CMP Journal 2025-08-05
Statistics
Nature Materials: 1
Physical Review Letters: 18
arXiv: 108
Nature Materials
Adaptive peptide dispersions enable drying-induced biomolecule encapsulation
Original Paper | Self-assembly | 2025-08-04 20:00 EDT
Dhwanit R. Dave, Salma Kassem, Maeva Coste, Lele Xu, Mona Tayarani-Najjaran, Darjan Podbevsek, Paola Colon-De Leon, Sheng Zhang, Luis Ortuno Macias, Deborah Sementa, María Pérez-Ferreiro, Nooshin Sadat Ayati, Muniyat A. Choudhury, Kelly Veerasammy, Selma Doganata, Tiffany Zhong, Cory Weng, Jorge Morales, Denize C. Favaro, Mateusz Marianski, So Yeon Ahn, Allie C. Obermeyer, Tong Wang, Tai-De Li, Xi Chen, Raymond Tu, Ye He, Rein V. Ulijn
Peptides are promising building blocks of designer materials with wide-ranging applications. These materials are stabilized by directional hydrogen-bonding patterns, giving rise to one-dimensional or two-dimensional assembly. It remains a challenge to mimic biology’s context-adaptive and flexible structures. Here we introduce minimalistic tripeptide sequences that form highly soluble dynamic ensembles through multivalent side-chain interactions. We observe these supramolecular dispersions undergo drying-induced sequential liquid-liquid phase separation followed by solidification, resulting in the formation of films of stiff, densely packed and porous peptide microparticles that can be instantaneously redispersed upon the re-introduction of water. Air-drying of peptide dispersions in the presence of proteins or small-molecule payloads results in efficient encapsulation and the retention of protein stability after redispersion, showing promise for the emulsification, encapsulation, protection and storage of biomacromolecules. The mechanism resembles the protective strategies in natural systems during desiccation, which rely on liquid-liquid phase separation to survive extreme conditions.
Self-assembly
Physical Review Letters
Optimal Overlapping Tomography
Research article | Quantum information architectures & platforms | 2025-08-04 06:00 EDT
Kiara Hansenne, Rui Qu, Lisa T. Weinbrenner, Carlos de Gois, Haifei Wang, Yang Ming, Zhengning Yang, Paweł Horodecki, Weibo Gao, and Otfried Gühne
Characterizing large-scale quantum systems is central to fundamental physics and essential for applications of quantum technologies. While a full characterization requires exponentially increasing resources, focusing on application-relevant information can often lead to significantly simplified analysis. Overlapping tomography is such a scheme, allowing one to obtain all the information contained in specific subsystems of multiparticle quantum systems in an efficient manner, but the ultimate limits of this approach remain elusive. We present protocols for overlapping tomography that are optimal with respect to the number of measurement settings. First, by providing algorithmic approaches based on graph theory we find the minimal number of Pauli settings, relating overlapping tomography to the problem of covering arrays in combinatorics. This significantly reduces the number of measurement settings, showing for instance that two-body overlapping tomography of nearest neighbors in qubit systems with planar topologies can always be performed with nine Pauli settings. Second, we prove that using general projective measurements, all $k$-body marginals can be reconstructed with only ${3}^{k}$ settings, independently of the system size. Finally, we demonstrate the practical applicability of our methods in a six-photon experiment. Our results will find applications in learning noise and interaction patterns in quantum computers as well as characterizing fermionic systems in quantum chemistry.
Phys. Rev. Lett. 135, 060801 (2025)
Quantum information architectures & platforms, Quantum information theory, Quantum tomography
Holography for the Ishibashi-Kawai-Kitazawa-Tsuchiya Matrix Model
Compactification | 2025-08-04 06:00 EDT
Franz Ciceri and Henning Samtleben
Holographic dualities that relate type II strings on near-horizon $\mathrm{D}p$ brane geometries to super Yang-Mills theories with sixteen supercharges in $p+1$ dimensions provide nonconformal generalizations of the famous AdS/CFT correspondence. For the extremal case $p=- 1$, this suggests a holographic duality for the Ishibashi-Kawai-Kitazawa-Tsuchiya (IKKT) matrix model—super Yang-Mills theory reduced to zero dimensions. Despite intriguing and highly nontrivial results in the IKKT model, this duality has remained largely unexplored so far. In this Letter, we consider the lowest supermultiplet of gauge invariant operators of the model and identify its states with the lowest Kaluza-Klein fluctuations of (Euclidean) IIB supergravity on the $\mathrm{D}(- 1)$ instanton background. We construct its holographic bulk realization as a one-dimensional maximal supergravity with 32 supercharges and local SO(10) invariance, capturing the full nonlinear dynamics. Analyzing the bulk Killing spinor equations, we construct the most general half-supersymmetric solutions, which typically break SO(10). We present their uplifts to IIB supergravity, and furthermore to $pp$ waves in twelve dimensions. These results provide the minimal setup for conducting precision tests of holography involving Einstein gravity.
Phys. Rev. Lett. 135, 061601 (2025)
Compactification, Field & string theory models & techniques, Gauge-gravity dualities, Gravity in dimensions other than four, Supergravity, Supersymmetric models
Entanglement Entropy as a Probe Beyond the Horizon
Entanglement entropy | 2025-08-04 06:00 EDT
Konstantinos Boutivas, Dimitrios Katsinis, Georgios Pastras, and Nikolaos Tetradis
The entanglement entropy of a free field in de Sitter space is enhanced by the squeezing of its modes. We show analytically that the expansion induces a term in the entanglement entropy that depends logarithmically on the size of the overall system, which may extend beyond the horizon. In cosmology the size of the system can be identified with the size of a spatially finite universe or with the wavelength of the first mode that exited the horizon in the beginning of inflation.
Phys. Rev. Lett. 135, 061602 (2025)
Entanglement entropy, Entanglement in field theory, Quantum cosmology, Quantum fields in curved spacetime, Quantum harmonic oscillator
Precision Measurement of the Branching Fraction of ${D}^{+}\rightarrow {\mu }^{+}{\nu }_{\mu }$
Research article | Branching fraction | 2025-08-04 06:00 EDT
M. Ablikim et al. (BESIII Collaboration)
Using $20.3\text{ }\text{ }{\mathrm{fb}}^{- 1}$ of ${e}^{+}{e}^{- }$ collision data collected at a center-of-mass energy of ${E}{\mathrm{c}.\mathrm{m}.}=3.773\text{ }\text{ }\mathrm{GeV}$ with the BESIII detector operating at the BEPCII collider, we determine the branching fraction of the leptonic decay ${D}^{+}\rightarrow {\mu }^{+}{\nu }{\mu }$ to be $(4.034\pm{}0.08{0}{\mathrm{stat}}\pm{}0.04{0}{\mathrm{syst}})\times{}{10}^{- 4}$. Interpreting our measurement with knowledge of the Fermi coupling constant ${G}{F}$, the masses of the ${D}^{+}$ and ${\mu }^{+}$ as well as the lifetime of the ${D}^{+}$, we determine ${f}{ {D}^{+}}|{V}{cd}|=(48.02\pm{}0.4{8}{\mathrm{stat}}\pm{}0.2{4}{\mathrm{syst}}\pm{}0.1{2}{\text{input}}\pm{}0.1{5}{\mathrm{EM}})\text{ }\text{ }\mathrm{MeV}$ after taking into account necessary radiative corrections. This result is a factor of 2.3 more precise than the previous best measurement. Using the value of the magnitude of the $c\rightarrow d$ Cabibbo-Kobayashi-Maskawa matrix element $|{V}{cd}|$ given by the global standard model fit, we obtain the ${D}^{+}$ decay constant ${f}{ {D}^{+}}=\phantom{\rule{0ex}{0ex}}(213.5\pm{}{2.1}{\mathrm{stat}}\pm{}{1.1}{\mathrm{syst}}\pm{}{0.8}{\text{input}}\pm{}{0.7}{\mathrm{EM}})\text{ }\text{ }\mathrm{MeV}$. Alternatively, using the value of ${f}{ {D}^{+}}$ from a precise lattice quantum chromodynamics calculation, we extract $|{V}{cd}|=0.2265\pm{}0.002{3}{\mathrm{stat}}\pm{}0.001{1}{\mathrm{syst}}\pm{}\phantom{\rule{0ex}{0ex}}0.000{9}{\text{input}}\pm{}0.000{7}_{\mathrm{EM}}$.
Phys. Rev. Lett. 135, 061801 (2025)
Branching fraction, Leptonic, semileptonic & radiative decays, Quark mixing, Charmed mesons, Flavor symmetries, Form factors, Lepton colliders
First Measurement of ${\nu }{e}$ and ${\overline{\nu }}{e}$ Charged-Current Single Charged-Pion Production Differential Cross Sections on Argon Using the MicroBooNE Detector
Research article | Neutrino interactions | 2025-08-04 06:00 EDT
P. Abratenko et al. (MicroBooNE Collaboration)
Understanding electron neutrino interactions is crucial for measurements of neutrino oscillations and searches for new physics in neutrino experiments. We present the first measurement of the flux-averaged ${\nu }{e}+{\overline{\nu }}{e}$ charged-current single charged-pion production cross section on argon using the MicroBooNE detector and data from the NuMI neutrino beam. The total cross section is measured to be $[0.93\pm{}0.13(\mathrm{stat})\pm{}0.27(\mathrm{syst})]\times{}{10}^{- 39}\text{ }\text{ }{\mathrm{cm}}^{2}/\mathrm{nucleon}$ at a mean ${\nu }{e}+{\overline{\nu }}{e}$ energy of 730 MeV. Differential cross sections are also reported in electron energy, electron and pion angles, and electron-pion opening angle.
Phys. Rev. Lett. 135, 061802 (2025)
Neutrino interactions, Electrons, Neutrinos, Pions, Neutrino detection
Next-to-Leading-Order QCD Predictions for the Nucleon Form Factors
Research article | Form factors | 2025-08-04 06:00 EDT
Yong-Kang Huang, Bo-Xuan Shi, Yu-Ming Wang, and Xue-Chen Zhao
We accomplish for the first time the next-to-leading-order QCD computations of the leading-twist contributions to the Dirac nucleon form factors by applying the hard-collinear factorization theorem rigorously. Our predictions for these baryon form factors indicate that the one-loop perturbative corrections to the hard-gluon-exchange contributions are numerically substantial for a wide range of momentum transfers. Including further the soft nonfactorizable contributions, we then perform the state-of-the-art analysis of the Dirac nucleon form factors, allowing for the most robust determinations of the nucleon distribution amplitudes from the comparison with the experimental data.
Phys. Rev. Lett. 135, 061901 (2025)
Form factors, Particle interactions, Quantum chromodynamics
Chirally Protected State Manipulation by Tuning One-Dimensional Statistics
Research article | Anyons | 2025-08-04 06:00 EDT
F. Theel, M. Bonkhoff, P. Schmelcher, T. Posske, and N. L. Harshman
Chiral symmetry is broken by typical interactions in lattice models, but the statistical interactions embodied in the anyon-Hubbard model are an exception. This is an example for a correlated hopping model where chiral symmetry protects a degenerate zero-energy subspace. Complementary to the traditional approach of anyon braiding in real space, we adiabatically evolve the statistical parameter and find nontrivial Berry phases and holonomies in this chiral subspace. The corresponding states possess stationary checkerboard patterns in their $N$-particle densities that are preserved under adiabatic manipulation. We give an explicit protocol for how these chirally protected zero-energy states can be prepared, observed, validated, and controlled.
Phys. Rev. Lett. 135, 063401 (2025)
Anyons, Bosons, Optical lattices & traps, Quantum state engineering, Ultracold gases, Bose-Hubbard model, Exact diagonalization
Ising Machine by Dimensional Collapse of Nonlinear Polarization Oscillators
Research article | Dynamics of nonlinear optical systems | 2025-08-04 06:00 EDT
Salvatore Chiavazzo, Marcello Calvanese Strinati, Claudio Conti, and Davide Pierangeli
Ising machines show promise as ultrafast hardware for optimizations encoded in Ising Hamiltonians but fall short in terms of success rate and performance scaling. Here, we propose a novel Ising machine that exploits the three-dimensional nature of nonlinear polarization oscillators to counteract these limitations. Based on the evolution of the optical polarization in third-order nonlinear media, the high-dimensional machine reaches the Ising ground state by the mechanism of ‘’dimensional collapse’’: the dynamics on the Poincar'e sphere undergoes a self-induced collapse into polarization fixed points mapping an Ising spin. Collapse from a spherical to a binary spin occurs when the polarization oscillator experiences iterative loss and anisotropic feedback. The photonic setup consists of polarization modulated pulses in a ${\chi }^{(3)}$ crystal subject to measurement and feedback. We numerically demonstrate the polarization machine achieves enhanced success probability on benchmark graphs and an exponential improvement in performance scaling with respect to coherent Ising machines due to its high-dimensional operation. The proposed Ising machine paves the way for a new class of Ising solvers with enhanced computing capabilities.
Phys. Rev. Lett. 135, 063801 (2025)
Dynamics of nonlinear optical systems, Neuromorphic computing, Polarization of light, Coupled oscillators, Ising model, Optical computing
Leaking Outside the Box: Kinetic Turbulence with Cosmic-Ray Escape
Research article | Cosmic ray acceleration | 2025-08-04 06:00 EDT
Evgeny A. Gorbunov, Daniel Grošelj, and Fabio Bacchini
Kinetic simulations of astrophysical plasmas featuring a novel technique for diffusive particle escape allow for self-consistent modeling of the escape and confinement of particles, such as cosmic rays, in true steady-state driven turbulence.
Phys. Rev. Lett. 135, 065201 (2025)
Cosmic ray acceleration, Cosmic ray sources, Electron-positron plasmas, Intergalactic medium, Magnetized plasma, Relativistic plasmas, Astrophysical electromagnetic fields, Astrophysical & cosmological simulations, First-principles calculations in plasma physics, Fokker-Planck & Vlasov model, Numerical relativity, Particle-in-cell methods, Plasma kinetic theory
Elastic Amplification from Negative Capacitance
Research article | Electric field effects | 2025-08-04 06:00 EDT
Mónica Graf, Natalya S. Fedorova, Hugo Aramberri, and Jorge Íñiguez-González
Ferroelectrics under suitable electric boundary conditions can present a negative capacitance response, whereby the total voltage drop across the ferroelectric opposes the externally applied bias. When the ferroelectric is in a heterostructure, this behavior yields a voltage amplification in the other elements, an effect that could be leveraged in low-power electronic devices. Interestingly, the mentioned voltage amplification should have an accompanying elastic effect. Specifically, in the typical case in which the materials in contact with the ferroelectric are nonpolar dielectrics, those should present an enhanced electrostrictive response. Here, we use atomistic simulations—of model ${\mathrm{PbTiO}}{3}/{\text{SrTiO}}{3}$ ferroelectric/dielectric superlattices displaying negative capacitance—to show that this is indeed the case: we reveal the enhanced elastic response of the dielectric layer and show that it is clearly linked to the voltage amplification. We argue that this ‘’elastic amplification’’ could serve as a convenient experimental fingerprint for negative capacitance. Further, we propose that it may be of interest on its own, e.g., for the development of low-power electromechanical actuators.
Phys. Rev. Lett. 135, 066101 (2025)
Electric field effects, Electrical properties, Ferroelectricity, Materials modeling
Visualization of Intervalley Coherent Phase in ${\mathrm{PtSe}}_{2}/\text{bilayer}$ Graphene Heterojunction
Research article | Density of states | 2025-08-04 06:00 EDT
Kai Fan, Ting-Fei Guo, Bohao Li, Wen-Xuan Qiu, Jian-Wang Zhou, Wen-Hao Zhang, Chao-Fei Liu, Fengcheng Wu, and Ying-Shuang Fu
The intervalley coherent (IVC) phase in graphene systems arises from the coherent superposition of wave functions of opposite valleys, whose direct microscopic visualization provides pivotal insight into the emergent physics. Here, we successfully visualize the IVC phase in a heterostructure of monolayer ${\mathrm{PtSe}}{2}$ and bilayer-graphene (BLG) on graphite. Using spectroscopic imaging scanning tunneling microscopy, we observe a $\sqrt{3}\times{}\sqrt{3}$ modulation pattern superimposed on the higher-order moir'e superlattice of the heterostructure, which correlates with a gap-opening feature around the Fermi level and displays an antiphase real-space conductance distribution of the two gap edges. Such modulation pattern and small gap vanish on the heterostructure of monolayer ${\mathrm{PtSe}}{2}$ on BLG-covered SiC substrate, due to the increased carrier density in the BLG. We provide a theoretical mechanism that the $\sqrt{3}\times{}\sqrt{3}$ modulation pattern originates from the IVC phase of BLG, which is magnified by the higher-order moir'e superlattice. Our work achieves visualization of the IVC phase, and develops an avenue for its generation and amplification via a moir'e interface.
Phys. Rev. Lett. 135, 066201 (2025)
Density of states, Electronic structure, Bilayer graphene, Molecular beam epitaxy, Scanning tunneling spectroscopy
Polarons and Exciton Polarons in Two-Dimensional Polar Materials
Research article | Electric polarization | 2025-08-04 06:00 EDT
V. Shahnazaryan, A. Kudlis, and I. V. Tokatly
We propose a macroscopic theory of optical phonons, Fr"ohlich polarons, and exciton polarons in two-dimensional (2D) polar crystalline monolayers. Our theory extends the classical macroscopic formulation of the electron-phonon problem in three-dimensional (3D) polar crystals to the new generation of 2D materials. Similarly to the 3D case, in our approach, the effective electron-phonon Hamiltonian is parametrized solely in terms of macroscopic experimentally accessible quantities—2D polarizabilities of the monolayer at low and high frequencies. We derive the dispersion of long wave length longitudinal optical (LO) phonons, which can be viewed as a 2D form of the Lyddane-Sachs-Teller relation, and study the formation of 2D Fr"ohlich polarons by adopting the intermediate coupling approximation. Finally, we apply this approach to excitons in polar 2D crystals and derive an effective potential of the electron-hole interaction dressed by LO phonons. Because of a specific dispersion of LO phonons, polarons and exciton polarons in 2D materials exhibit unique features not found in their 3D counterparts. As an illustration, the polaron and exciton polaron binding energies are computed for a representative set of 2D polar crystals, demonstrating the interplay between dimensionality, polarizability of materials, and electron-phonon coupling.
Phys. Rev. Lett. 135, 066202 (2025)
Electric polarization, Excitons, Optical phonons, Polarons, Boron nitride, Monolayer films, Variational wave functional methods
Metastability in Coexisting Competing Orders
Research article | Charge density waves | 2025-08-04 06:00 EDT
Yasamin Masoumi, Alberto de la Torre, and Gregory A. Fiete
The dynamical phase transition of a system with two coexisting competing order parameters is studied using the time-dependent-Ginzburg-Landau framework. The dynamics are induced by parameters capturing the physics of driving the system with an ultrafast laser pulse. A remarkable enhancement of the order parameter with a smaller mean-field value following the pump and the emergence of an induced metastable state is investigated through analytical and numerical studies. The effect of order parameter fluctuations on the exploration of the nonequilibrium free energy landscape reveals important information about the impact of both thermal and nonthermal fluctuations on the dynamics of the metastable state. Our results provide an interpretation of previously unexplained ultrafast experiments on superconductors with competing charge density wave order. Our formalism is relevant across broad classes of out-of-equilibrium systems beyond the condensed matter context, such as the Kibble-Zurek cosmological model.
Phys. Rev. Lett. 135, 066501 (2025)
Charge density waves, Charge dynamics, Dynamical phase transitions, Landau theory, Order parameters, Superconducting order parameter, High-temperature superconductors, Landau-Ginzburg theory, Time-dependent Ginzburg-Landau theory
Magnetic and Ferroelectric Phase Diagram of Twisted ${\mathrm{CrI}}_{3}$ Layers
Research article | Ferroelectricity | 2025-08-04 06:00 EDT
Haoshen Ye and Shuai Dong
Twisting layers provide a rich ore for exotic physics in low dimensions. Despite the abundant discoveries of twistronics from the aspect of electronic structures, ferroic moir'e textures are more plain and thus less concerned. Rigid lattice models are straightforward which can give a rough but intuitional description in most cases. However, taking ${\mathrm{CrI}}_{3}$ as a model system, here we will demonstrate that the interlayer stacking potential can spontaneously lead to structural relaxation, which plays a vital role to understand the ferroicity in the twisted superlattices. The magnetic ground state is sensitive to the stacking mode and twisting angles, which can be seriously affected by the structural relaxation. In particular, the expected magnetic bubbles are annihilated in its bilayer. In contrast, due to topological protection, the ferroelectric vortices are more robust to structural relaxation, as well as twisting angle and thickness. Because of the universal existence of spontaneous structural relaxation in twisted superlattices, our work may lead to a general revisitation of emerging physics of twistronics.
