is one of the phenomena so-called “reentrant phase separation” ,i.e., MIPS is suppressed when the Péclet number $ Pe$ (dimensionless self-propelled speed) is sufficiently large. We used a fundamental model of SPPs, i.e., overdamped Active Brownian Partcles (ABPs), to investigate the mechanism of the reentrancy of MIPS. We expect that elucidating the conditions under which MIPS occur is important, since MIPS is a phenomenon that can occur in a wide range of SPPs systems, and the potential applications of MIPS can also be wide range. Detailed investigation of particle motion revealed that a entire particle cluster deforms due to multiple slip deformation (known as plastic deformation in materials science). As $ Pe$ increases, the frequency of occurrence of slip-lines increases, and the particle motion becomes fluid-like. Therefore, the shape of the cluster becomes unstable and the number of particles in the cluster decreases. Let $ \bf{f}{LA}$ be the local spatial average of the self-propelled force generated by the particles. The observation of the inhomogeneity in the magnitude and direction of $ \bf{f}{LA}$ shows that $ \bf{f}{LA}$ is large on the cluster surface and generally orients toward the cluster inside. We determined that $ \bf{f}{LA}$ generates stress on the cluster, and it causes the multiple slip deformation.
Soft Condensed Matter (cond-mat.soft)
10 pages, 10 figures
Prenematic Fluctuations in Nanoparticle-Hosted Systems
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-03 20:00 EDT
Szymon Starzonek, Krzysztof Górny, Zbigniew Dendzik, Dejvid Črešnar, Aleš Iglič
This study combines broadband dielectric spectroscopy (BDS) experiments with molecular dynamics (MD) simulations to investigate the influence of nanoparticle (NP) inclusions on pretransitional phenomena in a liquid crystal (LC) host. We aimed to fill the existing gap between macroscopic observations and their microscopic origins. Our experimental results on SiO$ _2$ -doped 5CB composites demonstrate that while NP additions do not significantly change the isotropic-nematic transition temperature ($ T_c$ ), the pretransitional effects exhibit universal behavior, confirmed by identical critical exponents across all samples. The observed systematic decrease in dielectric permittivity is explained by MD simulations, which reveal that nanoparticles act as “seeds” for topological defects, forcing the surrounding LC molecules into a “hedgehog” configuration. This static, defect-induced structure leads to a local antiparallel alignment and cancellation of molecular dipoles, providing a direct microscopic mechanism for the macroscopic dielectric response and successfully bridging the micro-macro scales.
Soft Condensed Matter (cond-mat.soft)
Low-temperature anomalies in 1D hard rods with soft attractive nearest-neighbor interactions
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-03 20:00 EDT
Previous experiments and numerical simulations have revealed that a limited number of two- and three-dimensional particle systems contract in volume upon heating isobarically. This anomalous phenomenon is known as negative thermal expansion (NTE). Recently, in a study by [I. Travěnec and L. Šamaj: J. Phys. A: Math. Theor. {\bf 58}, 195005 (2025)], exactly solvable one-dimensional fluids of hard rods with various types of soft purely repulsive nearest-neighbor interactions were examined at low temperatures. The presence of the NTE anomaly in such systems heavily depends on the shape of the core-softened potential and, in some cases, is associated with jumps in chain spacing of the equidistant ground state at certain pressures. This paper focuses on one-dimensional fluids of hard rods with soft nearest-neighbor interactions that contain a basin of attraction with just one minimum. The ground-state analysis reveals that, for certain potentials, increasing the pressure can lead to a discontinuous jump in the mean spacing between particles. The low-temperature analysis of the exact equation of state indicates that the NTE anomaly is present if the curvature of the interaction potential increases with the distance between particles or if the potential exhibits a singularity within the basin of attraction. Isotherms of the compressibility factor, which measures the deviation of the thermodynamic behavior of a real gas from that of an ideal gas, demonstrate typical plateau or double-plateau shapes in large intervals of particle density.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
30 pages, 12 figures
Rashba-induced spin Hall response in a disordered $WTe_2$ four-terminal structure
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-03 20:00 EDT
Swastik Sahoo, Satadeep Bhattacharjee, Bhaskaran Muralidharan
The paramount acumen for controlling spin transport properties in nonmagnetic materials is the usage of spin-orbit coupling (SOC). We propose a model to calculate the spin hall angle (SHA) for the elemental transition metal dichalcogenide compound, $ WTe_2$ entrenched on the intrinsic Rashba SOC. This model, is based on the Landauer-Buttiker formalism for quantum transport, and the $ 4$ -terminal device setup with the presence of disorder from random onsite potential fluctuations. The SHA, including the mean and RMS values, also illustrate the mesoscopic oscillations, and the values obtained are $ 25%$ and $ 30%$ , respectively. The variation pattern of charge and spin current, along with the mean and spin Hall conductance, can be a comparative measure for other TMDs and monolayer Xenes. To validate our outcomes, we compare our results with experimental data and numerically extract real-space simulation results based on the nearest-neighbor tight binding (NNTB) model. Also our results are in line with the scaling theory of localization. This work sets the stage to calculate the spin Hall angle and spin Hall conductivity for other elemental monolayer Xenes and TMDs, considering the intrinsic scattering mechanisms. An extension of this work will be to explore the possible spintronics applications for extrinsic scattering, including side-jump and skew-jump scattering processes.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
