Soft Condensed Matter
Time-dependent pore-network modelling of Ostwald ripening in porous media
Ademola Isaac Adebimpe, Sajjad Foroughi, Branko Bijeljic et al. (+1 more)
We present a time-dependent pore-network model that couples transient mass transfer in the aqueous phase, capillary pressure heterogeneity, and realistic pore-throat geometries to capture the dynamic
evolution of gas clusters during Ostwald ripening in porous media. The model is applied to Bentheimer sandstone to study Ostwald ripening after imbibition to residual gas saturation. Both imbibition (shrinkage) and drainage (growth) events occur as the local capillary pressure in trapped gas clusters approaches
equilibrium. The model tracks event statistics, capillary pressure equilibration, cluster volume distributions, and spatial saturation profiles over 48 hours. While the volume-weighted average capillary pressure is constant, there is a rapid initial decline in average number-weighted cluster pressure and a shift in cluster size distributions toward fewer, larger ganglia, consistent with pore-scale imaging studies. Pore and throat occupancy analysis reveal persistent gas trapping in larger pore spaces. Since growth is by drainage, the pore-scale configuration of fluid is different from that predicted by an
equilibrium percolation-without-trapping model that only allows imbibition events. The model reproduces displacement and ganglion rearrangement during time-limited laboratory experiments, and can then provide predictions of trapped saturation, relative permeability and capillary pressure under field-scale conditions with application to hydrogen, natural gas and carbon dioxide storage in the subsurface.
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All authors Ademola Isaac Adebimpe, Sajjad Foroughi, Branko Bijeljic, Martin J. Blunt
Materials Science
Homogenization of one-dimensional periodic rod networks as special Cosserat rods
Vinayak and Ajeet Kumar
One-dimensional periodic rod networks are the structures that are obtained by periodically assembling its microstructural unit, a network of rods itself, in just one direction. In this work, we present a scheme for obtaining the nonlinear constitutive response of such structures when homogenized macroscopically as a continuum rod. To accurately capture arbitrary and large deformations, the geometrically exact special Cosserat rod theory is used for modeling the rod at both micro- and macroscales. By assuming the periodic structure to be strained uniformly, at macroscale, along its arc length, the full structure problem is reduced to just that of its microstructural unit but subjected to helically periodic boundary condition. The microscale problem, consisting of a network of rods and formulated in a variational setting, is solved in the presence of rod-joint constraints and helically periodic boundary conditions. The expressions for the macroscale rod's stress resultants, i.e. internal contact force and moment, and stiffnesses are then obtained. Finally, several numerical examples having different microstructural units are presented to demonstrate our method. First, the results corresponding to simpler square and cross microstructural units are presented and validated with the existing literature. Square microstructural units having helical constituent rods are then taken up which have application as artificial muscle fiber material. Eventually, homogenization of auxetic tubular metamaterials is performed. It is shown how various design parameters of these microstructural units can be tuned to obtain the desired macroscopic response.
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Materials Science · Cross-listed from physics.bio-ph
Statistical analysis of virion-cell interactions mediated by peptide nanofibrils and peptide amphiphiles using STEM tomography
Philipp Rieder, Julia La Roche, Orkun Furat et al. (+8 more)
Peptide nanofibrils (PNFs) and peptide amphiphiles (PAs) are promising tools for enhancing viral transduction and gene transfer. However, quantitative insight into how their supramolecular architecture governs virion-
cell interactions is limited. Here, we introduce a framework for the acquisition, processing, and statistical analysis of scanning transmission electron microscopy (STEM) tomograms to objectively quantify peptide-virion-
cell interactions. Using four transduction-enhancing peptides (D4, Vectofusin-1, palmitic acid-PA (pal-PA), and eicosapentaenoic-PA (eic-PA)), peptide aggregate morphology, interfacial contact areas, and the spatial organization of virions with respect to peptides and
cells were analyzed using advanced
geometric descriptors. All peptides efficiently captured virions, resulting in few free virions, but they differ in how strictly virions were spatially confined near the
cell surface. These differences reflect alternative spatial organization strategies, which are likely crucial factors influencing transduction-enhancing efficacy. Our approach provides a novel, generalizable method to evaluate infection-enhancing nanomaterials and guides the rational design of next-generation peptide assemblies for therapeutic viral delivery.
