CMP Journal 2025-04-01
Statistics
Nature Materials: 2
Nature Nanotechnology: 1
Nature Physics: 1
Physical Review Letters: 23
Physical Review X: 2
arXiv: 113
Nature Materials
Twist-assisted intrinsic toughening in two-dimensional transition metal dichalcogenides
Original Paper | Mechanical engineering | 2025-03-31 20:00 EDT
Xiaodong Zheng, Shizhe Feng, Chi Shing Tsang, Quoc Huy Thi, Wei Han, Lok Wing Wong, Haijun Liu, Chun-Sing Lee, Shu Ping Lau, Thuc Hue Ly, Zhiping Xu, Jiong Zhao
Material fractures are typically irreversible, marking a one-time event leading to failure. Great efforts have been made to enhance both strength and fracture toughness of bulk materials for engineering applications, such as by introducing self-recovery and secondary breaking behaviours. In low-dimensional structures, two-dimensional materials often exhibit exceptional strength but accompanied by extreme brittleness. Here we discover that the toughness of two-dimensional materials can be enhanced without sacrificing strength–by simply twisting the layers. Through in situ scanning transmission electron microscopy, supported by nanoindentation and theoretical analysis, we reveal that twisted bilayer structures enable sequential fracture events: initial cracks heal to form stable grain boundaries, which then shield subsequent fracture tips from stress concentration. This process consumes additional energy compared with conventional fracture, with toughness enhancement tunable through twist angle adjustment. The intrinsic toughening mechanism via twisting, along with the emerging electronic properties of twistronics that are currently attracting substantial attention, presents an exciting opportunity for future devices.
Mechanical engineering, Two-dimensional materials
Terahertz emission from giant optical rectification in a van der Waals material
Original Paper | Nonlinear optics | 2025-03-31 20:00 EDT
Taketo Handa, Chun-Ying Huang, Yiliu Li, Nicholas Olsen, Daniel G. Chica, David D. Xu, Felix Sturm, James W. McIver, Xavier Roy, Xiaoyang Zhu
The exfoliation and stacking of two-dimensional van der Waals crystals have created unprecedented opportunities in the discovery of quantum phases. A major obstacle to the advancement of this field is the limited spectroscopic access due to a mismatch in the sample sizes (10-6-10-5 m) and the wavelengths (10-4-10-3 m) of electromagnetic radiation relevant to their low-energy excitations. Here we introduce ferroelectric semiconductor NbOI2 as a two-dimensional van der Waals material capable of operating as a van der Waals terahertz emitter. We demonstrate intense and broadband terahertz generation from NbOI2 with an optical rectification efficiency that is more than one order of magnitude higher than that of ZnTe, the current standard terahertz emitter. Moreover, this NbOI2 terahertz emitter can be integrated into van der Waals heterostructures to enable on-chip near-field terahertz spectroscopy of a target van der Waals material and device. Our approach provides a general spectroscopic tool for two-dimensional van der Waals materials and quantum matter.
Nonlinear optics, Two-dimensional materials
Nature Nanotechnology
Investigating the effect of heterogeneities across the electrode
Original Paper | Batteries | 2025-03-31 20:00 EDT
Jungki Min, Seong-Min Bak, Yuxin Zhang, Mingyu Yuan, Nicholas F. Pietra, Joshua A. Russell, Zhifei Deng, Dawei Xia, Lei Tao, Yonghua Du, Hui Xiong, Ling Li, Louis A. Madsen, Feng Lin
Polymer electrolytes hold great promise for safe and high-energy batteries comprising solid or semi-solid electrolytes. Multiphase polymer electrolytes, consisting of mobile and rigid phases, exhibit fast ion conduction and desired mechanical properties. However, fundamental challenges exist in understanding and regulating interactions at the electrode|electrolyte interface, especially when using high-potential layered oxide active materials at the positive electrode. Here we demonstrate that depletion of the mobile conductive phase at the interface contributes to battery performance degradation. Molecular ionic composite electrolytes, composed of a rigid-rod ionic polymer with nanometric mobile cations and anions, serve as a multiphase platform to investigate the evolution of ion conductive domains at the interface. Chemical and structural characterizations enable the visualization of concentration heterogeneity and spatially resolve the interfacial chemical states over a statistically significant field of view for buried interfaces. We report that concentration and chemical heterogeneities prevail at electrode|electrolyte interfaces, leading to phase separation in polymer electrolytes. Understanding the hidden roles of interfacial chemomechanics in polymer electrolytes enables us to design an interphase tailoring strategy based on electrolyte additives to mitigate the interfacial heterogeneity and improve battery performance.
Batteries, Energy storage
Nature Physics
Output control of dissipative nonlinear multimode amplifiers using spacetime symmetry mapping
Original Paper | Fibre lasers | 2025-03-31 20:00 EDT
Chun-Wei Chen, Kabish Wisal, Mathias Fink, A. Douglas Stone, Hui Cao
In many linear and nonlinear systems, time-reversal symmetry makes it possible to control the output waves by appropriately shaping the input waves. However, time-reversal symmetry is broken in systems with energy dissipation, necessitating a different approach for relating the input and output fields. We theoretically consider a saturated multimode fibre amplifier in which light generates a heat flow and suffers thermo-optical nonlinearity, thus breaking time-reversal symmetry. We identify a spacetime symmetry that maps the target output back to an input field. This spacetime symmetry mapping applies phase conjugation, gain and absorption substitution but not time reversal, and it holds in a steady state and for slowly varying inputs. Our approach enables coherent wavefront control of nonlinear dissipative systems.
Fibre lasers, Nonlinear optics
Physical Review Letters
Large Collective Power Enhancement in Dissipative Charging of a Quantum Battery
Research article | Collective effects in atomic physics | 2025-03-31 06:00 EDT
Sagar Pokhrel and Julio Gea-Banacloche
We consider a model for a quantum battery consisting of a collection of $N$ two-level atoms driven by a classical field and decaying to a common reservoir. In the extensive regime, where the energy $E$ scales as $N$ and the fluctuations $\mathrm{\Delta }E/E\rightarrow 0$, our dissipative charging protocol yields a power proportional to ${N}^{2}$, a scaling that cannot be achieved in this regime by Hamiltonian protocols. The trade-off for this enhanced charging power is a relative inefficiency since a large fraction of the incoming energy is lost through spontaneous emission to the environment. Nevertheless, we find that the system can store a large amount of coherence and release the stored energy coherently through spontaneous emission, again with a power scaling as ${N}^{2}$.
Phys. Rev. Lett. 134, 130401 (2025)
Collective effects in atomic physics, Open quantum systems, Quantum thermodynamics, Superradiance & subradiance, Optical pumping
Correspondence Principle, Ergodicity, and Finite-Time Dynamics
Research article | Quantum chaos | 2025-03-31 06:00 EDT
Zhen-Qi Chen, Rui-Hua Ni, Yalei Song, Liang Huang, Jiao Wang, and Giulio Casati
The quantum-classical correspondence stands out as one of the most intriguing challenges in the realm of quantum mechanics. Within the context of quantum chaos, the conventional approach, which relies on spectral statistics to infer distinct classical dynamical properties, fails in typical scenarios, such as slow relaxation processes, dynamical localization, or other deviations from ergodicity. To address this difficulty, we propose a novel approach, the essence of which lies in associating a quantum energy shell with classical finite-time trajectories. Our results extend the knowledge of quantum-classical correspondence, offer explanations for previously conflicting findings, and also bear significance for applications in quantum metrology, sensing, and computation when the determination of the ergodicity degree of the quantum states is in need.
Phys. Rev. Lett. 134, 130402 (2025)
Quantum chaos, Quantum billiards, Chaos & nonlinear dynamics
Variational Ground-State Quantum Adiabatic Theorem
Research article | Adiabatic quantum optimization | 2025-03-31 06:00 EDT
Bojan Žunkovič, Pietro Torta, Giovanni Pecci, Guglielmo Lami, and Mario Collura
We present a variational quantum adiabatic theorem, which states that, under certain assumptions, the adiabatic dynamics projected onto a variational manifold follow the instantaneous variational ground state. We focus on low-entanglement variational manifolds and target Hamiltonians with classical ground states. Despite highly entangled intermediate states along the exact adiabatic path, the variational evolution converges to the target ground state. We demonstrate this approach with several examples that align with our theoretical analysis.
Phys. Rev. Lett. 134, 130601 (2025)
Adiabatic quantum optimization, Quantum algorithms, Quantum algorithms & computation, Adiabatic approximation, Variational approach
Playing Nonlocal Games across a Topological Phase Transition on a Quantum Computer
Research article | Nonlocality | 2025-03-31 06:00 EDT
Oliver Hart, David T. Stephen, Dominic J. Williamson, Michael Foss-Feig, and Rahul Nandkishore
Many-body quantum games provide a natural perspective on phases of matter in quantum hardware, crisply relating the quantum correlations inherent in phases of matter to the securing of quantum advantage at a device-oriented task. In this Letter, we introduce a family of multiplayer quantum games for which topologically ordered phases of matter are a resource yielding quantum advantage. Unlike previous examples, quantum advantage persists away from the exactly solvable point and is robust to arbitrary local perturbations, irrespective of system size. We demonstrate this robustness experimentally on Quantinuum’s H1-1 quantum computer by playing the game with a continuous family of randomly deformed toric code states that can be created with constant-depth circuits leveraging midcircuit measurements and unitary feedback. We are thus able to tune through a topological phase transition—witnessed by the loss of robust quantum advantage—on currently available quantum hardware. This behavior is contrasted with an analogous family of deformed Greenberger-Horne-Zeilinger states, for which arbitrarily weak local perturbations destroy quantum advantage in the thermodynamic limit. Finally, we discuss a topological interpretation of the game, which leads to a natural generalization involving an arbitrary number of players.
Phys. Rev. Lett. 134, 130602 (2025)
Nonlocality, Quantum correlations in quantum information, Quantum feedback, Quantum simulation, Topological order, Trapped ions
Parallel Accelerated Electron Paramagnetic Resonance Spectroscopy Using Diamond Sensors
Research article | Chemical Physics & Physical Chemistry | 2025-03-31 06:00 EDT
Zhehua Huang, Zhengze Zhao, Fei Kong, Zhecheng Wang, Pengju Zhao, Xiangtian Gong, Xiangyu Ye, Ya Wang, Fazhan Shi, and Jiangfeng Du
The nitrogen-vacancy (NV) center can serve as a magnetic sensor for electron paramagnetic resonance (EPR) measurements. Benefiting from its atomic size, the diamond chip can integrate a tremendous amount of NV centers to improve the magnetic-field sensitivity. However, EPR spectroscopy using NV ensembles is less efficient due to inhomogeneities in both sensors and targets. Spectral line broadening induced by ensemble averaging is even detrimental to spectroscopy. Here we show a kind of cross-relaxation EPR spectroscopy at zero field, where the sensor is tuned by an amplitude-modulated control field to match the target. The modulation makes detection robust to the sensors inhomogeneity, while zero-field EPR is naturally robust to the targets inhomogeneity. We demonstrate an efficient EPR measurement on an ensemble of $\sim 30\text{ }000\text{ }\text{ }\mathrm{NV}$ centers. Our method shows the ability to not only acquire unambiguous EPR spectra of free radicals, but also monitor their spectroscopic dynamics in real time.
Phys. Rev. Lett. 134, 130801 (2025)
Chemical Physics & Physical Chemistry, NV centers, Quantum control, Quantum sensing, Nitrogen vacancy centers in diamond, Electron paramagnetic resonance, Electron spin resonance
Hidden Multidimensional Modulation Side Channels in Quantum Protocols
Research article | Optical quantum information processing | 2025-03-31 06:00 EDT
Amita Gnanapandithan, Li Qian, and Hoi-Kwong Lo
Quantum protocols including quantum key distribution and blind quantum computing often require the preparation of quantum states of known dimensions. Here, we show that, rather surprisingly, hidden multidimensional modulation is often performed by practical devices. This violates the dimensional assumption in quantum protocols, thus creating side channels and security loopholes. Our work has important impacts on the security of quantum cryptographic protocols.
Phys. Rev. Lett. 134, 130802 (2025)
Optical quantum information processing, Quantum communication, Quantum communication, protocols & technology, Quantum cryptography
Geometric Interpretation of Timelike Entanglement Entropy
Research article | Gauge-gravity dualities | 2025-03-31 06:00 EDT
Michal P. Heller, Fabio Ori, and Alexandre Serantes
Analytic continuations of holographic entanglement entropy in which the boundary subregion extends along a timelike direction have brought a promise of a novel, time-centric probe of the emergence of spacetime. We propose that the bulk carriers of this holographic timelike entanglement entropy are boundary-anchored extremal surfaces probing analytic continuation of holographic spacetimes into complex coordinates. This proposal not only provides a geometric interpretation of all the known cases obtained by direct analytic continuation of closed-form expressions of holographic entanglement entropy of a strip subregion but crucially also opens a window to study holographic timelike entanglement entropy in full generality. We initialize the investigation of complex extremal surfaces anchored on a timelike strip at the boundary of anti-de Sitter black branes. We find multiple complex extremal surfaces and discuss possible principles singling out the physical contribution.
Phys. Rev. Lett. 134, 131601 (2025)
Gauge-gravity dualities, Quantum entanglement
Four-Loop Anomalous Dimension of Flavor Nonsinglet Twist-Two Operator of General Lorentz Spin in QCD: $\zeta (3)$ Term
Research article | Deep inelastic scattering | 2025-03-31 06:00 EDT
B. A. Kniehl and V. N. Velizhanin
We consider the anomalous dimension of the flavor nonsinglet twist-two quark operator of arbitrary Lorentz spin $N$ at four loops in QCD and construct its contribution proportional to $\zeta (3)$ in analytic form by applying advanced methods of number theory on the available knowledge of low-$N$ moments. In conjunction with similar results on the $\zeta (5)$ and $\zeta (4)$ contributions, this completes our knowledge of the transcendental part of the considered anomalous dimension. This also provides important constraints on the as-yet elusive all-$N$ form of the rational part. Via Mellin transformation, we thus obtain the exact functional form in $x$ of the respective piece of the nonsinglet Dokshitzer-Gribov-Lipatov-Altarelli-Parisi splitting function at four loops. This allows us to appreciably reduce the theoretical uncertainty in the approximation of that splitting function otherwise amenable from the first few low-$N$ moments.
Phys. Rev. Lett. 134, 131901 (2025)
Deep inelastic scattering, Perturbative QCD, Quantum chromodynamics, Strong interaction
Quark and Gluon Momentum Fractions in the Pion and in the Kaon
Research article | Lattice QCD | 2025-03-31 06:00 EDT
Constantia Alexandrou, Simone Bacchio, Martha Constantinou, Joseph Delmar, Jacob Finkenrath, Bartosz Kostrzewa, Marcus Petschlies, Luis Alberto Rodriguez Chacon, Gregoris Spanoudes, Fernanda Steffens, Carsten Urbach, and Urs Wenger (Extended Twisted Mass Collaboration)
We present the full decomposition of the momentum fraction carried by quarks and gluons in the pion and the kaon. We employ three gauge ensembles generated with ${N}_{f}=2+1+1$ Wilson twisted-mass clover-improved fermions at the physical quark masses. For both mesons we perform a continuum extrapolation directly at the physical pion mass, which allows us to determine for the first time the momentum decomposition at the physical point. We find that the total momentum fraction carried by quarks is 0.575(79) and 0.683(50) and by gluons 0.402(53) and 0.422(67) in the pion and in the kaon, respectively, in the $\overline{\mathrm{MS}}$ scheme and at the renormalization scale of 2 GeV. Having computed both the quark and gluon contributions in the continuum limit, we find that the momentum sum is 0.984(89) for the pion and 1.13(11) for the kaon, verifying the momentum sum rule.
Phys. Rev. Lett. 134, 131902 (2025)
Lattice QCD, Parton distribution functions, Kaons, Pions
Autoionization-Enhanced Rydberg Dressing by Fast Contaminant Removal
Research article | Atomic, optical & lattice clocks | 2025-03-31 06:00 EDT
Alec Cao, Theodor Lukin Yelin, William J. Eckner, Nelson Darkwah Oppong, and Adam M. Kaufman
Rydberg dressing is a powerful tool for entanglement generation in long-lived atomic states. While already employed effectively in several demonstrations, a key challenge for this technique is the collective loss triggered by blackbody-radiation-driven transitions to contaminant Rydberg states of opposite parity. We demonstrate the rapid removal of such contaminants using autoionization (AI) transitions found in alkaline-earth-like atoms. The AI is shown to be compatible with coherent operation of an array of optical clock qubits. By incorporating AI pulses into a stroboscopic Rydberg dressing (SRD) sequence, we enhance lifetimes by an order of magnitude for system sizes of up to 144 atoms, while maintaining an order of magnitude larger duty cycle than previously achieved. To highlight the utility of our approach, we use the AI-enhanced SRD protocol to improve the degree of achieved spin-squeezing during early time dressing dynamics. These results bring Rydberg dressing lifetimes closer to fundamental limits, opening the door to previously infeasible dressing proposals.
Phys. Rev. Lett. 134, 133201 (2025)
Atomic, optical & lattice clocks, Autoionization & Auger processes, Quantum simulation, Rydberg atoms & molecules
Dynamical Excitation Control and Multimode Emission of an Atom-Photon Bound State
Research article | Many-body localization | 2025-03-31 06:00 EDT
Claudia Castillo-Moreno, Kazi Rafsanjani Amin, Ingrid Strandberg, Mikael Kervinen, Amr Osman, and Simone Gasparinetti
Atom-photon bound states arise from the coupling of quantum emitters to the band edge of dispersion-engineered waveguides. Thanks to their tunable-range interactions, they are promising building blocks for quantum simulators. Here, we study the dynamics of an atom-photon bound state emerging from coupling a frequency-tunable quantum emitter—a transmon-type superconducting circuit—to the band edge of a microwave metamaterial. Employing precise temporal control over the frequency detuning of the emitter from the band edge, we examine the transition from adiabatic to nonadiabatic behavior in the formation of the bound state and its melting into the propagating modes of the metamaterial. Moreover, we experimentally observe multimode emission from the bound state, triggered by a fast change of the emitter’s frequency. Our Letter offers insight into the dynamic preparation of APBS and provides a method to characterize their photonic content, with implications in quantum optics and quantum simulation.
Phys. Rev. Lett. 134, 133601 (2025)
Many-body localization, Quantum quench, Quantum simulation, Superconducting quantum optics, SQUID, Superconducting qubits, Microwave techniques, Tight-binding model
Fluctuation-Induced Bistability of Fermionic Atoms Coupled to a Dissipative Cavity
Research article | Cavity quantum electrodynamics | 2025-03-31 06:00 EDT
Luisa Tolle, Ameneh Sheikhan, Thierry Giamarchi, Corinna Kollath, and Catalin-Mihai Halati
We investigate the steady state phase diagram of fermionic atoms subjected to an optical lattice and coupled to a high finesse optical cavity with photon losses. The coupling between the atoms and the cavity field is induced by a transverse pump beam. Taking fluctuations around the mean-field solutions into account, we find that a transition to a self-organized phase takes place at a critical value of the pump strength. In the self-organized phase the cavity field takes a finite expectation value and the atoms show a modulation in the density. Surprisingly, at even larger pump strengths two self-organized stable solutions of the cavity field and the atoms occur, signaling the presence of a bistability. We show that the bistable behavior is induced by the atoms-cavity fluctuations and is not captured by the mean-field approach.
Phys. Rev. Lett. 134, 133602 (2025)
Cavity quantum electrodynamics, Dissipative dynamics, Fermi gases, Open quantum systems & decoherence, Quantum cavities, Hubbard model
Observation of Nonaxisymmetric Standard Magnetorotational Instability Induced by a Free-Shear Layer
Research article | Laboratory studies of space & astrophysical plasmas | 2025-03-31 06:00 EDT
Yin Wang, Fatima Ebrahimi, Hongke Lu, Jeremy Goodman, Erik P. Gilson, and Hantao Ji
Theoretical and numerical results reveal that a free-shear layer in a hydrodynamically stable base flow can introduce nonaxisymmetric standard magnetorotational instability at magnetic Reynolds numbers larger than one, confirming recent experiments.
Phys. Rev. Lett. 134, 135101 (2025)
Laboratory studies of space & astrophysical plasmas, Magnetohydrodynamics, Plasma instabilities
Chiral Superfluid Helium-3 in the Quasi-Two-Dimensional Limit
Research article | Fermi surface | 2025-03-31 06:00 EDT
Petri J. Heikkinen, Lev V. Levitin, Xavier Rojas, Angadjit Singh, Nathan Eng, Andrew Casey, John Saunders, Anton Vorontsov, Nikolay Zhelev, Abhilash Thanniyil Sebastian, and Jeevak M. Parpia
Anisotropic pair breaking close to surfaces favors the chiral $A$ phase of the superfluid $^{3}\mathrm{He}$ over the time-reversal invariant $B$ phase. Confining the superfluid $^{3}\mathrm{He}$ into a cavity of height $D$ of the order of the Cooper pair size characterized by the coherence length ${\xi }{0}$—ranging between 16 nm (34 bar) and 77 nm (0 bar)—extends the surface effects over the whole sample volume, thus allowing stabilization of the $A$ phase at pressures $P$ and temperatures $T$ where otherwise the $B$ phase would be stable. In this Letter, the surfaces of such a confined sample are covered with a superfluid $^{4}\mathrm{He}$ film to create specular quasiparticle scattering boundary conditions, preventing the suppression of the superfluid order parameter. We show that the chiral $A$ phase is the stable superfluid phase under strong confinement over the full $P\text{- }T$ phase diagram down to a quasi-two-dimensional limit $D/{\xi }{0}=1$, where $D=80\text{ }\text{ }\mathrm{nm}$. The planar phase, which is degenerate with the chiral $A$ phase in the weak-coupling limit, is not observed. The gap inferred from measurements over the wide pressure range from 0.2 to 21.0 bar leads to an empirical ansatz for temperature-dependent strong-coupling effects. We discuss how these results pave the way for the realization of the fully gapped two-dimensional ${p}{x}+i{p}{y}$ superfluid under more extreme confinement.