11 pages, 6 figures, 2 page supplementary
Tunable Dot Platform for Controlling Electron Flow in Graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-03 20:00 EDT
Fereshte Ildarabadi, Stephen R. Power
We introduce an innovative graphene-based architecture to control electronic current flows. The tunable dot platform (TDP) consists of an array of gated dots, with independently adjustable potentials, embedded in graphene. Inspired by Mie theory, and leveraging multiscattering effects, we demonstrate that tailored current behavior can be achieved due to the variety of possible dot configurations. Optimization is performed using differential evolution, which identifies configurations that maximize specific objectives, such as directing or splitting an electron beam by tuning the angular dependence of scattering. Our results demonstrate the potential of the TDP to provide precise control over induced current flows in graphene, making it a promising component for next-generation electronic and electron optic devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Single-shot parity readout of a minimal Kitaev chain
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-03 20:00 EDT
Nick van Loo, Francesco Zatelli, Gorm O. Steffensen, Bart Roovers, Guanzhong Wang, Thomas Van Caekenberghe, Alberto Bordin, David van Driel, Yining Zhang, Wietze D. Huisman, Ghada Badawy, Erik P.A.M. Bakkers, Grzegorz P. Mazur, Ramón Aguado, Leo P. Kouwenhoven
Protecting qubits from noise is essential for building reliable quantum computers. Topological qubits offer a route to this goal by encoding quantum information non-locally, using pairs of Majorana zero modes. These modes form a shared fermionic state whose occupation – either even or odd – defines the fermionic parity that encodes the qubit. Crucially, this parity cannot be accessed by any measurement that probes only one Majorana mode. This reflects the non-local nature of the encoding and its inherent protection against noise. A promising platform for realizing such qubits is the Kitaev chain, implemented in quantum dots coupled via superconductors. Even a minimal chain of two dots can host a pair of Majorana modes and store quantum information in their joint parity. Here we introduce a new technique for reading out this parity, based on quantum capacitance. This global probe senses the joint state of the chain and enables real-time, single-shot discrimination of the parity state. By comparing with simultaneous local charge sensing, we confirm that only the global signal resolves the parity. We observe random telegraph switching and extract parity lifetimes exceeding one millisecond. These results establish the essential readout step for time-domain control of Majorana qubits, resolving a long-standing experimental challenge.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
Hybrid antiferroelectric-ferroelectric domain walls in noncollinear antipolar oxides
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-03 20:00 EDT
Ivan N. Ushakov, Mats Topstad, Muhammad Z. Khalid, Niyorjyoti Sharma, Christoph Grams, Ursula Ludacka, Jiali He, Kasper A. Hunnestad, Mohsen Sadeqi-Moqadam, Julia Glaum, Sverre M. Selbach, Joachim Hemberger, Petra Becker, Ladislav Bohatý, Amit Kumar, Jorge Íñiguez-González, Antonius T. J. van Helvoort, Dennis Meier
Antiferroelectrics are emerging as advanced functional materials and are fertile ground for unusual electric effects. For example, they enhance the recoverable energy density in energy storage applications and give rise to large electromechanical responses. Here, we demonstrate noncollinearity in dipolar order as an additional degree of freedom, unlocking physical properties that are symmetry-forbidden in classical antiferroelectrics. We show that noncollinear order of electric dipole moments in K$ _3$ [Nb$ _3$ O$ _6$ |(BO$ _3$ )$ _2$ ] leads to a coexistence of antiferroelectric and ferroelectric behaviors. Besides the double-hysteresis loop observed in antiferroelectrics, a pronounced piezoresponse and electrically switchable domains are observed, separated by atomically sharp and micrometer-long charged domain walls. Hybrid antiferroelectric-ferroelectric responses are expected in a wide range of noncollinear systems, giving a new dimension to the research on antiferroelectrics and multifunctional oxides in general.
Materials Science (cond-mat.mtrl-sci)
Impurity immersed in a two-component few-fermion mixture in a one-dimensional harmonic trap
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-07-03 20:00 EDT
We investigate a one-dimensional three-component few-fermion mixture confined in a parabolic external trap, where one component contains a single particle acting as an impurity. Focusing on the many-body ground state, we analyze how the interactions between the impurity and the other components influence the system’s structure. For fixed interaction strengths within the mixture, we identify a critical interaction strength with the impurity for which the system undergoes a structural transition characterized by substantial change in its spatial features. We explore this transition from the point of view of correlations and ground-state susceptibility. We remarkably find that this transition exhibits unique universality features not previously observed in other systems, highlighting novel many-body properties existing in multi-component fermionic mixtures.