Phys. Rev. Lett. 135, 066701 (2025)
Ferroelectricity, Magnetic texture, Twistronics, Magnetic multilayers, Multiferroics, Density functional theory, Molecular dynamics, Symmetries
Gambling Carnot Engine
Research article | Nonequilibrium fluctuations | 2025-08-04 06:00 EDT
Tarek Tohme, Valentina Bedoya, Costantino di Bello, Léa Bresque, Gonzalo Manzano, and Édgar Roldán
We propose a theoretical model for a colloidal heat engine driven by a feedback protocol that is able to fully convert the net heat absorbed by the hot bath into extracted work. The feedback protocol, inspired by gambling strategies, executes a sudden quench at zero work cost when the particle position satisfies a specific first-passage condition. As a result, the engine enhances both power and efficiency with respect to a standard Carnot cycle, surpassing Carnot’s efficiency at maximum power. Using first-passage and martingale theory, we derive analytical expressions for the power and efficiency far beyond the quasistatic limit and provide scaling arguments for their dependency with the cycle duration. Numerical simulations are in perfect agreement with our theoretical findings, and illustrate the impact of the data acquisition rate on the engine’s performance.
Phys. Rev. Lett. 135, 067101 (2025)
Nonequilibrium fluctuations, Nonequilibrium statistical mechanics
Large Deviations in Switching Diffusion: From Free Cumulants to Dynamical Transitions
Research article | Brownian motion | 2025-08-04 06:00 EDT
Mathis Guéneau, Satya N. Majumdar, and Grégory Schehr
We study the diffusion of a particle with a time-dependent diffusion coefficient $D(t)$ that switches between random values drawn from a distribution $W(D)$ at a fixed rate $r$. Using a renewal approach, we compute exactly the moments of the position of the particle $\langle{x}^{2n}(t)\rangle$ at any finite time $t$, and for any $W(D)$ with finite moments $\langle{D}^{n}\rangle$. For $t\gg 1$, we demonstrate that the cumulants $\langle{x}^{2n}(t){\rangle}_{c}$ grow linearly with $t$ and are proportional to the free cumulants of a random variable distributed according to $W(D)$. For specific forms of $W(D)$, we compute the large deviations of the position of the particle, uncovering rich behaviors and dynamical transitions of the rate function $I(y=x/t)$. Our analytical predictions are validated numerically with high precision, achieving accuracy up to ${10}^{- 2000}$.
Phys. Rev. Lett. 135, 067102 (2025)
Brownian motion, Stochastic resetting, Large deviation & rare event statistics, Random matrix theory
Nematic Order from Phase Synchronization of Shape Oscillations
Research article | Nematic order | 2025-08-04 06:00 EDT
Ioannis Hadjifrangiskou, Sumesh P. Thampi, and Rahil N. Valani
We show that a suspension of noninteracting deformable particles subjected to an oscillatory shear flow leads to development of nematic order that arises from the phenomenon of phase synchronization. The synchronized state corresponds to a unique, stable limit cycle confined in the toroidal state space. The limit cycle exists since, unlike rigid particles, deformable particles can modulate aspect ratio, adjust their tumbling rate, and thus achieve phase synchronization. These synchronized regions emerge as Arnold tongues in the parameter space of the driving amplitude and frequency. Considering the rheological implications of ordering dynamics in soft and active matter, our results motivate oscillatory shear flow experiments with deformable particles.
Phys. Rev. Lett. 135, 068101 (2025)
Nematic order, Particle-laden flows, Synchronization, Coupled oscillators, Dynamical systems, Phase space dynamics
Joint Distribution of Nuclear and Cytoplasmic mRNA Levels in Stochastic Models of Gene Expression: Analytical Results and Parameter Inference
Research article | Gene expression | 2025-08-04 06:00 EDT
Yiling Wang, Juraj Szavits-Nossan, Zhixing Cao, and Ramon Grima
Common stochastic models of gene expression predict the gene-specific distribution of total mRNA per cell but lack subcellular resolution. Here, for a broad class of transcription initiation models, we derive an exact steady-state solution for the joint distribution of nuclear and cytoplasmic mRNA, and demonstrate that fitting this solution to spatially resolved mRNA data enhances parameter identifiability. By accounting for extrinsic noise, we use the model to precisely quantify bursty expression across thousands of human genes and link it to their biological functions.
Phys. Rev. Lett. 135, 068401 (2025)
Gene expression, Stochastic inference, Stochastic processes, RNA, Master equation
arXiv
Stochastic Calculus Approach to Thermodynamics of Jump Processes
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-05 20:00 EDT
Stochastic thermodynamics is the field of study relating fluctuations in stochastic systems to thermodynamic quantities. The total entropy production (EP), is central to the thermodynamic classification of systems. Non-equilibrium systems manifestly all have non-zero EP and therefore impose an “arrow of time”. Thermodynamic inequalities are lower bounds on the total EP and are especially useful when only parts of systems are operationally accessible. We use a stochastic calculus approach to directly derive and generalise three classes of inequalities for Markov jump processes using correlations of path observables, e.g., currents and densities. Our theoretical predictions are compared with simulations, where a good agreement is observed. The thermodynamic bounds we investigate include the thermodynamic uncertainty relation (TUR), thermodynamic transport bound (TB), and thermodynamic correlation bound (CB). We provide insight into the saturation conditions for these bounds and to what degree saturation can be achieved. Additionally, for the TUR and TB, we show how the bounds are related, which includes identifying a diffusion coefficient for jump dynamics. %An example using a toy model shows how the CB may yield a negative lower bound on the total entropy production, contrary to the non-negative bound that the TUR and TB yield. Comparisons are drawn between the TUR and TB for relaxation and stationary processes in biologically relevant settings. Specifically, calmodulin folding dynamics and secondary active transport, where differences in long-time relaxation and convergence are observed. For a systematic way to construct models, we formulate two methods to drive systems out of equilibrium without changing the stationary probability distribution.
Statistical Mechanics (cond-mat.stat-mech)
Master Thesis
Quantum thermalization and the route to ergodicity
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-05 20:00 EDT
We consider a minimal model for quantum thermalization of coupled chaotic subsystems. The route towards ergodicity is explored as a function of the coupling strength. The results are contrasted with the predictions of standard Random Matrix Theory (RMT) and the Eigenstates Thermalization Hypothesis (ETH). We highlight a coupling regime of disparity between the spectral statistics that indicates chaos, and ergodicity measures that indicate lack of ETH thermalization. The analysis involves a revision of the energy shell concept, in a way that is consistent but independent of the semiclassical perspective.
Statistical Mechanics (cond-mat.stat-mech)
5 pages, 4 figures, 2 page Supplementary
Topolectrical circuit theory and realizations of topological, non-linear, and non-Hermitian phenomena
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-05 20:00 EDT
Electrical circuits offer a unique platform to explore physical phenomena, from topology to non-Hermitian effects. Investigations of the fundamental properties of this metamaterial platform are crucial to distinguish observed/measured quantities from intrinsic circuit responses. In this thesis, we delve into the analysis of voltage and impedance responses and their role in unveiling complex dynamics and profound physical principles. We reveal that even the simplest one-dimensional circuits exhibit intriguing voltage profiles. Our study of multi-dimensional and multi-structural lattice models shows size-dependent impedance responses, which challenge our current textbook knowledge. Building on these insights, we will present non-linear and non-Hermitian circuit applications, showcasing how electrical circuits provide a suitable platform for realizing intriguing physical phenomena.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
PhD Thesis, National University of Singapore, 2024, ScholarBank@NUS Repository, this https URL
High-magnitude, spatially variable, and sustained strain engineering of 2D semiconductors
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-05 20:00 EDT
Boran Kumral, Peter Serles, Pedro Guerra Demingos, Shuo Yang, Da Bin Kim, Dian Yu, Akhil Nair, Akshat Rastogi, Nima Barri, Md Akibul Islam, Jane Howe, Cristina H Amon, Sjoerd Hoogland, Edward H. Sargent, Chandra Veer Singh, Tobin Filleter
Crystalline two-dimensional (2D) semiconductors often combine high elasticity and in-plane strength, making them ideal for strain-induced tuning of electronic characteristics, akin to strategies used in silicon electronics. However, current techniques fall short in achieving high-magnitude (>1%), spatially resolved, and stable strain in these materials. Here, we apply biaxial tensile strain up to 2.2%, with +/-0.12% resolution over micrometre-scale regions in monolayer MoS2 via conformal transfer onto patterned substrates fabricated using two-photon lithography. The induced strain is stable for months and enables local band gap tuning of ~0.4 eV in monolayer MoS2, ~25% of its intrinsic band gap. This represents a distinct demonstration of simultaneous high-magnitude, spatially resolved, and sustained strain in 2D monolayers. We further extend the approach to bilayer WS2-MoS2 heterostructures. This strain-engineering technique opens a new regime of strain-enabled control in 2D semiconductors to support the development of wide-spectrum optoelectronic devices and nanoelectronics with engineered electronic landscapes.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
23 pages of main text with 5 figures and 26 pages of supplementary information with 13 figures
Nematic and partially polarized phases in rhombohedral graphene with varying number of layers: An extensive Hartree-Fock Study
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-05 20:00 EDT
Guillermo Parra-Martínez, Alejandro Jimeno-Pozo, Jose Angel Silva-Guillén, Francisco Guinea
Rhombohedral graphene systems with different number of layers feature an abundance of correlated phases and superconducting states in experimental measurements with different doping and displacement fields. Some of the superconducting pockets can emerge from - or close to - one of the correlated states. Therefore, studying the phase diagram of the correlated phases for varying number of layers could be useful to interpret the experimental observations. To achieve this, systematic Hartree-Fock calculations have been performed to build the phase diagram of rhombohedral (ABC-stacked) graphene for different number of layers, in the presence of long-range Coulomb interactions. By varying the external displacement field and carrier density, a cascade of metallic partially-isospin-polarized phases that spontaneously break spin and/or valley (flavor) symmetries is found. In addition, these states can present nematicity, stabilized by electron-electron interactions, exhibiting rich internal complexity. Polarized states are more stable for electron doping, and they are found for systems with up to 20 layers. Moreover, the tunability of the phase diagram via substrate screening and spin-orbit coupling proximity effects has been studied. Our results offer new insights into the role of correlations and symmetry breaking in graphitic systems which will motivate future experimental and theoretical works.
Strongly Correlated Electrons (cond-mat.str-el)
13 pages, 5 figures
Mean-field model for the bubble size distribution in coarsening wet foams
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-05 20:00 EDT
Jacob Morgan (1), Simon Cox (1) ((1) Department of Mathematics, Aberystwyth University, UK)
Aqueous foams are subject to coarsening, whereby gas from the bubbles diffuses through the liquid phase. Gas is preferentially transported from small to large bubbles, resulting in a gradual decrease of the number of bubbles and an increase in the average bubble size. Coarsening foams are expected to approach a scaling state at late times in which their statistical properties are invariant. Understanding of coarsening in foams with a moderate liquid content has been improved by recent experiments. However, a model predicting the observed bubble-size distribution in the scaling state, as a function of the liquid fraction $ \phi$ , has not yet been developed. To this end, we propose a three-dimensional mean-field bubble growth law for foams without inter-bubble adhesion, validated against bubble-scale simulations, and use it to derive a prediction of the scaling-state bubble-size distribution for any $ \phi$ from zero up to the unjamming transition $ \phi_\text{c} \approx 36%$ . We verify that the derived scaling state is approached from a variety of initial conditions using mean-field simulations implementing the proposed growth law. Comparing our predicted bubble-size distribution with previous simulations and experimental results, we likewise find a large population of small bubbles when $ \phi > 0$ , but there are qualitative differences from prior results which we attribute to the absence of rattlers, i.e. bubbles not pressed into contact with their neighbours, in our model.
Soft Condensed Matter (cond-mat.soft)
15 pages, 12 figures
Extraordinary transition at the edge of a correlated topological insulator
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-05 20:00 EDT
Francesco Parisen Toldin, Fakher F. Assaad, Max A. Metlitski
The interplay of topology and correlations defines a new playground to study boundary criticality in quantum systems. We employ large scale auxiliary field quantum Monte Carlo simulations to study a two-dimensional Kane-Mele-Hubbard model on the honeycomb lattice with zig-zag edges and the Hubbard U-term tuned to the three-dimensional XY bulk critical point. Upon varying the Hubbard-U term on the edge we observe a boundary phase transition from an ordinary phase with a helical Luttinger liquid edge decoupled from the critical bulk to an extraordinary-log phase characterized by a logarithmically diverging spin stiffness. We find that the spectral functions exhibit distinct features in the two phases giving potential experimental signatures.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Statistical Mechanics (cond-mat.stat-mech)
13 pages, 10 figures, including Supplemental Material
Quantum Annealing in SK Model Employing Suzuki-Kubo-deGennes Quantum Ising Mean Field Dynamics
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-08-05 20:00 EDT
Soumyaditya Das, Soumyajyoti Biswas, Bikas K. Chakrabarti
We study a quantum annealing approach for estimating the ground state energy of the Sherrington-Kirpatrick mean field spin glass model using the Suzuki-Kubo dynamics applied for individual local magnetization components. The solutions of the coupled differential equations, in discretized state, give a fast annealing algorithm (cost $ N^3$ ) in estimating the ground state of the model: Classical ($ E^0= -0.7629 \pm 0.0002$ ), Quantum ($ E^0=-0.7623 \pm 0.0001$ ) and Mixed ($ E^0=-0.7626 \pm 0.0001$ ), all of which are to be compared with the best known estimate $ E^0= -0.763166726 \dots$ . We infer that the continuous nature of the magnetization variable used in the dynamics here is the reason for reaching close to the ground state quickly and also the reason for not observing the de-Almeida-Thouless line in this approach.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech)
6 pages, 6 figures, 2 tables. Invited contribution for the Special Issue on “100 Glorious years of the Ising model” in Eur. Phys. J. B
Band mixing effects in one-dimensional charge transfer insulators
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-05 20:00 EDT
Samuel Milner, Steven Johnston, Adrian Feiguin
The low-energy properties of transition metal oxides (TMOs) are governed by the electrons occupying strongly correlated $ d$ -orbitals that are hybridized with surrounding ligand oxygen $ p$ orbitals to varying degrees. Their physics is thus established by a complex interplay between the transition-metal (TM)-ligand hopping $ t$ , charge transfer energy $ \Delta_\mathrm{CT}$ , and on-site TM Hubbard repulsion $ U$ . Here, we study the spectral properties of a one-dimensional (1D) analog of such a $ pd$ system, with alternating TM $ d$ and ligand anion $ p$ orbitals situated along a chain. Using the density matrix renormalization group method, we study the model’s single-particle spectral function, x-ray absorption spectrum, and dynamical spin structure factor as a function of $ \Delta_\mathrm{CT}$ and $ U$ . In particular, we present results spanning from the Mott insulating ($ \Delta_\mathrm{CT} > U$ ) to negative charge transfer regime $ \Delta_\mathrm{CT} < 0$ to better understand the ground and momentum-resolved excited state properties of these different regimes. Our results can guide new studies on TMOs that seek to situate them within the Mott-Hubbard/charge transfer insulator classification scheme.
Strongly Correlated Electrons (cond-mat.str-el)
15 pages, 8 figures
First-principles phonon physics using the Pheasy code
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-05 20:00 EDT
Changpeng Lin, Jian Han, Ben Xu, Nicola Marzari
Parameter-free calculations of lattice dynamics from first principles have achieved significant progress in the past decades, with a wealth of applications in thermodynamics, phase transitions, and transport properties of materials. Current approaches to derive the interatomic force constants (IFCs) of lattice potential become challenging and sometimes infeasible when going beyond third-order anharmonicity, due to the combinatorial explosion in the number of higher-order IFCs. In this work, we present a robust and user-friendly program, Pheasy, which accurately reconstructs the potential energy surface of crystalline solids via a Taylor expansion of arbitrarily high order. Given force-displacement datasets, the program enables an efficient and accurate extraction of IFCs using advanced machine-learning algorithms, and further calculates a wide range of harmonic and anharmonic phonon related properties. We show in three prototypical examples how the obtained IFCs have been successfully applied to study anharmonic lattice dynamics and thermal transport. Through these detailed benchmarks, we have also identified the optimal approach for IFC extractions and offered general guidelines for high-fidelity lattice-dynamical simulations, addressing the large uncertainties in the IFCs extracted from existing various schemes. Overall, the Pheasy project aims to create a phonon code ecosystem that connects diverse phonon simulation platforms and offers access to the broad research community.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
19 pages and 3 figures for main text; 29 pages with supplementary material
Substrate stiffness governs dynamics and self-organization of nascent biofilms
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-05 20:00 EDT
The evolutionary success of bacteria lies in their ability to form complex surface-associated communities in diverse biophysical settings. However, it remains poorly understood how compliance of soft surfaces, measured in terms of their elastic deformability, impacts the dynamics and self-organization of bacterial cells proliferating into colonies. Using experiments and biomechanical modelling, here we study the expansion and self-organization of bacterial cells into sessile colonies on soft substrates. The dynamics and spatiotemporal structures were captured by visualising growing bacterial colonies on nutrient-rich, soft agarose pads, with elastic modulus in the range ~0.3 kPA to ~100 kPA by varying the concentration of the agarose in the underlying substrate. Our results show that, at the scale of the colonies, significant differences emerge in the spreading dynamics and colony geometry as the substrate stiffness is altered: softer substrates promote distinct, multilayered colony structures, and as revealed by fractal analysis of the colony boundaries, they exhibit higher boundary roughness. In contrast, colonies growing on harder substrates first grow up to large monolayers, before undergoing the mono-to-multilayer transition (MTMT), showing nearly 300% increase in the overall colony area at MTMT. A simple biomechanical model captures the role of effective drag forces at different scales, acting on the colonies as they spread on substrates with different stiffness: higher drag in soft substrates drive early verticalisation of the colonies, while lower effective drag delays the MTMT, resulting in larger colony areas. Based on the results and biomechanical insights, a comprehensive data-backed numerical model is currently being developed. Our findings highlight the role of surface stiffness in determining the self-organization of bacterial cells into an expanding multi-scale colony.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
40 pages, 11 figures
Dynamic Interfacial Quantum Dipoles in Charge Transfer Heterostructures
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-05 20:00 EDT
Ziyu Liu, Emil Viñas Boström, Dihao Sun, Jordan Pack, Matthew Cothrine, Kenji Watanabe, Takashi Taniguchi, David G. Mandrus, Angel Rubio, Cory R. Dean
Hysteretic gate responses of two-dimensional material heterostructures serve as sensitive probes of the underlying electronic states and hold significant promise for the development of novel nanoelectronic devices. Here we identify a new mechanism of hysteretic behavior in graphene/$ h$ BN/$ \alpha$ -$ \mathrm{RuCl_3}$ charge transfer field effect devices. The hysteresis loop exhibits a sharp onset under low temperatures and evolves symmetrically relative to the charge transfer equilibrium. Unlike conventional flash memory devices, the charge transfer heterostructure features a transparent tunneling barrier and its hysteretic gate response is induced by the dynamic tuning of interfacial dipoles originating from quantum exchange interactions. The system acts effectively as a ferroelectric and gives rise to remarkable tunability of the hysteretic gate response under external electrical bias. Our work unveils a novel mechanism for engineering hysteretic behaviors via dynamic interfacial quantum dipoles.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Construction and Tuning of CALPHAD Models Using Machine-Learned Interatomic Potentials and Experimental Data: A Case Study of the Pt-W System
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-05 20:00 EDT
Courtney Kunselman, Siya Zhu, Doguhan Sariturk, Raymundo Arroyave
This work introduces PhaseForgePlus – a computationally efficient, fully open-source workflow for physically-informed CALPHAD model generation and parameter fitting. Using the Pt-W system as an example, we show that the integration of Machine Learning Potentials into the Alloy Theoretic Automated Toolkit can produce physically grounded Gibbs energy descriptions requiring only slight adjustments to produce accurate phase diagrams. Employing the Jansson derivative method in the context of experimental observations, such adjustments can be efficiently and robustly determined through gradient-informed optimization procedures.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
Optimizing $α’’$-Fe$_{16}$N$_2$ as permanent magnet via alloying
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-05 20:00 EDT
Bo Zhao, Ruiwen Xie, Imants Dirba, Lambert Alff, Oliver Gutfleisch, Hongbin Zhang
Based on systematic first-principles calculations, we investigate the effects of 27 alloying elements on the intrinsic magnetic properties of Fe$ _{16}$ N$ _2$ , in order to further optimize its properties for permanent magnet applications. Analysis on the thermodynamic stabilities based on formation energy and distance to the convex hull reveals that 20 elements can be substituted into Fe$ _{16}$ N$ _2$ , where there is no strong site-preference upon doping. It is observed that all alloying elements can essentially reduce the saturation magnetization, whereas the magnetic anisotropy can be significantly modified. In terms of the Boltzmann-average intrinsic properties, we identify 8 elements as interesting candidates, with Co, Mo, and W as the most promising cases for further experimental validations.