Phys. Rev. Lett. 134, 136001 (2025)
Fermi surface, Majorana fermions, Phase diagrams, Topological superconductors, Helium-3 superfluids, Thin films, Unconventional superconductors, Adiabatic demagnetization, BCS theory, Landau-Ginzburg theory, Nuclear magnetic resonance
Cooperation between Electron-Phonon Coupling and Electronic Interaction in Bilayer Nickelates ${\mathrm{La}}{3}{\mathrm{Ni}}{2}{\mathrm{O}}_{7}$
Research article | Electron-phonon coupling | 2025-03-31 06:00 EDT
Jun Zhan, Yuhao Gu, Xianxin Wu, and Jiangping Hu
The recent observation of high-${T}{c}$ superconductivity in the bilayer nickelate ${\mathrm{La}}{3}{\mathrm{Ni}}{2}{\mathrm{O}}{7}$ under pressure has garnered significant interest. While researches have predominantly focused on the role of electron-electron interactions in the superconducting mechanism, the impact of electron-phonon coupling (EPC) has remained elusive and unexplored. In this Letter, we perform first-principles calculations to study the phonon spectrum and electron-phonon coupling within ${\mathrm{La}}{3}{\mathrm{Ni}}{2}{\mathrm{O}}{7}$ under pressure and explore the interplay between EPC and electronic interactions on the superconductivity by employing functional renormalization group (FRG) approach. Our calculations reveal that EPC alone is insufficient to trigger superconductivity in ${\mathrm{La}}{3}{\mathrm{Ni}}{2}{\mathrm{O}}{7}$ under pressure. We identify unique out-of-plane and in-plane breathing phonon modes which selectively couple with the Ni ${d}{ {z}^{2}}$ and ${d}{ {x}^{2}- {y}^{2}}$ orbitals, showcasing an orbital-selective EPC. Within the bilayer two-orbital model, it is revealed that solely electronic interactions foster ${s}{\pm{}}$-wave pairing characterized by notable frustration in the band space, leading to a relatively low transition temperature. Remarkably, we find that the out-of-plane EPC can act in concert with electronic interactions to promote the interlayer pairing in the ${d}{ {z}^{2}}$ orbital, partially releasing the pairing frustration and thus elevating ${T}{c}$. In contrast, the inclusion of in-plane EPC only marginally affects the superconductivity, distinct from the cuprates. Potential experimental implications in ${\mathrm{La}}{3}{\mathrm{Ni}}{2}{\mathrm{O}}{7}$ are also discussed.
Phys. Rev. Lett. 134, 136002 (2025)
Electron-phonon coupling, Multiband superconductivity, Pairing mechanisms, Spin fluctuations, Superconducting order parameter
Closed Band-Projected Density Algebra Must Be Girvin-MacDonald-Platzman
Berry curvature | 2025-03-31 06:00 EDT
Ziwei Wang and Steven H. Simon
The band-projected density operators in a Landau level obey the Girvin-MacDonald-Platzman (GMP) algebra, and a large amount of effort in the study of fractional Chern insulators has been directed toward approximating this algebra in a Chern band. In this Letter, we prove that the GMP algebra, up to form factors, is the only closed algebra that projected density operators can satisfy in two and three dimensions, highlighting the central place it occupies in the study of Chern bands in general. A number of interesting corollaries follow.
Phys. Rev. Lett. 134, 136502 (2025)
Berry curvature, Fractional quantum Hall effect, Landau levels
Superconductivity in Twisted ${\mathrm{WSe}}_{2}$ from Topology-Induced Quantum Fluctuations
Research article | Superconductivity | 2025-03-31 06:00 EDT
Fang Xie, Lei Chen, Shouvik Sur, Yuan Fang, Jennifer Cano, and Qimiao Si
Recently, superconductivity has been observed in twisted ${\mathrm{WSe}}_{2}$ moir'e structures (Xia et al., Nature (London) 637, 833 (2025); Guo et al., Nature (London) 637, 839 (2025)). Its transition temperature is high, reaching a few percent of the Fermi temperature scale. Here, we advance a mechanism for superconductivity based on the notion that electronic topology enables quantum fluctuations in a suitable regime of intermediate correlations. In this regime, the Coulomb interaction requires that an active topological flat band and nearby wider bands are considered together. Compact molecular orbitals arise, which give rise to quantum fluctuations through topology-dictated hybridization with the other molecular orbitals. The hybridization competes with the active flat band’s natural tendency toward static electronic ordering, thereby weakening the latter; we link this effect with certain salient observations by experiments. Furthermore, the competition yields a quantum critical regime where quasiparticles are lost. The corresponding quantum critical fluctuations drive superconductivity. Broader implications and new connections among correlated materials platforms are discussed.
Phys. Rev. Lett. 134, 136503 (2025)
Superconductivity, Transition metal dichalcogenides, Dynamical mean field theory
Orbital-Excitation-Dominated Magnetization Dissipation and Quantum Oscillation of Gilbert Damping in Fe Films
Research article | Magnetization dynamics | 2025-03-31 06:00 EDT
Yue Chen, Haoran Chen, Xi Shen, Weizhao Chen, Yi Liu, Yizheng Wu, and Zhe Yuan
A strong thickness-dependent Gilbert damping oscillation in ultrathin Fe films suggests an effective way of tuning bands by doping or gating.
Phys. Rev. Lett. 134, 136701 (2025)
Magnetization dynamics, Magnetic thin films, Ferromagnetic resonance, First-principles calculations
Synthesized Acoustic Vortex-Frequency Comb via Rotational Doppler Effect
Research article | Acoustic metamaterials | 2025-03-31 06:00 EDT
Yurou Jia, Xuan Zhang, Suying Zhang, Guoqiang Xu, Taoyu Chen, Hongtao Zhou, Yechao Bai, Ying Cheng, Dajian Wu, Xiaojun Liu, and Cheng-Wei Qiu
The synergistic control of light’s frequency and orbital angular momentum (OAM) via integrated nonlinear ring microresonators is crucial for creating spatiotemporal optical waveforms and advancing optical metrology. A direct analog of this capability in acoustics is challenging due to the nonlinearity-based mechanisms’ dependence on external driving and limited frequency conversion efficiency. Here, we present an acoustic synthesized comb structure derived from spatiotemporal metasurfaces, concurrently controlling frequency and OAM characteristics with high conversion efficiency and removing the constraints of critical driving frequency and power level in nonlinear mechanisms. By optimizing comb structures, energy distributions among OAM modes are adjusted to different frequency lines. We finally propose spatiotemporal metalens devices based on vortex-frequency combs, enabling synchronously multiple-order spatial differential operations for parallel data processing. This Letter is groundbreaking in integrating spectral- and spatial-domain acoustic waves, promising multifunctional imaging and advantages in spatiotemporal beams.
Phys. Rev. Lett. 134, 137001 (2025)
Acoustic metamaterials, Acoustics, Frequency combs & self-phase locking
Synergistic Signatures of Group Mechanisms in Higher-Order Systems
Research article | Complex systems | 2025-03-31 06:00 EDT
Thomas Robiglio, Matteo Neri, Davide Coppes, Cosimo Agostinelli, Federico Battiston, Maxime Lucas, and Giovanni Petri
A new study of complex systems supports a growing trend that focuses more on analyzing a system’s collective behavior rather than on trying to uncover the underlying interaction mechanisms.
Phys. Rev. Lett. 134, 137401 (2025)
Complex systems, Complex networks, Information theory, Ising model, Spreading models
Liquid-Liquid Phase Transition in Simulated Supercooled Water Nanodroplets
Research article | Critical phenomena | 2025-03-31 06:00 EDT
Shahrazad M. A. Malek, Francesco Sciortino, Peter H. Poole, and Ivan Saika-Voivod
Using simulations, we demonstrate how a liquid-liquid phase transition (LLPT) manifests in supercooled water nanodroplets. Selecting an interaction potential for which a LLPT occurs in the bulk liquid, we conduct simulations of supercooled water nanodroplets having between 1000 and 80000 molecules. We show that as the droplet size decreases, the Laplace pressure grows large enough to drive the droplets through the transition from the low-density to the high-density liquid phase, and that all droplets in this size range are large enough to have cores exhibiting the structure and properties of bulk water. To guide experiments, we estimate the range of values for the critical pressure of the LLPT in real water that can be observed using nanodroplets, and propose structural and dynamical measures by which the LLPT in nanodroplets can be detected.
Phys. Rev. Lett. 134, 138001 (2025)
Critical phenomena, Equations of state, Liquid-liquid phase transition, Phase transitions, Nanoparticles, Water, Molecular dynamics
Segregation in Binary Mixture with Differential Contraction among Active Rings
Research article | Cellular organization, physiology & dynamics | 2025-03-31 06:00 EDT
Emanuel F. Teixeira, Carine P. Beatrici, Heitor C. M. Fernandes, and Leonardo G. Brunnet
Cell cortex contraction is vital for shaping cells, enabling movement, division, and responding to mechanical signals–processes crucial for multicellular organisms. Differential membrane contractions between cells significantly influence segregation. We present a model where active particle rings interact through differential contraction, showing that segregation arises from this mechanism, with ring activity functioning as an effective temperature. The interface decay exponent is close to $\lambda \sim 1/3$, differing from previous cluster fusion and diffusion model predictions.
Phys. Rev. Lett. 134, 138401 (2025)
Cellular organization, physiology & dynamics, Living matter & active matter, Molecular dynamics
Erratum: Nonmonotonic Energy Dependence of Net-Proton Number Fluctuations [Phys. Rev. Lett. 126, 092301 (2021)]
Correction | | 2025-03-31 06:00 EDT
J. Adam et al. (STAR Collaboration)
et al.
Phys. Rev. Lett. 134, 139902 (2025)
Physical Review X
Emergence of Sound in a Tunable Fermi Fluid
Research article | Collective effects in atomic physics | 2025-03-31 06:00 EDT
Songtao Huang, Yunpeng Ji, Thomas Repplinger, Gabriel G. T. Assumpção, Jianyi Chen, Grant L. Schumacher, Franklin J. Vivanco, Hadrien Kurkjian, and Nir Navon
Ultracold atomic Fermi gases provide a precise platform for testing Fermi liquid theory. Measurements of density responses and quasiparticle distributions confirm the theory’s validity across different interaction regimes.
Phys. Rev. X 15, 011074 (2025)
Collective effects in atomic physics, Fermi gases, Kinetic theory, Landau theory, Atomic gases, Quantum many-body systems, Ultracold gases, Fermi liquid theory
Multiobjective Optimization for Targeted Self-Assembly among Competing Polymorphs
Research article | Inverse problems | 2025-03-31 06:00 EDT
Sambarta Chatterjee and William M. Jacobs
A machine-learning-guided active learning framework to optimize material design balances stability and self-assembly kinetics to reveal insights into crystallization tradeoffs.
Phys. Rev. X 15, 011075 (2025)
Inverse problems, Optimization problems, Self-assembly
arXiv
Tunable effective diffusion of CO2 in aqueous foam
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-01 20:00 EDT
Cécile Aprili, Gwennou Coupier, Élise Lorenceau, Benjamin Dollet
Aqueous foams are solid materials composed of gases and liquids, exhibiting a large gas/liquid surface area and enabling dynamic exchanges between their fluid components. The structure of binary-gas foams, whose bubbles consist of a mixture of two gases having different affinities with the liquid, thus offers real potential for the dynamic separation of these gases at low cost. In single-gas foams, the foam structure evolves under the effect of gas flow induced by Laplace pressure differences, arising from heterogeneities in bubble size. This leads to the well-documented Ostwald ripening. In addition to these capillary effects, the structure of binary-gas foams can evolve under the effect of gas flow induced by partial (or osmotic) pressure differences, arising from heterogeneities in bubble composition. We experimentally investigate the shrinking of CO$ _2$ -laden 2D foams exposed to air, observing a crust of tiny bubbles at the front. We derive a non-linear diffusion model for the gas in the foam and propose a description of the whole foam as an effective, homogeneous medium, the key parameter being the gas permeability ratio across the foam’s soap films ($ \neq 1$ for CO$ _2/$ air). The effective diffusivity of the gas in the foam emerges from the coupling between foam structure and gas transport across soap films. We extrapolate it for various permeability ratios and show that it can vary continuously between the diffusivity of the gas in the liquid and that of the gas in the atmosphere, enabling tunable gas retention and release by controlling the composition of the atmosphere.
Soft Condensed Matter (cond-mat.soft), Fluid Dynamics (physics.flu-dyn)
9pages, 5 figures
Symmetry-Informed Graph Neural Networks for Carbon Dioxide Isotherm and Adsorption Prediction in Aluminum-Substituted Zeolites
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Marko Petković, José-Manuel Vicent Luna, El=ıza Beate Dinne, Vlado Menkovski, Sofía Calero
Accurately predicting adsorption properties in nanoporous materials using Deep Learning models remains a challenging task. This challenge becomes even more pronounced when attempting to generalize to structures that were not part of the training data.. In this work, we introduce SymGNN, a graph neural network architecture that leverages material symmetries to improve adsorption property prediction. By incorporating symmetry operations into the message-passing mechanism, our model enhances parameter sharing across different zeolite topologies, leading to improved generalization. We evaluate SymGNN on both interpolation and generalization tasks, demonstrating that it successfully captures key adsorption trends, including the influence of both the framework and aluminium distribution on CO$ _2$ adsorption. Furthermore, we apply our model to the characterization of experimental adsorption isotherms, using a genetic algorithm to infer likely aluminium distributions. Our results highlight the effectiveness of machine learning models trained on simulations for studying real materials and suggest promising directions for fine-tuning with experimental data and generative approaches for the inverse design of multifunctional nanomaterials.
Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG)
Entropic Order
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-01 20:00 EDT
Yiqiu Han, Xiaoyang Huang, Zohar Komargodski, Andrew Lucas, Fedor K. Popov
Ordered phases of matter, such as solids, ferromagnets, superfluids, or quantum topological order, typically only exist at low temperatures. Despite this conventional wisdom, we present explicit local models in which all such phases persist to arbitrarily high temperature. This is possible since order in one degree of freedom can enable other degrees of freedom to strongly fluctuate, leading to “entropic order”, whereby typical high energy states are ordered. Our construction, which utilizes interacting bosons, avoids existing no-go theorems on long-range order or entanglement at high temperature. We propose a simple model for high-temperature superconductivity using these general principles.
Statistical Mechanics (cond-mat.stat-mech), High Energy Physics - Theory (hep-th), Quantum Physics (quant-ph)
5+16 pages; 1+1 figures
Detection of anyon braiding through pump-probe spectroscopy
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-01 20:00 EDT
Xu Yang, Ryan Buechele, Nandini Trivedi
We show that the braiding of anyons in a quantum spin liquid leaves a distinct dynamical signature in the nonlinear pump-probe response. Using a combination of exact diagonalization and matrix product state techniques, we study the nonlinear pump-probe response of the toric code in a magnetic field, a model which hosts mobile electric $ e$ and magnetic $ m$ anyonic excitations. While the linear response signal oscillates and decays with time like $ \sim t^{-1.3}$ , the amplitude of the nonlinear signal for $ \chi^{(3)}{XZZ}$ features a linear-in-time enhancement at early times. The comparison between $ \chi^{(3)}{XZZ}$ , which involves the non-trivial braiding of $ e$ and $ m$ anyons, and $ \chi^{(3)}_{XXX}$ that involves the trivial braiding of the same types of anyons, serves to distinguish the braiding statistics of anyons. We support our analysis by constructing a hard-core anyon model with statistical gauge fields to develop further insights into the time dependence of the pump-probe response. Pump-probe spectroscopy provides a distinctive new probe of quantum spin liquid states, beyond the inconclusive broad features observed in single spin flip inelastic neutron scattering.
Strongly Correlated Electrons (cond-mat.str-el)
17 pages, 11 figures
The Chirality of Phonons: Definitions, Symmetry Constraints, and Experimental Observation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Shuai Zhang, Zhiheng Huang, Muchen Du, Tianping Ying, Luojun Du, Tiantian Zhang
Circularly polarized phonons with nonzero angular momentum (AM), also referred to as chiral phonons, have garnered increasing attention in recent studies. Many existing experimental/theoretical works identify chiral phonons based on pseudo-angular momentum (PAM) or the flipping of the polarization of the circularly polarized light (CPL) in the Raman scattering process. However, the accuracy and universality of these assumptions remain to be verified. Moreover, in condensed matter physics, symmetry strongly governs the scattering and interactions of phonons, quasi-particles, and external fields, profoundly affecting correlated physical phenomena. In this study, we first conduct an in-depth examination of the distinctions and interconnections among AM, PAM, helicity, and atomic motion–key characteristics inherent to chiral phonons–and then undertake a comprehensive study of phonon chirality, as well as their associated physical quantities, and experimental benchmarks under various magnetic point groups. By developing the symmetry-based framework for phonon chirality across magnetic point groups, we demonstrate that identifying chiral phonons solely through nonzero PAM or CPL polarization inversion is inadequate, challenging prior findings. This framework clarifies the relationship between symmetry and phonon chirality, revealing that phonon modes governed by different symmetries exhibit distinct experimental signatures, thereby advancing our understanding of these phenomena. Finally, experiments on five materials with distinct symmetries are conducted to validate our theoretical results. Supported by both theoretical rigor and experimental validation, our study represents a significant step forward in advancing research on symmetry-constrained phonons.
Materials Science (cond-mat.mtrl-sci), Optics (physics.optics)
Unexpected collapse of edge reconstruction in compressible Quantum Hall fluid within filling fraction range 2/3 to 1
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-01 20:00 EDT
Suvankar Purkait, Tanmay Maiti, Pooja Agarwal, Suparna Sahoo, Giorgio Biasiol, Lucia Sorba, Biswajit Karmakar
The edge structure of a gate-defined compressible quantum Hall fluids in the filling fraction range 2/3 to 1 is studied using the three reconstructed $ e^2/3h$ fractional edge modes of unity filling integer quantum Hall state. We find that the individually excited partially resolved $ e^2/3h$ edge modes of the bulk state equilibrate completely even at higher magnetic field when passing through the gate defined compressible fluid with filling between 2/3 and 1. This result is unexpected because edge reconstruction at the smooth boundary is generally expected due to dominant incompressibility at filling 2/3 and 1/3. Recently such reconstructed edge mode has been reported for the compressible fluid in the filling fraction range 1/3 to 2/3. In contrary, equilibration of fractional edge modes in the compressible fluid within the filling fraction range 2/3 to 1 becomes faster with increasing magnetic field. This anomalous results will stimulate further investigations on edge structure in these complex many body systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
7 pages, 4 figures
Machine Learning Potentials for Hydrogen Absorption in TiCr$_2$ Laves Phases
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Pranav Kumar, Fritz Körmann, Blazej Grabowski, Yuji Ikeda
The energetics of hydrogen absorption in C15 cubic and C14 hexagonal TiCr$ _2$ H$ _x$ Laves phases is investigated for $ 0 < x \le 6$ with density functional theory (DFT) and machine learning interatomic potentials (MLIPs). The MLIPs are trained with configurations generated through a series of active-learning schemes. Basin-hopping Monte Carlo (BHMC) simulations based on the MLIPs predict minimum-energy hydrogen configurations, along with enthalpies of formation and hydrogen orderings. The obtained phase transformations at 0 K agree well with the experiments at low temperatures. The hydrogen solubility limits in the low-concentration $ \alpha$ phases at 0 K are predicted to be $ x = 1.0$ and $ x = 1.5$ for the C15 and the C14 phases, respectively. At these concentrations, C15 TiCr$ _2$ H shows the $ Cc$ monoclinic symmetry, while C14 TiCr$ _2$ H$ _{1.5}$ shows the $ Ama2$ orthorhombic symmetry, both of which have not been reported for this system. The first and the second hydride phases, i.e., $ \beta$ and $ \beta’$ , at 0 K are found around $ x = 3$ and $ x = 4$ , respectively, for both the C15 and the C14 phases. In the second-hydride $ \beta’$ phases, C15 TiCr$ _2$ H$ _4$ shows the $ I4_1/a$ tetragonal symmetry, while C14 TiCr$ _2$ H$ _4$ shows the $ R\bar3c$ rhombohedral symmetry. Hydrogen repulsion are found to extend to edge-sharing interstices, affecting the hydrogen ordering. Furthermore, the $ 6h_2$ A$ _2$ B$ _2$ interstices are found to be energetically substantially more preferable for C14 TiCr$ _2$ H$ _x$ than the other A$ _2$ B$ _2$ interstices at low hydrogen concentrations, influencing the hydrogen-occupation trend.
Materials Science (cond-mat.mtrl-sci)
Nanocrystal tuned ammonia gas sensing technique via impedance spectroscopy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Neha Sharma, Debanjan Bhattacharjee, Sunita Kumari, Sandip Paul Choudhury
Ammonia is a harmful chemical hazard known for its widespread industrial use. Exposure to ammonia can cause environmental damage, human health hazards, and huge economic losses. Therefore, ammonia gas sensors are essential for detecting ammonia leaks to avoid serious accidental injury and death. In this study, we synthesize a nanostructured (WO3) n-type metal oxide semiconductor doped with a rare earth element-transition metal (Ce-Cu) via hydrothermal method for ammonia gas sensing application. Structural analysis was performed using XRD and FESEM. Further we investigate the optical properties via UV-visible spectroscopy, FTIR, and PL. We found that doping of (Ce-Cu) led to significant improvement in thermal stability for ammonia detection and selectivity performance compared to that pure one, across a wide frequency range. We believe that these studies will pave the way for exploring the use of Ce-Cu to improve the gas sensing properties of semiconductor-based gas sensors.