Quantum Gases (cond-mat.quant-gas)
Spin-disorder-induced angular anisotropy in polarized magnetic neutron scattering
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-03 20:00 EDT
I. Titov, M. Bersweiler, M.P. Adams, E.P. Sinaga, V. Rai, S. Liscak, M. Lahr, T.L. Schmidt, V.M. Kuchkin, A. Haller, K. Suzuki, N.-J. Steinke, D. Alba Venero, D. Honecker, J. Kohlbrecher, L.F. Barquin, A. Michels
We experimentally report a hitherto unseen angular anisotropy in the polarized small-angle neutron scattering (SANS) cross section of a magnetically strongly inhomogeneous material. Based on an analytical prediction using micromagnetic theory, the difference between the spin-up and spin-down SANS cross sections is expected to show a spin-disorder-induced anisotropy. The effect is particularly pronounced in inhomogeneous magnetic materials, such as nanoporous ferromagnets, magnetic nanocomposites, or steels, which exhibit large nanoscale jumps in the saturation magnetization at internal pore-matrix or particle-matrix interfaces. Analysis of the experimental neutron data constitutes a method for determining the exchange-stiffness constant. Our results are generic to the nuclear-magnetic interference terms contained in the polarized magnetic neutron scattering cross section and might also be of relevance to other neutron techniques.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Extremely Low Frequency Plasmons in Metallic Microstructures
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-03 20:00 EDT
JB Pendry, AJ Holden, WJ Stewart, I Youngs
The plasmon is a well established collective excitation of metals in the visible and near UV but at much lower frequencies dissipation destroys all trace of the plasmon and typical Drude behaviour sets in. We propose a mechanism for depression of the plasma frequency into the far infra red or even GHz band: periodic structures build of very thin wires dilute the average concentration of electrons and considerably enhance the effective electron mass through self-inductance. Computations replicate the key features and confirm our analytic theory. The new structure has novel properties not observed before in the GHz band, including some possible impact on superconducting properties.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Phys.Rev. Lett. 76 4773-6 (1996)
Phototactic Decision-Making by Micro-Algae
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-03 20:00 EDT
Shantanu Raikwar, Adham Al-Kassem, Nir S. Gov, Adriana I. Pesci, Raphaël Jeanneret, Raymond E. Goldstein
We study how simple eukaryotic organisms make decisions in response to competing stimuli in the context of phototaxis by the unicellular alga $ Chlamydomonas~reinhardtii$ . While negatively phototactic cells swim directly away from a collimated light beam, when presented with two beams of adjustable intersection angle and intensities, we find that cells swim in a direction given by an intensity-weighted average of the two light propagation vectors. This geometrical law is a fixed point of an adaptive model of phototaxis and minimizes the average light intensity falling on the anterior pole of the cell. At large angular separations, subpopulations of cells swim away from one source or the other, or along the direction of the geometrical law, with some cells stochastically switching between the three directions. This behavior is shown to arise from a population-level distribution of photoreceptor locations that breaks front-back symmetry of photoreception.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph), Cell Behavior (q-bio.CB)
6 pages, 5 figures, with Supplementary Material appended
Common superconducting transition in under and overdoped cuprate superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-03 20:00 EDT
Hércules H. Santana and, E. V. L. de Mello
Underdoped cuprate superconductors are believed to be strongly correlated with electronic systems with small phase stiffness leading to a large phase fluctuation region is known as the pseudogap state. With increasing doping it is generally agree that they become Fermi liquid, rendering the end of the superconductivity due to the sufficiently large electronic screening. However, this scenario does not stand against a recent experiment\cite{OverJJ2022} that combined magnetic susceptibility and Scanning Tunnelling Microscopy (STM) which measured superconducting gaps and amplitudes amid charge inhomogeneity far beyond the critical doping $ p_{\rm c} \approx 0.27$ . We reproduced these results by calculating the localized superconducting amplitudes that emerge out of charge inhomogeneities, which forms a mesoscopic granular superconductor with an array of Josephson junctions, whose average couplings determine the critical temperature $ T_{\rm c}$ . The calculations agree with the experiments and both yield that underdoped and overdoped compounds have superconducting long-range order by the same mechanism.