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All authors Philipp Rieder, Julia La Roche, Orkun Furat, Annalena Kuhn, Lena Rauch-Wirth, Kübra Kaygisiz, Fabian Zech, Jan Münch, Clarissa Read, Rüdiger Groß, Volker Schmidt
Mesoscale and Nanoscale Physics
Scattering matrix elements and energy spectrum of one-dimensional hybrid PT-symmetric finite systems
Vladimir Gasparian, Esther Jódar and Antonio Pérez-Garrido
In this work, we provide a complete description of the scattering
matrix elements and electron energy spectrum in one dimensional PT-symmetric hybrid finite systems, using the characteristic determinant approach. We present an analytical formulation of the problem and obtain a closed-form expression for the energy spectrum of the system, consisting of a region of real potential (passive region) surrounded by regions of gain and loss on the left and right, respectively. It has been shown that under certain conditions and a specific ratio between the real and imaginary parts of the complex potentials, it is possible to find analytical expressions for the spectral singularities at which the scattering
matrix elements of the hybrid structure tend to infinity at a specific real energy. Within the framework of the same approach, we present a compact analytical expression for the quantization condition that determines the energy spectrum of a model corresponding to the placement of a rigid
lattice within a finite-sized box.
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Soft Condensed Matter
Surface-Adsorbed Nanodroplets of Symmetric Diblock Copolymers Form Versatile and Stimuli-Responsive Nanostructures
Artem Petrov, Guillermo A. Hernández-Mendoza and Alfredo Alexander-Katz
Block copolymers often create droplets when placed on a substrate. Such nanostructured droplets can be arranged into regular microstructured arrays, thereby forming hierarchically organized materials that can be used in microelectronics, plasmonics, sensing, photonics, metamaterials production, and even cryptography. However, it is unclear if such materials can be stimuli-responsive, i.e., be able to change their nanostructure on a single droplet level upon applying external stimuli. In this work, we discovered that small (10-100 nm) surface-adsorbed droplets of symmetric diblock copolymers can form a multitude of different externally switchable nanostructures. We obtained a near-
equilibrium, comprehensive 4D diagram of droplet morphologies by performing large-scale self-consistent field theory (SCFT) calculations under various wetting and phase separation conditions. The SCFT modeling was augmented with a computational
algorithm that established an
equilibrium droplet morphology in a given system without assuming potentially
equilibrium structures prior to simulation. The discovered droplet nanostructures agreed excellently with previously published experimental data. Crucially, we showed that direct and reversible transitions between different droplet morphologies are possible upon changing the interaction strength between components, which can be tuned externally in experiments by adding surfactants or controlling temperature. We confirmed experimental realizability of such stimuli-responsiveness by modeling surfactant addition that led to a switch between droplet nanostructures. This work demonstrates that even the simplest symmetric diblock copolymers are able to produce versatile and stimuli-responsive structures on a surface when confined to a small nanodroplet. This opens the possibility to produce smart coatings with externally switchable hierarchical micro- and nanostructures.
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Materials Science · Cross-listed from physics.app-ph
Programmable Integrated Magnonic Meshes
Piero Florio, Matteo Vitali, Valerio Levati et al. (+9 more)
Integrated
circuits are a cornerstone of modern information technology, and analog wave-based architectures could enable fast and efficient processing beyond conventional charge electronics. In magnonics,
spin waves provide a highly tunable, compact and energy-efficient medium for on-chip microwave signal transport and processing. However, progress has been limited to isolated elements or short devices, severely limiting the overall functional complexity and scalability. Here we realize the key elements of universal magnonic circuitry, using a single-step direct
laser writing process in yttrium iron garnet, and monolithically cascade them in multi-stage programmable devices and networks. Using magneto-optical Kerr effect microscopy, we show efficient
spin-wave propagation and preserved phase coherence in waveguide structures for hundreds of wavelengths. In coupled waveguides, we observe complete and periodic power transfer over several coupling lengths, and in phase shifters we achieve arbitrary, tunable phase delays. By cascading these elements, we realize programmable splitters, frequency demultiplexers, and phase-controlled 2x2 routers, where output power and relative phase can be programmed on demand via external fields. Finally, we realize programmable magnonic interferometric meshes for on-chip
radio-frequency signal routing, with up to six magnonic inputs and outputs and seven cascaded stages, without the need for intermediate amplification. These direct-write cascaded networks bridge a long-standing gap in magnonic scalability, offering a viable pathway toward integrated, large-scale architectures for both classical and
quantum processing.