Materials Science (cond-mat.mtrl-sci)
Correlated cell movements drive epithelial finger formation
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-05 20:00 EDT
Sander C. Kammeraat, Yann-Edwin Keta, Paul Appleton, Ian P. Newton, Tanniemola B. Liverpool, Rastko Sknepnek, Inke Näthke, Silke Henkes
Epithelia form protective barriers in multicellular organisms. To maintain homeostasis, they must be able to regenerate and heal damaged areas. This occurs through collective cell migration, during which finger-like protrusions commonly appear. Whether these protrusions are driven by specialised leader cells, biochemical cues, or generic physical interactions remains unclear. Integrating in vitro imaging, agent-based simulations, and continuum modelling, we show that correlated active cell motion alone suffices to produce fingers. Leader cells, signalling, and proliferation modulate, but do not trigger, this pattern. Our results show that the key mechanism underlying a complex biological process can be understood using a general framework of the physics of dense active matter.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
13 pages, 5 figures, Supplementary Information as Appendix
Nondestructive optomechanical detection scheme for Bose-Einstein condensates
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-08-05 20:00 EDT
Cisco Gooding, Cameron R. D. Bunney, Samin Tajik, Sebastian Erne, Steffen Biermann, Jörg Schmiedmayer, Jorma Louko, William G. Unruh, Silke Weinfurtner
We present a two-tone heterodyne optical readout scheme to extract unequal-time density correlations along an arbitrary stationary interaction path from a pancake-shaped Bose-Einstein condensate, using a modulated laser probe. Analysing the measurement noise both from imprecision and backaction, we identify the standard quantum limit for the signal-extraction scheme, and examine how a class of two-mode squeezed initial states can be used to push beyond this limit. As an application, we show how the readout scheme can be used for an experimental realisation of acceleration-dependence of quantum-vacuum fluctuations in the system, including the analogue spacetime circular motion Unruh effect.
Quantum Gases (cond-mat.quant-gas), General Relativity and Quantum Cosmology (gr-qc)
14 pages, 2 figures
Collisional decoherence in a BEC double-well accelerometer
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-08-05 20:00 EDT
Kateryna Korshynska, Sebastian Ulbricht
BEC-based quantum sensors offer a huge, yet not fully explored potential in gravimetry and accelerometry. In this paper, we study a possible setup for such a device, which is a weakly interacting Bose gas trapped in a double-well potential. In such a trap, the gas is known to exhibit Josephson oscillations, which rely on the coherence between the potential wells. Applying the density matrix approach, we consider transitions between the coherent, partially incoherent, and fully incoherent states of the Bose gas. We show how, due to the presence of weak interactions, collisional decoherence causes the Josephson oscillations to decay with time. We further study the interplay of collisional interaction and external acceleration, which leads to shifts of the oscillation frequency. Finally, we investigate how this effect can be used to build a BEC double-well accelerometer and give analytical expressions for its expected sensitivity.
Quantum Gases (cond-mat.quant-gas)
A Crystallographic Metric for Continuous Quantification of Unit Cell Deformation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-05 20:00 EDT
Shannon Bernier, Gregory Bassen, Matthew Brem, Davor Tolj, Quentin Simmons, Tyrel M. McQueen
Describing the deviation of a real structure from a hypothetical higher-symmetry ideal can be a powerful tool to understand and interpret phase transitions. Here we introduce a simple yet effective metric that quantifies the degree of unit cell distortion relative to a cube, called the cubic deviation metric. This enables continuous comparisons between unit cells of different geometries. We demonstrate the potential of this tool with four separate case study applications to real material systems: 1) discontinuous structural phase transitions in pseudobrookites; 2) homological structure classification; 3) structure-correlated piezoelectricity in hexagonal materials; and 4) superconducting materials design in the cuprate family. Although this metric does not replace detailed structural or group theory analysis, it enables comparison across different compositional and structural compound variants, even in the presence of disorder or absence of group-subgroup correlation.
Materials Science (cond-mat.mtrl-sci)
33 pages including Apprendix, 14 figures, submitted to the Journal of Applied Crystallography
Prediction of Large Events in Directed Sandpiles
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-05 20:00 EDT
The degree of predictability of large avalanche events in the directed sandpile model is studied. A waiting time based prediction strategy which exploits the local anticorrelation of large events is discussed. With this strategy we show analytically and numerically that large events are predictable to some extent, and that this predictability persists in the thermodynamic limit. We introduce another strategy which predicts large avalanches in the future based on the present excess density in the sandpile. We obtain the exact conditional probabilities for large events given an excess density, and use this to determine the exact form of the ROC predictability curves. We show that for this strategy, the model is predictable only for finite lattice sizes, and unpredictable in the thermodynamic limit. This behaviour is to be contrasted with previously established numerical studies carried out for Manna sandpiles.
Statistical Mechanics (cond-mat.stat-mech)
19 pages, 18 figures
Magnetism at the interface of $MoSe_2/V_2O_5$ heterostructures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-05 20:00 EDT
Rohin Sharma, Diem Thi-Xuan Dang, Lilia M. Woods
Magnetism in doped transition metal dichalcogenide monolayers and van der Waals interfaced materials have motivated the search for sustainable magnetic states at the nanoscale with the prospect of building devices for spintronics applications. In this study, we report the existence of magnetism in a heterostructure made up of an $ MoSe_2$ transition metal dichalcogenide monolayer and a $ V_2O_5$ substrate. Using density functional theory simulations, we find that ferromagnetic ordering can be found in the $ MoSe_2/V_2O_5$ heterostructure even though the individual components are nonmagnetic. By examining the electronic structure and magnetic properties of this system we find how the occurring ferromagnetism evolves if the transition metal dichalcogenide or the $ V_2O_5$ substrate can host point defects. Our study suggests that the balance between charge transfer and spin reorganization can lead to interface magnetism in novel hybrid materials.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Sliding two-dimensional superconductivity and charge-density-wave state in a bulk crystal
New Submission | Superconductivity (cond-mat.supr-con) | 2025-08-05 20:00 EDT
Xiangqi Liu, Chen Xu, Jing Jiang, Haonan Wang, Shaobo Liu, Gan Liu, Ziyi Zhu, Jian Yuan, Wei Xia, Lianbing Wen, Jiawei Luo, Yixuan Luo, Xia Wang, Na Yu, Peihong Cheng, Leiming Chen, Rui Zhou, Jun Li, Yulin Chen, Shiwei Wu, Ke Qu, Wei Li, Guangming Zhang, Chungang Duan, Jianhao Chen, Xiaoxiang Xi, Zhenzhong Yang, Kai Liu, Yanfeng Guo
Superconductivity in the two-dimensional (2D) limit is a fertile ground for exotic quantum phenomena-many of which remain elusive in their 3D counterparts. While studies of 2D superconductivity have predominantly focused on mono- or few-layer systems, we demonstrate an alternative route-interlayer sliding in bulk crystals. Through a precisely controlled growth strategy, we engineer interlayer sliding in bulk 3R-NbSe2, deliberately disrupting [001] mirror symmetry and drastically suppressing interlayer coupling. Remarkably, this structural manipulation stabilizes Ising-type superconductivity coexisting with an unconventional charge-density-wave (CDW) state akin to that of monolayer 2H-NbSe2. The sliding phase exhibits a pronounced suppression of the upper critical field at low temperatures, revealing a delicate competition between Ising and Rashba spin-orbit coupling (SOC) in the globally noncentrosymmetric lattice. Intriguingly, the superconducting state displays two-fold symmetry, a signature that may arise from asymmetric SOC or a multi-component pairing order parameter. Our work establishes interlayer sliding as a symmetry-breaking tool to promote 2D superconductivity in bulk materials-without resorting to extrinsic intercalation or doping. More broadly, this approach sets a paradigm for unlocking hidden quantum states in layered materials, offering a new dimension in design of quantum matter.
Superconductivity (cond-mat.supr-con)
Main Text 36 Pages + 3 figures; SI 38 pages + 30 figures + 8 tables
Mixed spin states for robust ferromagnetism in strained SrCoO$_3$ thin films
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-05 20:00 EDT
Xiquan Zheng, Nicholas B. Brookes, Flora Yakhou-Harris, Yingjie Lyu, Jianbing Zhang, Qian Xiao, Xinyi Jiang, Qingzheng Qiu, Qizhi Li, Shilong Zhang, Xinqiang Cai, Pu Yu, Yi Lu, Yingying Peng
Epitaxial strain in transition-metal oxides can induce dramatic changes in electronic and magnetic properties. A recent study on the epitaxially strained SrCoO$ _3$ thin films revealed persistent ferromagnetism even across a metal-insulator transition. This challenges the current theoretical predictions, and the nature of the local spin state underlying this robustness remains unresolved. Here, we employ high-resolution resonant inelastic x-ray scattering (RIXS) at the Co-$ L_3$ edge to probe the spin states of strained SrCoO$ _3$ thin films. Compared with CoO$ _6$ cluster multiplet calculations, we identify a ground state composed of a mixed high- and low-spin configuration, distinct from the previously proposed intermediate-spin state. Our results demonstrate that the robustness of ferromagnetism arises from the interplay between this mixed spin state and the presence of ligand holes associated with negative charge transfer. These findings provide direct experimental evidence for a nontrivial magnetic ground state in SrCoO$ _3$ and offer new pathways for designing robust ferromagnetic systems in correlated oxides.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
6 pages, 4 figures
Cascade Crack in Chain of Beads
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-05 20:00 EDT
Meysam Bagheri, Thorsten Pöschel
We consider a homogeneous chain of spheres linked by liquid bridges under tension. The rupture of a single liquid bridge leads to a fragmentation cascade driven by the inverse relation between the capillary force and the sphere distances. The initial length of the liquid bridges determines the number and size of the fragments and the velocity of the fragmentation front.
Soft Condensed Matter (cond-mat.soft), Pattern Formation and Solitons (nlin.PS)
5 pages, 5 figures
Study of Optical Properties of MOCVD-Grown Rutile GeO2 Films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-05 20:00 EDT
Imteaz Rahaman, Anthony Bolda, Botong Li, Hunter D. Ellis, Kai Fu
Rutile germanium dioxide (r-GeO$ _2$ ) is a promising ultra-wide bandgap (UWBG) semiconductor, offering a high theoretical Baliga figure of merit, potential for p-type doping, and favorable thermal and electrical properties. In this work, we present a comprehensive optical investigation of crystalline r-GeO$ _2$ thin films grown on r-TiO$ _2$ (001) substrates via metal-organic chemical vapor deposition (MOCVD). Cathodoluminescence (CL) spectroscopy reveals broad visible emissions with distinct peaks near 470nm and 520nm. CL mapping indicates enhanced emission intensity in regions with larger crystalline domains, highlighting the correlation between domain size and optical quality. X-ray photoelectron spectroscopy (XPS) confirms the presence of Ge$ ^{4+}$ oxidation state and provides a bandgap estimation of $ \sim$ 4.75eV based on valence band and secondary electron cutoff analysis. UV–Vis transmittance measurements show a sharp absorption edge near 250–260nm, corresponding to an optical bandgap in the range of 4.81–5.0~eV. These findings offer valuable insights into the defect-related emission behavior and band-edge characteristics of r-GeO$ _2$ , reinforcing its potential for future applications in power electronics and deep-ultraviolet optoelectronic devices.
Materials Science (cond-mat.mtrl-sci)
18 pages, 5 figures
Opto- and magneto-tunable exceptional degeneracies in non-Hermitian ferromagnet/$p$-wave magnet junctions
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-05 20:00 EDT
Mohammad Alipourzadeh, Davood Afshar, Yaser Hajati
Unconventional $ p$ -wave magnets (UPMs) with odd-parity spin textures have attracted interest for their zero net magnetization and anisotropic spin-split Fermi surfaces. Here, we explore a non-Hermitian open quantum system composed of a ferromagnet and a UPM, subjected to an external magnetic field and off-resonant circularly polarized light (CPL), serving as tunable control parameters. We demonstrate the emergence of exceptional points (EPs) in the proposed junction, whose locations can be modulated by the intrinsic properties of the UPM. These EPs exhibit different multiplicities and formation conditions compared to those in even-parity magnets (dubbed $ d$ - wave altermagnets), a distinction attributable to the preserved time-reversal and broken inversion symmetries characteristic of UPMs. We find that both the unidirectional magnetic field (with adjustable strength and orientation) and the CPL induce momentum-direction-dependent modifications to the EPs, such as their shifting, tilting, merging, or annihilation, supported by analyses of spin projection and eigenvector overlap. Although both perturbations influence the EP structure, they operate via distinct mechanisms: CPL induces a global Floquet re-normalization, enabling dynamic tunability through light, whereas the unidirectional magnetic field selectively alters orientation-aligned terms, lacking such tunability. Beyond revealing EP dynamics in UPM-based junctions, our results highlight UPMs as promising platforms for non-Hermitian phenomena in future spintronics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Unified description of cuprate superconductors by fractionalized electrons emerging from integrated analyses of photoemission spectra and quasiparticle interference
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-05 20:00 EDT
Shiro Sakai, Youhei Yamaji, Fumihiro Imoto, Tsuyoshi Tamegai, Adam Kaminski, Takeshi Kondo, Yuhki Kohsaka, Tetsuo Hanaguri, Masatoshi Imada
Electronic structure of high-temperature superconducting cuprates is studied by analyzing experimental data independently obtained from two complementary spectroscopies, one, quasiparticle interference (QPI) measured by scanning-tunneling microscopy and the other, angle-resolved photoemission spectroscopy (ARPES) and by combining these two sets of data in a unified theoretical analysis. Through explicit calculations of experimentally measurable quantities, we show that a simple two-component fermion model (TCFM) representing electron fractionalization succeeds in reproducing various detailed features of these experimental data: ARPES and QPI data are concomitantly reproduced by the TCFM in full energy and momentum spaces. The measured QPI pattern reveals a signature characteristic of the TCFM, distinct from the conventional single-component prediction, supporting the validity of the electron fractionalization in the cuprate. The integrated analysis also solves the puzzles of ARPES and QPI data that are seemingly inconsistent with each other. The overall success of the TCFM offers a comprehensive understanding of the electronic structure of the cuprates. We further predict that a characteristic QPI pattern should appear in the unoccupied high-energy part if the fractionalization is at work. We propose that integrated-spectroscopy analyses offer a promising way to explore challenging issues of strongly correlated electron systems.
Strongly Correlated Electrons (cond-mat.str-el)
Main text: 26 pages, 23 figures / Supplementary materials: 5 pages, 11 figures
Percolation of random compact diamond-shaped systems on the square lattice
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-05 20:00 EDT
Charles S. do Amaral, Mateus G. Soares, Robert M. Ziff
We study site percolation on a square lattice with random compact diamond-shaped neighborhoods. Each site $ s$ is connected to others within a neighborhood in the shape of a diamond of radius $ r_s$ , where $ r_s$ is uniformly chosen from the set $ {i, i+1, \ldots, m}$ with $ i \leq m$ . The model is analyzed for all values of $ i = 0, \ldots, 7$ and $ m = i, \ldots, 10$ , where $ \overline{z}(i,m)$ denotes the average number of neighbors per site and $ p_c(i,m)$ is the critical percolation threshold. For each fixed $ i$ , the product $ \overline{z}(i,m),p_c(i,m)$ is found to converge to a constant as $ m \to \infty$ . Such behavior is expected when $ i=m$ (single diamond sizes), for which the product $ \overline{z}(i),p_c(i)$ tends toward $ 2^d\eta_c$ , where $ \eta_c$ is the continuum percolation threshold for diamond-shaped regions or aligned squares in two dimensions ($ d=2$ ). This case is further examined for $ i = 1, \ldots, 10$ , and the expected convergence is confirmed. The particular case $ i = m$ was first studied numerically by Gouker and Family in 1983. We also study the relation to systems of deposited diamond-shaped objects on a square lattice. For monodisperse diamonds of radius $ r$ , there is a direct mapping to percolation with a diamond-shaped neighborhood of radius $ 2r+1$ , but when there is a distribution of object sizes, there is no such mapping. We study the case of mixtures of diamonds of radius $ r=0$ and $ r=1$ , and compare it to the continuum percolation of disks of two sizes.
Statistical Mechanics (cond-mat.stat-mech)
$1/f$ noise in extremal dynamics
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-05 20:00 EDT
Rahul Chhimpa, Abha Singh, Avinash Chand Yadav
The Bak-Sneppen (BS) evolution model remains a well-studied example of self-organized criticality (SOC). We propose a simple variant of the BS model, where the global fitness fluctuations show $ 1/f^{\alpha}$ noise with a spectral exponent nearly equal to 1 (pink noise). To further corroborate, we compute the two-time autocorrelation function that decays logarithmically. The $ 1/f$ noise in the global fitness is robust and hyper-universal. We identify the dominance of non-trivial local fitness cross-power spectra.
Statistical Mechanics (cond-mat.stat-mech)
7 pages, 8 figures
Electrostatic Depletion Force in Complex Coacervates
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-05 20:00 EDT
The functionalities and applications of complex coacervates – liquid condensates resulting from liquid-liquid phase separation of charged polymers – are significantly influenced by the dispersion and aggregation states of guest macromolecules. Intriguingly, guest macromolecules exhibit a strong tendency to aggregate within coacervates even in the absence of apparent chemical incompatibility, indicating a universal aggregation mechanism at play in these environments. Using extensive MD simulations, we identify electrostatic depletion – a strong force arising from electrostatic correlations within the host polyelectrolyte network that drives guest aggregations. Due to electrostatic depletion, neutral polymers, low-charge-density polyelectrolytes, and intrinsically disordered proteins (IDPs) exhibit effective attractions in coacervates, in stark contrast to their behavior in dilute solutions. Unlike traditional depletion effect that requires mismatched length scale and morphology, electrostatic depletion is relevant in fluid systems where solute and solvent are both polymers with comparable size. Our discovery bridges a critical knowledge gap in the molecular physics of densely charged, crowded liquids and holds significant implications for the design of synthetic protocells and advanced drug delivery systems.