Superconductivity (cond-mat.supr-con)
6 pages, 4 figures submitted
More sophisticated is not always better: comparison of similarity measures for unsupervised learning of pathways in biomolecular simulations
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-03 20:00 EDT
Finding process pathways in molecular simulations such as the unbinding paths of small molecule ligands from their binding sites at protein targets in a set of trajectories via unsupervised learning approaches requires the definition of a suitable similarity measure between trajectories. We here evaluate the performance of four such measures with varying degree of sophistication, i.e., Euclidean and Wasserstein distances, Procrustes analysis and dynamical time warping, when analyzing trajectory data from two different biased simulation driving protocols in the form of constant velocity constraint targeted MD and steered MD. In a streptavidin-biotin benchmark system with known ground truth clusters, Wasserstein distances yielded the best clustering performance, closely followed by Euclidean distances, both being the most computationally efficient similarity measures. In a more complex A2a receptor-inhibitor system, however, the simplest measure, i.e., Euclidean distances, was sufficient to reveal meaningful and interpretable clusters.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph), Computational Physics (physics.comp-ph), Biomolecules (q-bio.BM)
This preprint is the unedited version of a manuscript that has been sent to a peer-reviewed scientific journal for consideration as article. Copyright with the authors and the publisher after publication
Electrostatics overcome acoustic collapse to assemble, adapt, and activate levitated matter
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-03 20:00 EDT
Sue Shi, Maximilian C. Hübl, Galien P. Grosjean, Carl P. Goodrich, Scott R. Waitukaitis
Acoustic levitation provides a unique method for manipulating small particles as it completely evades effects from gravity, container walls, or physical handling. These advantages make it a tantalizing platform for studying complex phenomena in many-particle systems, save for one severe limitation – particles suspended by sound interact via acoustic scattering forces, which cause them to merge into a single dense object. To overcome this “acoustic collapse”, we have developed a strategy that combines acoustic levitation with controlled electrostatic charging to assemble, adapt, and activate complex, many-particle systems. The key idea is to introduce electrostatic repulsion, which renders a so-called “mermaid” potential where interactions are attractive at short range and repulsive at long range. By controlling the balance between attraction/repulsion, we are able to levitate fully expanded structures where all particles are separated, fully collapsed structures where they are all in contact, and hybrid ones consisting of both expanded and collapsed components. We find that fully collapsed and expanded structures are inherently stable, whereas hybrid ones exhibit transient stability governed by acoustically unstable dimers. Furthermore, we show how electrostatics allow us to adapt between configurations on the fly, either by quasistatic discharge or discrete up/down charge steps. Finally, we demonstrate how large structures experience selective energy pumping from the acoustic field – thrusting some particles into motion while others remain stationary – leading to complex dynamics including coupled rotations and oscillations. Our approach provides an easy-to-implement and easy-to-understand solution to the pervasive problem of acoustic collapse, while simultaneously providing new insights into the assembly and activation of many-particle systems with complex interactions.
Soft Condensed Matter (cond-mat.soft)
Topological nodal $i$-wave superconductivity in PtBi$_2$
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-03 20:00 EDT
Susmita Changdar, Oleksandr Suvorov, Andrii Kuibarov, Setti Thirupathaiah, Grigoriy Shipunov, Saicharan Aswartham, Sabine Wurmehl, Iryna Kovalchuk, Klaus Koepernik, Carsten Timm, Bernd Büchner, Ion Cosma Fulga, Sergey Borisenko, Jeroen van den Brink
Most superconducting materials are well-understood and conventional in the sense that the pairs of electrons that cause the superconductivity by their condensation have the highest possible symmetry. Famous exceptions are the enigmatic high-$ T_c$ cuprate superconductors. Nodes in their superconducting gap are the fingerprint of their unconventional character and imply superconducting pairing of $ d$ -wave symmetry. Here, using angle-resolved photoemission spectroscopy, we observe that the Weyl semimetal PtBi$ _2$ harbors nodes in its superconducting gap, implying unconventional $ i$ -wave pairing symmetry. At temperatures below $ 10,\mathrm{K}$ , the superconductivity in PtBi$ _2$ gaps out its topological surface states, the Fermi arcs, while its bulk states remain normal. The nodes in the superconducting gap that we observe are located exactly at the center of the Fermi arcs, and imply the presence of topologically protected Majorana cones around this locus in momentum space. From this, we infer theoretically that robust zero-energy Majorana flat bands emerge at surface step edges. This not only establishes PtBi$ _2$ surfaces as unconventional, topological $ i$ -wave superconductors but also as a promising material platform in the ongoing effort to generate and manipulate Majorana bound states.
Superconductivity (cond-mat.supr-con)
3 figures embedded
Femtosecond signatures of optically induced magnons before ultrafast demagnetization
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-03 20:00 EDT
Reza Rouzegar (1), Oliver Franke (1), Gal Lemut (1), Oliver Gueckstock (1), Junwei Tong (1), Dieter Engel (2), Xianmin Zhang (3), Georg Woltersdorf (4), Piet Brouwer (1), Tobias Kampfrath (1), Quentin Remy (1) ((1) Department of Physics, Freie Universität Berlin, Berlin, Germany, (2) Max-Born-Institut für nichtlineare Optik und Kurzzeitspektroskopie, Berlin, Germany, (3) Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Material Science and Engineering, Northeastern University, Shenyang, China, (4) Institut für Physik, Martin-Luther-Universität Halle, Halle, Germany)