Materials Science (cond-mat.mtrl-sci)
Structural stability, elemental ordering, and transport properties in layered ScTaN2
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Baptiste Julien, Ian A. Leahy, Rebecca W. Smaha, John S. Mangum, Craig L. Perkins, Sage R. Bauers, Andriy Zakutayev
Some ternary TM nitrides are predicted to adopt layered structures that make them interesting for thermoelectric conversion and quantum materials applications. Synthesis of TM ternary nitride films by physical vapor deposition often favors disordered 3D structures rather than the predicted 2D-like layered structure. In this study, we investigate the structural interplay in the Sc-Ta-N material system, focusing on ScTaN2. We use a two-step combinatorial approach to deposit Sc-Ta-N films by RF co-sputtering and then process the resulting 3D-structured precursor with RTA. Synchrotron GIWAXS on films annealed at 1200 °C for 20 min reveals the nucleation of the layered structure (P63/mmc) within a composition window of Sc/(Sc+Ta) = 0.2-0.5. Analyzing the strong (002) superstructure reflection near 1:1:2 stoichiometry, indicative of long-range ordering, we estimate that 13.6% antisite defects are present in stoichiometric films. Interestingly, we find that the structure can accommodate large off-stoichiometry in the Ta-rich region (x < 0.5), facilitated by making an alloy with the nearly isostructural Ta5N6 compound that exists on a composition tie-line. Transport measurements on ScTaN2 reveal a nearly temperature-independent high carrier density (1021 cm-3), suggesting a heavily doped semiconductor or semimetallic character. The carrier mobility is relatively small (9.5 cm2V-1s-1 at 2 K) and the residual-resistivity ratio is small, suggesting that electrical conduction is dominated by defects or disorder. Measured magnetoresistance is indicative of weak antilocalization at low temperatures. We highlight the interplay between ScTaN2 and Ta5N6 in stabilizing layered structures, emphasizes the importance of cation order/disorder for potential tunable alloys, and suggests that ScTaN2 is promising platform for exploring electronic properties in a tie line of stoichiometry.
Materials Science (cond-mat.mtrl-sci)
Main text: 17 pages, 7 figures SI: 10 pages, 11 figures
Synthesis-related nanoscale defects in Mo-based Janus monolayers revealed by cross-correlated AFM and TERS imaging
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Tianyi Zhang, Andrey Krayev, Tilo H. Yang, Nannan Mao, Lauren Hoang, Zhien Wang, Hongwei Liu, Yu-Ren Peng, Yunyue Zhu, Eleonora Isotta, Maria E. Kira, Ariete Righi, Marcos A. Pimenta, Yu-Lun Chueh, Eric Pop, Andrew J. Mannix, Jing Kong
Two-dimensional (2D) Janus transition metal dichalcogenides (TMDs) are promising candidates for various applications in non-linear optics, energy harvesting, and catalysis. These materials are usually synthesized via chemical conversion of pristine TMDs. Nanometer-scale characterization of the obtained Janus materials’ morphology and local composition is crucial for both the synthesis optimization and the future device applications. In this work, we present a cross-correlated atomic force microscopy (AFM) and tip-enhanced Raman spectroscopy (TERS) study of Janus $ \mathrm{Mo}{\mathrm{Se}}^{\mathrm{S}}$ and Janus $ \mathrm{Mo}{\mathrm{S}}^{\mathrm{Se}}$ monolayers synthesized by the hydrogen plasma-assisted chemical conversion of $ \mathrm{MoSe}_2$ and $ \mathrm{MoS}_2$ , respectively. We demonstrate how the choice of the growth substrate and the starting TMD affects the morphology of the resulting Janus material. Furthermore, by employing TERS imaging, we demonstrate the presence of nanoscale islands (~20 nm across) of $ \mathrm{MoSe}2$ -$ \mathrm{Mo}{\mathrm{Se}}^{\mathrm{S}}$ ($ \mathrm{MoS}2$ -$ \mathrm{Mo}{\mathrm{S}}^{\mathrm{Se}}$ ) vertical heterostructures originating from the bilayer nanoislands in the precursor monolayer crystals. The understanding of the origins of nanoscale defects in Janus TMDs revealed in our study can help with further optimization of the Janus conversion process towards uniform and wrinkle-/crack-free Janus materials. Moreover, our work shows that cross-correlated AFM and TERS imaging is a powerful and accessible method for studying nanoscale composition and defects in Janus TMD monolayers.
Materials Science (cond-mat.mtrl-sci)
Single [2]catenanes in solution forming ${\sf 4}$-plats: a combined field theoretical and numerical approach
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-01 20:00 EDT
Franco Ferrari, Marcin R. Piątek
The statistical mechanics of [2]catenanes in a solution with constrained number of maxima and minima along a special direction (the height) is discussed. The interest in this system comes from the fact that, in the homopolymer case, it has analogies with self-dual anyon field theory models and has conformations that minimize the static energy and bear particular symmetries and properties. In the first part of this work we provide a procedure for deriving the equations of motion in the case of replica field theories in the limit of zero replicas. We compute also the partition function of the [2]catenane at the lowest order in the frame of the so-called background field method. In the second part the statistical mechanics of the system is investigated using numerical simulations based on the Wang-Landau Monte Carlo method. At equilibrium, independently of the temperature, it turns out that the conformations of the system are elongated in the height directions. The two rings composing the [2]catenanes have approximately the same heights and are aligned. The thermodynamic properties of the system are discussed and the results coming from the field theoretical approach are compared with those of the numerical simulations.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
16 pages, 7 figures, pdflatex
Development of a Capacitance Measurement for Pulsed Magnetic Fields
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
William K. Peria, Shengzhi Zhang, Sangyun Lee, Vivien S. Zapf, Choonjae Won, Sang-Wook Cheong, Minseong Lee
Capacitance measurements are crucial for probing the electrical properties of materials. In this study, we develop and implement a capacitance measurement technique optimized for pulsed magnetic fields. Our approach employs an auto-balancing bridge method, leveraging a high-bandwidth transimpedance amplifier to mitigate parasitic contributions from coaxial cables. This technique enables precise capacitance measurements in rapidly changing magnetic fields, as demonstrated in experiments on the magnetoelectric material NiCo$ _{2}$ TeO$ _{6}$ . The results reveal strong magnetoelectric coupling, including a pronounced hysteresis in capacitance that coincides with magnetization measurements and an enhanced energy dissipation peak at high sweep rates. Compared to traditional LCR meter measurements in DC fields, our method exhibits excellent agreement while providing additional insight into field-induced phase transitions. This work establishes a robust methodology for capacitance measurements in extreme conditions and opens new opportunities for studying multiferroic and correlated electron systems under high magnetic fields.
Materials Science (cond-mat.mtrl-sci)
6 pages, 5 figures
Cavity-assisted magnetization switching in a quantum spin-phonon chain
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-01 20:00 EDT
Mohsen Yarmohammadi, Peter M. Oppeneer, James K. Freericks
We propose a Néel magnetization switching mechanism in a hybrid magnon-phonon optical cavity system. A terahertz-pumped single-mode cavity photon couples to a spin-phonon chain, while the system dissipates energy via different baths. Our mean-field analysis reveals that the photon induces magnetization switching by generating strongly entangled magnon pairs with opposite momenta – a feature weakly present in the cavity-free system. This switching occurs only at specific drive frequencies, namely at low magnon energies and near the upper edge (perpendicular modes) of the two-magnon band. Our results underscore the roles of laser fluence, damping, and photon loss in modulating the switching process, offering a promising route for cavity-assisted magnetization control in opto-spintronics.
Strongly Correlated Electrons (cond-mat.str-el)
9 pages, 4 figures
A Topological Superconductor Tuned by Electronic Correlations
New Submission | Superconductivity (cond-mat.supr-con) | 2025-04-01 20:00 EDT
Haoran Lin, Christopher L. Jacobs, Chenhui Yan, Gillian M. Nolan, Gabriele Berruto, Patrick Singleton, Khanh Duy Nguyen, Yunhe Bai, Qiang Gao, Xianxin Wu, Chao-Xing Liu, Gangbin Yan, Suin Choi, Chong Liu, Nathan P. Guisinger, Pinshane Y. Huang, Subhasish Mandal, Shuolong Yang
A topological superconductor, characterized by either a chiral order parameter or a chiral topological surface state in proximity to bulk superconductivity, is foundational to topological quantum computing. As in other topological phases of matter, electronic correlations can tune topological superconductivity via modifications of the low-energy Fermiology. Such tuning has not been realized so far. Here we uncover a unique topological superconducting phase in competition with electronic correlations in 10-unit-cell thick FeTe$ _{x}$ Se$ {1-x}$ films grown on SrTiO$ {3}$ substrates. When the Te content $ x$ exceeds $ 0.7$ , we observe a rapid increase of the effective mass for the Fe $ d{xy}$ band, with the emergence of a superconducting topological surface state confirmed by high-resolution angle-resolved photoemission spectroscopy; however, near the FeTe limit, the system enters an incoherent regime where the topological surface state becomes unidentifiable and superconductivity is suppressed. Theory suggests that the electron-electron interactions in the odd-parity $ xy^-$ band with a strong $ d{xy}$ character lead to an orbital-selective correlated phase. Our work establishes FeTe$ _{x}$ Se$ _{1-x}$ thin films as a unique platform where electronic correlations sensitively modulate topological superconductivity, suggesting opportunities to use tunable electron-electron interactions to engineer new topological phases in a broad class of materials.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
Magneto transport of pressure induced flatbands in large angle twisted bilayer graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-01 20:00 EDT
Ayan Mondal, Priyanka Sinha, Bheema Lingam Chittari
Twisted bilayer graphene (TBG) exhibits flat electronic bands at the so-called magic angle ($ \sim 1.1^\circ$ ), leading to strong electron correlations and emergent quantum phases such as superconductivity and correlated insulating states. However, beyond the magic angle, the band structure generally remains dispersive, diminishing interaction-driven phenomena. In this work, we explore the equivalence between pressure-induced flatbands and the magic-angle flatband in large-angle TBG by systematically analyzing the role of interlayer coupling modifications under perpendicular pressure. We show that pressure-induced flatbands exhibit spatial localization similar to magic-angle TBG, with charge density concentrated in the AA-stacked regions. Furthermore, the Hall conductivity and magneto-transport properties under an external magnetic field reveal that these pressure-induced flatbands share key signatures with the quantum Hall response of magic-angle TBG. The obtained Hofstadter spectrum shows four consistent low-energy gaps across all twist angles under pressure, which align with the calculated Hall conductivity plateaus. Our findings suggest that pressure offers an alternative pathway to engineer flat electronic bands and correlated states in TBG, extending the landscape of tunable moiré materials beyond the constraints of the magic angle.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Mapping the Second Landau Level PH-Pfaffian State to the Lowest Landau Level
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-01 20:00 EDT
Recently we proposed a state described by the second Landau level (SLL) projection of the antiholomorphic Pfaffian wavefunction as a candidate for the ground state of the 5/2 fractional quantum Hall effect. In this paper we provide a mathematical proof that, when mapped to the lowest Landau level (LLL), the aforementioned state, which we call the SLL PH-Pfaffian state, becomes exactly a LLL projected orbital angular momentum l = -3 pairing Pfaffian state, which we call the LLL antiholomorphic f-wave pairing Pfaffian state, or the LLL af-Pfaffian state for short. We further prove that there is also an exact mapping between the upstream neutral Majorana fermion edge mode of the SLL PH-Pfaffian state and that of the LLL af-Pfaffian state. However, we find that while there exists an upstream neutral boson edge mode in the LLL af-Pfaffian state, it has no mapped counterpart in the SLL PH-Pfaffian state.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
External-field-induced altermagnetism in experimentally synthesized monolayer $\mathrm{CrX_3}$ (X=Cl, Br and I)
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Net-zero-magnetization magnets are attracting significant research interest, driven by their potential for ultrahigh density and ultrafast performance. Among these materials, the altermagnets possess alternating spin-splitting band structures and exhibit a range of phenomena previously thought to be exclusive to ferromagnets, including the anomalous Hall and Nernst effects, non-relativistic spin-polarized currents, and the magneto-optical Kerr effect. Bulk altermagnets have been experimentally identified, while two-dimensional (2D) altermagnets remain experimentally unexplored. Here, we take experimentally synthesized 2D ferromagnetic $ \mathrm{CrX_3}$ (X=Cl, Br and I) as the parent material and achieve altermagnetism through external field. First, we achieve the transition from ferromagnetism to antiferromagnetism through biaxial strain. Subsequently, we break the space inversion symmetry while preserving the mirror symmetry via an electric field, thereby inducing altermagnetism. Moreover, through the application of Janus engineering to construct $ \mathrm{CrX_{1.5}Y_{1.5}}$ (X$ \neq$ Y=Cl, Br and I), the phase transition from ferromagnetism to antiferromagnetism induced by strain alone is sufficient to trigger the emergence of altermagnetism. All six monolayers possess the symmetry of $ i$ -wave spin-splitting. The computational results suggest that $ \mathrm{CrCl_3}$ can be readily tuned to exhibit altermagnetism through external field in experiment, thanks to its low strain threshold for magnetic phase transition. Our work provides experimentally viable materials and methods for realizing altermagnetism, which can advance the development of 2D altermagnetism.
Materials Science (cond-mat.mtrl-sci)
7 pages, 6 figures. Welcome to follow up with experimental work
Time dependent Ginzburg-Landau theory for design of superconducting wire
New Submission | Superconductivity (cond-mat.supr-con) | 2025-04-01 20:00 EDT
In the present paper, we study the superconducting wire. It is known from Maxwell equations that the current creates magnetic field that suppresses superconductivity and wire starts to conduct with resistance. We consider the time dependent Ginzburg-Landau theory to resolve the problem. The solutions of the system of equations show that applied electric field, perpendicular to the axis of the wire and to the magnetic field restores superconductivity and wire starts to conduct without resistivity. We can increase the current to a new suppression of superconductivity and to restore superconductivity increasing the applied electric field. The aforementioned results permit us to conclude that the superconducting wire can transport a very strong current if the novel design discussed in the paper is applied.
Superconductivity (cond-mat.supr-con)
5 pages, 4 figures
Extremely high excitonic $g$-factors in 2D crystals by alloy-induced admixing of band states
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Katarzyna Olkowska-Pucko, Tomasz Woźniak, Elena Blundo, Natalia Zawadzka, Łucja Kipczak, Paulo E. Faria Junior, Jan Szpakowski, Grzegorz Krasucki, Salvatore Cianci, Diana Vaclavkova, Dipankar Jana, Piotr Kapuściński, Magdalena Grzeszczyk, Daniele Cecchetti, Giorgio Pettinari, Igor Antoniazzi, Zdeněk Sofer, Iva Plutnarová, Kenji Watanabe, Takashi Taniguchi, Clement Faugeras, Marek Potemski, Adam Babiński, Antonio Polimeni, Maciej R. Molas
Monolayers (MLs) of semiconducting transition metal dichalcogenides (\mbox{S-TMDs}) emit light very efficiently and display rich spin-valley physics, with gyromagnetic ($ g$ -) factors of about -4. Here, we investigate how these properties can be tailored by alloying. Magneto-optical spectroscopy is used to reveal the peculiar properties of excitonic complexes in Mo$ _{x}$ W$ _{1-x}$ Se$ _2$ MLs with different Mo and W concentrations. We show that the alloys feature extremely high $ g$ -factors for neutral excitons, that change gradually with the composition up to reaching values of the order of -10 for $ x \approx 0.2$ . First-principles calculations corroborate the experimental findings and provide evidence that alloying in S-TMDs results in a non-trivial band structure engineering, being at the origin of the high $ g$ -factors. The theoretical framework also suggests a higher strain sensitivity of the alloys, making them promising candidates for tailor-made optoelectronic devices.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
9 pages, 5 figures, SM
Tailoring spin reorientation and magnetic interaction for room-temperature spintronics in Tb-Doped SmFeO3 single crystal
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Mingzhu Xue, Xin Li, Shilei Ding, Qixin Li, Wenhao Di, Anhua Wu, Bin He, Shishen Yan, Wenyun Yang, Jinbo Yang
Selective doping with different R-site ions in rare-earth perovskite RFeO3 compounds offers an effective way to achieve atomic-scale tuning of the complex exchange interactions. In this study, the spin reorientation temperature of Tb-doped SmFeO3 (Sm0.7Tb0.3FeO3) single crystal is lowered to approximately 350 K, making it more suitable for room-temperature applications. Notably, the magnetic compensation point is absent at low temperatures, and both R3+ and Fe3+ ion moments can be fully saturated under high magnetic fields, suggesting that Tb3+ doping drives the R3+ and Fe3+ sublattices toward ferromagnetic coupling. Moreover, the hysteresis loop along the a-axis transitions from a double triangle shape below the spin reorientation temperature to a rectangular shape above the spin reorientation temperature, and the nucleation field exhibits a strong dependence on both the measurement temperature and the maximum applied magnetic field. Above results can be explained by a modified two-domain model with mean field correction. The results of magnetic domain measurements indicate that the emergence of the double-triangular hysteresis loop is jointly determined by domain wall motion and the nonlinear response of the parasitic magnetic moment along the a-axis. These findings provide valuable insights and new materials for advancing the use of RFeO3 compounds in spintronics.
Materials Science (cond-mat.mtrl-sci)
Learning phases with Quantum Monte Carlo simulation cell
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-01 20:00 EDT
Amrita Ghosh, Mugdha Sarkar, Ying-Jer Kao, Pochung Chen
We propose a new machine learning input data type, “spin-opstring”, derived from Stochastic Series Expansion Quantum Monte Carlo (QMC) simulations. It offers a compact, memory-efficient representation of QMC simulation cells, combining the initial state with an operator string that encodes the state’s evolution through imaginary time. Using supervised machine learning on two models, we demonstrate the input’s effectiveness in capturing both conventional and topological phase transitions. Additionally, we conduct a regression task to predict superfluid density, which reflects non-local properties of the quantum system, and achieve good accuracy. These results validate the spin-opstring as an effective input for machine learning applications.
Strongly Correlated Electrons (cond-mat.str-el), Disordered Systems and Neural Networks (cond-mat.dis-nn)
10 pages, 10 figures
Importance of bond exchange in MnC structural stability and half-metallic ferromagnetism: a comprehensive density functional benchmark study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Abdesalem Houari, Peter Bloechl
Recently, a first successful synthesis of the unknown bulk manganese monocarbide (MnC) has been reported. Suggested as a potential superhard material, the compound is found to crystallize in the zincblende (B3) structure. In the present work, we report an exhaustive density functional investigation on structural, electronic and magnetic properties of MnC, using different levels of exchange-correlation approximations. We show that SCAN meta-GGA and PBE0r hybrid functional outperform GGA-PBEsol, HSE06 hybrid functional and the mean field DFT+$ U$ +$ V$ ; in predicting correctly the experimental zincblende structure as the groundstate one. It is demonstrated that the bond exchange plays a crucial role in this stabilization. At theoretical equilibrium, hybrid functionals (PBE0r and HSE06) lead to a metallic behavior of MnC. Semilocal ones (PBEsol and SCAN) and mean field DFT+$ U$ +$ V$ , however, predict two opposite kinds of half-metallic ferromagnetism; opening a debate on the origin and the nature this behavior. If the latter is confirmed experimentally, MnC could be for importance as a spintronic material.
Materials Science (cond-mat.mtrl-sci)
14 pages, 7 figures
A Falsifiability Test for Classical Nucleation Theory
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-01 20:00 EDT
Camilla Beneduce, Diogo E. P. Pinto, Lorenzo Rovigatti, Flavio Romano, Petr Šulc, Francesco Sciortino, John Russo
Classical nucleation theory (CNT) is built upon the capillarity approximation, i.e., the assumption that the nucleation properties can be inferred from the bulk properties of the melt and the crystal. Although CNT’s simplicity and usefulness cannot be overstated, experiments and simulations regularly uncover significant deviations from its predictions, which are often reconciled through phenomenological extensions of the CNT, fueling the debate over the general validity of the theory. In this study, we present a falsifiability test for any nucleation theory grounded in the capillarity approximation. We focus on cases where the theory predicts no differences in nucleation rates between different crystal polymorphs. We then introduce a system in which all polymorphs have the same free energy (both bulk and interfacial) across all state points. Through extensive molecular simulations, we show that the polymorphs exhibit remarkably different nucleation properties, directly contradicting CNT’s predictions. We argue that CNT’s primary limitation lies in its neglect of structural fluctuations within the liquid phase.
Soft Condensed Matter (cond-mat.soft)
Phys. Rev. Lett. accepted
TCSP 2.0: Template Based Crystal Structure Prediction with Improved Oxidation State Prediction and Chemistry Heuristics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Lai Wei, Rongzhi Dong, Nihang Fu, Sadman Sadeed Omee, Jianjun Hu
Crystal structure prediction remains a major challenge in materials science, directly impacting the discovery and development of next-generation materials. We introduce TCSP 2.0, a substantial evolution of our template-based crystal structure prediction framework that advances predictive capabilities through synergistic integration of several key techniques into its major components. Building upon TCSP 1.0’s template-matching foundation, this enhanced version implements three critical innovations: (1) replacement of Pymatgen with deep learning-based BERTOS model for oxidation state prediction with superior performance, (2) implementation of sophisticated element embedding distance metrics for improved chemical similarity assessment, and (3) development of a robust majority voting mechanism for space group selection that reduces prediction uncertainty. TCSP 2.0 also expands its template base by incorporating template structures from Materials Cloud, C2DB, and GNoME databases alongside the original Materials Project repository, creating a more comprehensive structural foundation. Rigorous validation across 180 diverse test cases of the CSPBenchmark demonstrates TCSP 2.0’s exceptional performance, achieving 83.89% space-group success rate and 78.33% structural similarity accuracy for top-5 predictions, substantially outperforming both its predecessor and the competing modern CSP algorithms including CSPML and EquiCSP.