Soft Condensed Matter (cond-mat.soft)
Supercurrent Amplification in Nonequilibrium Superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2025-08-05 20:00 EDT
Qinghong Yang, Yuqi Cao, Dante M. Kennes, Zhiyuan Sun
In ultrafast experiments on superconductors, a pump laser pulse often heats up the electronic system and suppresses the density of superfluid electrons. Subsequently, the electrons undergo a cooling process due to electron-phonon thermalization so that the superfluid density recovers in time. We show that if a supercurrent is initiated by a probe pulse in the cooling process, an intriguing phenomenon of ‘supercurrent amplification’ occurs, meaning that the net current grows in time with the increasing superfluid density. Using the Boltzmann kinetic equation, we uncover its microscopic origin as the momentum-relaxing scattering of quasi-particles by impurities and phonons, in stark contrast to the widely accepted intuition that impurities always attenuate currents. We further show that supercurrent amplification has important experimental manifestations, including the ultrafast Meissener effect and an optical reflectivity exceeding unity.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
5 pages, 3 figures
Transport in Single Quantum Dots: A Review from Linear Response to Nonlinear Regimes
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-05 20:00 EDT
Gustavo Diniz, Silvio Quintino, Vivian V. França
Quantum dots are versatile systems for exploring quantum transport, electron correlations, and many-body phenomena such as the Kondo effect. While equilibrium properties are well understood through methods like the numerical renormalization group and density matrix renormalization group, nonequilibrium transport remains a major theoretical challenge. From the experimental point of view, recent advances in nanofabrication and measurement techniques have enabled the investigation of far-from-equilibrium regimes. These conditions give rise to new transport phenomena, where strong correlations and nonequilibrium dynamics interplay in complex ways; beyond the reach of conventional linear response theory. To meet these challenges, new approaches such as nonequilibrium Green’s functions, real-time NRG, and time-dependent DMRG have emerged. This work reviews the established results for quantum dot transport in and beyond the linear regime, highlights recent theoretical and experimental advances, and discusses open problems and future prospects.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Force and geometric signatures of the creep-to-failure transition in a granular pile
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-05 20:00 EDT
Qing Hao, Luca Montoya, Elena Lee, Luke K. Davis, Cacey Stevens Bester
Granular creep is the slow, sub-yield movement of constituents in a granular packing due to the disordered nature of its grain-scale interactions. Despite the ubiquity of creep in disordered materials, it is still not understood how to best predict the creep-to-failure regime based on the forces and interactions among constituents. To address this gap, we perform experiments to explore creep and failure in quasi two-dimensional piles of photoelastic disks, allowing the quantification of both grain movements and grain-scale contact force networks. Through controlled external disturbances, we investigate the emergence and evolution of grain rearrangements, force networks, and voids to illuminate signatures of creep and failure. Surprisingly, the force chain structure remains dynamic even in the absence of particle motion. We find that shifts in force chains provide an indication to larger, avalanche-scale disruptions. We reveal connections between these force signatures and the geometry of the voids in the pile. Overall, our novel experiments and analyses deepen our mechanical and geometric understanding of the creep-to-failure transition in granular systems.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci), Statistical Mechanics (cond-mat.stat-mech)
Metallophilicity Enhances Electron Transport through Parallel Organometallic 1D Chain Junctions Formed In Situ
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-05 20:00 EDT
Sigifredo Luna, Hannah E Skipper, Brent Lawson, Eric S Cueny, Maria Kamenetska
We reveal the role of aurophilic interactions in the formation and conductance of gold cyanide molecular wires of variable length-to-width ratios assembled at the tip of an STM break junction in ambient conditions. Specifically, we identify electron transport signatures through 1D single chains containing variable number of monomeric repeats of gold cyanide AuCN, linked in series (AuCN)n, and through adjacent molecular wires linked in parallel. When bound in series, destructive quantum interference causes an exponential decay of conductance in (AuCN)n 1D wires for n=1-3. But when bound in parallel, aurophilic coupling through the gold atoms of neighboring chains reorders electronic states and results in significant enhancement of conductance. Our work reveals that metallophilicity can play a significant role in junction assembly and electron transport characteristics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Impact of quantum coherence on the dynamics and thermodynamics of quenched free fermions coupled to a localized defect
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-08-05 20:00 EDT
Beatrice Donelli, Gabriele De Chiara, Francesco Scazza, Stefano Gherardini
We investigate the non-equilibrium quantum dynamics and thermodynamics of free fermions suddenly coupled to a localized defect in a one-dimensional harmonic trap. This setup realizes a quantum quench transformation that gives rise to the orthogonalization of the system’s wave-function as an effect of the localized perturbation. Using the Loschmidt echo and the Kirkwood-Dirac quasiprobability (KDQ) distribution of the work done by the defect, we quantify the extent and rate of the orthogonalization dynamics. In particular, we show that initializing the system in a coherent superpositions of energy eigenstates leads to non-classical features, such as Wigner function’s negativity and non-positivity of the work KDQ distribution. Starting from simple single-particle superpositions and then progressing with coherent and cat states of few-body fermionic systems, we uncover how quantum coherence and few-body correlations shape the out-of-equilibrium response due to the presence of the defect.
Quantum Gases (cond-mat.quant-gas), Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
19 pages, 12 figures. Comments and feedback are welcome
Confinement geometry governs the impact of external shear stress on active stress-driven flows in microtubule-kinesin active fluids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-05 20:00 EDT
Joshua H. Dickie, Tianxing Weng, Yen-Chen Chen, Yutian He, Saloni Saxena, Robert A. Pelcovits, Thomas R. Powers, Kun-Ta Wu
Active fluids generate internal active stress and exhibit unique responses to external forces such as superfluidity and self-yielding transitions. However, how confinement geometry influences these responses remains poorly understood. Here, we investigate microtubule-kinesin active fluids under external shear stresses in two geometries. In slab-like confinement (a narrow-gap cavity), external stresses propagated throughout the system, leading to stress competition and a kinematic transition that shifted dynamics from active stress-dominated to shear stress-dominated flow. At the transition, we estimate the active stress to be ~1.5 mPa. Simulation supported that this transition arises from stress competition. In contrast, in ring-like confinement (a toroidal system), external forces acted locally, inducing a mini cavity flow that triggered self-organized reconfiguration rather than direct entrainment. These findings show that the response of active fluids to external forcing depends not only on the magnitude of the applied stress but also on how confinement geometry directs and redistributes that stress, revealing a new approach to controlling active fluid behavior by combining static geometrical design with dynamic external stimuli for real-time modulation of flow patterns. Such control strategies may be applied to microfluidic systems, where external inputs such as micromechanical actuators can dynamically tune active fluid behavior within fixed device geometries, enabling transitions between chaotic and coherent flows for tasks such as mixing, sorting, or directed transport.
Soft Condensed Matter (cond-mat.soft), Fluid Dynamics (physics.flu-dyn)
Experimental evidence of disordered crystalline premixing in sputter-deposited Ni(V)/Al multilayers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-05 20:00 EDT
Michael J Abere, Paul G. Kotula, Jonathan S. Paras, David P. Adams
The sputter deposition of alternating layers of Ni(V) and Al forms a reactive multilayer known to undergo self-propagating formation reactions when ignited. The sequential deposition process leads to nm-scale premixing of reactants at each included interface which ultimately affects multilayer exothermicity. This work performs the direct measurement of a disordered face-centered cubic (FCC) solid solution premixed phase at the interfaces of Ni(V)/Al multilayers via scanning transmission electron microscopy. The crystallinity of the observed phase differs from previously reported a priori predictions of an amorphous interlayer. The disordered FCC phase retains its symmetry after annealing for 16 h at 135 C, but the lattice parameter shifts consistent with an Al-rich composition. The existence of a crystalline premix in Ni(V)/Al is attributed to the electronic contribution to the entropy of crystallization.
Materials Science (cond-mat.mtrl-sci)
Local interface effects modulate global charge order and optical properties of 1T-TaS$_2$/1H-WSe$_2$ heterostructures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-05 20:00 EDT
Samra Husremović, Valerie S. McGraw, Medha Dandu, Lilia S. Xie, Sae Hee Ryu, Oscar Gonzalez, Shannon S. Fender, Madeline Van Winkle, Karen C. Bustillo, Takashi Taniguchi, Kenji Watanabe, Chris Jozwiak, Aaron Bostwick, Eli Rotenberg, Archana Raja, Katherine Inzani, D. Kwabena Bediako
1T-TaS$ _2$ is a layered charge density wave (CDW) crystal exhibiting sharp phase transitions and associated resistance changes. These resistance steps could be exploited for information storage, underscoring the importance of controlling and tuning CDW states. Given the importance of out-of-plane interactions in 1T-TaS$ _2$ , modulating interlayer interactions by heterostructuring is a promising method for tailoring CDW phase transitions. In this work, we investigate the optical and electronic properties of heterostructures comprising 1T-TaS$ _2$ and monolayer 1H-WSe$ _2$ . By systematically varying the thickness of 1T-TaS$ _2$ and its azimuthal alignment with 1H-WSe$ _2$ , we find that intrinsic moiré strain and interfacial charge transfer introduce CDW disorder in 1T-TaS$ _2$ and modify the CDW ordering temperature. Furthermore, our studies reveal that the interlayer alignment impacts the exciton dynamics in 1H-WSe$ _2$ , indicating that heterostructuring can concurrently tailor the electronic phases in 1T-TaS$ _2$ and the optical properties of 1H-WSe$ _2$ . This work presents a promising approach for engineering optoelectronic behavior of heterostructures that integrate CDW materials and semiconductors.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Primitive chain network simulations of the creep of entangled polymers
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-05 20:00 EDT
Yuichi Masubuchi, Giovanni Ianniruberto, Giuseppe Marrucci
Although the behavior of entangled polymers in startup shear flows with constant shear rates has been thoroughly investigated, the response under creep has not been frequently considered. In this study, primitive chain network simulations, based on a multi-chain sliplink model, are modified so as to describe creep experiments. Creep simulations are compared to a literature dataset of an entangled polybutadiene solution, and qualitative agreement is found in the nonlinear range, i.e., under large stresses. Simulations allow one to extract details of the transient molecular motion, and results suggest that the deformation-induced disentanglement is relatively mild in the stress-controlled mode as compared to the rate-controlled one, because coherent molecular tumbling at the start of flow is disrupted.
Soft Condensed Matter (cond-mat.soft)
17 pages, 7 figures
Unconventional Altermagnetism in Quasicrystals: A Hyperspatial Projective Construction
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-05 20:00 EDT
Yiming Li, Mingxiang Pan, Jun Leng, Yuxiao Chen, Huaqing Huang
Altermagnetism, a novel magnetic phase characterized by symmetry-protected, momentum-dependent spin splitting and collinear compensated magnetic moments, has thus far been explored primarily in periodic crystals. In this Letter, we extend the concept of altermagnetism to quasicrystals – aperiodic systems with long-range order and noncrystallographic rotational symmetries. Using a hyperspatial projection framework, we construct decorated Ammann-Beenker and Penrose quasicrystalline lattices with inequivalent sublattices and investigate a Hubbard model with anisotropic hopping. We demonstrate that interaction-induced Néel order on such lattices gives rise to alternating spin-polarized spectral functions that reflect the underlying quasicrystalline symmetry, revealing the emergence of unconventional $ g$ -wave (octagonal) and $ h$ -wave (decagonal) altermagnetism. Our symmetry analysis and low-energy effective theory further reveal unconventional altermagnetic spin splitting, which is compatible with quasicrystalline rotational symmetry. Our work shows that quasicrystals provide a fertile ground for realizing unconventional altermagnetic phases beyond crystallographic constraints, offering a platform for novel magnetisms and transport phenomena unique to quasiperiodic systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
27 pages, 15 figures
Resonant Fields Inducing Energy Towers in Lieb Quantum Spin Lattice
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-05 20:00 EDT
We study a ferromagnetic XXZ Heisenberg model on a Lieb lattice. A set of exact eigenstates is constructed based on the restricted spectrum generating algebra (RSGA) when a resonant staggered magnetic field is applied. These states are identical to the eigenstates of a system of two coupled angular momenta. Furthermore, we find that the RSGA can be applied to other eigenstates of the Lieb lattice in an approximate manner. Numerical simulations reveal that there exist sets of eigenstates, which obey a quasi-RSGA. These states act as energy towers within the low-lying excited spectrum, indicating that they are quantum many-body scars.
Strongly Correlated Electrons (cond-mat.str-el)
Twistronics and moiré superlattice physics in 2D transition metal dichalcogenides
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-05 20:00 EDT
Dawei Zhai, Hongyi Yu, Wang Yao
The moiré superlattices formed by stacking 2D semiconducting transition metal dichalcogenides (TMDs) with twisting angle or lattice mismatch have provided a versatile platform with unprecedented tunability for exploring many frontier topics in condensed matter physics, including optical, topological and correlation phenomena. This field of study advances rapidly and a plethora of exciting experimental and theoretical progresses have been achieved recently. This review aims to provide an overview of the fundamental properties of TMDs moiré superlattices, as well as highlight some of the major breakthroughs in this captivating field.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Momentum distribution and correlation of free particles in the Tsallis statistics using conventional expectation value and equilibrium temperature
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-05 20:00 EDT
We applied the Tsallis statistics with the conventional expectation value to a system of free particles, adopting the equilibrium temperature which is often called the physical temperature. The entropic parameter $ q$ in the Tsallis statistics is less than one for power-law-like distribution. The well-known relation between the energy and the temperature in the Boltzmann–Gibbs statistics holds in the Tsallis statistics, when the equilibrium temperature is adopted. We derived the momentum distribution and the correlation in the Tsallis statistics. The momentum distribution and the correlation in the Tsallis statistics are different from those in the Boltzmann–Gibbs statistics, even when the equilibrium temperature is adopted. These quantities depend on $ q$ and $ N$ , where $ N$ is the number of particles. The correlation exists even for free particles. The parameter $ q$ satisfies the inequality $ 1-1/(3N/2+1) < q < 1$ .
Statistical Mechanics (cond-mat.stat-mech)
7 pages
Thermal transport and the impact of hydrogen adsorption in Linde Type A zeolitic imidazolate frameworks
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-05 20:00 EDT
Thermal transport in metal-organic frameworks (MOFs) is of practical interest in diverse applications such as gas storage and separations, since insufficient heat dissipation can lead to detrimental effects. Despite investigations, influence of molecular infiltration on the heat transport remains unclear in many of MOFs due to poor understanding of mechanisms governing heat conductions. Here, we report molecular dynamics investigations of thermal transport properties in zeolitic imidazolate frameworks (ZIFs). We investigated Linde Type A topological ZIFs (ZIF-lta) exhibiting exceptionally low thermal conductivity with unusual trend of temperature dependence deviating from many crystalline materials, despite long-range crystalline order in them. We demonstrate that heat is predominantly carried by phonons with mean free paths comparable to their wavelengths, analogous to diffusons in amorphous solids owing to strong anharmonicity caused by complexity of unit cell consisting of a large number of metal centers. We further show that adsorbed hydrogen molecules increase thermal conductivity of ZIFs, mainly contributed by additional vibrational modes, as a result of gas-gas or gas-framework interactions. Our work advances fundamental understanding into the thermal transport in MOFs and suggests a means to engineer heat conduction via gas infiltrations.
Materials Science (cond-mat.mtrl-sci)
Using surface plasmons to detect spin inertia
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-05 20:00 EDT
Recent experiments demonstrate that spin dynamics may acquire an inertial effect in a few metallic magnets, deviating from the traditional inertia-free dynamics. It remains an open question to ascertain the physical mechanisms and universality of the spin inertia across diverse magnetic systems. Here, we show that spin inertia generates nutation spin waves in the terahertz regime, which can hybridize with the surface plasmons in two-dimensional (2D) conducting materials such as graphene. By exciting hybrid spin wave-plasmon modes and analyzing the reflection spectrum of a 2D material$ |$ magnet heterostructure, we propose a method to quantitatively determine the strength of spin inertia in magnetic layers. Our approach is universally applicable to all types of magnetic insulators and could advance the future exploration of the magnitude and physical mechanism of spin inertia.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
7 pages, 2 figures
Parametric pair production of collective excitations in a Bose-Einstein condensate
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-08-05 20:00 EDT
Victor Gondret, Rui Dias, Clothilde Lamirault, Léa Camier, Amaury Micheli, Charlie Leprince, Quentin Marolleau, Scott Robertson, Denis Boiron, Christoph I. Westbrook
By exciting the transverse breathing mode of an elongated Bose-Einstein condensate, we parametrically produce longitudinal collective excitations in a pairwise manner. This process also referred to as Faraday wave generation, can be seen as an analog to cosmological particle production. Building upon single particle detection, we investigate the early time dynamics of the exponential growth and compare our observation with a Bogoliubov description. The growth rate we observe experimentally is in very good agreement with theoretical predictions, demonstrating the validity of the Bogoliubov description and thereby confirming the smallness of quasiparticle interactions in such an elongated gas. We also discuss the presence of oscillations in the atom number, which are due to pair correlations and to the rate at which interactions are switched off.
Quantum Gases (cond-mat.quant-gas), General Relativity and Quantum Cosmology (gr-qc), Pattern Formation and Solitons (nlin.PS), Quantum Physics (quant-ph)
5+5 pages, this work is dedicated to Renaud Parentani
The planar parafermion algebra: The $\mathbb{Z}_{N}$ clock model and the coupled Temperley-Lieb algebra
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-05 20:00 EDT
Remy Adderton, Murray T. Batchelor
The Hamiltonian of the $ N$ -state clock model is written in terms of a coupled Temperley-Lieb (TL) algebra defined by $ N-1$ types of TL generators. This generalizes a previous result for $ N=3$ obtained by J. F. Fjelstad and T. Månsson [J. Phys. A {\bf 45} (2012) 155208]. The $ \mathbb{Z}{N}$ -symmetric clock chain Hamiltonian expressed in terms of the coupled TL algebra generalizes the well known correspondence between the $ N$ -state Potts model and the TL algebra. The algebra admits a pictorial description in terms of a planar algebra involving parafermionic operators attached to $ n$ strands. A key ingredient in the resolution of diagrams is the string Fourier transform. The pictorial presentation also allows a description of the Hilbert space. We also give a pictorial description of the representation related to the staggered XX spin chain. Just as the pictorial representation of the TL algebra has proven to be particularly useful in providing a visual and intuitive way to understand and manipulate algebraic expressions, it is anticipated that the pictorial representation of the coupled TL algebra may lead to further progress in understanding various aspects of the $ \mathbb{Z}{N}$ clock model, including the superintegrable chiral Potts model.
Statistical Mechanics (cond-mat.stat-mech)
22 pages
A Non-Local Orientation Field Phase-Field Model for Misorientation- and Inclination- Dependent Grain Boundaries
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-05 20:00 EDT
We propose to incorporate grain boundary (GB) anisotropy in phase-field modeling by extending the standard partial differential equations formulation to include a non-local functional of an orientation field. Regardless of the number of grains in the simulation, the model uses a single orientation field and incorporates grain misorientation and inclination information obtained from sampling the orientation field at optimized locations in the vicinity of the grain boundary. The formalism enables simple and precise tuning of GB energy anisotropy while avoiding an extensive fitting procedure. The functional includes an explicit GB anisotropy function to control the GB energy as a function of both misorientation and inclination. The model is validated by reproducing the linear grain growth rate, Wulff shapes with varying misorientations and anisotropic coefficients, and analytical equilibrium dihedral angles at triple junctions. Polycrystalline simulations demonstrate grain growth, coalescence, triple junction behavior, and the influence of anisotropy on grain morphology.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
Bose-Hubbard model in the canonical ensemble: a beyond mean-field approach
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-08-05 20:00 EDT
Ultracold atoms in optical lattices are versatile testbeds to study and manipulate equilibrium and out-of-equilibrium aspects of quantum many-body systems whose behavior can be described by Hubbard-type Hamiltonians. In this paper, we consider an ansatz wave-function which respects total particle-number conservation for such systems and goes beyond mean-field theory; this wave-function has the same complexity in the number of parameters as the mean-field Gutzwiller ansatz, and captures quantum correlations and entanglement via projection onto an effective low-energy manifold. This ansatz can be exploited to study quantum phases observed in a large class of systems realizable in such experimental platforms and is useful to study quantum dynamics. We show that the relaxation dynamics of various out-of-equilibrium initial states under sudden quench of Hamiltonian parameters can be studied with this ansatz wavefunction within the framework of time-dependent variational principle. We present a quantitative comparison with small-scale exact diagonalization results in the 1D Bose-Hubbard model with and without external trapping potentials.