Optically induced demagnetization of 3d metallic ferromagnets proceeds as fast as ~100 fs and is a crucial prerequisite for spintronic applications, such as ultrafast magnetization switching and spin transport. On the 100 fs time scale, the magnetization dynamics is widely understood in the context of temperature models considering energy transfers between conduction electrons, magnons and crystal lattice. However, on even faster time scales, the flow of both angular momentum and energy between these subsystems has so far not been studied. Here, we measure ultrafast demagnetization by ultrabroadband THz-emission spectroscopy. We find that the rate of change of the magnetization does not rise instantaneously, but on a time scale as short as 10 fs. This rise is a signature that a transfer of angular momentum from the magnons to conduction electrons proceeds in less than 10 fs, before substantial demagnetization has happened. We further conclude that most of the spin dissipated by the lattice is transferred via magnon-lattice rather than electron-lattice interaction. These results show that the limiting speed of magnetization dynamics is not demagnetization, as generally believed, and harnessing the earliest magnon dynamics could be a new route towards an even faster spintronics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Midveins regulate the shape formation of drying leaves
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-03 20:00 EDT
Kexin Guo, Yafei Zhang, Massimo Paradiso, Yuchen Long, K. Jimmy Hsia, Mingchao Liu
Dried leaves in nature often exhibit curled and crumpled morphologies, typically attributed to internal strain gradients that produce dome-like shapes. However, the origin of these strain gradients remains poorly understood. Although leaf veins–particularly the midvein–have been suggested to influence shape formation, their mechanical role has not been systematically investigated. Here, we demonstrate that mechanical constraints imposed by the midvein play a crucial role in generating the diverse morphologies that emerge during leaf drying. Combining numerical simulations and theoretical analysis, we show that a uniformly shrinking leaf lamina constrained by a non-shrinking midvein gives rise to two distinct types of configurations: curling-dominated and folding-dominated morphologies. In the curling-dominated regime, both S-curled and C-curled shapes emerge, with C-curled configurations more commonly observed due to their lower elastic energy. In contrast, the folding-dominated regime features folding accompanied by edge waviness. Theoretical modeling reveals a linear relationship between midvein curvature and mismatch strain, consistent with simulation results. Moreover, we find that the morphological outcome is governed by the ratio of bending stiffnesses between the lamina and the midvein. We construct a comprehensive phase diagram for the transitions between different configurations. These findings provide a mechanical framework for understanding shape formation in drying leaves, offering new insights into natural morphing processes and informing the design of bio-inspired morphable structures.
Soft Condensed Matter (cond-mat.soft), Applied Physics (physics.app-ph), Biological Physics (physics.bio-ph)
19 pages, 9 figures
Correlation-driven quantum geometry effects in a Kondo system
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-03 20:00 EDT
Ruizi Liu, Zehan Chen, Xingkai Cheng, Xiaolin Ren, Yiyang Zhang, Xuezhao Wu, Chengping Zhang, Kun Qian, Ching Ho Chan, Junwei Liu, Kam Tuen Law, Qiming Shao
Quantum geometry, including quantum metric and Berry curvature, which describes the topology of electronic states, can induce fascinating physical properties. Symmetry-dependent nonlinear transport has emerged as a sensitive probe of these quantum geometric properties. However, its interplay with strong electronic correlations has rarely been explored in bulk materials, particularly in a Kondo lattice system. Here, we uncover correlation-driven quantum geometry in centrosymmetric antiferromagnetic iron telluride (FeTe). We experimentally observe the quantum metric quadrupole-induced third-order nonlinear transport, whose angular dependence reflects magnetic structure in FeTe. The nonlinear transport signals follow Kondo lattice crossover and vanish at high temperatures. Our theory suggests that a Kondo lattice formed at low temperatures explains the emergence of quantum geometry, which is induced by the opening of a hybridization gap near the Fermi energy. This discovery establishes a paradigm where quantum geometry arises not from static symmetry breaking but from dynamic many-body effects and provides a zero-field probe for sensing antiferromagnetic order.
Strongly Correlated Electrons (cond-mat.str-el)
19 pages, 4 figures for the manuscript
Tailoring hard magnetic properties of Fe2MnSn Heusler alloy via interstitial modification: A first-principles approach
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-03 20:00 EDT
Junaid Jami, Rohit Pathak, N. Venkataramani, K.G. Suresh, Amrita Bhattacharya
We employ first-principles calculations to explore interstitial engineering as a strategy to tailor the hard magnetic properties of Fe2MnSn Heusler alloy, establishing its potential as a rare-earth-free permanent magnet. By introducing light interstitial elements – B, C, H, N, O, and F – at varying concentrations (1.56-12.5 at%), we uncover significant enhancements in structural stability, magnetization, Curie temperature, and magnetocrystalline anisotropy. These dopants preferentially occupy octahedral interstitial sites in the hexagonal phase of Fe2MnSn, leading to localized lattice distortions that enhance its magnetic characteristics. Notably, at 12.5 at% doping, B, C, N, and O induce a critical transition from in-plane to out-of-plane magnetic anisotropy – achieved without 5d or rare-earth elements – highlighting a sustainable pathway to high-performance magnets. Among these, N-doped Fe2MnSn exhibits the highest uniaxial anisotropy (0.61 MJ/m^3), followed by the B-doped (0.44 MJ/m^3) alloy. The magnetization of the doped compounds surpasses that of conventional ferrites and gap magnets like MnAl and MnBi. The Curie temperature sees a substantial boost, reaching 1058 K for O-doped Fe2MnSn and 1000 K for the C-doped alloy. Although N-doping results in a modest increase in Tc (744 K vs. 729 K for the pristine alloy), it delivers superior hard magnetic properties, with the highest magnetic hardness (0.65) and an enhanced maximum energy product (0.36 MJ/m^3), making it a strong candidate for gap magnet applications. These findings highlight interstitial doping as a viable route to engineer rare-earth-free permanent magnets with optimized magnetic performance.