Materials Science (cond-mat.mtrl-sci)
15 pages
Fluctuations and Correlations of Local Topological Order Parameters in Disordered Two-dimensional Topological Insulators
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-01 20:00 EDT
Roberta Favata, Nicolas Baù, Antimo Marrazzo
Two-dimensional topological insulators are characterized by an insulating bulk and conductive edge states protected by the nontrivial topology of the bulk electronic structure. They remain robust against moderate disorder until Anderson localization occurs and destroys the topological phase. Interestingly, disorder can also induce a topological phase - known as a topological Anderson insulator - starting from an otherwise pristine trivial phase. While topological invariants are generally regarded as global quantities, we argue that space-resolved topological markers can act as local order parameters, revealing the role of fluctuations and correlations in the local topology under Anderson disorder and vacancies. With this perspective, we perform numerical simulations of disorder-driven topological phase transitions in the Haldane and Kane-Mele models, using supercells with both open and periodic boundary conditions. We find that short-scale fluctuations of topological markers vanish upon coarse-graining, except at the topological phase transition, where their correlation length peaks and large-scale fluctuations remain.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech)
8 pages, 5 figures, Supplementary material
A mean-field theory for heterogeneous random growth with redistribution
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-04-01 20:00 EDT
Maximilien Bernard, Jean-Philippe Bouchaud, Pierre Le Doussal
We study the competition between random multiplicative growth and redistribution/migration in the mean-field limit, when the number of sites is very large but finite. We find that for static random growth rates, migration should be strong enough to prevent localisation, i.e. extreme concentration on the fastest growing site. In the presence of an additional temporal noise in the growth rates, a third partially localised phase is predicted theoretically, using results from Derrida’s Random Energy Model. Such temporal fluctuations mitigate concentration effects, but do not make them disappear. We discuss our results in the context of population growth and wealth inequalities.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech), General Economics (econ.GN), Probability (math.PR), Populations and Evolution (q-bio.PE)
Breaking a superfluid harmonic dam: Observation and theory of rarefaction flow, Riemann invariants and sonic horizon dynamics
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-04-01 20:00 EDT
Shashwat Sharan, Judith Gonzalez Sorribes, Patrick Sprenger, Mark A. Hoefer, P. Engels, Boaz Ilan, M. E. Mossman
Dilute-gas Bose-Einstein condensates are a prime testbed for the study of superfluid hydrodynamics. In a channel geometry, these systems are known to host prototypical hydrodynamic effects such as shocks, rarefaction waves and solitons, forming a bridge between classical and quantum dynamics. Here, we present a combined experimental and theoretical study of the dry-bed dam-break problem in a channel geometry, a hallmark problem of nonlinear dynamics. Our setup extends the canonical setting by adding harmonic confinement, or an effective bathymetry, along the channel, further enhancing the richness of dynamics. We obtain an analytical solution of the 1D Gross-Pitaevskii (GP) equation for the harmonic dam-break problem that provides further insight. Experimentally, we characterize the flow by measuring its Riemann invariant coordinates and find good agreement with computations of the 3D GP equation as well as with the analytical solution. Our experimental observation of a sonic horizon, and the prediction of collisions between such horizons at longer times, offer an intriguing perspective for further studies.
Quantum Gases (cond-mat.quant-gas), Pattern Formation and Solitons (nlin.PS)
5 pages, 4 figures, 2 pages of end matter
Magnetoelectric control of spin helicity and nonreciprocal charge transport in a multiferroic metal
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Daiki Yamaguchi (1 and 2), Aki Kitaori (1 and 3), Naoto Nagaoka (2 and 4), Yoshinori Tokura (1, 2 and 5) ((1) Department of Applied Physics, The University of Tokyo, (2) RIKEN Center for Emergent Matter Science (CEMS), (3) Institute of Engineering Innovation, The University of Tokyo, (4) Fundamental Quantum Science Program, TRIP Headquarters, RIKEN, (5) Tokyo College, The University of Tokyo)
A multiferroic state with both electric polarization ($ P$ ) and magnetization ($ M$ ) shows the inherently strong $ P$ -$ M$ coupling, when $ P$ is induced by cycloidal (Néel-wall like) spin modulation. The sign of $ P$ is determined by clockwise or counterclockwise rotation of spin, termed the spin helicity. Such a multiferroic state is not limited to magnetic insulators but can be broadly observed in conductors. Here, we report the current-induced magnetoelectric control of the multiferroics in a helimagnetic metal YMn$ _6$ Sn$ _6$ and its detection through nonreciprocal resistivity (NRR). The underlying concept is the coupling of the current with the toroidal moment $ T \sim P \times M \sim (\hat{q} \times \chi_v) \times M$ as well as with the magneto-chirality $ \chi_v \times M$ , where $ \hat{q}$ and $ \chi_v$ being the unit modulation wave vector and the vector spin chirality, respectively. We furthermore observe an enhancement of NRR by the spin-cluster scattering via $ \chi_v$ and its fluctuation. These findings may pave a way to exploration of multiferroic conductors and application of the spin-helicity degree of freedom as a state-variable.
Materials Science (cond-mat.mtrl-sci)
Solvation enhances folding cooperativity and the topology dependence of folding rates in a lattice protein model
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-01 20:00 EDT
Nhung T. T. Nguyen, Pham Nam Phong, Duy Manh Le, Minh-Tien Tran, Trinh Xuan Hoang
The aqueous solvent profoundly influences protein folding, yet its effects are relatively poorly understood. In this study, we investigate the impact of solvation on the folding of lattice proteins by using Monte Carlo simulations. The proteins are modelled as self-avoiding 27-mer chains on a cubic lattice, with compact native states and structure-based Gō potentials. Each residue that makes no contacts with other residues in a given protein conformation is assigned a solvation energy {\epsilon}_s , representing its full exposure to the solvent. We find that a negative {\epsilon}_s , indicating a favorable solvation, increases the cooperativity of the folding transition by lowering the free energy of the unfolded state, increasing the folding free energy barrier, and narrowing the folding routes. This favorable solvation also significantly improves the correlation between folding rates and the native topology, measured by the relative contact order. Our results suggest that Gō model may overestimate the importance of native interactions and a solvation potential countering the native bias can play a significant role. The solvation energy in our model can be related to the polar interaction between water and peptide groups in the protein backbone. It is therefore suggested that the solvation of peptide groups may significantly contribute to the exceptional folding cooperativity and the pronounced topology-dependence of folding rates observed in two-state proteins.
Soft Condensed Matter (cond-mat.soft), Biomolecules (q-bio.BM)
11 pages, 8 figures, accepted for publication in J. Chem. Phys
Energetic preference and topological constraint effects on the formation of DNA twisted toroidal bundles
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-01 20:00 EDT
Nhung T. T. Nguyen, Anh T. Ngo, Trinh X. Hoang
DNA toroids are compact torus-shaped bundles formed by one or multiple DNA molecules being condensed from the solution due to various condensing agents. It has been shown that the DNA toroidal bundles are twisted. However, the global conformations of DNA inside these bundles are still not well understood. In this study, we investigate this issue by solving different models for the toroidal bundles and performing replica-exchange molecular dynamics (REMD) simulations for self-attractive stiff polymers of various chain lengths. We find that a moderate degree of twisting is energetically favorable for toroidal bundles, yielding optimal configurations of lower energies than in other bundles corresponding to spool-like and constant radius of curvature arrangements. The REMD simulations show that the ground states of the stiff polymers are twisted toroidal bundles with the average twist degrees close to those predicted by the theoretical model. Constant-temperature simulations show that twisted toroidal bundles can be formed through successive processes of nucleation, growth, quick tightening and slow tightening of the toroid, with the two last processes facilitating the polymer threading through the toroid’s hole. A relatively long chain of 512 beads has an increased dynamical difficulty to access the twisted bundle states due to the polymer’s topological constraint. Interestingly, we also observed significantly twisted toroidal bundles with a sharp U-shaped region in the polymer conformation. It is suggested that this U-shaped region makes the formation of twisted bundles easier by effectively reducing the polymer length. This effect can be equivalent to having multiple chains in the toroid.
Soft Condensed Matter (cond-mat.soft)
11 pages, 10 figures, supplementary material
J. Chem. Phys. 158, 114904 (2023)
Reinforcement Learning for Active Matter
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-01 20:00 EDT
Wenjie Cai, Gongyi Wang, Yu Zhang, Xiang Qu, Zihan Huang
Active matter refers to systems composed of self-propelled entities that consume energy to produce motion, exhibiting complex non-equilibrium dynamics that challenge traditional models. With the rapid advancements in machine learning, reinforcement learning (RL) has emerged as a promising framework for addressing the complexities of active matter. This review systematically introduces the integration of RL for guiding and controlling active matter systems, focusing on two key aspects: optimal motion strategies for individual active particles and the regulation of collective dynamics in active swarms. We discuss the use of RL to optimize the navigation, foraging, and locomotion strategies for individual active particles. In addition, the application of RL in regulating collective behaviors is also examined, emphasizing its role in facilitating the self-organization and goal-directed control of active swarms. This investigation offers valuable insights into how RL can advance the understanding, manipulation, and control of active matter, paving the way for future developments in fields such as biological systems, robotics, and medical science.
Soft Condensed Matter (cond-mat.soft), Machine Learning (cs.LG), Robotics (cs.RO), Biological Physics (physics.bio-ph)
16 pages, 8 figures
Quantitative imaging of nonlinear spin-wave propagation using diamond quantum sensors
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-01 20:00 EDT
Kensuke Ogawa, Moeta Tsukamoto, Yusuke Mori, Daigo Takafuji, Junichi Shiogai, Kohei Ueda, Jobu Matsuno, Jun-ichiro Ohe, Kento Sasaki, Kensuke Kobayashi
Spin waves propagating in magnetic materials exhibit nonlinear behavior due to the competition between excitation and relaxation at large amplitudes, providing an attractive platform for exploring nonlinear wave dynamics. In particular, spin waves with a non-zero wavenumber that carry momentum undergo nonlinear relaxation and experience wavenumber modulation in the nonlinear regime. We image the nonlinear spin-wave propagation in two yttrium iron garnet thin films with distinct spin-wave decay rates using a wide-field quantum diamond microscope. We obtain quantitative distributions of spin-wave amplitude and phase in varying excitation microwave strength. As a result, we observe a threshold in the spin-wave amplitude beyond which nonlinear effects become evident and confirm that this threshold is consistent with theoretical predictions based on four-magnon scattering for both samples. Moreover, as the amplitude of the spin waves increases, modulation of the wavenumber is observed across the field of view. We attribute this modulation primarily to the spin waves generated by multi-magnon scattering. Our quantitative measurements provide a pathway for visualizing nonlinear spin-wave dynamics and are crucial for deepening our understanding of the underlying mechanisms.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
10 pages, 6 figures, and supplementary materials
Self-Similar Bridge between Regular and Critical Regions
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-01 20:00 EDT
V.I. Yukalov, E.P. Yukalova, D. Sornette
In statistical and nonlinear systems, two qualitatively distinct parameter regions are typically identified: the regular region, characterized by smooth behavior of key quantities, and the critical region, where these quantities exhibit singularities or strong fluctuations. Due to their starkly different properties, these regions are often perceived as being weakly related, if at all. However, we demonstrate that these regions are intimately connected, a relationship that can be explicitly revealed using self-similar approximation theory. This framework enables the prediction of observable quantities near the critical point based on information from the regular region and vice versa. Remarkably, the method relies solely on asymptotic expansions with respect to a parameter, regardless of whether the expansion originates in the regular or critical region. The mathematical principles of self-similar theory remain consistent across both cases. We illustrate this connection by extrapolating from the regular region to predict the existence, location, and critical indices of a critical point of an equation of state for a statistical system, even when no direct information about the critical region is available. Conversely, we explore extrapolation from the critical to the regular region in systems with discrete scale invariance, where log-periodic oscillations in observables introduce additional complexity. Our findings provide insights and solutions applicable to diverse phenomena, including material fracture, stock market crashes, and earthquake forecasting.
Statistical Mechanics (cond-mat.stat-mech), Mathematical Physics (math-ph)
Latex file, 32 pages, 12 figures
Physics 7 (2025) 9
Coupling molecular spin qubits with 2D magnets for coherent magnon manipulation
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-01 20:00 EDT
Sourav Dey, Gonzalo Rivero-Carracedo, Andrei Shumilin, Carlos Gonzalez-Ballestero, José J. Baldoví
Magnonics is an emerging field widely considered as a paradigm shift in information technology that uses spin waves for data storage, processing and transmission. However, the coherent control of spin waves in 2D magnets still remains a challenge. Herein, we investigate the interplay between molecular spins and magnons in hybrid heterostructures formed by [CpTi(cot)] and VOPc spin qubits deposited on the surface of the air-stable 2D van der Waals ferromagnet CrSBr using first principles. Our results show that different molecular rotation configurations significantly impact on qubit relaxation time and alter the magnon spectra of the underlying 2D magnet, allowing the chemical coherent control of spin waves in this material. We predict the feasibility of an ultrafast magnon-qubit interface with minimized decoherence, where exchange coupling plays a crucial role. This work opens new avenues for hybrid quantum magnonics, enabling selective tailoring through a versatile chemical approach.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
5 figures
Penetration of surface effects on structural relaxation and particle hops in glassy films
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-01 20:00 EDT
Qiang Zhai, Hai-Yao Deng, Xin-Yuan Gao, Leo S.I. Lam, Sen Yang, Ke Yan, Chi-Hang Lam
A free surface induces enhanced dynamics in glass formers. We study the dynamical enhancement of glassy films with a distinguishable-particle lattice model of glass free of elastic effects. We demonstrate that the thickness of the surface mobile layer depends on temperature differently under different definitions, although all are based on local structure relaxation rate. The rate can be fitted to a double exponential form with an exponential-of-power-law tail. Our approach and results exclude elasticity as the unique mechanism for the tail. Layer-resolved particle hopping rate, potentially a key measure for activated hopping, is also studied but it exhibits much shallower surface effects.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
Dewetting Dynamics of Unstable Lubricant Impregnated Surfaces in Liquid Environment
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-01 20:00 EDT
This article outlines a thorough stability analysis by means of both theoretical and experimental modeling for Omni-phobic Lubricant Impregnated Surfaces (LIS). The liquid-repellent properties, particularly with regard to water and oil, have gained substantial attention due to their numerous potential applications. The theoretical section of this study focuses on the validation of mathematical models to understand the underlying principles driving the stability of Omni-phobic LIS. Theoretical insights about the interaction of surface texture, chemical composition, impregnated, and ambient liquid properties contribute to a better understanding of the mechanisms that govern stability. A series of experiments were performed to understand better the stability of fabricated Omni-phobic LIS under cyclopentane and water environments, including viscosity and surface texture variations, especially post-spacing variation. The experimental results validate the theoretical predictions and provide valuable statistical information regarding possible model modification. The replaced oil or nucleation sites can be explained through CHNT. The analysis was further validated with experimentally observed nucleation sites. This confirms the accuracy of the nucleation predictions and supports the underlying theoretical model. According to the CLW model, the length of a liquid’s penetration into a cylinder/square-shaped capillary is expressed as a square root of time. Our findings contribute to designing a stable LIS and then determining the model followed by an unstable one. The proposed MLW model validated the experimental results. In addition, these experimental data points fit the different capillary imbibition regimes such as inertial, early viscous etc. This contributes to the development of robust and durable solutions for practical applications.
Soft Condensed Matter (cond-mat.soft)
39 pages, 12 figures, 6 SI images
Optical lattice quantum simulator of dynamics beyond Born-Oppenheimer
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-04-01 20:00 EDT
Javier Argüello-Luengo, Alejandro González-Tudela, J. Ignacio Cirac
Here, we propose a platform based on ultra-cold fermionic molecules trapped in optical lattices to simulate nonadiabatic effects as they appear in certain molecular dynamical problems. The idea consists in a judicious choice of two rotational states as the simulated electronic or nuclear degrees of freedom, in which their dipolar interactions induce the required attractive or repulsive interactions between them. We benchmark our proposal by studying the scattering of an electron or a proton against a hydrogen atom, showing the effect of electronic exchange and inelastic ionization as the mass ratio between the simulated nuclei and electrons (a tunable experimental parameter in our simulator) becomes comparable. These benchmarks illustrate how the simulator can qualitatively emulate phenomena like those appearing in molecular dynamical problems even if the simulated interaction occurs in two-dimensions with a dipolar scaling. Beyond the molecular implementation proposed here, our proposal can be readily extrapolated to other atomic platforms, e.g., based on fermionic Rydberg atoms.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
5 pages, 4 figures and End Matter
VacHopPy: A Python package for vacancy hopping analysis based on ab initio molecular dynamics simulations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Taeyoung Jeong, Kun Hee Ye, Seungjae Yoon, Dohyun Kim, Yunjae Kim, Jung-Hae Choi
Multiscale modeling, which integrates material properties from ab initio calculations into device-scale models, is a promising approach for optimizing semiconductor devices. However, a key challenge remains: while ab initio methods yield diffusion parameters specific to individual migration paths, device models require a single set of effective parameters that capture overall diffusion. To bridge this gap, we present VacHopPy an open-source Python package for vacancy hopping analysis based on ab initio molecular dynamics (AIMD). VacHopPy extracts an effective set of parameters for vacancy hopping: hopping distance, hopping barrier, number of effective paths, correlation factor, and jump attempt frequency, by statistically integrating thermodynamic, kinetic, and geometric contributions across all hopping paths. It also offers tools for tracking vacancy trajectories and for detecting phase transitions in AIMD simulations. The applicability of VacHopPy is demonstrated in three materials: face-centered cubic Al, rutile TiO2, and monoclinic HfO2. The effective parameters accurately reflect temperature-dependent diffusion behavior and show good agreement with previous experimental observations. Expressed in a simplified form suitable for device models, these parameters remain valid across a broad temperature range spanning several hundred Kelvins. Furthermore, our findings highlight the critical role of anisotropic thermal vibrations in overall diffusion, a factor frequently overlooked in other frameworks but inherently considered in VacHopPy. Overall, VacHopPy provides a robust framework for bridging atomistic and device-scale models, enabling more reliable multiscale simulations.
Materials Science (cond-mat.mtrl-sci)
Accelerating Surface Composition Characterization of Thin-Film Materials Libraries using Multi-Output Gaussian Process Regression
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
F. Thelen, F. Lourens, A. Ludwig
Efficient characterization of surface compositions across high-dimensional materials spaces is critical for accelerating the discovery of surface-dominated functional materials. While X-ray photoelectron spectroscopy allows detailed surface composition investigation, it remains a time-intensive technique. In this work, it is demonstrated that Gaussian process regression can be used to accurately predict surface compositions from rapidly acquired volume composition data obtained by energy-dispersive X-ray spectroscopy, drastically reducing the number of required surface measurements. As a proof of principle, an exemplary system, the oxide Mg-Mn-Al-O, is synthesized as a composition-spread thin-film materials library and analyzed by high-throughput methods. We show that the surface composition of the entire library can be predicted with an accuracy of 96% with only 13 measurements, reducing the total measurement time by 277 h. This is a scalable and data-efficient solution for integrating surface analysis into materials discovery workflows.
Materials Science (cond-mat.mtrl-sci)
Many body quantum chaos and time reversal symmetry
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-01 20:00 EDT
Weijun Wu, Saumya Shivam, Amos Chan
We investigate universal signatures of quantum chaos in the presence of time reversal symmetry (TRS) in generic many body quantum chaotic systems (gMBQCs). We study three classes of minimal models of gMBQCs with TRS, realized through random quantum circuits with (i) local TRS, (ii) global TRS, and (iii) TRS combined with discrete time-translation symmetry. In large local Hilbert space dimension $ q$ , we derive the emergence of random matrix theory (RMT) universality in the spectral form factor (SFF) at times larger than the Thouless time $ t_{\mathrm{Th}}$ , which diverges with system sizes in gMBQCs. At times before $ t_{\mathrm{Th}}$ , we identify universal behaviour beyond RMT by deriving explicit scaling functions of SFF in the thermodynamic limit. In the simplest non-trivial setting - preserving global TRS while breaking time translation symmetry and local TRS - we show that the SFF is mapped to the partition function of an emergent classical ferromagnetic Ising model, where the Ising spins correspond to the time-parallel and time-reversed pairings of Feynman paths, and external magnetic fields are induced by TRS-breaking mechanisms. Without relying on the large-$ q$ limit, we develop a second independent derivation of the Ising scaling behaviour of SFF using space-time duality and parity symmetric non-Hermitian Ginibre ensembles. Moreover, we show that many body effects originating from time-reversed pairings of Feynman paths manifest in the two-point autocorrelation function (2PAF), the out-of-time-order correlator (OTOC), and the partial spectral form factor - quantities sensitive to both eigenvalue and eigenstate correlations. We establish that the fluctuations of 2PAF are governed by an emergent three-state Potts model, leading to an exponential scaling with the operator support size, at a rate set by the three-state Potts model. [See full abstract in the paper]
Statistical Mechanics (cond-mat.stat-mech), High Energy Physics - Theory (hep-th), Chaotic Dynamics (nlin.CD), Quantum Physics (quant-ph)
36+13 pages, 22+11 figures
Chiral symmetry and magnetism in a 3D Kagome lattice: RPt$_2$B (R = La and Nd) prototype crystals
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-01 20:00 EDT
C. E. Ardila-Gutiérrez, D. Torres-Amaris, Rafael González-Hernández, Aldo. H. Romero, A. C. Garcia-Castro
Chirality in crystals arises from the exclusive presence of proper symmetry operations, such as rotations and screw axes, while lacking improper operations like inversion, mirror planes, and roto-inversions. Crystallographic chirality is expected to be coupled with magnetic responses in magnetically active chiral compounds. Therefore, this study investigates the interplay between structural chirality and magnetic ordering in the rare-earth platinum boride family, RPt$ _2$ B, where R denotes lanthanide elements. Our results show that the R sites structurally form a chiral three-dimensional Kagome lattice, which can lead to magnetic frustration resolved through chiral antiferromagnetic orderings in conjunction with chiral symmetry. Symmetry analysis reveals that these chiral antiferromagnetic states are low-energy states, competing with higher-in-energy (001) ferromagnetic configuration. We also identified Kramers-type Weyl points in the electronic structure without magnetic response. In the magnetically active chiral compound NdPt$ 2$ B, Zeeman splitting lifts degeneracies at the high-symmetry points; however, Weyl points persist due to the breaking of time-reversal (T) and inversion (P) symmetries. We also estimate the anomalous Hall conductivity, a measurable observable of the allowed topological features finding a value of $ \sigma{xy} = 293$ S$ \cdot$ cm$ ^{-1}$ comparable with another Kagome magnetic materials like Mn$ _3$ PtN and FeSn, for example. This study elucidates the intricate interplay among chirality, magnetism, and topology in rare-earth Kagome materials.