Quantum Gases (cond-mat.quant-gas), Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
16 pages, 7 figures
A Novel Methodology of Visualizing Orthorhombic Phase Uniformity in Ferroelectric Hf0.5Zr0.5O2 Devices Using Piezoresponse Force Microscopy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-05 20:00 EDT
Wei-Cheng Peng, Hsien-Yang Liu, Cheng-Yu Yu, Artur Useinov, Tian-Li Wu
Ferroelectric Hf0.5Zr0.5O2 (HZO) thin films are promising for next-generation memory and logic devices due to their CMOS compatibility and scalability. The spatial uniformity of the orthorhombic (O) phase is crucial for optimizing ferroelectric properties like remnant polarization. This work introduces a novel piezoresponse force microscopy (PFM) approach for 2D mapping of O-phase uniformity in HZO films (5 nm, 9 nm, and 20 nm), further quantifing O-phase distribution by distinguishing polarized O-phase regions from non-polarized tetragonal/monoclinic (T/M) phases. Our results reveal that the 9 nm film exhibits the most uniform O-phase and highest remnant polarization. This PFM-based method enables comprehensive phase characterization without requiring complicated facilities, broadening access to phase analysis and advancing ferroelectric thin-film research for memory and logic applications.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
6 pages, 7 figures
Exact diagonalization study of energy level statistics in harmonically confined interacting bosons
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-08-05 20:00 EDT
We present an exact diagonalization study of the spectral properties of bosons harmonically confined in a quasi-2D plane and interacting via repulsive Gaussian potential. We consider the lowest $ 100$ energy levels for systems of $ N=12, 16$ and $ 20$ bosons both for the moderate and strong interaction regimes for the non-rotating ($ L_{z}=0$ ) and the rotating single-vortex state ($ L_{z}=N$ ). For higher angular momenta, $ L_{z}=2N$ and $ L_{z}=3N$ , only the strong interaction regime is considered. While the nearest-neighbor spacing distribution (NNSD) $ P(s)$ and the ratios of consecutive level spacings distribution $ P(r)$ are used to study the short-range correlations, the Dyson-Mehta $ \Delta_3$ statistic and the level number variance $ \Sigma^2(L)$ are used to examine the long-range correlations. In the moderate interaction regime when the interaction energy is small compared to the trap energy, the non-rotating system exhibits a Poisson distribution, characteristic of the regular energy spectra. In the strong interaction regime when the interaction energy is comparable to the trap energy, the non-rotating system exhibits chaotic behavior signified by GOE distribution. Furthermore, in the rotating case for the single-vortex state ($ L_{z} = N$ ) in the moderate interaction regime, the system exhibits signatures of weak chaos with some degree of regularity in the energy-level spectra. However, in the strong interaction regime for the rotating case with $ L_{z} = N$ , $ 2N$ and $ 3N$ , the system exhibits strong chaotic behavior. The rotation is found to contribute to an enhancement of chaotic behavior in the system for both the moderate and the strong interaction regimes. Our results of NNSD analysis are supported by the analysis of the ratios of consecutive level spacings distribution $ P(r)$ .
Quantum Gases (cond-mat.quant-gas), Chaotic Dynamics (nlin.CD), Quantum Physics (quant-ph)
13 pages, 8 figures
Photoinduced Low Spin to High Spin Transition in a [2x2] Fe(II) Metallogrid: Diode Laser-Pumped Photocrystallography at the P11 Beamline in PETRA III, DESY
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-05 20:00 EDT
Krishnayan Basuroy, Jose de Jesus Velazquez-Garcia, Sreeju Sreekantan Nair Lalithambika, Argha Barman, Torben Reuss, Guillaume Pompidor, Alexander Grebentsov, Önder Akçaalan, Simone Techert
We report on the photoinduced spin crossover (SCO) transition from a 2HS-2LS to a 3HS-1LS state in a [2x2] Fe(II) metallogrid complex using molecular crystals with static photocrystallography at a first ever attempt in the beamline P11 of the PETRA III synchrotron, DESY. A class 3B diode laser was used to induce the transition under controlled irradiation conditions. Structural characterization was achieved through single-crystal X-ray diffraction (SCXRD) measurements post-irradiation, revealing significant changes in average Fe-N distances, consistent with SCO behavior. Our experimental setup enables precise alignment necessary for photo-excitation using a class 3B diode laser along with a compact focusing optics. The longest dimension of the combined setup of the diode head and the focusing optics is not more than 32cm. The setup showcasing the utility of a compact diode laser system which can even be conveniently used in synchrotron-based pump-probe photocrystallography experiments for a wide range of molecular crystals.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph), Optics (physics.optics)
Optical properties of emeraldine salt polymers from ab initio calculations: comparison with recent experimental data
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-05 20:00 EDT
Renato Colle, Pietro Parruccini, Andrea Benassi, Carlo Cavazzoni
We present absorption coefficient {\alpha}({\omega}), transverse dielectric function {\epsilon}({\omega}), optical conductivity {\sigma}({\omega}), and reflectance R({\omega}) calculated for an emeraldine salt conducting polymer in its crystalline three-dimensional polaronic structure. We utilize Kohn-Sham DFT electronic wavefunctions and energies implemented in the expression of the macroscopic transverse dielectric function in the framework of the band theory without the electron-hole interaction. Contributions of intra-band transitions are taken into account by adding a Drude-like term to the dielectric function calculated ab-initio. Comparison with optical properties, recently measured on high-quality emeraldine salts (Nature 441(2006)65-68), and with optical absorption spectra, recorded on other emeraldine salts, is very satisfactory. The calculated spectra are discussed in terms of energy-band structure, density of states, inter- and intra-band transitions and transverse dielectric function.
Materials Science (cond-mat.mtrl-sci)
J.Phys.Chem. B 111 (2007) 2800-2805
Quantum Path-integral Method for Fictitious Particle Hubbard Model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-05 20:00 EDT
Zhijie Fan, Tianning Xiao, Youjin Deng
We formulate a path-integral Monte Carlo algorithm for simulating lattice systems consisting of fictitious particles governed by a generalized exchange statistics. This method, initially proposed for continuum systems, introduces a continuous parameter $ \xi$ in the partition function that interpolates between bosonic ($ \xi = 1$ ) and fermionic ($ \xi = -1$ ) statistics. We generalize this approach to discrete lattice models and apply it to the two-dimensional Hubbard model of fictitious particles, including the Bose- and Fermi-Hubbard models as special cases. By combining reweighting and $ \xi$ -extrapolation techniques, we access both half-filled and doped regimes. In particular, we demonstrate that the method remains effective even in strongly correlated, doped systems where the fermion sign problem hinders conventional quantum Monte Carlo approaches. Our results validate the applicability of the fictitious particle framework on lattice models and establish it as a promising tool for sign-problem mitigation in strongly interacting fermionic systems.
Strongly Correlated Electrons (cond-mat.str-el)
Floquet theory and applications in open quantum and classical systems
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-05 20:00 EDT
Masahiro Sato, Tatsuhiko N. Ikeda
This article reviews theoretical methods for analyzing Floquet engineering (FE) phenomena in open (dissipative) quantum or classical systems, with an emphasis on our recent results. In many theoretical studies for FE in quantum systems, researchers have used the Floquet theory for closed (isolated) quantum systems, that is based on the Schrödinger equation. However, if we consider the FE in materials driven by an oscillating field like a laser, a weak but finite interaction between a target system and an environment (bath) is inevitable. In this article, we describe these periodically driven dissipative systems by means of the quantum master (GKSL) equation. In particular, we show that a nonequilibrium steady state appears after a long driving due to the balance between the energy injection by the driving field and the release to the bath. In addition to quantum systems, if we try to simply apply Floquet theory to periodically driven classical systems, it failed because the equation of motion (EOM) is generally nonlinear, and the Floquet theorem can be applied only to linear differential equations. Instead, by considering the distribution function of the classical variables (i.e., Fokker-Planck equation), one can arrive at the effective EOM for the driven systems. We illustrate the essence of the Floquet theory for classical systems. On top of fundamentals of the Floquet theory, we review representative examples of FEs (Floquet topological insulators, inverse Faraday effects in metals and magnets, Kapitza pendulum, etc.) and dissipation-assisted FEs.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
Review article, 27 pages (2 column), 16 figures, 2 tables
Deep Learning-Driven Prediction of Microstructure Evolution via Latent Space Interpolation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-05 20:00 EDT
Sachin Gaikwad, Thejas Kasilingam, Owais Ahmad, Rajdip Mukherjee, Somnath Bhowmick
Phase-field models accurately simulate microstructure evolution, but their dependence on solving complex differential equations makes them computationally expensive. This work achieves a significant acceleration via a novel deep learning-based framework, utilizing a Conditional Variational Autoencoder (CVAE) coupled with Cubic Spline Interpolation and Spherical Linear Interpolation (SLERP). We demonstrate the method for binary spinodal decomposition by predicting microstructure evolution for intermediate alloy compositions from a limited set of training compositions. First, using microstructures from phase-field simulations of binary spinodal decomposition, we train the CVAE, which learns compact latent representations that encode essential morphological features. Next, we use cubic spline interpolation in the latent space to predict microstructures for any unknown composition. Finally, SLERP ensures smooth morphological evolution with time that closely resembles coarsening. The predicted microstructures exhibit high visual and statistical similarity to phase-field simulations. This framework offers a scalable and efficient surrogate model for microstructure evolution, enabling accelerated materials design and composition optimization.
Materials Science (cond-mat.mtrl-sci), Artificial Intelligence (cs.AI)
7 figures
Supercurrents and tunneling in massive many-vortex necklaces and star-lattices
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-08-05 20:00 EDT
Alice Bellettini, Vittorio Penna
Recently, cold atoms mixtures have attracted broad interest due to their novel properties and exotic quantum effects with respect to single-component systems. In this paper the focus is on massive many-vortex states and their dynamics. Vortex configurations characterized by the same discrete rotational symmetry are investigated when confined within topologically nonequivalent geometries, and the relative stability properties at varying number of vortices and infilling mass are highlighted. It is numerically shown how massive many-vortex systems, in a mixture of Bose-Einstein condensates, can host the bosonic tunneling of the infilling component both in a disordered way, with tunneling events involving two or more close vortices, or in an almost-periodic way when the vortices are organized in persisting necklaces or star-lattices. The purpose is to explore a variety of situations involving the interplay between the highly-nonlinear vortex dynamics and the inter-vortex atomic transfer, and so to better understand the conditions for the onset of Josephson supercurrents in rotating systems, or to reveal phenomena that could be of interest for a future application e.g. in the context of atomtronics.
Quantum Gases (cond-mat.quant-gas)
22 pages, 18 figures
Mesoscale variations of chemical and electronic landscape on the surface of Weyl semimetal Co$_3$Sn$_2$S$_2$ visualized by ARPES and XPS
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-05 20:00 EDT
Sudheer Anand Sreedhar, Matthew Staab, Mingkun Chen, Robert Prater, Zihao Shen, Giuseppina Conti, Ittai Sidilkover, Zhenghong Wu, Eli Rotenberg, Aaron Bostwick, Chris Jozwiak, Hadas Soifer, Slavomir Nemsak, Sergey Y. Savrasov, Vsevolod Ivanov, Valentin Taufour, Inna M. Vishik
The multiple crystalline terminations in magnetic Weyl semimetal Co$ _3$ Sn$ _2$ S$ _2$ display distinct topological and trivial surface states, which have successfully been distinguished experimentally. However, a model of pure terminations is known to be inadequate because these surfaces exhibit a high degree of spatial heterogeneity and point disorder. Here we perform a spectromicroscopy study of the surface chemistry and surface electronic structure using photoemission measurements in combination with first-principles calculations of core levels. We identify an intermediate region with properties distinct from both the sulfur and tin terminations, and demonstrate that the spectral features in this region can be associated with a disordered tin termination with a varying density of surface tin-vacancies. Finally, we show how a combination of algorithmic and machine learning analysis of photoemission data can be used to extract identifying features, classify spatial regions, and correlate local chemistry with local electronic structure.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
Focused Ion Beam patterning of MnSb(1-101) based spintronic devcies
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-05 20:00 EDT
Stuart N. Holmes, Jonathan Gough, Ethan Dommett, Gavin R. Bell
Low temperature transport measurements are presented of ferromagnetic MnSb devices with the magnetic properties patterned using a Ga focused ion beam FIB system at 30 keV. FIB patterning introduces disorder and this is quantified in this paper through measurements of the longitudinal resistivity and the anomalous Hall effect contribution to the Hall conductivity. The MnSb structural phase is the niccolite phase with a surface state in addition to bulk states. FIB doses up to 1E16 Ga ions per square cm reduces the anisotropic magnetoresistance signal but increases the size of the anomalous Hall effect signal in out of plane magnetic fields, B. The anomalous Hall effect contribution to the Hall conductivity is e squared divided by h in the undamaged devices, where e is the electronic charge and h is Plancks constant. This quantity is sensitive to the level of disorder induced by the Ga ion beam, reducing to zero at dose levels greater than 1E16 Ga ions per square cm. The resistivity shows a logarithmic B dependence after the magnetization has saturated with the low field anisotropic magnetoresistance contribution of 0.12 percent. The conductivity change is e squared divided by h in the magnetic field range of logarithmic B behavior. The resistivity shows a reduced fit to a logarithmic B dependence at high FIB dose levels and is dependent on the damage uniformity. Patterning nanostructured magnetic behavior in MnSb, with compatibility to altermagnetic materials, in particular the niccolite phase of CrSb and non trivial Berry phase contributions to transport make this ferromagnetic material and patterning technique useful for future spintronic device development.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
18 pages, 7 figures, 27 references
Unraveling the Molecular Structure of Lipid Nanoparticles through in-silico Self-Assembly for Rational Delivery Design
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-05 20:00 EDT
Xuan Bai, Yu Lu, Tianhao Yu, Kangjie Lv, Cai Yao, Feng Shi, Andong Liu, Kai Wang, Wenshou Wang, Chris Lai
Lipid nanoparticles (LNPs) are a leading platform in the delivery of RNA-based therapeutics, playing a pivotal role in the clinical success of mRNA vaccines and other nucleic acid drugs. Their performance in RNA encapsulation and delivery is critically governed by the molecular structure of ionizable lipids and the overall formulation composition. However, mechanistic insight into how these factors govern LNP architecture and function remains limited, primarily owing to the challenges of capturing nanoscale assembly and organization using experimental techniques. Here, we employ coarse-grained molecular dynamics simulations to systematically investigate how ionizable lipid chemistry influences LNP self-assembly, internal organization, and surface properties. We further explore the effects of formulation ratios and pH-dependent deprotonation on both the internal structure and surface morphology of LNPs. Leveraging these insights, we demonstrate how in silico structural characteristics can inform the rational design of novel ionizable lipids and optimization of formulation ratios, supported with experimental validations. Our findings offer a molecular-level understanding of LNP assembly dynamics and architecture, thereby establishing a computational framework linking lipid chemistry and LNP formulation to the structure and performance of LNP, to advance the rational design of novel LNP delivery systems.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
Self-organisation – the underlying principle and a general model
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-05 20:00 EDT
Recent observations of coordinated self-organisation (SO) of stress and structure in granular systems provide insight into the fundamental principle underlying this phenomenon. It is first argued here that SO emerges when a minute subset of configurations are significantly more stable than the rest and therefore survive the noise in the system much longer to be observed. This principle goes deeper than recently proposed energy considerations. Guided by this principle, a statistical mechanics model is formulated then for SO in these systems and its extension to three dimensions is outlined. The principle holds beyond granular systems and the model is extended next to describe emergence of SO in more general systems. The application of the model is illustrated for the specific example of laning. Parallels of the modelling approach to traditional statistical mechanics provide useful insight that should assist in modelling SO in other out-of-equilibrium systems.
Statistical Mechanics (cond-mat.stat-mech), Adaptation and Self-Organizing Systems (nlin.AO)
6 pages, submitted
Data-driven ANN model for estimating unfrozen water content in the thermo-hydraulic simulation of frozen soils
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-05 20:00 EDT
Mingpeng Liu, Peizhi Zhuang, Raul Fuentes
This study integrates a data-driven model for estimating the unfrozen water content into the thermo-hydraulic coupling simulation of frozen soils. An artificial neural network (ANN) was employed to develop this data-driven model using a dataset from the literature. Thereafter, a numerical algorithm was developed to implement the data-driven model into the thermo-hydraulic simulation. In the numerical algorithm, the frozen and unfrozen zones are distinguished first according to the freezing temperature, where the unfrozen water at frozen nodes is updated using the ANN model. Subsequently, discretized hydraulic and thermal equations are solved sequentially and iteratively using Newton-Raphson method until the temperature and unfrozen water content satisfy the tolerance simultaneously. Horizontal and vertical freezing experiments are used to verify the reliability of the proposed algorithm. The computed variations in temperature, total water, unfrozen water, and ice content achieve good agreements with measured data. Some key features of frozen soils, such as water migration and ice formation, and the increase in total water content, are reproduced by the developed algorithm. Additionally, the comparison between the ANN model and existing empirical equations for determining unfrozen water content demonstrates that the ANN model offers a better performance.
Soft Condensed Matter (cond-mat.soft)
Exploring Weak Turbulence of Phonon and Magnon Beams in Magneto-Acoustic Ultrathin Films
New Submission | Other Condensed Matter (cond-mat.other) | 2025-08-05 20:00 EDT
Vladimir L. Safonov, Derek A. Bas, Andrew Franson, Piyush J. Shah, Michael E. McConney, Michael Newburger, Michael R. Page
This study presents a simple theoretical model describing narrow envelope surface acoustic waves
(phonons) and spin waves (magnons) in an ultrathin ferromagnetic film. Based on the general
principles of weak wave turbulence, the model considers interactions between beams of an ideal
phonon gas and a weakly non-ideal magnon gas, which represent magnetoacoustic oscillations in
the system. Equations for the wave envelopes of phonons and magnons, along with their harmonics,
are derived, incorporating nonlinear effects from three- and four-particle interactions. In
the general non-resonant case, linear stationary envelope simulations are sufficient. These clarify
the experimentally observed angular dependence of the transmitted acoustic signal with respect
to the orientation of the magnetic field. The study highlights increased energy losses associated
with enhanced magnetoacoustic coupling. Given the broad interdisciplinary interest in weak turbulence
phenomena within condensed matter physics and nonlinear wave dynamics, our model
offers significant predictive capabilities and greatly simplifies calculations of quasiparticle beam
interactions.
Other Condensed Matter (cond-mat.other), Applied Physics (physics.app-ph)
16 pages, 5 figures
Characterizing and modeling the mechanical behavior of an anion exchange membrane for carbon capture applications
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-05 20:00 EDT
Sara Sarbaz, Zhi Xin Liu, Heidi Feigenbaum, Samaneh Bayati, Winston Wang, Jennifer Wade, Husain Mithaiwala, Matthew D. Green
A new direct air capture (DAC) technology uses a moisture swing (MS) process with anion exchange membranes, potentially offering a more energy-efficient way to remove CO2 from the air. In this MS process, the membrane absorbs CO2 as it dries and releases it when water is added. Understanding the mechanical behavior of these membranes is essential for improving the design and efficiency of DAC systems and prolonging sorbent lifetime. This study tested one anion exchange membrane, Fumasep FAA-3, under mechanical loading and various temperature and humidity conditions to measure its swelling, stiffness, strength, plastic deformation, and stress relaxation. Experimental results were used to identify a mechanical model for FAA-3 that can be used to predict the material’s nonlinear viscous behavior under various loads and environments.
Soft Condensed Matter (cond-mat.soft)
Advanced SQUID-on-lever scanning probe for high-sensitivity magnetic microscopy with sub-100-nm spatial resolution
New Submission | Superconductivity (cond-mat.supr-con) | 2025-08-05 20:00 EDT
Timur Weber (1), Daniel Jetter (2), Jan Ullmann (1), Simon A. Koch (1), Simon F. Pfander (1), Katharina Kress (2), Andriani Vervelaki (2), Boris Gross (2), Oliver Kieler (3), Ute Drechsler (4), Priya R. Baral (5), Arnaud Magrez (5), Reinhold Kleiner (1), Armin W. Knoll (4), Martino Poggio (2 and 6), Dieter Koelle (1) ((1) University of Tübingen, (2) University of Basel, (3) PTB Braunschweig, (4) IBM Reserach Europe Zürich, (5) EPFL Lausanne, (6) Swiss Nanoscience Institute Univ. Basel)
Superconducting quantum interference devices (SQUIDs) are exceptionally sensitive magnetometers capable of detecting weak magnetic fields. Miniaturizing these devices and integrating them onto scanning probes enables high-resolution imaging at low-temperature. Here, we fabricate nanometer-scale niobium SQUIDs with inner-loop sizes down to 10 nm at the apex of individual planar silicon cantilevers via a combination of wafer-scale optical lithography and focused-ion-beam (FIB) milling. These robust SQUID-on-lever probes overcome many of the limitations of existing devices, achieving spatial resolution better than 100 nm, magnetic flux sensitivity of $ 0.3~\mu\Phi_0/\sqrt{\rm{Hz}}$ , and operation in magnetic fields up to about 0.5 T at 4.2 K. Nanopatterning via Ne- or He-FIB allows for the incorporation of a modulation line for coupling magnetic flux into the SQUID or a third Josephson junction for shifting its phase. Such advanced functionality, combined with high spatial resolution, large magnetic field range, and the ease of use of a cantilever-based scanning probe, extends the applicability of scanning SQUID microscopy to a wide range of magnetic, normal conducting, superconducting, and quantum Hall systems. We demonstrate magnetic imaging of skyrmions at the surface of bulk Cu$ _2$ OSeO$ _3$ . Analysis of the point spread function determined from imaging a single skyrmion yields a full-width-half-maximum of 87 nm. Moreover, we image modulated magnetization patterns with a period of 65 nm.