Materials Science (cond-mat.mtrl-sci)
Wilson Line and Disorder Invariants of Topological One-Dimensional Multiband Models
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-07-03 20:00 EDT
R. Moola, A. Mckenna, M. Hilke
Topological invariants, such as the winding number, the Chern number, and the Zak phase, characterize the topological phases of bulk materials. Through the bulk-boundary correspondence, these topological phases have a one-to-one correspondence to topological edge states, which are robust to certain classes of disorder. For simple models like the Su-Schrieffer-Heeger (SSH) model, the computation of the winding number and Zak phase are straightforward, however, in multiband systems, this is no longer the case. In this work, we introduce the unwrapped Wilson line across the Brillouin zone to compute the bulk topological invariant. This method can efficiently be implemented numerically to evaluate multiband SSH-type models, including models that have a large number of distinct topological phases. This approach accurately captures all topological edge states, including those overlooked by traditional invariants, such as the winding number and Zak phase. To make a connection to experiments, we determine the sign of the topological invariant by considering a Hall-like configuration. We further introduce different classes of disorder that leave certain edge states protected, while suppressing other edge states, depending on their symmetry properties. Our approach is illustrated using different one-dimensional models, providing a robust framework for understanding topological properties in one-dimensional systems.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
10 pages
Data-driven high-throughput search for the accelerated discovery of rare-earth-free permanent magnets
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-03 20:00 EDT
Junaid Jami, Nitish Bhagat, Amrita Bhattacharya
An integrated data-driven approach combined with a high-throughput framework based on first-principles calculations was used to discover novel rare-earth-free permanent magnets, focusing on binary alloys. Compounds were screened systematically based on their elemental composition, structure, stability, and magnetization. Density functional theory (DFT) calculations were performed on the selected candidates to evaluate their magnetocrystalline anisotropy energy (MAE) and Curie temperature (Tc), resulting in the identification of ten promising materials. A thorough literature review was done to assess reports of prior existence, which confirmed the novelty of ZnFe and Fe8N. Their ferromagnetic ground state was re-established through DFT, and structural stability was confirmed via negative formation enthalpies, phonon spectra, and elastic criteria. Tetragonal ZnFe and Fe8N exhibit high saturation magnetization (>1 T), large anisotropy constants (>0.5 MJ/m^3), and high Tc (>1200 K). Their magnetic hardness parameters (kappa = 0.85 for ZnFe and 0.70 for Fe8N) further support their potential as gap magnets. These findings highlight the efficacy of our high-throughput screening, which may serve as a theoretical blueprint for the experimental realization of these materials.
Materials Science (cond-mat.mtrl-sci)
1/ f noise and two-level systems in MBE-grown Al thin films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-03 20:00 EDT
Shouray Kumar Sahu, Yen-Hsun Glen Lin, Kuan-Hui Lai, Chao-Kai Cheng, Chun-Wei Wu, Elica Anne Heredia, Ray-Tai Wang, Yen-Hsiang Lin, Juainai Kwo, Minghwei Hong, Juhn-Jong Lin, Sheng-Shiuan Yeh
Aluminum thin films are essential to the functionalities of electronic and quantum devices, where two-level systems (TLS) can degrade device performance. MBE-grown Al films may appeal to these applications due to their low TLS densities. We studied the energy distributions of TLS densities, g(E), in 10-nm-thick MBE-grown and electron-beam evaporated Al films through 1/f noise measurements between 80 and 360 K. At 300 K, the noise magnitudes in MBE-grown films are about three times lower than in the electron-beam evaporated films, corresponding to the g(E) values about ten times lower in the former than in the latter. Compared with previously established observations, we identified that the 1/f noise was generated by thermally activated TLS at grain boundaries.