Strongly Correlated Electrons (cond-mat.str-el), Other Condensed Matter (cond-mat.other)
Control of the magnetic hopfion lattice in helimagnet with the external field and anisotropy
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-01 20:00 EDT
Konstantin L. Metlov, Artem S. Tarasenko, Yulia A. Bezus, Maxim M. Gordey
A generalized micromagnetic model of hopfions in a helimagnet with a two-dimensional (allowing both radial and azimuthal dependence) profile function is considered. Calculations confirm the elliptical stability of hopfions and the previously obtained analytical expression for the upper critical field of their lattice. Dependencies of the hopfion lattice periods on the magnitude of the applied external magnetic field and the uniaxial anisotropy constant of the material are obtained. It is shown that in an anisotropic helimagnet, the hopfion lattice has a layered (graphite-like) layout, which can be controlled by the external field and the uniaxial anisotropy.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Pattern Formation and Solitons (nlin.PS)
7 pages, 4 figures. This is bilingual submission and the primary version is Russian, but English translation is also provided
POINT$^{2}$: A Polymer Informatics Training and Testing Database
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Jiaxin Xu, Gang Liu, Ruilan Guo, Meng Jiang, Tengfei Luo
The advancement of polymer informatics has been significantly propelled by the integration of machine learning (ML) techniques, enabling the rapid prediction of polymer properties and expediting the discovery of high-performance polymeric materials. However, the field lacks a standardized workflow that encompasses prediction accuracy, uncertainty quantification, ML interpretability, and polymer synthesizability. In this study, we introduce POINT$ ^{2}$ (POlymer INformatics Training and Testing), a comprehensive benchmark database and protocol designed to address these critical challenges. Leveraging the existing labeled datasets and the unlabeled PI1M dataset, a collection of approximately one million virtual polymers generated via a recurrent neural network trained on the realistic polymers, we develop an ensemble of ML models, including Quantile Random Forests, Multilayer Perceptrons with dropout, Graph Neural Networks, and pretrained large language models. These models are coupled with diverse polymer representations such as Morgan, MACCS, RDKit, Topological, Atom Pair fingerprints, and graph-based descriptors to achieve property predictions, uncertainty estimations, model interpretability, and template-based polymerization synthesizability across a spectrum of properties, including gas permeability, thermal conductivity, glass transition temperature, melting temperature, fractional free volume, and density. The POINT$ ^{2}$ database can serve as a valuable resource for the polymer informatics community for polymer discovery and optimization.
Materials Science (cond-mat.mtrl-sci), Artificial Intelligence (cs.AI), Machine Learning (cs.LG)
Amplitude mode at the superfluid-insulator transition on a random lattice
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-04-01 20:00 EDT
Vishnu Pulloor Kuttanikkad, Rajesh Narayanan, Thomas Vojta
We study the superfluid-insulator quantum phase transition of interacting bosons by means of large-scale Monte Carlo simulations in the presence of both topological and generic quenched disorders. Recent work has demonstrated that the amplitude mode at this transition broadens and localizes in the presence of dilution disorder, whereas it remains a well-defined delocalized excitation for topological (connectivity) disorder. Here, we analyze the crossover between systems with purely topological disorder and systems with additional bond randomness to disentangle the roles that disorder and interactions play for amplitude mode localization. Specifically, we analyze the scalar susceptibility and its spectral density on both sides of the quantum phase transition. We also discuss the implications of our results for the potential observation of amplitude mode localization in experiments.
Quantum Gases (cond-mat.quant-gas), Disordered Systems and Neural Networks (cond-mat.dis-nn)
submitted to the FQMT24 special issue of EPJ-ST
Dynamics away from Equilibrium of a Disordered Binary Alloy
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-01 20:00 EDT
Aly Abuelmaged, Eric Dohner, Shang-Jie Liou, Herbert F Fotso
We study the nonequilibrium dynamics of a binary disordered alloy when it is subjected to an interaction quench. Our study uses a nonequilibrium embedding scheme (DMFT+CPA) that combines the capacity of DMFT (dynamical mean field theory) to treat strongly correlated systems and the capacity of CPA (coherent potential approximation) to treat disordered systems, to effectively address the interplay of disorder and interaction for the nonequilibrium system. Our solution is applied on the equilibrium binary disordered and interacting alloy for the calculation of the density of states. This equilibrium density of states shows the modifications of the disorder-driven gap by the interaction and that of the interaction-driven Mott gap by the disorder. Next, we assess the relaxation of the system that is initially in equilibrium at a given temperature, and then abruptly has its interaction strength changed from zero to a finite value at which it is kept constant. The system undergoes a short time transient and then settles into a long-time state in a process that depends in a nontrivial manner on the disorder and interaction strength. In addition, we calculate the effective temperature of the system after it has gone through its initial transient and settled into its long-time state. The long-time effective temperature is increased with increasing final interaction strength. However, for a given final interaction, the final temperature can be tuned by the disorder strength over a broad range, with stronger disorder leading to lower temperature. Altogether, the results illustrate the nontrivial interplay between disorder and interaction for a binary alloy away from equilibrium.
Strongly Correlated Electrons (cond-mat.str-el)
8 pages, 5 figures
DC-driven separation of fractional flux quanta in two-band superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2025-04-01 20:00 EDT
Anton O. Pokusinkyi, Oleksandr V. Dobrovolskiy
Two-band superconductors host vortices from superfluid condensates of different electron bands. These vortices carry a fractional flux quantum and attract each other, coalescing to form a composite vortex with the whole flux quantum $ \phi_0$ . However, due to the differences in viscosity and flux of the vortices across different bands, composite vortices may dissociate into fractional components. Here, we theoretically explore an approach to control the dissociation of composite vortices into fractional components and their separation into stationary and fast-moving ones through dc current and pinning strength variation. To this end, we numerically solve the dynamic equation of motion for a single dc-driven composite vortex in a periodic pinning potential. As the pinning strength increases, we observe a transition from depinning followed by dissociation in the weak-pinning regime to dissociation from the pinned state in the strong-pinning regime. Under moderately strong pinning, fractional vortices from one condensate may become immobile while those from the other may even move faster than the original composite vortex just before the dissociation. The predicted pinning- and dc-controlled separation of fractional flux quanta appeals for experimental investigation and potential application in fluxonic devices.
Superconductivity (cond-mat.supr-con)
6 pages, 3 figures
Magnetoelectric training of multiferroic domains in Mn$_2$GeO$_4$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Naëmi Leo, Jonathan S. White, Michel Kenzelmann, Takashi Honda, Tsuyoshi Kimura, Dennis Meier, Manfred Fiebig
We study the trilinear magnetoelectric coupling between ferroelectric, ferromagnetic, and antiferromagnetic domains in the spin-spiral multiferroic Mn$ _2$ GeO$ _4$ , imaging the evolution of domains under both magnetic and electric fields via optical second harmonic generation. Once activated, this trilinear coupling enables the highly repeatable inversion of an inhomogeneous ferroelectric domain pattern upon global reversal of the magnetization. We specifically consider the initial domain evolution from zero-field cooling and find that polarization and magnetization domains form independently when entering the multiferroic phase. From here, a field training process is required to obtain the domain inversion mentioned above. We explain this training behavior of the complex magnetoelectric coupling as a pathway from metastable to equilibrium domain patterns, a process relevant to understanding the magnetoelectric behavior in other multiferroic materials with highly interlinked coexisting order parameters.
Materials Science (cond-mat.mtrl-sci)
11 pages, 7 figures
A semiclassical nonequilibrium Green’s Function approach to electron transport in systems exhibiting electron-phonon couplings
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-01 20:00 EDT
We formulate a semiclassical theory for electron transport in open quantum systems with electron-phonon interactions adequate for situations when the system’s phonon dynamics is comparable with the electron transport timescale. Starting from the Keldysh non-equilibrium Green’s function formalism we obtain equations of motion for the retarded and lesser electronic Green’s functions including contributions due to the phonon dynamics up to second order in the electron-phonon coupling strength. The resulting equations assume that the system’s phonon follow classical time-local dynamics with delta-correlated noise. We apply our method to the study of the charging/discharging of a periodically driven quantum dot, and a three-level model for a single-electron pump, analyzing the signatures in the transient current, electron population and process performance of the phonon dynamics. For these systems, we consider external harmonic driving of the phonon at frequencies comparable with the electron modulation, and different scenarios, varying electron-phonon coupling strength, coupling to the electron part of the system, and in phase and anti-phase driving. Our results illustrate that our method provides an efficient protocol to describe the effects of nuclear motion in ultrafast transient phenomena.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Double commutator method for a two band Bose-Einstein condensate: superfluid density of a flat band superfluid
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-04-01 20:00 EDT
In this work, we propose a double commutator method for a general two-band bosonic superfluid. First and foremost, we prove that the sum of the superfluid and normal densities is equal to the weight of the f-sum rule. This weight can be easily determined by analyzing the ground state wave function. Once we have determined the excitation gap of the upper band, we can calculate the normal density by evaluating the average value of a double commutator between the velocity operator and the Hamiltonian. As an application of this method, we investigate the superfluid density of a flat band Bose-Einstein condensate (BEC). Using the Bogoliubov method, we calculate the sound velocity and excitation gap, which allows us to obtain the normal and superfluid densities explicitly. Our findings indicate that the superfluid density is directly proportional to the product of the square of the sound velocity and the compressibility. Furthermore, the existence of a non-vanishing superfluid density depends on the form of the interaction. For example, in the case of U(2) invariant interactions, the superfluid density is zero. Additionally, we have observed that for small interactions, the superfluid density is directly proportional to the product of the interaction parameter and the quantum metric. The double commutator method indicates that the correction of the excitation gap by interactions is the origin of the non-vanishing superfluid density of a flat band BEC. Up to the linear order of the interaction parameters, all the results for the excitation gap, the normal and superfluid densities in a flat band BEC can also be obtained through a simple perturbation theory. Our work provides another unique perspective on the superfluid behavior of a flat band BEC.
Quantum Gases (cond-mat.quant-gas), Superconductivity (cond-mat.supr-con), Quantum Physics (quant-ph)
Modeling Framework to Predict Melting Dynamics at Microstructural Defects in TNT-HMX High Explosive Composites
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Ethan Holbrook, Matthew P. Kroonblawd, Brenden W. Hamilton, H. Keo Springer, Alejandro Strachan
Many high explosive (HE) formulations are composite materials whose microstructure is understood to impact functional characteristics. Interfaces are known to mediate the formation of hot spots that control their safety and initiation. To study such processes at molecular scales, we developed all-atom force fields (FFs) for Octol, a prototypical HE formulation comprised of TNT (2,4,6-trinitrotoluene) and HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine). We extended a FF for TNT and recasted it in a form that can be readily combined with a well-established FF for HMX. The resulting FF was extensively validated against experimental results and density functional theory calculations. We applied the new combined TNT-HMX FF to predict and rank surface and interface energies, which indicate that there is an energetic driver for coarsening of microstructural grains in TNT-HMX composites. Finally, we assess the impact of several microstructural environments on the dynamic melting of TNT crystal under ultrafast thermal loading. We find that both free surfaces and planar material interfaces are effective nucleation points for TNT melting. However, MD simulations show that TNT crystal is prone to superheating by at least 50 K on sub-nanosecond timescales and that the degree of superheating is inversely correlated with surface and interface energy. The modeling framework presented here will enable future studies on hot spot formation processes in accident scenarios that are governed by strong coupling between microstructural interfaces, material mechanics, momentum and energy transport, phase transitions, and chemistry.
Materials Science (cond-mat.mtrl-sci)
56 pages, 12 figures
Twisted Nodal Superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2025-04-01 20:00 EDT
Recent proposals for the realization of time-reversal symmetry breaking and topological superconductivity in twisted nodal superconductors have led to a surge of theoretical and experimental studies of these systems, marking one of the newest entries in the rapidly growing field of moiré materials. The interplay between order parameters of the separate layers makes twisted superconductors unique, leading to additional emergent phenomena in regimes usually not of importance in moiré physics, such as bulk interfaces and large twist angles. We review the physics of twisted nodal superconductors, highlighting both similarities and qualitative differences with other moiré platforms. While inspired by the rise of moiré materials, the field is anchored in studies of unconventional superconductivity preceding the moiré era, which we discuss in detail. In addition to summarizing the developments at the present stage, we present a detailed outlook on the major open questions in the field and some of the most exciting future directions.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
submitted invited review to Annual Reviews of Condensed Matter Physics
Superconductivity in High-Entropy Antimonide M$_{1-x}$Pt$_x$Sb (M = equimolar Ru, Rh, Pd, and Ir)
New Submission | Superconductivity (cond-mat.supr-con) | 2025-04-01 20:00 EDT
Daigorou Hirai, Naoto Uematsu, Koh Saitoh, Naoyuki Katayama, Koshi Takenaka
The high-entropy concept was applied to the synthesis of transition-metal antimonides, M1-xPtxSb (M = equimolar Ru, Rh, Pd, and Ir). High-entropy antimonide samples crystallized in a pseudo-hexagonal NiAs-type crystal structure with a P63/mmc space group were successfully synthesized through a conventional solid-state reaction and subsequent quenching. A detailed investigation of the composition and equilibration conditions confirmed the reversible phase transition between a multi-phase state at low temperature and an entropy-driven single-phase solid solution at high temperatures. Electrical resistivity, magnetization, and heat capacity measurements of single-phase M1-xPtxSb (x = 0.2) samples revealed a bulk superconducting transition at 2.15(2) K. This study demonstrates that the high-entropy concept provides numerous opportunities for the discovery of new functional materials such as superconductors.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
13 pages, 6+2 figures, 1+2 tables
Inorg. Chem., 62, 14207-14215 (2023)
Pinalites: Optical properties and Quantum Magnetism of Heteroanionic A$_3$MO$_5$X$_2$ Compounds
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Heteroanionic compounds, which contain two or more types of anions, have emerged as a promising class of materials with diverse properties and functionalities. In this paper, I review the experimental findings on Ca3ReO5Cl2 and related com-pounds that exhibit remarkable pleochroism and novel quantum magnetism. I discuss how the heteroanionic coordination affects the optical and magnetic properties by modulating the d-orbital states of the transition metal ions and then compare these materials with other heteroanionic and monoanionic compounds and highlight the potential of A3MO5X2 materials for future exploration of materials and phenomena.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
12 pages, 3 figures, 1 table
Inorg. Chem., 63, 4001-4010 (2024)
The limits of knowledge in classical physics resemble the quantum uncertainty relation
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-01 20:00 EDT
Building upon a recent analysis of the measurement process in Hamiltonian mechanics, this article investigates the Bayesian epistemology of classical physics – the landscape of accessible probability distributions over phase space. I prove a thermodynamic limitation on the information that can be obtained about a classical system by means of observations: A direct analogue of the Robertson-Schrödinger quantum uncertainty relation controls the acquisition of information at the classical microscale. Central to this theorem is the notion of the “quality” of a measuring probe; a temperature-dependent strictly positive quantity that serves as a figure of merit of the probe, and that plays the role of $ 1/\hbar$ in the classical uncertainty relation. This study sets the stage for a new area of research into resource theories of classical measurement, in which high-quality measurements and high-information states of knowledge are the limited resources.
Statistical Mechanics (cond-mat.stat-mech), Classical Physics (physics.class-ph), Quantum Physics (quant-ph)
22 pages, 1 figure
Vapor-mediated wetting and imbibition control on micropatterned surfaces
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-01 20:00 EDT
Ze Xu, Raphael Saiseau, Olinka Ramírez Soto, Stefan Karpitschka
Wetting of micropatterned surfaces is ubiquitous in nature and key to many technological applications like spray cooling, inkjet printing, and semiconductor processing. Overcoming the intrinsic, chemistry- and topography-governed wetting behaviors often requires specific materials which limits applicability. Here, we show that spreading and wicking of water droplets on hydrophilic surface patterns can be controlled by the presence of the vapor of another liquid with lower surface tension. We show that delayed wicking arises from Marangoni forces due to vapor condensation, competing with the capillary wicking force of the surface topography. Thereby, macroscopic droplets can be brought into an effective apparent wetting behavior, decoupled from the surface topography, but coexisting with a wicking film, cloaking the pattern. We demonstrate how modulating the vapor concentration in space and time may guide droplets across patterns and even extract imbibed liquids, devising new strategies for coating, cleaning and drying of functional surface designs.
Soft Condensed Matter (cond-mat.soft), Fluid Dynamics (physics.flu-dyn)
15 pages, 12 Figures
Topological Electronic Structure and Transport Properties of the Distorted Rutile-type WO$_2$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Yuto Muramatsu, Daigorou Hirai, Mitsuaki Kawamura, Susumu Minami, Yoshitaka Ikeda, Takahiro Shimada, Keita Kojima, Naoyuki Katayama, Koshi Takenaka
We elucidate the transport properties and electronic structures of distorted rutile-type WO2. Electrical resistivity and Hall effect measurements of high-quality single crystals revealed the transport property characteristics of topological materials; these characteristics included an extremely large magnetoresistance of 13,200% (2 K and 9 T) and a very high carrier mobility of 25,700 cm2 V-1 s-1 (5 K). First-principles calculations revealed Dirac nodal lines (DNL) near the Fermi energy in the electronic structure when spin-orbit interactions (SOIs) were absent. Although these DNLs mostly disappeared in the presence of SOIs, band crossings at high-symmetry points in the reciprocal space existed as Dirac points. Furthermore, DNLs protected by nonsymmorphic symmetry persisted on the ky = {\pi}/b plane. The unique transport properties originating from the topological electronic structure of chemically and thermally stable WO2 could represent an opportunity to investigate the potential electronic applications of the material.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
9 pages, 6 figures, 1 table
APL Mater. 13, 011119 (2025)
Paramagnetic half-moon shaped diffuse scattering arising from 3D magnetic frustration
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-01 20:00 EDT
Nelly Natsch, Tara N. Tošić, Jian-Rui Soh, Nicola A. Spaldin
We use spin dynamics simulations to determine the origin of the unusual correlated diffuse scattering, characterised by half-moon shapes bridging the magnetic Bragg peaks, observed in the polarised elastic neutron scattering from manganese tungstate, MnWO\textsubscript{4}. We first fit a Heisenberg Hamiltonian with twelve nearest-neighbour exchange interactions and single-ion anisotropy to the experimental ground-state magnon dispersion. We then show via spin dynamics simulations that our model Hamiltonian both reproduces the experimentally observed half-moon features and captures their persistence into the paramagnetic regime. Moreover, we identify the three-dimensional, competing antiferromagnetic interactions driving this behavior. Our work complements earlier studies of half-moon-shaped signatures in pyrochlore and triangular structures, by providing insight into their origin in a zigzag chain geometry with three-dimensional competing exchange interactions.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Colossal enhancement of spin transmission through magnon confinement in an antiferromagnet
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Sajid Husain, Maya Ramesh, Xinyan Li, Sergei Prokhorenko, Shashank Kumar Ojha, Aiden Ross, Koushik Das, Boyang Zhao, Hyeon Woo Park, Peter Meisenheimer, Yousra Nahas, Lucas Caretta, Lane W. Martin, Se Kwon Kim, Zhi Yao, Haidan Wen, Sayeef Salahuddin, Long-Qing Chen, Yimo Han, Rogerio de Sousa, Laurent Bellaiche, Manuel Bibes, Darrell G.Schlom, Ramamoorthy Ramesh
Since Felix Bloch’s introduction of the concept of spin waves in 1930, magnons (the quanta of spin waves) have been extensively studied in a range of materials for spintronics, particularly for non-volatile logic-in-memory devices. Controlling magnons in conventional antiferromagnets and harnessing them in practical applications, however, remains a challenge. In this letter, we demonstrate highly efficient magnon transport in an LaFeO$ _3$ /BiFeO$ _3$ /LaFeO$ _3$ all-antiferromagnetic system which can be controlled electrically, making it highly desirable for energy-efficient computation. Leveraging spin-orbit-driven spin-charge transduction, we demonstrate that this material architecture permits magnon confinement in ultrathin antiferromagnets, enhancing the output voltage generated by magnon transport by several orders of magnitude, which provides a pathway to enable magnetoelectric memory and logic functionalities. Additionally, its non-volatility enables ultralow-power logic-in-memory processing, where magnonic devices can be efficiently reconfigured via electrically controlled magnon spin currents within magnetoelectric channels.
Materials Science (cond-mat.mtrl-sci)
12 pages, 4 figures
Altermagnetism and Weak Ferromagnetism
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
I. V. Solovyev, S. A. Nikolaev, A. Tanaka
Using a realistic model relevant to La$ _2$ CuO$ _4$ and other altermagnetic perovskite oxides, we study interrelations between weak ferromagnetism (WF), anomalous Hall effect (AHE), and net orbital magnetization (OM). All of them can be linked to the form of Dzyaloshinskii-Moriya (DM) interactions. Nevertheless, while spin WF is induced by the DM vector components having the same sign in all equivalent bonds, AHE and OM are related to alternating-sign components, which do not contribute to any canting of spins. The microscopic model remains invariant under the symmetry operation $ { \mathcal{S}|{\bf t} }$ , combining the shift $ {\bf t}$ of antiferromagnetically coupled sublattices to each other with the spin flip $ \mathcal{S}$ . Thus, the band structure remains Kramers-degenerate, but the time-reversal symmetry is broken, providing a possibility to realize AHE in antiferromagnetic substances. The altermagnetic splitting of bands, breaking the $ { \mathcal{S}|{\bf t}}$ symmetry, does not play a major role in the problem. More important is the orthorhombic strain, responsible for finite values of AHE and OM.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
6 pages, 3 figures
XY-Ashkin-Teller Phase Diagram in d=3
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-01 20:00 EDT
Alpar Turkoglu, A. Nihat Berker
The phase diagram of the Ashkin-Tellerized XY model in spatial dimension $ d=3$ is calculated by renormalization-group theory. In this system, each site has two spins, each spin being an XY spin, that is having orientation continuously varying in 2\pi radians. Nearest-neighbor sites are coupled by two-spin and four-spin interactions. The phase diagram has ordered phases that are ferromagnetic and antiferromagnetic in each of the spins, and phases that are ferromagnetic and antiferromagnetic in the multiplicative spin variable. The phase diagram exhibits two symmetrically situated reverse bifurcation points of the phase boundaries. The renormalization-group flows are in terms of the doubly composite Fourier coefficients of the exponentiated energy of nearest-neighbor spins.