Superconductivity (cond-mat.supr-con)
11 pages, 4 figures
The birefringent spin-laser as a system of coupled harmonic oscillators
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-05 20:00 EDT
Velimir Labinac, Jiayu David Cao, Gaofeng Xu, Igor Žutić
Adding spin-polarized carriers to semiconductor lasers strongly changes their properties and, through the transfer of angular momentum, leads to the emission of the circularly polarized light. In such spin-lasers the polarization of the emitted light can be modulated an order of magnitude faster than its intensity in the best conventional lasers. This ultrafast operation in spin-lasers relies on the large linear birefringence, usually viewed as detrimental in spin and conventional lasers, which couples the two linearly-polarized emission modes. We show that the dynamical properties of birefringent spin-lasers under intensity and polarization modulation are accurately described as coupled harmonic oscillators. Our model agrees with the intensity-equation description which, unlike the common complex field components describing the role of birefringence in laser dynamics, uses simpler real quantities and allows analytical solutions. We further predict unexplored operation regimes and elucidate the difference between the weak and strong coupling in spin-lasers.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics)
19 pages, 10 figures, Phys. Rev. B, in press
Orbital Inverse Faraday and Cotton-Mouton Effects in Hall Fluids
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-05 20:00 EDT
Gabriel Cardoso, Erlend Syljuåsen, Alexander V. Balatsky
We report two light-induced orbital magnetization effects in quantum Hall (QH) fluids, stemming from their transverse response. The first is a purely transverse contribution to the inverse Faraday effect (IFE), where circularly polarized light induces a DC magnetization by stirring the charged fluid. This contribution dominates the IFE in the QH regime. The second is the orbital inverse Cotton-Mouton effect (ICME), in which linearly polarized light generates a DC magnetization. Since the applied field in the ICME does not break time-reversal symmetry, the induced magnetization directly probes the chiral orbital response of the fluid at the driving frequency. We estimate that the resulting magnetization lies in the range of 0.5-10 Bohr magnetons per charge carrier in materials such as graphene and transition-metal dichalcogenides (TMDs) in the QH regime. Finally, we show that the induced magnetization is accompanied by a local correction to the static particle density, enabling optical quantum printing of density profiles into the QH fluid.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
5 + 9 pages
From trigonal to triclinic: Symmetry-tuned Rashba effects in buckled honeycomb SrHfO$_{3}$-based heterostructures
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-05 20:00 EDT
Harnessing the interplay of symmetry breaking and spin-orbit coupling, we investigate Rashba spin splitting in buckled honeycomb (SrHfO$ _3$ )$ _2$ /(LaAlO$ _3$ )$ _4$ (111) superlattices using density functional theory (DFT) calculations with a Hubbard $ U$ term and a Wannier-based tight-binding (TB) model. In the non-centrosymmetric $ P1$ phase, pronounced Rashba-type splitting emerges near the $ M$ and $ K$ points accompanied by a helical in-plane spin texture, while the centrosymmetric $ P321$ phase remains spin-degenerate. A Wannier-based tight-binding Hamiltonian, extended analytically with on-site spin-orbit coupling, reproduces the DFT results. A Rashba coefficient of $ \alpha_R = 0.34$ eV$ \cdot$ Angstrom and energy $ E_R = 29$ meV are extracted directly from the DFT band structure placing the system among moderately strong oxide Rashba materials. $ \Gamma$ -phonon calculation confirms the dynamical stability of the $ P1$ structure and the results reveal the critical role of symmetry breaking and inter-orbital hybridization in enabling Rashba effects, supported by enhanced imaginary second-nearest-neighbor hoppings and Berry curvature. These findings establish SrHfO$ _3$ -based buckled heterostructures as a promising platform for engineering Rashba effects in oxide-based spintronic devices.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
10 pages, 8 figures
Benchmarking total energies with Hund’s J terms in Hubbard-corrected spin-crossover chemistry
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-05 20:00 EDT
Lórien MacEnulty, João Paulo Almeida de Mendonça, Roberta Poloni, David D. O’Regan
The effect of the Hund’s J terms in various DFT+U+J corrections to semi-local spin-density functional theory is assessed for a series of four octahedrally coordinated Fe(II) spin-crossover molecules spanning the covalent end of the ligand field spectrum. We report values and analyze trends for the Hubbard U and Hund’s J parameters determined via minimum-tracking linear response for all valence atomic subspaces and relevant spin states in these molecules. We then methodically apply them via simplified rotationally-invariant Hubbard functionals in search of the simplest combination to yield reliable adiabatic energy differences with respect to those obtained using CASPT2/CC. The observed failure of canonical, positively-signed Hund’s J terms in furthering the already robust capacity of DFT+U to obtain accurate energetics prompts an evaluation of their limitations when seeking to account for the static correlation phenomena in such strongly covalent systems and suggests directions for their improvement.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph), Computational Physics (physics.comp-ph)
7 figures (+1 in appendix, +4 in SI), 2 tables (+1 in SI)
Topological phases and spontaneous symmetry breaking: the revenge of the original Su-Schrieffer-Heeger model
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-05 20:00 EDT
Polina Matveeva, Dmitri Gutman, Sam T. Carr
We study the interplay of spontaneous symmetry breaking and topological properties in interacting one-dimensional models. We solve these models using bozonization and identify topologically non-trivial phases by counting the additional degeneracy (affiliated with the edge modes) of a finite-size system relative to the infinite one. We find even if the mean-field solution is topological, this may not be true when it arises from spontaneous symmetry breaking, including in the Su-Schrieffer-Heeger (SSH) model. This implies that the original SSH model, as presented by Su, Schrieffer, and Heeger, is topologically trivial, as opposed to its mean-field version. A spinful version, on the other hand, does exhibit a topologically non-trivial phase. In that state, both mean-field solutions are topologically non-trivial and correspond to non-interacting SSH chains in the opposite phases with the winding number $ \nu=1$ . We show that this phase is protected by a chiral symmetry, similar to the non-interacting phases.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
11 pages
Path-Integral Formulation of Bosonic Markovian Open Quantum Dynamics with Monte Carlo stochastic trajectories using the Glauber-Sudarshan P, Wigner, and Husimi Q Functions and Hybrids
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-08-05 20:00 EDT
Toma Yoneya, Kazuya Fujimoto, Yuki Kawaguchi
The Monte Carlo (MC) trajectory sampling of stochastic differential equations (SDEs) based on the quasiprobabilities, such as the Glauber-Sudarshan P, Wigner, and Husimi Q functions, enables us to investigate bosonic open quantum many-body dynamics described by the Gorini-Kossakowski-Sudarshan-Lindblad (GKSL) equation. In this method, the MC samplings for the initial distribution and stochastic noises incorporate quantum fluctuations, and thus, we can go beyond the mean-field approximation. However, description using SDEs is possible only when the corresponding Fokker-Planck equation has a positive-semidefinite diffusion matrix. In this work, we analytically derive the SDEs for arbitrary Hamiltonian and jump operators based on the path-integral formula, independently of the derivation of the Fokker-Planck equation (FPE). In the course of the derivation, we formulate the path-integral representation of the GKSL equation by using the $ s$ -ordered quasiprobability, which systematically describes the aforementioned quasiprobabilities by changing the real parameter $ s$ . The essential point of this derivation is that we employ the Hubbard-Stratonovich (HS) transformation in the path integral, and its application is not always feasible. We find that the feasible condition of the HS transformation is identical to the positive-semidefiniteness condition of the diffusion matrix in the FPE. In the benchmark calculations, we confirm that the MC simulations of the obtained SDEs well reproduce the exact dynamics of physical quantities and non-equal time correlation functions of numerically solvable models, including the Bose-Hubbard model. This work clarifies the applicability of the approximation and gives systematic and simplified procedures to obtain the SDEs to be numerically solved.
Quantum Gases (cond-mat.quant-gas), Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
39 pages, 5 figures
Significant Mobility Enhancement in Coupled AlGaN/GaN Quantum Wells considering Inter-Well Distance and Asymmetric Widths
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-05 20:00 EDT
Le Tri Dat, Tran Trong Tai, Truong Van Tuan, Vo Van Tai, Nguyen Duy Vy
We demonstrate that coupled AlGaN/GaN quantum wells with asymmetric widths ($ L_1-L_2<30 $ A achieve up to 4.5 times higher mobility than single wells at optimal separation (d = 100 A). Crucially, mobility surpasses single wells when d>40 A reversing the trend at smaller distances. This enhancement stems from double-layer screening that suppresses remote/background impurities and dislocations, while LO phonon scattering remains unaffected. For identical wells, coupled systems underperform single wells at d<40 A but exceed them beyond this threshold. Peak gains occur at cryogenic temperatures (77 K). Our results provide a robust theoretical framework to optimize mobility in AlGaN/GaN heterostructures, reducing experimental trial-and-error in quantum device engineering.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
A Clarification on Quantum-Metric-Induced Nonlinear Transport
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-05 20:00 EDT
Xiao-Bin Qiang, Tianyu Liu, Zi-Xuan Gao, Hai-Zhou Lu, X. C. Xie
Over the years, Berry curvature, which is associated with the imaginary part of the quantum geometric tensor, has profoundly impacted many branches of physics. Recently, quantum metric, the real part of the quantum geometric tensor, has been recognized as indispensable in comprehensively characterizing the intrinsic properties of condensed matter systems. The intrinsic second-order nonlinear conductivity induced by the quantum metric has attracted significant recent interest. However, its expression varies across the literature. Here, we reconcile this discrepancy by systematically examining the nonlinear conductivity using the standard perturbation theory, the wave packet dynamics, and the Luttinger-Kohn approach. Moreover, inspired by the Dirac model, we propose a toy model that suppresses the Berry-curvature-induced nonlinear transport, making it suitable for studying the quantum-metric-induced nonlinear conductivity. Our theory can be further extended to include disorder effects and higher-order quantum geometric contributions, paving the way for a more comprehensive and systematic understanding of nonlinear transport.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Invited by Advanced Science. Main text: 5 pages, 2 figures, 1 table. Supplemental material: 10.5 pages
Symmetry-adapted models for multifold fermions with spin-orbit coupling
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-05 20:00 EDT
Multifold fermions, quasiparticles with multiple degeneracy protected by crystalline symmetries, exhibit a variety of intriguing phenomena stemming from their large topological charges and unique band structures. A comprehensive understanding of their response to external stimuli remains challenging, especially for types protected by nonsymmorphic symmetries where various degrees of freedom are intricately coupled. Here, we systematically construct effective models for multifold fermions that incorporate external fields based on crystalline symmetry. Specifically, we develop a $ \boldsymbol{k} \cdot \boldsymbol{p}$ model for the threefold fermion protected by space group I2$ _1$ 3 (No.199) in the presence of spin–orbit coupling, and derive the terms for external fields. By complementing this with a tight-binding model, we investigate the magnetic field response and reveal the pair annihilation of magnetic monopoles. Furthermore, we construct a $ \boldsymbol{k} \cdot \boldsymbol{p}$ model for the eightfold fermion in space group P$ \bar{4}3n1’$ (No.218), including its coupling to external fields. This work provides a robust theoretical foundation for advancing the study of external field responses and transport phenomena in multifold fermions, opening new avenues to explore their rich physics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
14 pages, 3 figures
Inertial Imaging of Dual Mass Distributions on a Graphene Nanodrum: A Computational Study
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-05 20:00 EDT
Adhinarayan Naembin Ashok, Sanjam Bedi, Taha Ashraf Ali Shaikh, Jai Aadhithya Ramesh, Adarsh Ganesan
This paper presents the possibility for inertial imaging of spatially patterned annular mass distributions of a circular graphene nanodrum resonator. By placing two distinct analytes in concentric annular regions, we harness the vibrational mode-specific sensitivities of the nanodrum to estimate their respective mass densities. An analytical formulation based on the Rayleigh-Ritz principle is developed to relate radial mass loading to modal frequency shifts. Finite element simulations are performed in COMSOL Multiphysics to obtain the shifts in the resonance frequency of vibrational modes under varying geometrical configurations of annular rings. By processing these frequency shifts through a transformation matrix, we estimate the concomitant mass distributions of annular rings. The results indicate that the estimation errors are lower for analytes placed near the antinodal regions of the dominant vibration mode, with the lowest error being 1.82 % for analyte A and 2.03 % for analyte B. Furthermore, thinner annular rings demonstrate enhanced detection accuracy due to reduced modal overlap. This study demonstrates an analytical strategy for mass detection using a graphene nanodrum by providing insights into optimal analyte placement and structural design for high-precision multi-target mass sensing applications.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
8 pages, 11 figures
Reducing critical current for spin-transfer-torque-induced magnetization reversal in CPP-GMR devices: effect of low damping and enhanced spin scattering asymmetry in $Co_2FeGa_{0.5}Ge_{0.5}$ Heusler alloy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-05 20:00 EDT
Vineet Barwal, Hirofumi Suto, Yuya Sakuraba
Spin-transfer torque (STT) in magnetoresistance devices has enabled key applications such as STT-magnetoresistive random access memory, spin torque oscillators, and energy-assisted magnetic recording. In the device structures, where a free layer (FL) magnetization is manipulated by spin injection from a spin injection layer (SIL), the critical current density required for operation is directly proportional to the damping ($ \alpha$ ) constant of FL and inversely proportional to the STT efficiency, which depends on the spin polarization ($ P$ ) of the materials. Here, we investigate the effect of low $ \alpha$ and high $ P$ of $ Co_2FeGa_{0.5}Ge_{0.5}$ (CFGG) Heusler alloy on the operation current required for STT-induced magnetization reversal in current perpendicular-to-plane giant magnetoresistance devices. Devices with CFGG as a FL material achieved a large reduction in the operation current, as compared to those with conventional NiFe-FL owing to the very low $ \alpha$ of CFGG, demonstrating the advantage of CFGG as a FL material. As the advantage of high spin polarization CFGG for SIL, we analyzed the effect of bilayer SIL consisting of CoFe and thin CFGG layers, focusing on utilizing the spin scattering asymmetry at the CoFe/CFGG interface. Devices with the CoFe/CFGG-SIL exhibited the lowest critical current, demonstrating enhanced STT efficiency. In addition, the correlation of STT efficiency with magnetoresistance ratio were comprehensively investigated, showing that device-to-device distribution in STT-efficiency was smaller in CoFe/CFGG-SIL. These findings highlight the potential of CFGG Heusler alloy and CoFe/CFGG bilayer structures as key components for the development of efficient and stable STT-based spintronic devices.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Efforts in Modeling the Mechanics and Chemistry of Energetic Materials Across Scales
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-05 20:00 EDT
Paul Lafourcade, Nicolas Bruzy, Paul Bouteiller, Jean-Bernard Maillet, Christophe Denoual
Recent developments dedicated to the building of multiscale mechanical and chemical constitutive laws for energetic molecular crystals are presented and discussed. In particular, various tools have been specifically incorporated in molecular dynamics codes to facilitate the subsequent information transfer to the continuum, i.e. finite elements simulation codes. Atomistic simulations have been augmented with the capability to follow specific deformation paths as well as local Lagrangian mechanical metrics, enabling the computation of materials flow stress surface. This mechanistic library allowed the construction of a comprehensive non-linear hyperelastic continuum model including crystal plasticity and twinning for TATB. Besides, recent advances in analyzing reactive molecular dynamics simulations with unsupervised learning algorithms has enabled the identification and calibration of chemical decomposition kinetics for RDX and TATB single crystal. In the present work, the procedure is applied to $ \beta$ -HMX and extended with the calibration of a multi-components equation of state. These two ingredients are implemented in a finite-element code in order to model the shock-to-detonation transition at the mesoscale level and to study dimensionality effects in quasi-static hotspots. Finally, these dedicated efforts towards a comprehensive multiscale modeling of explosives has also given rise to the need for new prospective experiments, discussed throughout the paper.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Computational Physics (physics.comp-ph)
Intrinsic physical properties of flexible van der Waals semiconductor InSe
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-05 20:00 EDT
Jacob Svane, Kim-Khuong Huynh, Yong P. Chen, Bo Brummerstedt Iversen
InSe is a van der Waals semiconductor in which mechanical flexibility, high electronic mobility, and non-trivial electronic structures converge, making it an attractive platform for both intriguing fundamental studies and promising device developments. However, the nucleation and growth of phase-pure, intrinsic InSe crystals require stringent thermodynamical conditions, and have therefore remained elusive. Since InSe melts incongruently, the widely used synthesis methods based on cooling of a 1:1 In-Se mixture will produce either aggregates of multiphase crystallites or uncontrolled In-rich, heavily electron-doped InSe. This fundamental thermodynamic constraint provides a compelling explanation for the large discrepancies observed in the reported physical properties of InSe. We overcome these limitations by utilizing the traveling solvent floating zone (TSFZ) method to produce high quality, centimeter-size InSe single crystals. Electrical, thermal, and thermoelectric transport measurements demonstrate that TSFZ-InSe single crystals closely approach the intrinsic limit, establishing it as a benchmark material for the future studies of this important material.
Materials Science (cond-mat.mtrl-sci)
Emerging electro-optic molecular crystals for optoelectronic integration
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-05 20:00 EDT
Keishi Sunami, Sachio Horiuchi, Yoriko Sonoda, Naomi Fujiki, Toshiki Higashino, Yuki Atsumi, Shoji Ishibashi, Jun’ya Tsutsumi
The rapid advancement of communication technology necessitates the development of hybrid optical modulators that integrate silicon photonics with electro-optic (EO) materials to enable ultrafast, low-power, and compact photonic devices. However, no existing material simultaneously meets the requirements for high EO performance, process compatibility, and thermal stability, which are essential for practical optoelectronic integration. Here, we present 4-(4’-nitrophenylazo)diphenylamine (NDPA) and its derivative, novel nonlinear optical molecular crystals discovered through materials screening incorporating crystal habit prediction. They demonstrate crystallization into high-quality aligned thin films and ultrafine silicon slot fillings through the capillary action of melts. The resulting EO performance much exceed that of conventional lithium niobate and are comparable to state-of-the-art EO polymers, with excellent thermal stability maintained for over 1000 hours at 393 K. The present EO materials satisfying all the requirements above are promising candidates for silicon-organic hybrid optical modulators, opening a significant step toward scalable and high-performance optoelectronic technologies.