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All authors Piero Florio, Matteo Vitali, Valerio Levati, Rasheed M. Ishola, Luca Ciaccarini Mavilla, Nora Lecis, Carsten Dubs, Riccardo Bertacco, Marco Madami, Silvia Tacchi, Daniela Petti, Edoardo Albisetti
Quantum Gases
Low-temperature Depletion of Superfluid Density in the Absence of Galilean Symmetry
Viktor Berger, Nikolay Prokof'ev and Boris Svistunov
Landau theory of superfluidity associates low-temperature flow of the normal component with the
phonon wind. This picture does not apply to superfluids in which Galilean invariance is broken either by disorder, porous media, or
lattice potential, and the
phonon wind is no longer solely responsible for depletion of the superfluid component. Based on Popov's hydrodynamic action with anharmonic terms, we present a general theory for low-temperature ($T$) dependence of the superfluid stiffness, which reproduces Landau result as a special case when several parameters of the hydrodynamic action are fixed by Galilean invariance, and validate it with numerical simulations of interacting
lattice bosons. In a broader context, our approach reveals universal low-temperature thermodynamics of superfluids with an intrinsic connection between finite-$T$ and finite-size ($L$) effects implying universal scaling, $T^{d+1}$ and $1/L^{d+1}$, respectively, for a large class of thermodynamic quantities. We discuss the experimental detection of this law, and compare our prediction to the existing literature.
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Materials Science
Dilute Zn alloying in biodegradable Mg wires: microstructure, mechanical performance, and degradation behavior
Jiří Ryjáček, Leonard Hlodák, Jiří Liška et al. (+3 more)
Dilute Mg-Zn wires are of great interest for biodegradable small-bone fixation, as magnesium degradation can support bone-related processes, while low zinc additions may provide biological benefits without compromising biocompatibility. In this work, the influence of Zn content below the room-temperature solubility limit was assessed in Mg-Zn wires intended for resorbable implant applications. Mg-0.4Zn, Mg-0.6Zn, Mg-0.8Zn, and Mg-1.5Zn
alloys were processed by single-step direct hot extrusion into thin wires and characterized by correlative microstructural analysis, tensile testing, bending experiments, and in vitro degradation. All compositions achieved a recrystallized fine equiaxed grain size of 5.0-5.9 um and exhibited ultimate tensile strengths of 246-256 MPa with elongations of 23-28 %. In these thin wires, Zn content had only a limited effect on grain size, tensile properties, and bending behavior, although lower-Zn
alloys showed a pronounced sharp yield point. Bending was governed mainly by extrusion texture and preserved reversible plasticity through twinning and detwinning. Simulated body fluid caused rapid localized degradation and loss of mechanical integrity within 7 days, while the biologically more relevant DMEM-based medium better reflected the expected in vivo response. Together, these findings support dilute Mg-Zn wires as a simple material platform for the development of future resorbable bone fixation devices.
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All authors Jiří Ryjáček, Leonard Hlodák, Jiří Liška, Jan Pinc, Tomáš Herma, Karel Tesař
Strongly Correlated Electrons
Quantized Collective Fluctuations in Correlated Fermion Systems
S.S. Onuchin, Ya. S. Lyakhova, L.D. Silakov et al. (+1 more)
Collective excitations in fermionic systems play a crucial role in determining their physical properties. An important challenge is to develop efficient theoretical approaches for describing these excitations and their coupling to fermionic degrees of freedom. In this work, we revisit the problem of quantifying the contributions of individual bosonic modes of collective fluctuations to observable properties of correlated
fermion systems within the framework of the Fluctuating Local Field (FLF) method. Whereas the auxiliary field in this method was previously considered only classically, we formulate its systematic extension termed
Quantum FLF (Q-FLF) that incorporates selected bosonic Matsubara modes, thus tailoring it to description of
quantum collective fluctuations. As a testbed, we apply the approach to a half-filled one-dimensional Hubbard chain and compute the Green's function, the total energy, and the
antiferromagnetic susceptibility. Our results demonstrate that the proposed scheme enables an efficient and selective characterization of the contributions of individual bosonic modes. In particular, low Matsubara frequencies are found to have a quantitative impact on integrated observables such as total energy and
antiferromagnetic susceptibility. At the same time, an accurate description of single-particle properties requires inclusion of higher-frequency bosonic modes.