Statistical Mechanics (cond-mat.stat-mech)
4 pages, 3 figures, 1 reverse-bifurcating phase diagram
Exact Solution of the Frustrated Potts Model with Next-Nearest-Neighbor Interactions in One Dimension: An AI-Aided Discovery
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-01 20:00 EDT
The one-dimensional $ J_1$ -$ J_2$ $ q$ -state Potts model is solved exactly for arbitrary $ q$ , based on using OpenAI’s latest reasoning model o3-mini-high to exactly solve the $ q=3$ case. The exact results provide insights to outstanding physical problems such as the stacking of atomic or electronic orders in layered materials and the formation of a $ T_c$ -dome-shaped phase often seen in unconventional superconductors. The work is anticipated to fuel both the research in one-dimensional frustrated magnets for recently discovered finite-temperature application potentials and the fast moving topic area of AI for sciences.
Statistical Mechanics (cond-mat.stat-mech), Mathematical Physics (math-ph)
6 pages, 4 figures
Efficient defect healing of single-walled cabron nanotubes through $ \mathrm{C}{2}\mathrm{H}{2} $-assisted multiple-cycle treatment with air exposure
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Man Shen, Taiki Inoue, Mengyue Wang, Yuanjia Liu, Yoshihiro Kobayashi
Defects in single-walled carbon nanotubes (SWCNTs) degrade their mechanical,electrical, and thermal properties, limiting their potential applications. To realize the diverse applications of SWCNTs, it is essential to enhance their crystallinity through effective defect healing. However, traditional thermal treatments typically require temperatures above 1800°C, which can alter the nanotube structure. Previously, defect healing of SWCNTs was achieved at a relatively low temperature of 1100°C, using C$ _{2}$ H$ _{2}$ assistance, but the efficiency was limited. In this study, we developed a C$ _{2}$ H$ _{2}$ -assisted multiple-cycle process at an even lower temperature of 1000°C combined with air exposure, achieving highly efficient defect healing while preserving the nanotube structure. The combination of multiple-cycle treatment and air exposure between cycles was found to promote defect activation, suppress the formation of amorphous carbon, and enhance the effectiveness of defect healing. Additionally, we successfully healed commercially available bulk-scale SWCNTs (super-growth SWCNTs), noting that their healing behavior differed from lab-grown SWCNTs with smaller diameters synthesized from nanodiamond. The efficient and structure-preserved healing process developed in this study broadens the potential applications of high-quality SWCNTs, including flexible electronics, high-performance composites, and energy storage devices.
Materials Science (cond-mat.mtrl-sci)
submitted version
ACS Appl. Mater. Interfaces 2025
Measurement-induced phase transitions for free fermions in a quasiperiodic potential
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-04-01 20:00 EDT
Toranosuke Matsubara, Kazuki Yamamoto, Akihisa Koga
We study the dynamics under continuous measurements for free fermions in a quasiperiodic potential by using the Aubry-André-Harper model with hopping rate $ J$ and potential strength $ V$ . On the basis of the quantum trajectory method, we obtain the phase diagram for the steady-state entanglement entropy and demonstrate that robust logarithmic system-size scaling emerges up to a critical potential strength $ V_c/J \sim 2.3$ . Moreover, we find that the measurement induces entanglement phase transitions from the logarithmic-law phase to the area-law phase for the potential strength $ V< V_c$ , while any finite measurement stabilizes the area-law phase for $ V>V_c$ . This result is distinct from the entanglement scaling in the unitary limit, where volume-law and area-law phases undergo a transition at $ V/J=2$ . To further support the phase diagram, we analyze the connected correlation function and find that it shows algebraic decay in the logarithmic-law phase, while it decays quickly in the area-law phase. Our results can be tested in ultracold atoms by introducing quasiperiodic potentials and continuously monitoring the local occupation number with an off-resonant probe light.
Quantum Gases (cond-mat.quant-gas), Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
12 pages, 10 figures
Two-electron edge states in a double SSH-chain of quantum dots
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-01 20:00 EDT
We study an interacting two-body model with adjustable spin tunneling in the context of the double SSH chains for a quantum dot system. We discovered that varying interaction strengths and spin tunneling significantly influence the properties of correlated edge states in the energy spectrum obtained through exact diagonalization. We observe that stronger interactions lead to longer decay lengths of these states. Conversely, the decay length decreases as the difference in intracell or intercell tunneling increases. Importantly, the decay length is strongly correlated with the dynamical behavior of two particles; specifically, an increase in decay length corresponds to a decrease in motion frequency. This conclusion is supported by the observation of the expectation value of coordinate operators of the particles.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
High-Throughput Exploration of NV-like Color Centers Across Host Materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Oscar Groppfeldt, Joel Davidsson, Rickard Armiento
Point defects in semiconductors offer a promising platform for advancing quantum technologies due to their localized energy states and controllable spin properties. Prior research has focused on a limited set of defects within materials such as diamond, silicon carbide, and hexagonal boron nitride. We present a high-throughput study to systematically identify and evaluate point defects across a diverse range of host materials, aiming to uncover previously unexplored defects in novel host materials suitable for use in quantum applications. A range of host materials are selected for their desirable properties, such as appropriate bandgaps, crystal structure, and absence of d- or f-electrons. The Automatic Defect Analysis and Qualification (ADAQ) software framework is used to generate vacancies, substitutions with s- and p-elements, and interstitials in these materials and use density functional theory to calculate key properties such as Zero-Phonon Lines (ZPLs), ionic displacements, Transition Dipole Moments (TDMs), and formation energies. Special attention is given to charge correction methods for materials with dielectric anisotropy. We uncover new defect-host combinations with advantageous properties for quantum applications: 28 defects across 11 isotropic and 2 anisotropic host materials show properties similar to the nitrogen-vacancy (NV) center in diamond. Beryllium (Be) substitutional defects in SrS, MgS, and SrO emerge as particu- larly promising. These findings contribute to diversifying and enhancing the materials available for quantum technologies.
Materials Science (cond-mat.mtrl-sci)
Three-dimensional Optical Reconstruction of colloidal electrokinetics via multiplane imaging
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-01 20:00 EDT
Flip de Jong, Pablo Diez-Silva, Jui-Kai Chen, Raúl Pérez-Peláez, Sudipta Seth, Harishankar Balakrishnan, Bing-Yang Shih, Maarten Rosmeulen, Santi Nonell, Susana Rocha, Andrey Klymchenko, Luis Liz-Marzán, Roger Bresolí-Obach, Manuel I. Marqués, Rafael Delgado Buscalioni, Johan Hofkens, Boris Louis
Selective manipulation of particles is crucial in many fields, ranging from chemistry to biology and physics. Dielectrophoresis stands out due to its high selectivity potential and the absence of need for labels. To fully understand and control the phenomenon, observation of the dynamic of nanoparticles under DEP needs to be performed in the three spatial dimensions. However, not many microscopy approaches offer such capability at fast frame rates (>100fps) and high resolution. Here, we used widefield microscopy, to follow the spatiotemporal dynamics of fluorescently labelled polystyrene nanoparticles of 200 nm under positive and negative dielectrophoresis conditions. This real-time 3D imaging technique allows for single particle tracking, enabling super-resolved reconstruction of the DEP force and electrokinetic flows with unprecedented detail. We compare the differences for positive and negative dielectrophoresis conditions and rationalize these by direct comparison with dynamic modeling results. The framework shown here shows great promise to elucidate the frequency-dependent DEP behavior of nanoparticle, crucial for particle manipulation and sorting.
Soft Condensed Matter (cond-mat.soft)
Toward the detection of spin-vortex-induced loop currents in a single bilayer Bi$_2$Sr$_2$CaCu$2$O${8+δ}$ thin film and their possible use as qubits: Model calculations for three nano-island architecture
New Submission | Superconductivity (cond-mat.supr-con) | 2025-04-01 20:00 EDT
Hayato Taya, Yuto Takatsu, Hiroyasu Koizumi
A theory for cuprate superconductivity predicts the existence of nano-sized loop currents called, spin-vortex-induced loop currents (SVILCs)''. In this wok, we first calculate magnetic fields produced by them in a single bilayer Bi$ _2$ Sr$ _2$ CaCu$ _2$ O$ _{8+\delta}$ (Bi-2212) thin film for the purpose of detecting the SVILCs. The estimated magnitude of the magnetic field at the point 10$ a$ ($ a$ is the lattice constant of the CuO$ _2$ plane) above the surface could be in the order of 100mT; thus, they may be detectable by currently available detection methods. Next, we investigate the use of them as qubits (the SVILC qubits’’) in an architecture composed of three nano-islands of the thin film; and consider the use of the detection of the magnetic field generated by the SVILCs as the qubit readout. We show there are a number of energy levels suitable for qubit states that can be manipulated by external current feeding, and the magnetic field generated by the SVILCs is large enough to be used for the readout.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
Exchange cross-talk mitigation in dense quantum dot arrays
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-01 20:00 EDT
Daniel Jirovec, Pablo Cova Fariña, Stefano Reale, Stefan D. Oosterhout, Xin Zhang, Elizaveta Morozova, Sander de Snoo, Amir Sammak, Giordano Scappucci, Menno Veldhorst, Lieven M. K. Vandersypen
Coupled spins in semiconductor quantum dots are a versatile platform for quantum computing and simulations of complex many-body phenomena. However, on the path of scale-up, cross-talk from densely packed electrodes poses a severe challenge. While cross-talk onto the dot potentials is nowadays routinely compensated for, cross-talk on the exchange interaction is much more difficult to tackle because it is not always directly measurable. Here we propose and implement a way of characterizing and compensating cross-talk on adjacent exchange interactions by following the singlet-triplet avoided crossing in Ge. We show that we can easily identify the barrier-to-barrier cross-talk element without knowledge of the particular exchange value in a 2x4 quantum dot array. We uncover striking differences among these cross-talk elements which can be linked to the geometry of the device and the barrier gate fan-out. We validate the methodology by tuning up four-spin Heisenberg chains. The same methodology should be applicable to longer chains of spins and to other semiconductor platforms in which mixing of the singlet and the lowest-energy triplet is present or can be engineered. Additionally, this procedure is well suited for automated tuning routines as we obtain a stand-out feature that can be easily tracked and directly returns the magnitude of the cross-talk.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Revealing quantum phase string effect in doped Mott-insulator: a tensor network state approach
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-01 20:00 EDT
Wayne Zheng, Jia-Xin Zhang, Zheng-Yuan Yue, Zheng-Cheng Gu, Zheng-Yu Weng
We apply the fermionic tensor network (TN) state method to understand the strongly correlated nature in a doped Mott insulator. We conduct a comparative study of the $ \sigma t$ -$ J$ model, in which the no-double-occupancy constraint remains unchanged but the quantum phase string effect associated with doped holes is precisely switched off. Thus, the ground state of the $ \sigma t$ -$ J$ model can serve as a well-controlled reference state of the standard $ t$ -$ J$ model. In the absence of phase string, the spin long-range antiferromagnetic (AFM) order is found to be essentially decoupled from the doped holes, and the latter contribute to a Fermi-liquid-like compressibility and a coherent single-particle propagation with a markedly reduced pairing tendency. In contrast, our TN calculations of the $ t$ -$ J$ model indicate that the AFM order decreases much faster with doping and the single-particle propagation of doped holes gets substantially suppressed, concurrently with a much stronger charge compressibility at small doping and a significantly amplified Cooper pairing tendencies. These findings demonstrate that quantum many-body interference from phase strings plays a pivotal role in the $ t$ -$ J$ model, mediating long-range entanglement between spin and charge degrees of freedom.
Strongly Correlated Electrons (cond-mat.str-el)
12 pages, 11 figures
Theory of hydrodynamic forces in electric double layers
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-01 20:00 EDT
C. Cramail, R. Lhermerout, E. Charlaix
We present a theory of the hydrodynamic forces in the drainage flow of an electrolyte between a sphere and a plane with charged surfaces. Our theory considers a thin electrolyte film which is at all times in local equilibrium across its thickness. In addition to the usual lubrication force, we explicit the electro-kinetic force due to the transport of the diffuse electrical charges as well as the diffusio-kinetic force due to the transport of the excess ion concentration in the Electrostatic Double Layers (EDLs). Our general formalism covers both the case of non-overlapping EDLs and of overlapping EDLs. We study more specifically the mechanical impedance induced by an oscillatory motion of small amplitude of the surfaces. Among our main results, we show that the increase in damping due to the electro-kinetic effect is not monotonic with the surface charge, and we predict a diffusio-kinetic stiffness with a long-range decay in power minus four of the sphere-plane gap susceptible to overcoming the stiffness of the equilibrium Derjaguin-Landau-Verwey-Overbeek force. The comparison of our results with experiments could allow one to confront the theories of electrolyte transport in the Electrostatic Double Layers without adjustable parameters.
Soft Condensed Matter (cond-mat.soft), Fluid Dynamics (physics.flu-dyn)
29 pages, 8 figures
$s_{\pm}$ pairing via interlayer interaction in La${2.85}$Pr${0.15}$Ni$_2$O$_7$ Thin Films under Ambient Pressure
New Submission | Superconductivity (cond-mat.supr-con) | 2025-04-01 20:00 EDT
We demonstrate that interlayer (s_{\pm})-wave pairing dominates superconductivity in La({2.85})Pr({0.15})Ni(_2)O(7) thin films through self-consistent mean-field calculations. We further show that applying a perpendicular electric field breaks layer equivalence, generating nodal structures, Fermi arcs, and finite low-energy states in the (d{x^2-y^2}) orbital. Our results quantitatively align with recent experimental observations for the superconducting gaps, and we propose experimental symmetry-breaking perturbations as a direct test for the interlayer pairing mechanism.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
10 pages, 8 figures, including the supplemental material
He-Mg compounds and helium-driven nonmetal transition in metallic magnesium
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Y. S. Huang, H. X. Song, Q. D. Hao, X. L. Pan, D. Wang, H. Wang, Y. F. Wang, Y. Sun, Hua Y. Geng
The polymorphism and mechanism of helium compounds is crucial for understanding the physical and chemical nature of He-bearing materials under pressures. Here, we predict two new types of He-bearing compounds, MgHe and MgnHe (n = 6, 8, 10, 15, 18), being formed above 750 GPa by unbiased ab initio structure search. An unexpected bandgap is opened up in MgHe at as low as around 200 GPa. This is the first case of noble gas driven metal-nonmetal transition in all elements. The same mechanism is demonstrated also being applicable to other metallic elements, and making beryllium transform into a non-metallic state, a triumph that is impossible otherwise. Furthermore, the stability of the simple cubic phase of Mg (Mg-sc) is greatly enhanced by mixing with He, which lowers the critical pressure of pure Mg-sc from about 1.1 TPa down to 750 GPa to form ordered substitutional alloying phase of MgnHe on a simple cubic lattice of Mg. This is the first report on Mg-based noble gas substitutional alloy, in sharp contrast to the conventional wisdom that He preferring interstitial sites. The observed striking influences of He demonstrate the rich physics and chemistry of He-bearing compounds under ultra-high pressures.
Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other), Chemical Physics (physics.chem-ph), Computational Physics (physics.comp-ph)
22 pages, 5 figures, with supporting materials
Phys. Rev. B 110, 214102 (2024)
Can a ferroelectric diode be a selector-less, universal, non-volatile memory?
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Soumya Sarkar, Xiwen Liu, Deep Jariwala
Recent advances in silicon foundry-process compatible ferroelectric (FE) thin films have reinvigorated interest in FE-based non-volatile memory (NVM) devices. Ferroelectric diodes (FeDs) are two-terminal NVM devices exhibiting rectifying current-voltage hysteretic characteristics that enable self-selecting designs critical for high-density memory. We examine progress in FeDs based on CMOS-compatible HZO, AlScN, and emerging van der Waals ferroelectrics. While FeDs demonstrate promising ON/OFF ratios and rectification capabilities, they face persistent challenges including limited write-cycling endurance, elevated operating voltages, and insufficient read currents. We provide materials-focused strategies to enhance reliability and performance of FeDs for energy-efficient electronic memory applications, with emphasis on their unique self-rectifying capabilities that eliminate the need for selector elements in crossbar arrays for compute in memory applications.
Materials Science (cond-mat.mtrl-sci)
First-Principle Investigation On Chromium Decorated Graphene-based Systems for Hydrogen Storage
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Pratyasha Tripathy, Hetvi Jadav, Himanshu Pandey
Sorbent materials like Cr decorated 2D materials are explored among its storage options. 2D material like graphene has been used as it has a high surface to volume ratio. A comparative study is done with Cr adsorbed in defect-free and single vacancy defect graphene systems. Ab-initio calculations are performed with and without Van der Waals interaction to check the hydrogen storage efficiency. Efficiency is determined by calculating the binding energy of the system. The preferred range for binding energy for reversible hydrogen storage, as determined by the Department of Energy, US, is between 0.2-0.6 eV. This work also visualizes the thermal stability spectrum of the efficient materials at 300 K using molecular dynamics calculations, predicting their stability at room temperature.
Materials Science (cond-mat.mtrl-sci)
10 pages, 5 figures
Semisuper Efimov effect induced by resonant pair exchange in mixed dimensions
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-04-01 20:00 EDT
We introduce a new member to the class of semisuper Efimov effect, where infinite bound states emerge with their binding energies obeying the universal scaling law of $ E_n\sim e^{-2(\pi n/\gamma)^2}$ for sufficiently high excitation $ n\in\mathbb{N}$ . Our system consists of a pair of two-component fermions in three dimensions at infinite scattering length, which furthermore interact with a boson confined in two dimensions so as to form a three-body bound state at zero energy. When another boson is added, exchange of the resonant pair of fermions between two bosons leads to the semisuper Efimov effect of such four particles with the scaling exponent $ \gamma$ determined by the mass ratio of boson to fermion. If bosons live in three dimensions, infinite bound states do not emerge but some of them may survive for a large mass ratio, making our findings potentially relevant to two-neutron halo nuclei as well as ultracold atoms.
Quantum Gases (cond-mat.quant-gas), Nuclear Theory (nucl-th)
5 pages, 3 figures
Superconducting Spin-Singlet QuBit in a Triangulene Spin Chain
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-01 20:00 EDT
Chen-How Huang, Jon Ortuzar, M. A. Cazalilla
Chains of triangular nanographene (triangulene), recently identified as realizing the valence-bond solid phase of a spin-$ 1$ chain, offer a promising platform for quantum information processing. We propose a superconducting spin-singlet qubit based on these chains grown on a superconducting substrate. Using the numerical renormalization group (NRG), we find a manifold of two lowest-lying, isolated spin-singlet states that undergo an avoided crossing. A qubit utilizing these states is thus protected from random-field noise and quasi-particle poisoning. We also introduce a mesoscopic device architecture, based on a triple quantum dot coupled to a superconducting junction, that quantum simulates the spin chain and enables control and readout of the qubit. An effective two-level description of the device is validated using time-dependent NRG.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
16 pages, 7 pages, 1 table
Dynamical Networking using Gaussian fields
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-01 20:00 EDT
Nadine du Toit (Department of Physics, Stellenbosch University), Kristian K. Müller-Nedebock (Department of Physics, Stellenbosch University, National Institute for Theoretical and Computational Sciences, Stellenbosch)
A novel field theoretical approach towards modelling dynamic networking in complex systems is presented. An equilibrium networking formalism which utilises Gaussian fields is adapted to model the dynamics of particles that can bind and unbind from one another. Here, \textit{networking} refers to the introduction of instantaneous co-localisation constraints and does not necessitate the formation of a well-defined transient or persistent network. By combining this formalism with Martin-Siggia-Rose generating functionals, a weighted generating functional for the networked system is obtained. The networking formalism introduces spatial and temporal constraints into the Langevin dynamics, via statistical weights, thereby accounting for all possible configurations in which particles can be networked to one another. A simple example of Brownian particles which can bind and unbind from one another demonstrates the tool and that this leads to results for physical quantities in a collective description. Applying the networking formalism to model the dynamics of cross-linking polymers in a mixture, we can calculate the average number of networking instances. As expected, the dynamic structure factors for each type of polymer show that the system collapses once networking is introduced, but that the addition of a repulsive time-dependent potential above a minimum strength prevents this. The examples presented in this paper indicate that this novel approach towards modelling dynamic networking could be applied to a range of synthetic and biological systems to obtain theoretical predictions for experimentally verifiable quantities.