Materials Science (cond-mat.mtrl-sci), Optics (physics.optics)
21 pages, 6 figures, 2 tables, Supporting Information attached at the end of the manuscript
Comparative molecular dynamics simulations of charged solid-liquid interfaces with different water models
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-05 20:00 EDT
Mahdi Tavakol, Kislon Voïtchovsky
Aqueous solid-liquid interfaces (SLI) are ubiquitous in nature and technology, often hosting molecular-level processes with macroscopic consequences. Molecular dynamics (MD) simulations offer a tool of choice to investigate interfacial phenomena with atomistic precision, but there exists a large number of water models, each optimised for a different purpose. Here we compare the ability of common water models to accurately simulate the interface between a charged silica surface and an aqueous solution containing NaCl. We first compare the bulk dielectric constant of water and its dependence on salt concentration for SPC/Fw, SPC/e, TIPS3p, H2O/DC, TIP3P-Fw, OPC3, TIP3P, TIP3P-FB, TIP3P-ST, FBA/e, and TIPS3p-PPPM, revealing large variations between models. Simulating the interface with silica for the most suitable water models (SPC/Fw, H2O/DC, TIP3-ST and TIPS3p-PPPM) show some intrinsic consistency with continuum predictions (Poisson-Boltzmann) whereby the free energy minima obtained from MD and the analytical model are in agreement, provided the latter includes the MD-determined total charge of ions in the Stern layer and dielectric constant. This consistency stands even for water models with a dielectric constant off by 10%. For salt concentrations higher than 0.21 M NaCl, the formation of random ion-ion pairs limits the reproducibility of the MD results and the applicability of the analytical method. The results highlight the applicability of the analytical model down to the nanoscale, provided a priory knowledge of the Stern layer charge is available. The findings could have significant implications for MD simulations of SLIs, especially at charged or electrified interfaces.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
Main text: 23 pages, 5 figure Supplementary Information (combined): 4 pages, 4 figures
Quantum Skyrmion Qudit in a Triangular-lattice magnet
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-05 20:00 EDT
D. Maroulakos, A. Wal, A. Ugulava, O. Kharshiladze, L. Chotorlishvili
Since the pioneering work Lohani et. al., Phys. Rev. X 9, 041063 (2019), it became clear that quantum skyrmions have highly unusual properties as compared to the classical skyrmions and, due to their quantumness, cannot be described by continuous magnetic textures akin to the classical skyrmions. Competing nearest-neighbor and next-nearest-neighbor ferromagnetic and antiferromagnetic interactions in triangular spin-frustrated magnets lead to the formation of quantum skyrmion states. In frustrated magnets, skyrmions are characterized by the helical degree of freedom, which can store quantum information. In the limit of a weak electric field, the system can be described as a two-level system, i.e., a skyrmion qubit. Here, we propose a more general formulation of the problem and obtain general analytic solution of the model previously introduced in Psaroudaki et. al., Phys. Rev. Lett. 127, 067201 (2021). Our solution is valid not only for small barrier but for the arbitrary electric field. In the case of a significant barrier, we prove that the system’s state is not a Skyrmion qubit as it was thought before, but a Skyrmion qudit. We constructed the density matrix of the Skyrmion qudit and studied its evolution in time. The obtained results suggest that the proposed model can be exploited further to meet the needs of quantum information theory and quantum skyrmionics. We showed that the $ l_1$ norm of coherence of the skyrmion quantum qudit is a thousand times larger than the coherence of the skyrmion quantum qubit. The obtained result opens new perspectives for quantum skyrmion-based resource theory.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
9 pages, 1 figure
Contact-induced molecular reorganization in E. coli model lipid membranes
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-05 20:00 EDT
Nicolo Tormena, Teuta Pilizota, Kislon Voïtchovsky
Biological membranes are complex, dynamic structures essential for cellular compartmentalization, signaling, and mechanical integrity. The molecular organization of eukaryotic membranes has been extensively studied, including the lipid raft-mediated lateral organization and the influence of the specific molecular interactions. Bacterial membranes were traditionally viewed as compositionally simpler and structurally uniform. Recent evidence, however, reveals that they possess significant lipid diversity and can form functional microdomains reminiscent of eukaryotic lipid rafts, despite lacking sterols and sphingolipids. Yet, the impact of unspecific physical contacts on the local molecular organization and evolution of the prokaryotic membranes remains poorly understood. Here we use a model lipid membrane mimicking the composition of Escherichia coli’s inner membrane to investigate the impact of contacting substrates on the membrane nanoscale evolution, when close to its transition temperature, $ T_m$ . As expected, the presence of a substrate lowers the $ T_m$ by $ \sim$ 10 °C and induces a differential leaflet transition. However, it also slows down the phase transition kinetics by almost 2 orders of magnitude while simultaneously enabling a spinodal-like lateral molecular reorganization. This creates local alterations of the phase of the membrane, with the emergence of mechanically stiffer, yet still fluid nanodomains evolving over substrate-dependent timescales, consistent with a substrate-biased lipid flip-flop mechanism. The results verify previous theoretical predictions and demonstrate that a general physical mechanism – driven by membrane-surface interactions – can spontaneously induce lipid domain formation in bacterial membranes. This is bound to have notable consequences for its function and mechanical role, including in processes like osmotic pressure regulation.
Soft Condensed Matter (cond-mat.soft)
Main text: 24 pages, 5 figures Supplementary information (combined): 13 pages, 13 figures, 4 tables
The Magnetic Ground State of Atacamite Cu$_2$Cl(OH)$_3$: The Crucial Role of Frustrated Zigzag Chains Revealed by Inelastic Neutron Scattering
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-05 20:00 EDT
J. L. Allen, L. Heinze, R. A. Mole, S. Süllow, O. Janson, S. Nishimoto, R. A. Lewis, K. C. Rule
We report inelastic neutron scattering (INS) measurements on the magnetically frustrated $ S=\frac12$ sawtooth-chain compound atacamite Cu$ _2$ Cl(OH)$ _3$ featuring inequivalent Cu(1) and Cu(2) sites. Transverse to the sawtooth chains, INS reveals two dispersive spin-wave modes and a gap of at least 0.75 meV. This behavior is rationalized within a zigzag-chain model of Cu(2) spins in an effective magnetic field of Cu(1) spins. The model is compatible with first-principles calculations and accounts for INS dispersions within linear spin-wave theory calculations. Our results reveal a unique case of an effective separation of energy scales between two differently oriented one-dimensional chains, with the zigzag-chain model being essential to fully characterize atacamite’s low-energy magnetism.
Strongly Correlated Electrons (cond-mat.str-el), Other Condensed Matter (cond-mat.other)
Main: 7 pages, 5 figures. Supplemental: 13 pages, 11 figures
A theory of strange metals
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-05 20:00 EDT
I present a theory of strange metals that is based on the following asumptions: (i) wavelike coherence is lost at each hop between neighboring atoms in the solid, i.e. the metal is bad, (ii) the carriers move independently from one another and (iii) the motion of the charge carriers obeys the correspondence principle, i.e. the quantum-mechanically averaged carrier diffusion in time is the same as in the classical case. The theory explains $ T$ -linear resistivity with apparently Planckian scattering rates as well as both the stretched Drude and displaced Drude peaks that are commonly observed in optical absorption experiments. The present framework might also indicate a solution to the problem of universal dielectric relaxation in insulators.
Strongly Correlated Electrons (cond-mat.str-el)
Shear-driven memory effects in carbon black gels
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-05 20:00 EDT
In recent years, significant effort has been devoted to developing smart materials whose mechanical properties can adapt under physical stimuli. Particulate colloidal gels, which behave as solids but can also flow under stress, have emerged as promising candidates. Resulting from the attractive interaction between their constituents, their network architecture exhibit solid-like properties even at very low volume fractions. This structural flexibility allows them to adopt various configurations and store structural information making them highly susceptible to memory effects. Shear flow, applied through rheometry, offers a simple and effective way to tune their properties and imprint a ``rheological memory’’ of the flow history. However, the precise relationship between flow history and viscoelastic response remains elusive, largely due to the limited structural characterization of these systems during flow and after flow cessation. Here, we use ultra-small angle X-ray scattering (USAXS) to reveal a strong structural memory in the solid state, where the microstructure formed under shear is retained after flow cessation. We identify two distinct mechanisms of structural memory, as governed by the ratio of viscous to attractive forces, namely, the Mason number. Using recently developed fractal scaling laws, we show that the rheology is fully determined by the gel microstructure. Notably, these gels exhibit a double-fractal architecture, highlighting the remarkably broad range of length scales over which these disordered materials are structured. By clarifying how memory is encoded, our results offer strategies to tune shear sensitivity of colloidal gels and design smart materials.
Soft Condensed Matter (cond-mat.soft)
Solving Sudoku Using Oscillatory Neural Networks
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-08-05 20:00 EDT
Stefan Porfir, Bram F. Haverkort, Federico Sbravati, Aida Todri-Sanial
This paper explores the application of Oscillatory Neural Networks (ONNs) to solving Sudoku puzzles, presenting a biologically inspired approach based on phase synchronization. Each cell is represented by an oscillator whose phase encodes a digit, and the synchronization is governed by the Kuramoto model. The system dynamically evolves towards a valid solution by having the puzzle constraints encoded into the weight matrix of the network, and through a proposed novel phase mapping of the Sudoku digits. Experimental results show that ONNs achieve high performance for puzzles with moderate difficulty and outperform Hopfield Neural Networks, particularly in cases with up to 20 initially unknown values. Although the performance decreases with increased ambiguity, ONNs still produce correct solutions in some of the iterations, cases in which the baseline Hopfield Neural Network algorithm fails. The findings support ONNs as a viable alternative for solving constraint optimization problems and reinforce their relevance within emerging non-von Neumann computing paradigms.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Emerging Technologies (cs.ET)
5 pages, 7 figures
Orientational Effects in the Low Pair Continuum of Aluminium
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-05 20:00 EDT
Thomas Gawne, Zhandos A Moldabekov, Oliver S Humphries, Motoaki Nakatsutsumi, Sebastian Schwalbe, Jan Vorberger, Ulf Zastrau, Tobias Dornheim, Thomas R Preston
We compare the predictions of the dynamic structure factor (DSF) of ambient polycrystalline aluminium from time-dependent density functional theory (TDDFT) in the pair continuum regime to recent ultrahigh resolution x-ray Thomson scattering measurements, collected at the European XFEL. TDDFT predicts strong anisotropy in the DSF at the wavenumber examined here, even with $ q$ -blurring accounted for. The experimental spectrum has more than sufficient resolution and signal-to-noise levels to resolve these orientation dependencies, and therefore the orientational averaging of the polycrystalline sample is observed rigorously. Once the orientation averaging is accounted for, TDDFT is able to reproduce the experimental spectrum adequately. Finally, comparisons of predicted DSFs from jellium to experiment demonstrates the importance of accounting for lattice effects in modelling the spectrum from a polycrystal.
Materials Science (cond-mat.mtrl-sci), Plasma Physics (physics.plasm-ph)
Breaking Peierls theorem in polyacetylene chains via topological design
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-05 20:00 EDT
Xinnan Peng, Marco Lozano, Jie Su, Lulu Wang, Diego Soler-Polo, Thomas Tuloup, Junting Wang, Shaotang Song, Ming Wah Wong, Jiangbin Gong, Junzhi Liu, Franz J Giessibl, Pavel Jelínek, Jiong Lu
Peierls theorem postulates that a one-dimensional (1D) metallic chain must undergo a metal-to-insulator transition via lattice distortion, resulting in bond length alternation (BLA) within the chain. The validity of this theorem has been repeatedly proven in practice, as evidenced by the absence of a metallic phase in low-dimensional atomic lattices and electronic crystals, including conjugated polymers, artificial 1D quantum nanowires, and anisotropic inorganic crystals. Overcoming this transition enables realizing long-sought organic quantum phases of matter, including 1D synthetic organic metals and even high-temperature organic superconductors. Herein, we demonstrate that the Peierls transition can be globally suppressed by employing lattice topology engineering of classic trans-polyacetylene chains connected to open-shell nanographene terminals. The appropriate topology connection enables an effective interplay between the zero-energy modes (ZMs) of terminal and the finite odd-membered polyacetylene (OPA) chains. This creates a critical topology-defined highest occupied molecular orbital (HOMO) that compensates for bond density variations, thereby suppressing BLA and reestablishing their quasi-1D metallic character. Moreover, it also causes the formation of an unconventional boundary-free resonance state, being delocalized over the entire chain with non-decaying spectral weight, distinguishing them from traditional solitons observed in polyacetylene. Our finding sets the stage for pioneering the suppression of material instability and the creation of synthetic organic quantum materials with unconventional quantum phases previously prohibited by the Peierls transition.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
38 pages, 15 figures
Dynamical axion fields coupled with one-dimensional spinless fermions
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-08-05 20:00 EDT
Yuto Hosogi, Koichiro Furutani, Yuki Kawaguchi
We investigate coupled dynamics of spinless fermions on a one-dimensional lattice and spins on the links. When the hopping integral and the on-site potential of the fermions depend on the direction of the link spins, the low-energy effective theory predicts that the link spins behave as a dynamical axion field in 1+1 dimensions. The axion field $ \theta$ is coupled to the electric field $ E$ as $ \theta E$ , through which the link spins rotate in response to the applied electric field or the chemical potential gradient for charge-neutral fermions. This is the inverse phenomenon of Thouless pumping in the Rice-Mele model. After analyzing the dynamics by approximating the link spins with the classical ones and utilizing the axion Lagrangian, we show the full-quantum dynamics using the tensor network method. Even though we do not explicitly introduce the axion Lagrangian in solving the fermion-spin coupled many-body dynamics, the full-quantum results agree well with those with the classical spin approximation, including the dynamics of the axion field and fermion transport. In addition, we find that the quantum correlation between spins accelerates the dynamics of axion fields as the suppression of the expectation values of the link spins allows them to rotate easily. We also propose a possible experimental setup for cold-atomic systems to implement the Hamiltonian in this study.
Quantum Gases (cond-mat.quant-gas)
15 pages, 10 figures
Detecting entanglement with transport measurement in weakly interacting and fluctuating systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-05 20:00 EDT
Zhenhua Zhu, Gu Zhang, Dong E. Liu
Measuring entanglement entropy in interacting, multipartite systems remains a significant experimental challenge. We address this challenge by developing a protocol to measure von Neumann entropy (VNE) and mutual information in quantum transport systems with both many-body interactions and multiple subsystems. Our analysis indicates that the vital connection between VNE and two-point correlation functions persists under these realistic conditions. The measurement is shown to be feasible for systems with boundary interactions and, critically, for bulk-interacting systems subject to a quantum quench of their internal couplings. Our work provides a pathway to experimentally quantify entanglement in complex interacting systems and establishes mutual information as an experimentally accessible indicator for system-environment entanglement.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
17 pages, 1 figure
Classical-to-Quantum Crossover in 2D TMD Field-Effect Transistors: A First-Principles Study via Sub-10 nm Channel Scaling Beyond the Boltzmann Tyranny
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-05 20:00 EDT
Two-dimensional transition metal dichalcogenides present compelling prospects for next-generation low-power and high-frequency field-effect transistors. However, scaling 2D TMD FETs into the sub-10 nm regime remains challenging due to technical complexity. Moreover, short-channel effects in this length scale are not yet fully understood. In this work, we investigate the transport properties of 2D TMD nanojunctions with channel lengths from 12 down to 3 nm, using first-principles calculations that integrate the nonequilibrium Green function formalism implemented in density functional theory (NEGF-DFT) and an effective gate model. Our simulations reveal a classical-to-quantum crossover in electron transport during transistor downscaling, governed by two critical temperatures: Tc, which marks the crossover from thermionic emission to quantum tunneling, and Tt, beyond which thermionic emission dominates and the subthreshold swing approaches its classical limit. The shortest 3 nm junction exhibits pronounced quantum tunneling up to 500 K and achieves a subthreshold swing superior to the Boltzmann tyranny, enabled by the steep energy dependence of the transmission coefficient. This quantum-tunneling-enhanced switching behavior demonstrates the potential of ultra-scaled 2D FETs to surpass classical efficiency constraints, offering a promising route toward energy-efficient, quantum-enabled computing technologies. This study presents a predictive, atomistic methodology for quantifying quantum transport and identifies the transition in electron transport mechanisms from semiclassical thermionic current in long-channel to quantum tunneling in short-channel 2D TMD FETs, offering critical design insights for leveraging quantum-classical hybrid transistor technology.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
12 pages, 6 figures
Cavity-QED-controlled two-dimensional Moiré Excitons without twisting
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-05 20:00 EDT
Francesco Troisi, Hannes Hübener, Angel Rubio, Simone Latini
We propose an all-optical Moiré-like exciton confinement by means of spatially periodic optical cavities. Such periodic photonic structures can control the material properties by coupling the matter excitations to the confined photons and their quantum fluctuations. We develop a low energy non-perturbative quantum electro-dynamical description of strongly coupled excitons and photons at finite momentum transfer. We find that in the classical limit of a laser driven cavity the induced optical confinement directly emulates Moiré physics. In a dark cavity instead, the sole presence of quantum fluctuations of light generates a sizable renormalization of the excitonic bands and effective mass. We attribute these effects to long-range cavity-mediated exciton-exciton interactions which can only be captured in a non-perturbative treatment. With these findings we propose spatially structured cavities as a promising avenue for cavity material engineering.
Materials Science (cond-mat.mtrl-sci), Quantum Physics (quant-ph)
Avalanche Dynamics in Stick-Slip Cutting of Molybdenum Disulfide
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-05 20:00 EDT
Pawel Koczanowski, Paolo Nicolini, Hesam Khaksar, Enrico Gnecco
We have investigated nanoscale wear on multilayered MoS2, the flagship transition metal dichalcogenide, by elastically driving sharp diamond tips under normal loads sufficient to induce in-plane fracture. The accompanying friction and the resulting wear structures were first characterized by atomic force microscopy (AFM), revealing a stick-slip regime that drives progressive exfoliation of MoS2 chips. At high normal forces, the slip phase displays hallmark signatures of avalanche dynamics, observed for the first time at the nanoscale, evidenced by a Generalized Extreme Value distribution of friction force drops. The AFM characterization is corroborated by molecular dynamics simulations, which reproduce experimental trends and uncover atomistic details of the wear process, including local amorphization, layer curving, and the involvement of distinct dissipative channels. Notably, it appears that only one-fifth of the energy inputted into the system is used to damage the MoS2 surface irreversibly. These results offer new insight into the physical mechanisms governing friction and wear in layered solids and provide a framework for precision cutting and nanomachining in van der Waals materials, relevant to next-generation devices at sub-micrometer scales.
Materials Science (cond-mat.mtrl-sci)
Quantum thermalization in a dimerized J1-J2 model
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-05 20:00 EDT
We revisit the J1-J2 frustrated Heisenberg spin-1/2 chain with dimerization ({\delta}) or modulation in the nearest-neighbor couplings to investigate its thermalization behavior. While the dimerization tends to induce localization, the next-nearest-neighbor interaction J2 generally favors thermalization, making the assessment of the model’s compliance with the Eigenstate Thermalization Hypothesis (ETH) particularly subtle. The challenge is further compounded by the model’s SU(2) symmetry; the study of ETH compliance is necessarily done for each symmetry sector but separating different sectors of this symmetry is known to be a computationally demanding task. The current study is driven by two main motivations: first, to explore whether the well-known ground-state phases of the model have any bearing on its thermalization properties; and second, to understand how the interplay between two competing factors, namely, the non-uniformity (via {\delta}) and the beyond-nearest-neighbor interactions (via J2) governs the system’s approach to thermal equilibrium. A systematic analysis shows that the ETH is most strongly satisfied for intermediate values of {\delta} (~ 0.5) with J2 ranging from intermediate (~ 0.5) to large (~ 1)- a parameter regime falls within the spiral ground-state phase. It is also found that when the system is in the gapless ground-state phase (which falls within the N’eel phase), the ETH is more prone to violation. In the regime of large {\delta} and small J2, the system is seen to enter a localized phase (characterized here by modulation in density-of-states; assessing ETH compliance is less meaningful for this phase.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
9 pages, 10 figures
Oscillating chemical reactions enable communication between responsive hydrogels
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-05 20:00 EDT
Joseph J. Webber, Thomas D. Montenegro-Johnson
Responsive hydrogels can sense environmental stimuli and respond as actuators by expelling water and changing shape. In this article, we develop theory to demonstrate that groups of responsive hydrogels can also communicate with each other, by utilising the effect of elastic deformation on chemical reaction dynamics. Specifically, we consider a system of two spatially-separated chemically responsive hydrogels suspended in a solution in which a Belousov-Zhabotinsky (BZ)-type reaction occurs. Solving for the gel dynamics with the transport of solvent through the poroelastic network and the chemical kinetics, we show how the periodic swelling-deswelling oscillations of each gel can become coupled, and how this coupling can be exploited to send signals from one gel to the other via mechanical manipulation of the sender that affect the local (and thus global) frequency of oscillation.
Soft Condensed Matter (cond-mat.soft)
8 pages, 5 figures, with supplementary material following the main body of the paper. Accepted by Phys. Rev. Research
Efficient spin-pumping and spin-to-charge conversion in epitaxial Mn$_3$Sn(0001) noncollinear antiferromagnetic films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-05 20:00 EDT
Surya N. Panda, Ning Mao, Nikolai Peshcherenko, Xiaolong Feng, Yang Zhang, Anastasios Markou, Claudia Felser, Edouard Lesne
The generation and control of spin currents are crucial for advancing next-generation spintronic technologies. These technologies depend on materials capable of efficiently sourcing and interconverting spin and charge currents, while overcoming some limitations associated with conventional ferromagnets and heavy metals. Kagome topological antiferromagnetic Weyl semimetals, such as Mn$ _3$ Sn, present unique advantages owing to their distinct magnetic order and significant Berry curvature-driven transport phenomena. In this study, we systematically investigate spin current generation and spin-to-charge conversion phenomena in epitaxial (0001)-oriented Mn$ _3$ Sn thin films. Our findings reveal a spin Hall angle of 0.9$ %$ and a nearly isotropic in-plane spin Hall conductivity of 44.4~($ \hbar$ /e) $ \Omega^{-1}$ .cm$ ^{-1}$ at room temperature, originating from a combination of intrinsic and extrinsic contributions, as discussed in light of first-principle calculations. Furthermore, in Mn$ _3$ Sn(0001)/Ni$ _{81}$ Fe$ _{19}$ heterostructures, we observe a high spin-mixing conductance of 28.52 nm$ ^{-2}$ and an interfacial spin-transparency of approximately 72$ %$ . Notably, we also find that the spin diffusion length in Mn$ _3$ Sn(0001) epitaxial films exceeds 15 nm at room temperature. Our results highlight the potential of the topological Weyl noncollinear antiferromagnet Mn$ _3$ Sn as an efficient material for spin transport and conversion in prospective spintronic applications.