Materials Science (cond-mat.mtrl-sci)
6 pages, 5 figures
Investigating the Fermi-Hubbard model by the Tensor-Backflow method
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-03 20:00 EDT
Recently, a variational wave-function based on the tensor representation of backflow corrections has achieved state-of-the-art energy precision in solving Fermi-Hubbard-type models. However, the Fermi-Hubbard model is very challenging to solve, and the validity of a method relies on investigating the ground state’s physical property. For simplicity, we name the tensor representation of backflow corrections as the Tensor-Backflow in this work. We apply the Tensor-Backflow method to investigate the Fermi-Hubbard model on two-dimensional lattices as large as 256 sites, under various interaction strengths $ U$ , electron fillings $ n$ and boundary conditions. Energy precision can be further improved by considering more backflow terms, such as considering backflow terms from next-nearest-neighbours or from all sites. Energy extrapolations on 64-site lattices give competitive results to the gradient optimized fPEPS with the bond dimension as large as $ D$ =20. For cases of $ n$ =0.875 and $ U$ =8 on the $ 16\times 16$ lattice under open boundary condition, by considering nearest-neighbour backflow terms, obtained energy is only $ 4.5\times 10^{-4}$ higher than the state-of-the-art method fPEPS with the bond dimension $ D$ =20. For periodic boundary condition, the variational wave-function is not enforced on any prior symmetry, meanwhile linear stripe order is successfully obtained. Under the same filling and $ U$ =10,12, energies obtained from initializations with the obtained wave-function for $ U$ =8 are lower than that from direct optimizations, meanwhile energies are competitive to or even better than state-of-the-art tensor network methods. For cases of $ n$ =0.8 and 0.9375, results consistent with the phase diagram from AFQMC are obtained by direct optimizations.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
STEM Diffraction Pattern Analysis with Deep Learning Networks
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-07-03 20:00 EDT
Sebastian Wissel, Jonas Scheunert, Aaron Dextre, Shamail Ahmed, Andreas Bayer, Kerstin Volz, Bai-Xiang Xu
Accurate grain orientation mapping is essential for understanding and optimizing the performance of polycrystalline materials, particularly in energy-related applications. Lithium nickel oxide (LiNiO$ _{2}$ ) is a promising cathode material for next-generation lithium-ion batteries, and its electrochemical behaviour is closely linked to microstructural features such as grain size and crystallographic orientations. Traditional orientation mapping methods–such as manual indexing, template matching (TM), or Hough transform-based techniques–are often slow and noise-sensitive when handling complex or overlapping patterns, creating a bottleneck in large-scale microstructural analysis. This work presents a machine learning-based approach for predicting Euler angles directly from scanning transmission electron microscopy (STEM) diffraction patterns (DPs). This enables the automated generation of high-resolution crystal orientation maps, facilitating the analysis of internal microstructures at the nanoscale. Three deep learning architectures–convolutional neural networks (CNNs), Dense Convolutional Networks (DenseNets), and Shifted Windows (Swin) Transformers–are evaluated, using an experimentally acquired dataset labelled via a commercial TM algorithm. While the CNN model serves as a baseline, both DenseNets and Swin Transformers demonstrate superior performance, with the Swin Transformer achieving the highest evaluation scores and the most consistent microstructural predictions. The resulting crystal maps exhibit clear grain boundary delineation and coherent intra-grain orientation distributions, underscoring the potential of attention-based architectures for analyzing diffraction-based image data. These findings highlight the promise of combining advanced machine learning models with STEM data for robust, high-throughput microstructural characterization.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG)
Electron-phonon vertex correction effect in superconducting H3S
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-03 20:00 EDT
Shashi B. Mishra, Hitoshi Mori, Elena R. Margine
The Migdal-Eliashberg (ME) formalism provides a reliable framework for describing phonon-mediated superconductivity in the adiabatic regime, where the electronic Fermi energy exceeds the characteristic phonon energy. In this work, we go beyond this limit by incorporating first-order vertex corrections to the electron-phonon (e-ph) interaction within the Eliashberg formalism and assess their impact on the superconducting properties of H3S and Pb using first-principles calculations. For H3S, where the adiabatic assumption breaks down, we find that vertex corrections to the e-ph coupling are substantial. When combined with phonon anharmonicity and the energy dependence of the electronic density of states, the predicted critical temperature (Tc) is in very good agreement with experimental observations. In contrast, for elemental Pb, where the adiabatic approximation remains valid, vertex corrections have a negligible effect, and the calculated Tc and superconducting gap closely match the predictions of the standard ME formalism. These findings demonstrate the importance of non-adiabatic corrections in strongly coupled high-Tc hydrides and establish a robust first-principles framework for accurately predicting superconducting properties across different regimes.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
16 pages, 6 figures, 13 pages of Supplementary Information
Sub-barrier cavitation in liquid helium
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-03 20:00 EDT
Mikhail Pekker, Mikhail N. Shneider
In this paper, the tunneling mechanism of cavitation in liquid helium for 3He and 4He is considered on the basis of the Schrödinger-like equation. It is assumed that the pairwise interactions of helium atoms are determined by the Lennard-Jones potential. The kinetics of nucleation and the mechanism that limits the growth of cavitation bubbles in liquid helium are considered, taking into account their growth in a negative pressure field.