Soft Condensed Matter (cond-mat.soft)
19 pages, 5 figures. This revised version is currently under review at EPJ E
Plasmons in N-layer systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-01 20:00 EDT
Taehun Kim, E. H. Hwang, Hongki Min
In multilayer structures, the coupling between layers gives rise to unique plasmon modes, but analytic solutions are typically available only for bilayers due to the increasing complexity as the number of layers increases. We investigate plasmons in multilayer structures, including the effects of interlayer tunneling. By introducing the Coulomb eigenvector basis for multilayer systems, which can be solved exactly using Kac-Murdock-Szegő Toeplitz matrices, we analytically derive the long-wavelength plasmon dispersions both with and without interlayer tunneling. In the $ N$ -layer systems, we find that, in the absence of interlayer tunneling, the out-of-phase acoustic or charge neutral plasmon modes with linear dispersions ($ \omega_\alpha\propto q/\sqrt{ {1-\cos{\left(\frac{\alpha-1}{N}\pi\right)}}}$ for $ \alpha = 2, 3, \cdots, N$ ) exist, while the in-phase classical plasmon mode exhibits its conventional dispersion ($ \omega_1\propto \sqrt{q}$ ). When interlayer tunneling is present, the out-of-phase modes develop plasmon gaps that are governed by specific interband transitions, whereas the classical mode remains unaffected. These findings have broad applicability to general coupled-layer structures.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
13 pages, 3 figures
Electronic structure of UGe$_2$ at ambient pressure: comparison with X-ray photoemission spectra
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
M. Samsel-Czekała (1), M. Werwiński (2), A. Szajek (2), G. Chełkowska (3), R. Troć (1) ((1) W. Trzebiatowski Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wrocław, Poland, (2) Institute of Molecular Physics, Polish Academy of Sciences, Poznań, Poland, (3) A. Chełkowski Institute of Physics, Silesian University, Katowice, Poland)
Based on experimental crystallographic data, electronic structure of UGe$ _2$ have been calculated and compared with our results of X-ray photoelectron spectroscopy (XPS) measurements. We employed two different advanced full potential (FP) methods: FP-local-orbital (FPLO) and FP-linear augmented plane waves (Wien2k) codes for non-magnetic and ferromagnetic states. Starting from the local spin-density approximation (LSDA) or generalised gradient approximation (GGA), we verified either the orbital polarisation (OP) correction or the GGA+U approach for the U 5f-electrons, changing Coulomb-repulsion energies U in the range 0-4 eV. Satisfying agreement was achieved between experimental and our calculated magnetic moments using ab-initio LSDA+OP and non-ab-initio GGA+U approaches, the latter for realistic U values of 2-3 eV. We proved by the LSDA+OP approach an existence of the Fermi surface nesting vector along the a axis, possibly responsible for the triplet superconducting pairing. The calculated data reveal predominantly an itinerant U 5f-electron character of bands near the Fermi level, EF, with only small contributions from the U 6d and Ge 4p states. The experimental XPS spectrum of valence bands (VB) also contains the sharp main 5f-electron peak at EF, a wide hump (around -2 eV), and broad small peaks at higher energies. In the calculated XPS spectrum, the width of the main 5f-electron peak varies between 0.8 and 1.4 eV, depending on a method used in computations, but the hump remains unresolved. A newly observed asymmetric 1-eV satellite in the experimental 4f-core XPS spectrum together with known 3-eV and 7-eV satellites suggest dual behaviour of U-5f-electrons in UGe$ _2$ , the feature is inferred also from the VB studies.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el), Computational Physics (physics.comp-ph)
Intermetallics 19 (2011) 1411-1419
Revealing the Low Temperature Phase of FAPbI$_3$ using Machine-Learned Potential
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Sangita Dutta, Erik Fransson, Tobias Hainer, Benjamin M. Gallant, Dominik J. Kubicki, Paul Erhart, Julia Wiktor
FAPbI$ _3$ is a material of interest for its potential in solar cell applications, driven by its remarkable optoelectronic properties. However, the low-temperature phase of FAPbI$ _3$ remains poorly understood, with open questions surrounding its crystal structure, octahedral tilting, and the arrangement of formamidinium (FA) cations. Using our trained machine-learned potential in combination with large-scale molecular dynamics simulations, we provide a detailed investigation of this phase, uncovering its structural characteristics and dynamical behavior. Our analysis reveals the octahedral tilt pattern and sheds light on the rotational dynamics of FA cations in the low temperature phase. Strikingly, we find that the FA cations become frozen in a metastable configuration, unable to reach the thermodynamic ground state. By comparing our simulated results with experimental nuclear magnetic resonance (NMR) and inelastic neutron scattering (INS) spectra, we demonstrate good agreement, further validating our findings. This phenomenon mirrors experimental observations and offers a compelling explanation for the experimental challenges in accessing the true ground state. These findings provide critical insights into the fundamental physics of FAPbI$ _3$ and its low-temperature behavior, advancing our understanding of this technologically important material.
Materials Science (cond-mat.mtrl-sci)
Non-Abelian Gauge Enhances Self-Healing for Non-Hermitian Topological Su-Schrieffer-Heeger Chain
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-01 20:00 EDT
Yazhuang Miao, Yiming Zhao, Yong Wang, Xiaolong Zhao, Xuexi Yi
This work introduces and analyzes a non-Hermitian Su-Schrieffer-Heeger (SSH) model generalized through spin-dependent non-Abelian SU(2) gauge couplings. By incorporating SU(2) symmetry transformations that couple explicitly to spin degrees of freedom, our model demonstrates distinct topological properties originating from the interplay between non-Hermiticity and gauge-induced spin-orbit coupling. Exact diagonalization and generalized Brillouin zone (GBZ) analyses reveal distinct spectral phases, characterized by complex-energy loops under periodic boundary conditions (PBC) and substantial localization indicative of the non-Hermitian skin effect (NHSE) under open boundary conditions (OBC). We define a gauge-invariant winding number for non-Hermitian chiral symmetry, clarifying the topological transitions. Furthermore, we uncover a novel self-healing phenomenon in response to dynamically introduced scattering potentials, showing significant robustness enhancement induced by appropriate non-Abelian SU(2) couplings. These findings clarify how non-Abelian gauge interactions can control spin-dependent localization and dynamical stability in non-Hermitian topological systems, guiding the development of tunable quantum devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Other Condensed Matter (cond-mat.other)
Deep Nets as Hamiltonians
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-04-01 20:00 EDT
Neural networks are complex functions of both their inputs and parameters. Much prior work in deep learning theory analyzes the distribution of network outputs at a fixed a set of inputs (e.g. a training dataset) over random initializations of the network parameters. The purpose of this article is to consider the opposite situation: we view a randomly initialized Multi-Layer Perceptron (MLP) as a Hamiltonian over its inputs. For typical realizations of the network parameters, we study the properties of the energy landscape induced by this Hamiltonian, focusing on the structure of near-global minimum in the limit of infinite width. Specifically, we use the replica trick to perform an exact analytic calculation giving the entropy (log volume of space) at a given energy. We further derive saddle point equations that describe the overlaps between inputs sampled iid from the Gibbs distribution induced by the random MLP. For linear activations we solve these saddle point equations exactly. But we also solve them numerically for a variety of depths and activation functions, including $ \tanh, \sin, \text{ReLU}$ , and shaped non-linearities. We find even at infinite width a rich range of behaviors. For some non-linearities, such as $ \sin$ , for instance, we find that the landscapes of random MLPs exhibit full replica symmetry breaking, while shallow $ \tanh$ and ReLU networks or deep shaped MLPs are instead replica symmetric.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech), Artificial Intelligence (cs.AI), Machine Learning (cs.LG), Probability (math.PR)
19+7 pages
Relevance of the Computational Models of Bacterial Interactions in the simulation of Biofilm Growth
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-01 20:00 EDT
Gabriel Santos-Díaz, Álvaro Rodríguez-Rivas, Alejandro Cuetos
This study explores the application of elongated particle interaction models, traditionally used in liquid crystal phase research, in the context of early bacterial biofilm development. Through computer simulations, using an agent based model, of the repulsive and attractive of Kihara models and Hertz interaction model, we investigate the possibilities and limitations for modelling biofilm formation and growth. Our approach focuses on understanding how mechanical forces due to the interaction between cells, in addition to growth and diffusive parameters, influence the formation of complex bacterial communities. By comparing such force models, we evaluate their impact on the structural properties of bacterial microcolonies. The results indicate that, although the specific force model has some effect on biofilm properties, the intensity of the interaction between bacteria is the most important determinant. This study highlights the importance of properly selecting interaction strength in simulations to obtain realistic representations of biofilm growth, and suggests which adapted models of rod-shaped bacterial systems may offer a valid approach to study the dynamics of complex biofilms.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
12 pages, 5 figures
Contrasting exchange-field and spin-transfer torque driving mechanisms in all-electric electron spin resonance
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-01 20:00 EDT
Jose Reina-Galvez, Matyas Nachtigall, Nicolas Lorente, Jan Martinek, Christoph Wolf
Understanding the coherent properties of electron spins driven by electric fields is crucial for their potential application in quantum-coherent nanoscience. In this work, we address two distinct driving mechanisms in electric-field driven electron-spin resonance as implemented in scanning tunneling spectroscopy. We study the origin of the driving field using a single orbital Anderson impurity, connected to polarized leads and biased by a voltage modulated on resonance with a spin transition. By mapping the quantum master equation into a system of equations for the impurity spin, we identify two distinct driving mechanisms. Below the charging thresholds of the impurity, electron spin resonance is dominated by a magnetically exchange-driven mechanism or field-like torque. Conversely, above the charging threshold spin-transfer torque caused by the spin-polarized current through the impurity drives the spin transition. Only the first mechanism enables coherent quantum spin control, while the second one leads to fast decoherence and spin accumulation towards a non-equilibrium steady-state. The electron spin resonance signals and spin dynamics vary significantly depending on which driving mechanism dominates, highlighting the potential for optimizing quantum-coherent control in electrically driven quantum systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
Robust Magnetic Polaron Percolation in the Antiferromagnetic CMR System EuCd$_2$P$_2$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-01 20:00 EDT
Marvin Kopp, Charu Garg, Sarah Krebber, Kristin Kliemt, Cornelius Krellner, Sudhaman Balguri, Mira Mahendru, Fazel Tafti, Theodore L. Breeze, Nathan P. Bentley, Francis L. Pratt, Thomas J. Hicken, Hubertus Luetkens, Jonas A. Krieger, Stephen J. Blundell, Tom Lancaster, M. Victoria Ale Crivillero, Steffen Wirth, Jens Müller
Antiferromagnetic EuCd$ 2$ P$ 2$ has attracted considerable attention due to its unconventional (magneto)transport properties. At a temperature $ T{\rm peak}$ significantly above the magnetic ordering temperature $ T\textrm{N} = 11,$ K a large peak in resistivity is observed which gets strongly suppressed in magnetic field, resulting in a colossal magnetoresistance (CMR), for which magnetic fluctuations and the formation of ferromagnetic clusters have been proposed as underlying mechanisms. Employing a selection of sensitive probes including fluctuation spectroscopy and third-harmonic resistance, Hall effect, AC susceptibility and $ \mu$ SR measurements, allows for a direct comparison of electronic and magnetic properties on multiple time scales. We find compelling evidence for the formation and percolation of magnetic polarons, which explains the CMR of the system. Large peaks in the weakly-nonlinear transport and the resistance noise power spectral density at zero magnetic field signify an inhomogeneous, percolating electronic system below $ T^\ast \approx 2,T_\textrm{N}$ with a percolation threshold at $ T_{\rm peak}$ . In magnetic fields, the onset of large negative MR in the paramagnetic regime occurs at a universal critical magnetization similar to ferromagnetic CMR materials. The size of the magnetic polarons at the percolation threshold is estimated to $ \sim 1 - 2,$ nm. The mechanism of magntic cluster formation and percolation in EuCd$ _2$ P$ _2$ appears to be rather robust despite large variations in carrier concentration and likely is relevant for other Eu-based antiferromagnetic CMR systems.
Strongly Correlated Electrons (cond-mat.str-el)
Krylov complexity in quantum many-body scars of spin-1 models
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-01 20:00 EDT
Qingmin Hu, Wen-Yi Zhang, Yunguang Han, Wen-Long You
Weak ergodicity breaking, particularly through quantum many-body scars (QMBS), has become a significant focus in many-body physics. Krylov state complexity quantifies the spread of quantum states within the Krylov basis and serves as a powerful diagnostic for analyzing nonergodic dynamics. In this work, we study spin-one XXZ magnets and reveal nonergodic behavior tied to QMBS. For the XY model, the nematic Néel state exhibits periodic revivals in Krylov complexity. In the generic XXZ model, we identify spin helix states as weakly ergodicity-breaking states, characterized by low entanglement and nonthermal dynamics. Across different scenarios, the Lanczos coefficients for scarred states display an elliptical pattern, reflecting a hidden SU(2) algebra that enables analytical results for Krylov complexity and fidelity. These findings, which exemplify the rare capability to characterize QMBS analytically, are feasible with current experimental techniques and offer deep insights into the nonergodic dynamics of interacting quantum systems.
Strongly Correlated Electrons (cond-mat.str-el)
9 pages, 6 figures
Phase Separation in Mixtures of Nematic and Isotropic Fluids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-01 20:00 EDT
Margarida M. Telo da Gama, Rodrigo C. V. Coelho
Mixtures of nematic liquid crystals and isotropic fluids display a diverse range of phase behaviors, arising from the coupling between orientational order and concentration fluctuations. In this review, we introduce a simplified mathematical framework that integrates the Landau-de Gennes free energy for nematic ordering with the Cahn-Hilliard free energy for phase separation. We derive the corresponding governing equations and analyze the stability of uniform phases, along with the resulting interfacial phenomena. The review concludes with a brief discussion highlighting key differences in phase separation between mixtures of isotropic fluids with passive and active nematics.
Soft Condensed Matter (cond-mat.soft)
Renormalized mechanics and stochastic thermodynamics of growing model protocells
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-01 20:00 EDT
Jordan L. Shivers, Michael Nguyen, Aaron R. Dinner, Petia Vlahovska, Suriyanarayanan Vaikuntanathan
Uncovering the rules governing the nonequilibrium dynamics of the membranes that define biological cells is of central importance to understanding the physics of living systems. We theoretically and computationally investigate the behavior of model protocells – flexible quasispherical vesicles – that exchange membrane constituents, internal volume, and heat with an external reservoir. The excess chemical potential and osmotic pressure difference imposed by the reservoir act as generalized thermodynamic driving forces that modulate vesicle morphology. We identify an associated nonequilibrium morphological transition between a weakly driven regime, in which growing vesicles remain quasispherical, and a strongly driven regime, in which vesicles accommodate rapid membrane uptake by developing surface wrinkles. This transition emerges due to the renormalization of membrane mechanical properties by nonequilibrium driving. Further, using insights from stochastic thermodynamics we propose a minimal vesicle growth-shape law that remains robust even in strongly driven, far-from-equilibrium regimes.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
Position-Momenta Uncertainties in Classical Systems
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-01 20:00 EDT
Dipesh K. Singh, P. K. Mohanty
We design a thermal bath that preserves the conservation of a system’s angular momentum or allows it to fluctuate around a specified nonzero mean while maintaining a Boltzmann distribution of energy in the steady this http URL demonstrate that classical particles immersed in such baths exhibit position-momentum uncertainties with a strictly positive lower bound proportional to the absolute value of the mean angular momentum. The proportionality constant, $ c$ , is dimensionless and independent of the system’s parameters. Remarkably, while $ c$ is universally bounded by unity, it attains the exact value $ c=1/2$ for particles in central potentials.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
5 pages, 2 pdf figs, Supplemental Material
Effect of Interlayer Stacking on the Electronic Properties of 1$T$-TaS$_2$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-01 20:00 EDT
Nelson Hua, Francesco Petocchi, Henry G. Bell, Gabriel Aeppli, Philipp Werner, Simon Gerber
Controlled stacking of van der Waals materials is a powerful tool for exploring the physics of quantum condensed matter. Given the small binding between layers, exploitation for engineering will require a breakthrough in stacking methodology, or an ability to take advantage of thicker defective stacks. Here we describe computational groundwork for the latter, using – on account of its promise for cold memory applications – 1$ T$ -TaS$ _2$ as a model system. Comparing recursive Hendricks-Teller calculations and Monte Carlo simulations to published X-ray diffraction data, we obtain the key parameters describing the random stacking in mesoscopic flakes. These then regulate the electronic structures via specification of the random stacks in dynamical mean-field theory simulations. Hubbard repulsion induces strongly correlated metallic, band and Mott insulating layers, providing compelling evidence that electronic properties follow from the coexistence of more than the metallic and insulating planes associated by ordinary band theory.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Chiral order emergence in the kagome $J_1-J_3$ Heisenberg model driven by site disorder
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-01 20:00 EDT
Coraline Letouze, Pascal Viot, Laura Messio
The $ J_1-J_3$ Heisenberg model on the kagome lattice is know to exhibit a fascinating emergent $ q=4$ Potts order (or $ K_4$ ) due to the order-by-disorder mechanism: for large $ J_3>0$ , fluctuations select one among the four equivalent collinear ground states, which themselves belong to a larger ground state manifold. We study this model with a rate $ p$ of magnetic site vacancies through a numerical approach. First, we analyze the effect of few impurities on the ground state, favouring non-coplanar configurations. Second, for finite dilutions, we perform parallel tempering Monte Carlo simulations in the $ (T,p)$ plane, showing the emergence of a low-temperature chiral phase and the progressive destruction of the $ q=4$ Potts transition. This is a rare example of competing order parameters that exclude each other, whith the chiral one appearing only due to disorder.
Statistical Mechanics (cond-mat.stat-mech), Strongly Correlated Electrons (cond-mat.str-el)
6 pages, 6 figures, a supplemental material
Low-energy electron microscopy as a tool for analysis of self-assembled molecular layers on surfaces
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-01 20:00 EDT
Low-energy electron microscopy (LEEM) is a surface science method that works primarily in the UHV environment. It provides information complementary to the other established techniques: it extends the limited view of scanning probe microscopies from nanometers to micrometers and measurement time down to tens of milliseconds, enabling to visualize the changes during sample treatment, e.g., annealing, deposition, and gas or light exposure. From the point of structural analysis, it allows the measurement of diffraction patterns from an area of diameter below 200 nm and imaging of phase distribution on the surfaces either through dark-filed imaging or LEEM-I(V) fingerprinting. The advanced modes provide local angle-resolved photoelectron spectra and surface potential distribution. In this review, we aim to describe the utilization of LEEM to study self-assembled molecular structures on solid surfaces. We present the LEEM instrumentation and analysis of measured data in a tutorial way to provide the necessary background knowledge to enter the field. In the second part, we summarize the knowledge obtained by LEEM for several selected systems, which points to the strength of LEEM in understanding the self-assembled molecular systems and its synergy with other surface science techniques.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Tunable macroscopic defect patterns induced by a low-frequency AC electric field in ferroelectric nematic liquid crystals
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-01 20:00 EDT
Natalia Podoliak, Lubor Lejcek, Martin Cigl, Vladimira Novotna
Regulation of topological structures and pattern formation is attracting wide interest in the field of condensed matter. Liquid crystals (LCs) represent soft matter with a remarkable combination of fluidity and anisotropic properties. Topological defects may appear in confined LCs under external stimuli. Recently discovered ferroelectric nematics (NF) opened exceptional opportunities in technologies owing to high permittivity and polarisation. Polar properties of NF supply more variability to topological structures. In this research, we present tunable 2D topological defect arrays in NF compound, induced by an alternating (AC) electric field in simple sandwich cells without pre-patterning. The observed arrays of defects form pseudo-square lattices, which character and periodicity depend on the frequency of the applied field and partially on the cell thickness. The observed effect is explained to occur due to the competition between elastic and electrical forces. The proposed system can be useful to create reconfigurable spatially periodic polarisation structures.
Soft Condensed Matter (cond-mat.soft)
21 pages, 3 figures
Density wave order with antiphase feature associated with the pseudogap in cuprate superconductor Bi2+xSr2-xCuO6+delta
New Submission | Superconductivity (cond-mat.supr-con) | 2025-04-01 20:00 EDT
Zhaohui Wang, Han Li, Shengtai Fan, Jiasen Xu, Huan Yang, Hai-Hu Wen
The strong correlation effect in cuprate superconductors have greatly enriched the phase diagram showing the co-existence of superconductivity with many intertwined orders. One of the prominent issues concerning the superconductivity mechanism is about the pseudogap phase which behaves either as cooperator or competitor for superconductivity and its fundamental reason remains still elusive. Here we report the measurements of scanning tunneling microscopy/spectroscopy (STM/STS) in the model superconducting system Bi2+xSr2-xCuO6+delta with a transition temperature Tc~7 K. Although this system is supposed to be slightly overdoped, a pseudogap feature can be easily observed in the energy region of about 20-60 meV. A modulation of local density of states (LDOS) with a periodicity of about 4a0/3 (a0: Cu-O-Cu bond length) can be easily observed, which is also supported by the Fourier transformation pattern with wavevectors at about (0,+-3pi/2a0) and (+-3pi/2a0,0). Surprisingly, we find that the LDOS exhibits a clear antiphase feature in the pseudogap energy region below and above the Fermi energy, indicating that it is an intrinsic feature of the pseudogap phase. We interpret this modulation and antiphase feature as a possible consequence of the pair density wave due to the Amperean pairing with finite momentum. Our results give a deep insight on the understanding of the pseudogap phase in cuprate superconductors.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
Main text has 23 pages, 4 figures; 10 pages for Supplementary Information with 9 figures
Simplified Cofactor Conditions for Cubic to Tetragonal, Orthorhombic, and Monoclinic Phase Transformations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Cofactor Conditions (CCs) are geometric compatibility conditions mathematically derived from the crystallographic theory of martensitic phase transformation. The CCs guarantee compatible interfaces between the austenite and the parallelled twin of the martensite with any volume fraction, yielding a wide range of microstructures during phase transformation. In recent times, CCs have demonstrated tremendous applications in the rational design of low hysteresis/fatigue shape memory alloys and shape memory ceramics. In this paper, we present a simplified form of the CCs for Type I/II twins using the eigenspace of transformation stretch tensor and twin axes. We further show the explicit forms and visualizations of the simplified CCs for Cubic to Tetragonal, Cubic to Orthorhombic, and Cubic to Monoclinic I/II phase transformations. The simplified form has revealed a more straightforward correlation between the lattice parameters and the CCs, and thus provides a more convenient tool for the rational design of phase-transforming materials.