Materials Science (cond-mat.mtrl-sci)
Droplet Removal by Capillary Lifting
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-05 20:00 EDT
Ke Sun, Jack R. Panter, Alvin C. M. Shek, Yonas Gizaw, Kislon Voïtchovsky, Halim Kusumaatmaja
The removal of liquid droplets from solid surfaces is central to cleaning, coatings and oil recovery. Here we investigate liquid droplets capillary lifted by an immiscible working liquid. The rising working liquid triggers the formation of a capillary bridge between the solid and the air interface, which can lead to full, partial, or no droplet dewetting. Our theoretical model predicts, and experiments confirm, that the effectiveness of droplet removal can be tuned by manipulating the droplet contact angle with the solid and the interfacial tensions at play. Significantly, dewetting can be enhanced by employing working liquids with high interfacial tension, in contrast to common surface cleaning strategies where surfactants are used to reduce interfacial tension. Our findings can open new avenues for droplet manipulation with reduced resources and more sustainable environmental impact.
Soft Condensed Matter (cond-mat.soft)
Three-magnon scattering of spin wave on edge-localized mode in thin ferromagnetic film
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-05 20:00 EDT
Julia Kharlan, Roman Verba, Krzysztof Sobucki, Paweł Gruszecki, Maciej Krawczyk
Three-wave scattering is a fascinating phenomenon with many applications in various technologies. Reducing the system symmetry greatly affects three-wave scattering, which, in this case, goes beyond the simple momentum conservation law. In this study, we examine three-magnon scattering at the edge of a thin ferromagnetic film, when a bulk spin wave interacts with an edge-localized propagating spin-wave upon the reflection. This creates new bulk spin waves at mixed frequencies by means of three-magnon confluence or stimulated splitting processes. Using our developed analytical theory, which has been confirmed by full micromagnetic simulations, we demonstrate that the amplitude of the wave generated in the stimulated splitting process is several times larger than that generated in the confluence process, primarily due to the lower group velocity. Furthermore, intensity of inelastically scattered waves exhibit a pronounced dependence on the incidence angle and frequency of the edge spin wave that goes beyond existing qualitative models. We show that the observed behaviors can only be explained by taking into account, that the scattered waves are created by several elementary three-magnon processes involving the incident and reflected waves. The complex nature of the scattered wave creation results in a strong sensitivity of its amplitude to the phase accumulation of spin waves upon reflection.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
12 pages, 4 figures
Theory of nonlinear magnetoelectric transport effects in normal-metal $-$ magnetic-insulator heterostructures
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-05 20:00 EDT
Oliver Franke, Piet W. Brouwer
Heterostructures of normal metals (N) and magnetic insulators (F) show paradigmatic effects, such as spin-Hall magnetoresistance and electric drag currents. These effects are linear in the applied electric field $ E(\omega)$ . Normal-metal $ -$ magnetic-insulator heterostructures also exhibit a characteristic nonlinear response quadratic in $ E(\omega)$ , referred to as unidirectional spin-Hall magnetoresistance or spin-torque diode effect. In this article, we develop a theory of the bilinear response of FN bilayers and NFN trilayers for finite frequencies $ \omega$ of the driving field and for four contributions that have been previously considered in the literature: Joule heating, phonon-mediated unidirectional magnetoresistance, the spin-torque diode effect, and magnonic unidirectional spin-Hall magnetoresistance. We identify their distinct dependencies on frequency and the magnetization direction of the magnetic insulator and examine their scaling with magnetic field and system geometry, providing a framework for experimental differentiation.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
12 + 9 pages, 6 figures. This a companion article to arXiv:2408.13099v2
On thermalization of a system with discrete phase space
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-05 20:00 EDT
We investigate the thermalization of a stochastic system with discrete phase space, initially at equilibrium at temperature $ T_i$ and then termalizing in an environment at temperature $ T_f$ , considering both cases $ T_i > T_f$ and $ T_i < T_f$ . For the simple case of a system with constant energy gaps, we show that the relation between the time scales of the cooling and heating processes is not univocal, and depends on the magnitude of the energy gap itself. Specifically the eigenvalues of the corresponding stochastic matrix set the time scales of the relaxation process and for large energy gaps the cooling process is found to exhibit the shortest relaxation times to equilibrium while the heating process is found to be faster at all scales for small gaps. We consider both the Kullback-Leibler divergence and the Fisher information and its related quantities to quantify the degree of thermalization of the system. In the intermediate to long time regime both quantities are found to bear the same type of information concerning the rate of thermalization, and follow the ordering predicted by the dynamic eigenvalues. We then consider a more complex system with a more intricate stochastic matrix, namely a 1D Ising model, and confirm the findings on the existence of two regimes, one in which cooling becomes faster than heating. We make contact with a previous work where an harmonic oscillator was used as working fluid and the heating process was always found to be faster than the cooling one.
Statistical Mechanics (cond-mat.stat-mech)
Complexation of a Thermoresponsive Brush-Type Polyelectrolyte with an Oppositely Charged Surfactant: Effect of Temperature and Surfactant Concentration
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-05 20:00 EDT
Hernán A. Ritacco, Macos D. Fernández Leyes, Zulma Quirolo, M. M. Soledad Lencina, Cecilia del Barrio, Rafael Márquez, Jaqueline Fernández, Jhon Sánchez Morales
Responsive drug delivery vectors can be designed using oppositely charged polyelectrolyte-surfactant complexes. As a model, we created a brush-type copolymer (PECop), combining alginate and Poly(N-isopropylacrylamide) (PNIPAAm), whose side chains respond to temperature. Aggregation of PECop with the cationic surfactant dodecyltrimethylammonium bromide (DTAB) was examined versus surfactant concentration and temperature. We used surface tension, electrophoretic mobility, zeta potential, potentiometry, light scattering, and atomic force microscopy to analyze the complexes. PECop/DTAB complexes form spherical, monodisperse aggregates in certain surfactant ranges, even though the copolymer itself is polydisperse. The binding isotherms combine features of oppositely charged polyelectrolyte/surfactant systems and hydrophobically modified polymers. Compared to alginate alone, PECop binds six times more DTAB at 1 mM surfactant concentration. Temperature responsiveness depends on surfactant concentration (cs). The surfactant triggers progressive collapse of polymer chains, maximized at cs = 2.8 mM, where thermo-responsiveness is lost. For cs 10 mM, size increases above LCST. This inversion in thermal response with rising surfactant concentration suggests changing aggregate structure, offering new avenues for drug delivery system design using these polymer-surfactant complexes.
Soft Condensed Matter (cond-mat.soft), Chemical Physics (physics.chem-ph)
arXiv admin note: substantial text overlap with arXiv:1707.02451
Floquet odd-parity collinear magnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-05 20:00 EDT
Tongshuai Zhu, Di Zhou, Huaiqiang Wang, Jiawei Ruan
Altermagnets (AMs), recently discovered unconventional magnets distinct from ferro- and antiferromagnets, have rapidly emerged as a prominent frontier in condensed matter physics. AMs are characterized by alternating collinear magnetic moments with zero net magnetization in real space, and spin splittings with even-parity symmetry in momentum space. However, their counterparts exhibiting odd-parity spin splitting remain largely unexplored. Here, based on symmetry argument, we show that such unconventional odd-parity magnets can be induced from collinear antiferromagnets. Remarkably, using effective model analysis within Floquet-theory framework, we demonstrate that circularly polarized light irradiation of conventional antiferromagnetic lattices induces both $ p$ - and $ f$ -wave magnets, realizing novel magnetic states dubbed Floquet odd-parity collinear magnets. Moreover, we also uncover light-induced antiferromagnetic Chern insulating states in the $ f$ -wave magnets. The proposed Floquet odd-parity magnet is confirmed by first-principles calculations of MnPSe$ _{3}$ under circularly polarized light. Our work not only proposes a new class of unconventional magnets, but also opens an avenue for light-induced magnetic phenomena in spintronic applications.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Automated Construction of Artificial Lattice Structures with Designer Electronic States
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-05 20:00 EDT
Ganesh Narasimha, Mykola Telychko, Wooin Yang, Arthur P. Baddorf, P. Ganesh, An-Ping Li, Rama Vasudevan
Manipulating matter with a scanning tunneling microscope (STM) enables creation of atomically defined artificial structures that host designer quantum states. However, the time-consuming nature of the manipulation process, coupled with the sensitivity of the STM tip, constrains the exploration of diverse configurations and limits the size of designed features. In this study, we present a reinforcement learning (RL)-based framework for creating artificial structures by spatially manipulating carbon monoxide (CO) molecules on a copper substrate using the STM tip. The automated workflow combines molecule detection and manipulation, employing deep learning-based object detection to locate CO molecules and linear assignment algorithms to allocate these molecules to designated target sites. We initially perform molecule maneuvering based on randomized parameter sampling for sample bias, tunneling current setpoint and manipulation speed. This dataset is then structured into an action trajectory used to train an RL agent. The model is subsequently deployed on the STM for real-time fine-tuning of manipulation parameters during structure construction. Our approach incorporates path planning protocols coupled with active drift compensation to enable atomically precise fabrication of structures with significantly reduced human input while realizing larger-scale artificial lattices with desired electronic properties. To underpin of efficiency of our approach we demonstrate the automated construction of an extended artificial graphene lattice and confirm the existence of characteristic Dirac point in its electronic structure. Further challenges to RL-based structural assembly scalability are discussed.
Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG)
Ferroelectric Epsilon-WO3 Nanoparticles and Its Bipolaron Driven Opto-electronic Properties at Room Temperature
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-05 20:00 EDT
Mohammad M. Rahaman, Jose Flores, Mohamed Y. Noor, Md Mohsinur R. Adnan, Alex Blackston, Enam Chowdhury, Roberto C. Myers, Michael Newburger, Pelagia-Irene Gouma
A unique polymorph of binary tungsten trioxide, the epsilon phase of WO3, has non-centrosymmetric ferroelectric structure, typically stable below -43 degree C in bulk. We have stabilized the epsilon-WO3 at room temperature (RT) and nanostructured powders via flame spray pyrolysis synthesis. These nanopowders are drop cast into uniform thin films to enable RT measurement of ferroelectric and optoelectronic properties. We report ferroelectric hysteresis, nanoscale domains, and dipole switching measured via Piezo-response force microscopy (PFM). The epsilon-WO3 films also display optical second harmonic generation (SHG) and anticlockwise ferroelectric butterfly capacitance versus voltage hysteresis, further demonstrating the ferroelectric nature of epsilon-WO3. Remarkably, epsilon-WO3 shows ferroelectric polarization responses to optical stimuli and form bipolaron at RT, a spin-zero quasiparticle previously found only in cryogenic temperatures. The bipolaron formation and its interaction with electro-optical stimuli results in a single layer solid-state blue coloration, a ferrochromic effect. A mechanism of the ferrochromic effect is discussed. In summary, epsilon-WO3 appears to be a ferroelectric with the simplest structure, forming bosonic spin-zero bipolaron at RT, and it’s dipoles respond to opto-electrical signals; therefore, this material holds significant promise for transforming the field of optoelectronics.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
21 Pages, 4 Figures
Interface Structure and Electronic Properties in Cubic Boron Nitride - Diamond Heterostructures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-05 20:00 EDT
Cody L. Milne, Hector Gomez, Adway Gupta, A. Glen Birdwell, Sergey Rudin, Elias J. Garratt, Bradford B. Pate, Tony G. Ivanov, Arunima K. Singh, Mahesh R. Neupane
Heterointerfaces of cubic boron nitride (cBN) with diamond have garnered significant interest due to their ultra-wide bandgaps and small lattice mismatch ($ \sim1.5$ %), offering promising advancements in high-power and high-frequency electronic devices. However, the realization of this heterointerface has been limited by challenging growth conditions and insufficient understanding of interfacial properties. In this work, we employ density-functional theory to investigate the structural and electronic properties of diamond/cBN heterostructures as a function of interfacial stoichiometry, cBN thickness, and surface termination and passivation. Formation energies and interfacial bond lengths reveal that boron-terminated heterojunctions are the most stable while abrupt nitrogen-terminated heterojunctions are least stable, but can be stabilized by carbon-mixing. Bandstructures are computed for the heterostructures using hybrid functionals, where we find the abrupt boron-terminated and nitrogen-terminated heterojunctions exhibit $ p$ -type and $ n$ -type conductivity, respectively, while carbon-mixed heterojunctions retain wide insulating bandgaps ($ 4.2-4.4$ eV). The effective masses of the abrupt interfaces are found to vary strongly with stoichiometry. Intriguingly, charge analysis reveals two-dimensional electron or hole gas regions with ultra-high densities on the order of $ 10^{14}$ cm$ ^{-2}$ , with distinct spatial localization on either side of the interface. Band alignments show type-I and type-II band offsets tunable by interfacial composition. Further analysis of the band alignments reveals that the diamond valence bands consistently lie above the cBN valence bands by $ 0.25-2.1$ eV. Interestingly, the interface termination type switches the relative conduction band position of diamond relative to the cBN conduction band, exhibiting a type-I to type-II band alignment transition.
Materials Science (cond-mat.mtrl-sci)
Design and demonstration of a direct air capture system with moisture-driven CO2 delivery into aqueous medium
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-05 20:00 EDT
Justin Flory, Samantha Taylor, Shuqin Li, Sunil Tiwari, Garrett Cole, Amory Lowe, Lindsey Hamblin, Samuel Piorkowski, Matthew Ryan, Thiago Stangherlin Barbosa, Jason Kmon, Nick Lowery, Joel Eliston, Jason C. Quinn, John McGowen, Matthew D. Green, Klaus Lackner, Wim Vermaas
A moisture-driven air capture (DAC) system was designed and demonstrated. A laboratory-scale system delivering ~1 g CO2 per day was demonstrated in a laminar flow hood and a small pilot-scale system that could deliver ~100 g CO2 daily was operated outdoors in a 4.2 m2 (areal surface area) raceway pond. Elongated mesh tube packets were designed to contain AER beads with high surface area for contacting the air and were found to reduce drying and CO2 loading time ~4-fold over larger mesh bags. Whereas this system was designed for CO2 delivery for cultivating photosynthetic microbes, its potential uses are much broader and include CO2 use in the food and beverage industry, conversion to fuels and chemicals, and sequestration. Techno-economic assessments for a practical scenario based on current results are $ 670/tonne to capture CO2 into an alkaline solution and an additional $ 280/tonne to extract CO2 from solution, purify and compress to 15 MPa for sequestration. An aspirational scenario modelling reasonable improvements to develop AER sorbents with a capacity of 4 mmol CO2 per gram of sorbent and water uptake of 50 wt.%, which leads to sorbent drying and loading within 1 h, shows a potential to reach $ 51/tonne to capture CO2 into an alkaline solution and an additional $ 109/tonne to get to 15 MPa for sequestration. Life cycle analysis shows the aspirational moisture-driven process uses up to 87% less energy than thermal and/or vacuum swing DAC by using energy from water evaporation; however, ~330 wt.% water uptake by the sorbent contained in a hydrophilic mesh packets leads to ~33-fold higher water use than the thermodynamic limits, which emphasizes future research is needed to increase sorbent hydrophobicity while maintaining and further increasing ion exchange capacity needed to bind CO2.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
14 pages, 11 figures. To be submitted to Energy & Environmental Science
Enhancing the ergodicity of Worldvolume HMC via embedding Generalized-thimble HMC
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-05 20:00 EDT
Masafumi Fukuma, Yusuke Namekawa
The Worldvolume Hybrid Monte Carlo (WV-HMC) method [arXiv:2012.08468] is an efficient and versatile algorithm that simultaneously mitigates both the sign problem and the ergodicity problem – the latter being intrinsic to algorithms based on Lefschetz thimbles. We consider a situation in which the maximum flow time can be set to a small value, as occurs when WV-HMC is applied to the doped Hubbard model using a nonphysical redundant parameter. An optimal choice of this parameter significantly reduces the sign problem on the original integration surface and allows the maximum flow time to remain small, a feature that facilitates increasing the system size while keeping the computation time modest. However, as the worldvolume becomes a thin layer, it becomes increasingly difficult to explore it efficiently, leading to potential ergodicity issues. To overcome this limitation, we propose embedding the Generalized-thimble HMC (GT-HMC) into the WV-HMC framework. GT-HMC performs HMC updates on a deformed surface at a fixed flow time. Although it suffers from ergodicity issues due to infinitely high potential barriers at the zeros of the Boltzmann weight, it enables more efficient exploration within the allowed region. Furthermore, its molecular dynamics step size can typically be taken to be larger than in WV-HMC. GT-HMC is thus better suited for sampling regions where ergodicity issues are not serious. We provide a proof that GT-HMC can be embedded within the WV-HMC algorithm, and verify that the two methods – the pure WV-HMC and the combined version – yield consistent results within statistical errors for the two-dimensional doped Hubbard model on a $ 6 \times 6$ spatial lattice at $ T/\kappa = 1/6.4\simeq 0.156$ and $ U/\kappa = 8.0$ with Trotter number $ N_t = 20$ ($ \kappa$ : hopping parameter).
Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Lattice (hep-lat), High Energy Physics - Theory (hep-th)
32 pages, 12 figures
Classification of Average Crystalline Topological Superconductors through a Generalized Real-Space Construction
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-05 20:00 EDT
Sarvesh Srinivasan, Jian-Hao Zhang, Yang Qi, Zhen Bi
We investigate a novel class of topological superconducting phases protected by exact fermion-parity symmetry and average crystalline symmetries. These phases belong to the broader class of average crystalline symmetry-protected topological (ACSPT) states and include numerous examples of intrinsic ACSPTs – topological phases that arise only in the presence of disorder or decoherence. Unlike conventional symmetry-protected topological (SPT) phases, which require exact symmetry protection, average SPT (ASPT) phases remain robust as long as the symmetry is restored on average across disorder realizations or mixed-state ensembles. To classify these phases, we extend the real-space block state construction framework to account for average crystalline symmetries. In this generalized setting, lower-dimensional cells are decorated with ASPT phases, and the obstruction-free conditions are reformulated to incorporate the constraints imposed by average symmetry at block intersections. This provides a physically transparent and systematic method for classifying ASPTs with spatial symmetries that are only preserved statistically. We further validate our classification using a generalized spectral sequence analysis, which serves as an independent consistency check. Our results demonstrate that many crystalline topological superconductors remain well defined under realistic imperfections, and they uncover a rich landscape of intrinsically average-symmetry-protected phases that have no analog in clean systems.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
29 pages, 12 figures. Appendix: 68 pages, 47 figures
Simulating high-temperature superconductivity in moiré WSe2
New Submission | Superconductivity (cond-mat.supr-con) | 2025-08-05 20:00 EDT
Yiyu Xia, Zhongdong Han, Jiacheng Zhu, Yichi Zhang, Patrick Knüppel, Kenji Watanabe, Takashi Taniguchi, Kin Fai Mak, Jie Shan
The emergence of high transition temperature (Tc) superconductivity in strongly correlated materials remains a major unsolved problem in physics. High-Tc materials, such as cuprates, are generally complex and not easily tunable, making theoretical modelling difficult. Although the Hubbard model–a simple theoretical model of interacting electrons on a lattice–is believed to capture the essential physics of high-Tc materials, obtaining accurate solutions of the model, especially in the relevant regime of moderate correlation, is challenging. The recent demonstration of robust superconductivity in moiré WSe2, whose low-energy electronic bands can be described by the Hubbard model and are highly tunable, presents a new platform for tackling the high-Tc problem. Here, we tune moiré WSe2 bilayers to the moderate correlation regime through the twist angle and map the phase diagram around one hole per moiré unit cell (v = 1) by electrostatic gating and electrical transport and magneto-optical measurements. We observe a range of high-Tc phenomenology, including an antiferromagnetic insulator at v = 1, superconducting domes upon electron and hole doping, and unusual metallic states at elevated temperatures including strange metallicity. The highest Tc occurs adjacent to the Mott transition, reaching about 6% of the effective Fermi temperature. Our results establish a new material system based on transition metal dichalcogenide (TMD) moiré superlattices that can be used to study high-Tc superconductivity in a highly controllable manner and beyond.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)