Soft Condensed Matter (cond-mat.soft)
On the influence of reference sample properties on magnetic force microscopy calibrations
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-03 20:00 EDT
Baha Sakar, Christopher Habenschaden, Sibylle Sievers, Hans Werner Schumacher
Magnetic force microscopy (MFM) allows the characterization of magnetic stray field distributions with high sensitivity and spatial resolution. Based on a suitable calibration procedure, MFM can also yield quantitative magnetic field values. This process typically involves measuring a reference sample to determine the distribution of the tip’s stray field or stray field gradient at the sample surface. This distribution is called the tip transfer function (TTF) and is derived through regularized deconvolution in Fourier space. The properties of the reference sample and the noise characteristics of the detection system significantly influence the derived TTF, thereby limiting its validity range. In a recent study, the tip stray field distribution, and hence the TTF, of an MFM tip was independently measured in real space using a nitrogen vacancy center as a quantum sensor, revealing considerable discrepancies with the reference-sample-based TTF. Here, we analyze the influence of the feature distribution of the reference sample and the MFM measurement parameters on the resulting TTF. We explain the observed differences between quantum-calibrated stray field distributions and the classical approach by attributing them to a loss of information due to missing or suppressed spectral components. Furthermore, we emphasize the importance of the spectral coverage of the TTF. Our findings indicate that for high-quality reconstruction of the stray field of a sample under test (SUT), it is more critical to ensure a strong overlap of frequency components between the reference sample and the SUT than to achieve an accurate real-space reconstruction of the tip stray field distribution.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Advancing Magnetic Materials Discovery – A structure-based machine learning approach for magnetic ordering and magnetic moment prediction
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-03 20:00 EDT
Apoorv Verma, Junaid Jami, Amrita Bhattacharya
Accurately predicting magnetic behavior across diverse materials systems remains a longstanding challenge due to the complex interplay of structural and electronic factors and is pivotal for the accelerated discovery and design of next-generation magnetic materials. In this work, a refined descriptor is proposed that significantly improves the prediction of two critical magnetic properties – magnetic ordering (Ferromagnetic vs. Ferrimagnetic) and magnetic moment per atom – using only the structural information of materials. Unlike previous models limited to Mn-based or lanthanide-transition metal compounds, the present approach generalizes across a diverse dataset of 5741 stable, binary and ternary, ferromagnetic and ferrimagnetic compounds sourced from the Materials Project. Leveraging an enriched elemental vector representation and advanced feature engineering, including nonlinear terms and reduced matrix sparsity, the LightGBM-based model achieves an accuracy of 82.4% for magnetic ordering classification and balanced recall across FM and FiM classes, addressing a key limitation in prior studies. The model predicts magnetic moment per atom with a correlation coefficient of 0.93, surpassing the Hund’s matrix and orbital field matrix descriptors. Additionally, it accurately estimates formation energy per atom, enabling assessment of both magnetic behavior and material stability. This generalized and computationally efficient framework offers a robust tool for high-throughput screening of magnetic materials with tailored properties.
Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG)
Photoelastic Grain Solver v2.0: An updated tool for analysis of force measurements in granular materials
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-03 20:00 EDT
Carmen L. Lee, Lori McCabe, Ben McMillan, Abrar Naseer, Dong Xie, Ted Brzinski, Karen E. Daniels, Tejas Murthy, Kerstin Nordstrom
Photoelastic force imaging is an experimental technique whereby a birefringent granular material is imaged with a polariscope to characterize the internal stress state of a granular material. Photoelasticimetry is the only proven experimental technique that allows researchers to measure the shear and normal forces at every particle contact in a granular packing. In 2017, Kollmer et al. [Rev. Sci. Instrum. 88, 051808 (2017)] developed an open-source software to perform this analysis. Here, we present the next substantial update to this software package. The new version improves resolution and efficiency and substantially changes the software architecture. The structural changes better facilitate add-ons, modules, and future improvements to the performance, accessibility, and versatility of the tool. Besides updates to the core software, we introduce new infrastructure to support the ongoing development of software, documentation, and training materials. The full development team, software, and supporting resources are available at this https URL .
Soft Condensed Matter (cond-mat.soft)
4 pages, 3 figures, 1 table
Extrinsic Orbital Hall Effect and Orbital Relaxation in Mesoscopic Devices
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-03 20:00 EDT
Anderson L. R. Barbosa, Hyun-Woo Lee, Tatiana G. Rappoport
Despite recent advances in orbitronics, the influence of disorder on the orbital Hall effect and orbital relaxation mechanisms remains poorly understood. In this work, we numerically investigate the role of disorder in orbital transport within mesoscopic devices using a real-space tight-binding model on a two-dimensional square lattice that hosts atomic orbitals capable of carrying atomic orbital angular momentum. By considering devices with varying geometries–square and rectangular–and systematically tuning disorder strength, we examine the disorder effect on orbital Hall current (OHC) generation, and orbital relaxation. Our results reveal a strong dependence of the OHC and orbital Hall angle on disorder strength. In square devices, we demonstrate that the orbital Hall response can be strongly enhanced by disorder and its dependence on the disorder strength indicates the dominance of skew-scattering mechanism in the diffusive regime. In rectangular geometries, the orbital current decays exponentially with increasing device width, from which the orbital relaxation length is extracted. These findings provide critical insights into disorder-driven orbital transport phenomena and lay the foundation for designing next-generation orbitronic devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Stabilization of long-range order in low-dimensional nonequilibrium $O(N)$ models
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-03 20:00 EDT
Oriana K. Diessel, Jaewon Kim, Ehud Altman
It is now well established that the Mermin-Wagner theorem can be circumvented in nonequilibrium systems, allowing for the spontaneous breaking of a continuous symmetry and the emergence of long-range order in low dimensions. However, only a few models demonstrating this violation are known, and they often rely on specific mechanisms that may not be generally applicable. In this work, we identify a new mechanism for nonequilibrium-induced long-range order in a class of $ O(N)$ -symmetric models. Inspired by the role of long-range spatial interactions in equilibrium, consider the effect of non-Markovian dissipation, in stabilizing long range order in low-dimensional nonequilibrium systems. We find that this alone is insufficient, but the interplay of non-Markovian dissipation and slow modes due to conservation laws can effectively suppress fluctuations and stabilize long-range order.
Statistical Mechanics (cond-mat.stat-mech), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Gases (cond-mat.quant-gas)