Materials Science (cond-mat.mtrl-sci)
21 pages
Asymptotic Freedom and Finite-size Scaling of Two-dimensional Classical Heisenberg Model
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-01 20:00 EDT
Dingyun Yao, Chao Zhang, Z. Y. Xie, Zhijie Fan, Youjin Deng
The classical Heisenberg model is one of the most fundamental models in statistical and condensed matter physics. Extensive theoretical and numerical studies suggest that, in two dimensions, this model does not exhibit a finite-temperature phase transition but instead manifests asymptotic freedom. However, some research has also proposed the possibility of a Berezinskii-Kosterlitz-Thouless (BKT) phase transition over the years. In this study, we revisit the classical two-dimensional (2D) Heisenberg model through large-scale simulations with linear system sizes up to $ L=16384$ . Our Monte-Carlo data, without any extrapolation, clearly reveal an exponential divergence of the correlation length $ \xi$ as a function of inverse temperature $ \beta$ , a hallmark of asymptotic freedom. Moreover, extrapolating $ \xi$ to the thermodynamic limit in the low-temperature regime achieves close agreement with the three-loop perturbative calculations. We further propose a finite-size scaling (FSS) ansatz for $ \xi$ , demonstrating that the pseudo-critical point $ \beta_L$ diverges logarithmically with $ L$ . The thermodynamic and finite-size scaling behaviors of the magnetic susceptibility $ \chi$ are also investigated and corroborate the prediction of asymptotic freedom. Our work provides solid evidence for asymptotic freedom in the 2D Heisenberg model and advances understanding of finite-size scaling in such systems.
Statistical Mechanics (cond-mat.stat-mech)
Ambient and high pressure studies of structural, electronic and magnetic properties of EuZn$_2$P$_2$ single crystal
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Damian Rybicki, Kamila Komędera, Janusz Przewoźnik, Łukasz Gondek, Czesław Kapusta, Karolina Podgórska, Wojciech Tabiś, Jan Żukrowski, Lan Maria Tran, Michał Babij, Zbigniew Bukowski, Ladislav Havela, Volodymyr Buturlim, Jiri Prchal, Martin Divis, Petr Kral, Ilja Turek, Itzhak Halevy, Jiri Kastil, Martin Misek, Dominik Legut
A thorough study of EuZn$ _2$ P$ _2$ single crystals, which were grown from Sn flux, was performed using both bulk (heat capacity, ac susceptibility, dc magnetization, electrical resistivitivity, magnetoresistance) and microscopic (Mössbauer spectroscopy) techniques. Electrical resistance and magnetic susceptibility were measured also under high pressure conditions (up to 19 GPa and 9.5 GPa, respectively). Further insight into electronic properties and phonons is provided by ab initio calculations. The results indicate that EuZn$ _2$ P$ _2$ is an antiferromagnet with strong Eu-Eu exchange coupling of ferromagnetic type within the basal plane and weaker antiferromagnetic interaction along the c axis. The Eu magnetic moments are tilted from the basal plane. Hydrostatic pressure strongly affects both magnetic (increase of the Néel temperature) and electronic (suppression of the band gap and semi metallic behavior) properties, indicating a strong interplay of structure with magnetic and electronic degrees of freedom.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Phys. Rev. B 110, 014421 (2024)
Quantum phase diagram of the extended spin-3/2 Kitaev-Heisenberg model: A DMRG study
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-01 20:00 EDT
Gui-Xin Liu, Ting-Long Wang, Yi-Fan Jiang
Recently there has been considerable excitement surrounding the promising realization of high-spin Kitaev material, such as the quasi-2D compound CrI$ _3$ and CrGeTe$ _3$ . However, the stability of quantum spin liquids (QSL) against single ion anisotropy (SIA) in these materials and the global quantum phase diagram of the extended spin-3/2 Kitaev model with finite SIA remain unclear. In this study, we perform large-scale density matrix renormalization group (DMRG) to explore the quantum phase diagram of the generalized spin-3/2 Kitaev-Heisenberg (K-H) model accompanied with SIA $ A_c$ . In the $ A_c=0$ limit, the spin-3/2 K-H model exhibits a quantum phase diagram similar to that of a spin-1/2 system, including two QSLs around antiferromagnetic and ferromagnetic Kitaev models. For models with finite $ A_c$ , we map out the quantum phase diagram around two Kitaev points and observe distinct types of in-plane vortex orders developed from these two QSL phases. Interestingly, series of nearly degenerate vortex configurations are discovered in each vortex phases. Using linear spin-wave theory, we demonstrate that these vortex configurations can be understood as a consequence of the quantum correction on a continuous family of degenerate classical states.
Strongly Correlated Electrons (cond-mat.str-el)
4.5 pages, 4 figures plus Supplemental Material
Ranked percolation model for the caking time of amorphous molecular powders
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-01 20:00 EDT
Vasco C. Braz, Nuno A. M. Araújo
When amorphous molecular powders are exposed to high humidity levels or temperatures, the particle viscosity increases due to plasticization, promoting the formation of sinter bridges between pairs of particles in contact. Over time, these bridges facilitate particle agglomeration, eventually leading to the formation of a macroscopic cake that alters the mechanical properties and affects product quality. In this work, we model the caking process of amorphous powders subjected to a temperature shock as a bond percolation problem and investigate how particle bed heterogeneities influence the percolation threshold and, consequently, the expected caking times. Our findings indicate that a slight dispersion in particle size lowers the percolation threshold compared to a monodisperse bed or random percolation in polydisperse systems. Furthermore, we show that the expected caking time exhibits a non-monotonic behavior with the size dispersion, initially decreasing for low dispersion values and increasing for higher values. These results provide insights into the role of the particle size distribution on the caking dynamics of amorphous molecular powders
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
Unveiling superconducting properties of an equiatomic hexagonal high entropy alloy via muon spin relaxation and rotation measurement
New Submission | Superconductivity (cond-mat.supr-con) | 2025-04-01 20:00 EDT
Sonika Jangid, Pavan Kumar Meena, Niraj P. Atale, Rhea Stewart, Adrian D. Hillier, R. P. Singh
Superconducting high-entropy alloys (HEAs) present a unique platform for studying the effect of disorder, composition, and crystal structure on superconducting pairing. In this study, we present a comprehensive bulk and microscopic investigation of the rarely observed equiatomic hexagonal HEA Nb-Mo-Ru-Re-Ir using magnetization, resistivity, heat capacity, and muon spin relaxation and rotation ($ \mu$ SR) measurements. Our findings confirm bulk type-II superconductivity with a transition temperature of 4.63(2) K and a high upper critical field. Heat capacity and transverse-field $ \mu$ SR data reveal conventional s-wave superconductivity, while zero-field $ \mu$ SR results suggest the preservation of time-reversal symmetry in the superconducting state. These findings provide valuable insights into the superconducting pairing mechanism in disordered multicomponent systems.
Superconductivity (cond-mat.supr-con)
9 pages, 6 figures
Magnetic Confinement of a Bubble of Supercooled $^3$He-A
New Submission | Other Condensed Matter (cond-mat.other) | 2025-04-01 20:00 EDT
Luke Whitehead, Andrew Casey, Richard P. Haley, Petri J. Heikkinen, Lev V. Levitin, Adam J. Mayer, Xavier Rojas, Tineke Salmon, John Saunders, Alex Thomson, Dmitry E. Zmeev, Samuli Autti
We have designed and constructed a magnet surrounding a cylindrical volume of superfluid helium-3 to isolate a region of metastable, supercooled A-phase, entirely surrounded by bulk A-phase - isolating the ‘bubble’ from rough surfaces that can trigger the transition to the stable B-phase. We outline the design of the experimental cell and magnet, and show that the performance of the magnet is consistent with simulations, including the capability to producing the high field gradient required for generating a bubble. Future plans include the investigation of possible intrinsic mechanisms underpinning the A-B transition, with potential implications for early-universe cosmological phase transitions.
Other Condensed Matter (cond-mat.other)
7 pages, 3 figures
Dynamical properties of particulate composites derived from ultradense stealthy hyperuniform sphere packings
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-01 20:00 EDT
Carlo Vanoni, Jaeuk Kim, Paul J. Steinhardt, Salvatore Torquato
Stealthy hyperuniform (SHU) many-particle systems are distinguished by a structure factor that vanishes not only at zero wavenumber (as in ``standard’’ hyperuniform systems) but also across an extended range of wavenumbers near the origin. We generate disordered SHU packings of identical and `nonoverlapping’ spheres in $ d$ -dimensional Euclidean space using a modified collective-coordinate optimization algorithm that incorporates a soft-core repulsive potential between particles in addition to the standard stealthy pair potential. These SHU packings are ultradense, spanning a broad spectrum of structures depending on the stealthiness parameter $ \chi$ . We consider two-phase media composed of hard particles derived from ultradense SHU packings embedded in a matrix phase, with varying stealthiness parameter $ \chi$ and packing fractions $ \phi$ . Our main objective is the estimation of the dynamical physical properties of such two-phase media, namely, the effective dynamic dielectric constant and the time-dependent diffusion spreadability, which is directly related to nuclear magnetic relaxation in fluid-saturated porous media. We show through spreadability that two-phase media derived from ultradense SHU packings exhibit faster interphase diffusion due to the higher packing fractions achievable compared to media obtained without soft-core repulsion. The imaginary part of the effective dynamic dielectric constant of SHU packings vanishes at a small wavenumber, implying perfect transparency for the corresponding wavevectors. We also obtain cross-property relations between transparency characteristics and long-time behavior of the spreadability for such two-phase media. Our results demonstrate that disordered two-phase media derived from ultradense SHU packings exhibit advantageous transport and optical behaviors of both theoretical and experimental significance.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci), Statistical Mechanics (cond-mat.stat-mech)
Synergy of Doob Transformation and Montroll Defect Theory for Random Walks in External Potentials
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-01 20:00 EDT
We present a systematic method for constructing stochastic processes by modifying simpler, analytically solvable random walks on discrete lattices. Our framework integrates the Doob $ h$ -transformation with the Montroll defect theory, overcoming the strict constraints associated with each method alone. By combining these two approaches, we map random walks in simple potentials onto processes involving more general external potentials and metastable states. Explicit analytical expressions relate the transformed process to the original one, facilitating direct investigation of exponential decay rates and additional dynamical modes. As an illustrative example, we demonstrate our method by analyzing a random walker in a linear potential modified to include a metastable state, revealing distinct exponential decay regimes relevant to escape dynamics.
Statistical Mechanics (cond-mat.stat-mech)
Multiscale Insights of Domain Unfolding in Fibrin Mechanical Response
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-01 20:00 EDT
Vivek Sharma, Poulomi Sadhukhan
Fibrinogen, the monomeric unit of fibrin, the main constituent of blood clot, has a very complex structure. The fibrinogen builds the fibrin fiber and network through the half-staggered packing via knob-hole interaction and the $ \alpha$ C crosslinkers. Due to its rich structure, the elastic behavior also shows a unique nature of very high stretchability and multiple regimes in stress-strain behaviour, which is not yet fully understood. We develop an Unfolding-incorporated Coarse-Grained Polymer (UCGP) model for fibrinogen to study the effect of domain unfolding on the mechanical behavior of fibrin fiber and network. Our model captures the stretching behavior of fibrinogen as observed in AFM and all-atom simulations. We further extend our model to fibrin fiber to study the effect of molecular unfolding at the fiber and network level. We anticipate that our model will be able to account for the nonlinear mechanical behavior of crosslinked fibrin gel. It is possibly the first model of this sort to consider the precise, controllable knowledge of the effects of domain unfolding in crosslinked proteins. This model can also be used to model systems that have sacrificial bonds.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
13 pages, 13 figures
Thermodynamic Features of a Heat Engine Coupled with Exponentially Decreasing Temperature Across the Reaction Coordinate, as well as Perspectives on Nonequilibrium Thermodynamics
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-01 20:00 EDT
In this study, we advance the understanding of non-equilibrium systems by deriving thermodynamic relations for a heat engine operating under an exponentially decreasing temperature profile. Such thermal configurations closely mimic spatially localized heating such as laser-induced thermal gradients. Using exact analytical solutions, we show that this arrangement results in significantly higher velocity, entropy production, and extraction rates than piecewise thermal profiles, while exhibiting reduced irreversibility and complexity relative to linear or quadratic gradients. We further examine the thermodynamic behavior of the Brownian particles in the networks. Our study reveals that the velocity and entropy production rates remain independent of network size; on the contrary, extensive quantities such as total entropy depend on the number of microstates. Additionally, we show that a Brownian particle in a ratchet potential with spatially varying temperature achieves directed motion, even without external forces driven by solely thermal asymmetry. These findings highlight the critical role of temperature asymmetry in controlling the transport processes and optimizing the particle dynamics. This in turn will have promising applications in microfluidic devices and nanoscale sensors. Finally, we explore the influence of the system parameters on the efficiency and performance of the heat engine. The exponential temperature profiles enable faster velocities while simultaneously exhibiting higher efficiency compared with other thermal arrangements. Moreover, by addressing key questions on entropy production, we provide insights into the transition between nonequilibrium and equilibrium systems and contribute tools for optimizing energy-efficient systems in both natural and engineered settings.
Statistical Mechanics (cond-mat.stat-mech)
15 pages, 11 figures
Synthesis of europium-based crystals containing As or P by a flux method: attempts to grow EuAgP single crystals
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Karolina Podgórska, Damian Rybicki, Lan Maria Tran, Wojciech Tabiś, Łukasz Gondek, Michał Babij
Europium-based materials are highly attractive due to their diverse range of physical properties. In these studies, we aimed to synthesize single crystals of the potentially topological semimetallic compound EuAgP, which up to this day has only been obtained in polycrystalline form. The flux method was employed for the syntheses, using fluxes such as: Bi, Sn, Pb, and In, in their various ratios. The purpose of using Bi flux was to try synthesizing an analog of EuAgAs single crystals, by fully substituting arsenic with phosphorus. The obtained crystals were characterized by x-ray diffraction and scanning electron microscopy. Despite many unsuccessful attempts to synthesize EuAgP single crystals, the study provides valuable insights into how different fluxes and their ratios influence the final synthesis product. It also underscores the complexity of designing analogs between arsenides and phosphides.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Solid State Sciences, 158, 107736 (2024)
Thermal transport in superconductor heterostructures: some recent progress
New Submission | Superconductivity (cond-mat.supr-con) | 2025-04-01 20:00 EDT
This article reviews recent advances in low-temperature electronic thermal transport properties of thermally biased superconductor heterostructures focusing on the two-terminal transport. Since the last decade, ferromagnetism has been widely used to enhance the thermoelectricity in heterostructures based on ordinary superconductors. The possibility of getting giant thermoelectric effects with optimum thermal conductance by breaking the electron-hole symmetry of the ordinary superconductor boosted the research in this direction. Recently, attention has been paid to the role of triplet Cooper pairs that emerged in ferromagnetic junctions and the possibility of advanced applications. Other forms of magnetism, specifically antiferromagnetism and altermagnetism, have been investigated to unravel the behavior of the thermal and charge current in thermally biased junctions. In parallel to ordinary superconductors, junctions with unconventional superconductors have been explored for the same purpose. Thermal transport in superconducting bilayers has been studied using advanced materials like Dirac and topological materials, including Weyl semimetals. Significant attention has been paid to thermally biased topological Josephson junctions to explore the phase-tunable current in recent times. Weyl Josephson junctions, multi-terminal Josephson junctions, and various other multilayer junctions have also been studied to engineer large thermoelectric effects and various functionalities with potential applications in superconductor-based thermal device components.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
16 pages and 7 figures; submitted for invited topical review article in Journal of Physics: Condensed Matter; comments are welcome
Local basis for interacting topological bands
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-01 20:00 EDT
Nishchhal Verma, Raquel Queiroz
The discovery of correlated states in moire materials has challenged the established methods of projecting interactions into a local Wannier basis due to topological obstructions that manifest in extended interactions. This difficulty can sometimes be evaded by decomposing the band into a basis of extended itinerant states and a lattice of local states, using the heavy fermion prescription. We revisit this framework by systematically identifying the dominant interaction channels guided by the eigenvalues of the projected density operator. This approach can be applied both to tight-binding and continuum models, allowing us to identify a hierarchy in interaction scales that can be universally used to reduce the Hilbert space dimension and determine an appropriate local basis for modeling electronic correlations in interacting topological materials.
Strongly Correlated Electrons (cond-mat.str-el)
5 pages, 4 figures
Quench dynamics via recursion method and dynamical quantum phase transitions
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-01 20:00 EDT
Ilya Shirokov, Viacheslav Hrushev, Filipp Uskov, Ivan Dudinets, Igor Ermakov, Oleg Lychkovskiy
The recursion method provides a powerful framework for studying quantum many-body dynamics in the Lanczos basis, which is recursively constructed within the Krylov space of operators. Recently, it has been demonstrated that the recursion method, when supplemented by the universal operator growth hypothesis, can effectively compute autocorrelation functions and transport coefficients at infinite temperature. In this work, we extend the scope of the recursion method to far-from-equilibrium quench dynamics. We apply the method to spin systems in one, two, and three spatial dimensions. In one dimension we find a clear evidence that the convergence of the method is limited in time by the dynamical quantum phase transition.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
The structure and topology of an amorphous metal-organic framework
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-01 20:00 EDT
Thomas C. Nicholas, Daniel F. Thomas du Toit, Louise A. M. Rosset, Davide M. Proserpio, Andrew L. Goodwin, Volker L. Deringer
Amorphous metal-organic frameworks are an important emerging materials class that combine the attractive physical properties of the amorphous state with the versatility of metal-organic framework (MOF) chemistry. The structures of amorphous MOFs have largely been inferred by drawing analogies to crystalline polymorphs and inorganic glasses, but ultimately the validity of such structural models has been challenging to establish either experimentally or computationally. Here we use a unified data-driven approach, combining experimental scattering data and active machine learning for interatomic potentials, to determine the structure of an amorphous zeolitic imidazolate framework (a-ZIF) – the canonical amorphous MOF. Our results reveal clear differences between the structure of a-ZIF and that of other amorphous tetrahedral networks, allowing us to invalidate the long-standing assumption that these inorganic and hybrid glasses are topologically equivalent. To this end, we introduce a systematic notation for the network topology of amorphous solids, building a bridge to the successful use of topology analysis in crystalline MOFs and to materials informatics. Our work provides insights into the structure and topology of the archetypal amorphous MOF and opens up new avenues for modelling and understanding amorphous framework materials more generally.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
The fundamental localization phases in quasiperiodic systems: A unified framework and exact results
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-04-01 20:00 EDT
Xin-Chi Zhou, Bing-Chen Yao, Yongjian Wang, Yucheng Wang, Yudong Wei, Qi Zhou, Xiong-Jun Liu
The disordered quantum systems host three types of quantum states, the extended, localized, and critical, which bring up various distinct fundamental phases, including the pure phases and coexisting ones with mobility edges. The quantum phases involving critical states are of particular importance, but are less understood compared with the other ones, and the different phases have been separately studied in different quasiperiodic models. Here we propose a unified framework based on a spinful quasiperiodic system which unifies the realizations of all the fundamental Anderson phases, %with or without mobility edges, with the exact and universal results being obtained for these distinct phases. Through the duality transformation and renormalization group method, we show that the pure phases are obtained when the (emergent) chiral symmetry preserves in the proposed spin-1/2 quasiperiodic model, which provides a criteria for the emergence of the pure phases or the coexisting ones with mobility edges. Further, we uncover a new universal mechanism for the critical states that the emergence of such states is protected by the generalized incommensurate matrix element zeros in the spinful quasiperiodic model, as a novel generalization of the quasiperiodic hopping zeros in the spinless systems. We also show with the Avila’s global theory the criteria of exact solvability for the present unified quasiperiodic system, with which we identify several new quasiperiodic models derived from the spinful system hosting exactly solvable Anderson phases. In particular, we reach a single model that hosts all the seven fundamental phases of Anderson localization. Finally, an experimental scheme is proposed to realize these models using quasiperiodic optical Raman lattices.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
23 pages, 7 figures
How interacting Bose gases scatter light
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-04-01 20:00 EDT
Konstantinos Konstantinou, Yansheng Zhang, Paul H. C. Wong, Feiyang Wang, Yu-Kun Lu, Nishant Dogra, Christoph Eigen, Tanish Satoor, Wolfgang Ketterle, Zoran Hadzibabic
The innate tendency of identical bosons to bunch, seen in the Hanbury Brown-Twiss effect and Bose-Einstein condensation, is a primary manifestation of quantum statistics. This tendency can enhance the rates of fundamental processes such as atom-atom and atom-light scattering if the atoms scatter into already occupied quantum states. For non-interacting bosons, the enhancement of light scattering is simply given by the bosonic-stimulation factor $ 1 + N_{\rm f}$ , where $ N_{\rm f}$ is the occupation of the atom’s final momentum state. Here, we study scattering between off-resonant light and atoms in a quasi-homogeneous Bose gas with tunable interactions and show that even weak interactions, which do not significantly alter the momentum distribution, have a dramatic effect on the atom-light scattering. Due to (spatially local) beyond-mean-field atomic correlations, weak repulsive interactions can completely suppress the bosonic enhancement of scattering, while attractive ones increase the scattering rate. Moreover, if the interactions are rapidly tuned, light scattering reveals correlation dynamics that are orders of magnitude faster than the momentum-space population dynamics. Its extreme sensitivity to dynamical beyond-mean-field effects makes off-resonant light scattering a simple and powerful probe of many-body physics in ultracold atomic gases.
Quantum Gases (cond-mat.quant-gas), Atomic Physics (physics.atom-ph), Quantum Physics (quant-ph)
Main text: 6 pages, 4 figures; Methods: 4 pages, 7 figures
Intertwining bulk and surface: the case of UTe$_2$
New Submission | Superconductivity (cond-mat.supr-con) | 2025-04-01 20:00 EDT
UTe$ _2$ has been the focus of numerous experimental and theoretical studies in recent years, as it is recognized as an odd-parity bulk superconductor. Its surface has also been probed, revealing charge density wave (CDW), pair density wave (PDW), and time-reversal symmetry breaking (TRSB). In this work, we propose that the interplay between the order parameters observed on the surface and in the bulk of UTe$ _2$ may be crucial in explaining some of the unusual features detected by surface probes in this material. Through a phenomenological analysis, we can account for three distinctive experimental signatures observed on the surface of UTe$ _2$ : i) the apparent suppression of CDW order at the upper critical field of the bulk superconducting state; ii) the magnetic field-induced imbalance of the Fourier peaks associated with the CDW; iii) the onset of TRSB at the bulk superconducting critical temperature and its field-trainability. Furthermore, we propose specific experimental checks to validate our conjecture, which we believe could be promptly achieved.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
6 pages, 3 figures