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All authors S.S. Onuchin, Ya. S. Lyakhova, L.D. Silakov, A.N. Rubtsov
Statistical Mechanics
Activated random walk exhibits self-organized criticality
Christopher Hoffman, Tobias Johnson, Matthew Junge et al. (+1 more)
To explain the ubiquity of power laws and fractals in nature, Bak, Tang, and Wiesenfeld formulated simple conditions for a system to self-organize into a critical state. Dickman, Muñoz, Vespignani, and Zapperi postulated that the self-organized critical state matches the critical state in corresponding fixed-energy models undergoing traditional phase transitions. Although the theory has been applied broadly over the past five decades, no mathematical model has been proven to exhibit the conjectured behavior. Indeed, the originally proposed abelian sandpile model displays nonuniversal behavior stemming from its slow mixing. Marking the first result of its kind, we prove that the 1-d activated random walk model mixes quickly into a stationary state with power-law avalanches and limiting critical density that equals the critical value for the fixed-energy version.
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All authors Christopher Hoffman, Tobias Johnson, Matthew Junge, Josh Meisel
Mesoscale and Nanoscale Physics
Observation of single antiferromagnetic magnon modes through tunnelling spectroscopy of spin-1/2 Kitaev system a-RuCl3
Servet Ozdemir, Mikhail Kashchenko and Kostya S. Novoselov
The small-gap room-temperature
semiconductor a-RuCl3, which is known to undergo a Mott-Hubbard transition at low temperatures, is one of the most promising candidates for realisation of an exotic matter form, the
quantum spin liquid state, which may have applications in
quantum computing. Although extensively investigated by
neutron scattering techniques, electronic study of this system in the form of van der Waals
heterostructures has been limited mainly to
graphene proximity. Here we report a systematic study of planar and tunnelling electronic properties of a-RuCl3 films, where we observe an n-type field effect on a-RuCl3 films at room temperature, with a Mott
insulator nature onset below 120 K. For films of three-layer thickness and below we find inelastic scattering features, below the Néel temperature of 7-14.5 K, which we attribute to single
magnon modes. Our study confirms preserved low-temperature signatures of the zigzag
antiferromagnetic order in the atomically thin limit and its single
magnon modes within the continuum through tunnelling spectroscopy.
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Soft Condensed Matter
Insights into the electrorheological and electrohydrodynamic regimes in electrically driven emulsion
Majid Bahraminasr and Anand Yethiraj
Recently, we reported the electrorheoimaging (ERI) technique (Bahraminasr et al, 2026), and found that frequency-dependent electric field of an oil-in-oil emulsion yields two distinct regimes: a high-frequency dipolar, electrorheological (ER) regime and a low-frequency electrohydrodynamic (EHD) regime. In this work, we identify a phenomenological model to fit the results in the ER regime to a classic yield-stress fluid, and find collapse onto a master curve upon rescaling, consistent with a yield stress that grows approximately as $E^2$. Macroscopic small-amplitude oscillatory shear (SAOS) rheology is compared with passive microrheology employing differential dynamic microscopy (DDM), with the close agreement implying scale independence of the ER behaviour, and indicating that, unlike steady shear, SAOS measurements do not restructure these samples and probe underlying material properties. Finally, under the presence of both steady shear and electric fields in the EHD regime, the emulsion forms banded structures composed of alternating droplet-rich and droplet-depleted regions. We explore recurrence and divergence in the location of these bands: they emerge within seconds of field application and decay rapidly after the field is switched off. Using the Jensen–Shannon divergence between radial intensity profiles, we show that the driven structure loses
memory on timescales of order $1~s$ commensurate with the timescale of the EHD convection roll. For much longer field-off intervals successive banding events become statistically independent.
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Materials Science · Cross-listed from physics.data-an
FitED: A User-Centric, Extensible Software Environment for Robust Peak-Profile and General Functional Data Fitting
Mustafa Mahmoud Aboulsaad
Reliable parameter extraction from experimental data is essential for quantitative analysis across spectroscopy, diffraction, photoluminescence, chromatography, microscopy, and time-resolved measurements. However, nonlinear fitting often remains difficult to reproduce, especially when complex models, correlated parameters, uncertain derived quantities, and user-dependent fitting choices are involved. We present FitED, a Python-based desktop application for nonlinear fitting of one-dimensional scientific data that combines an accessible graphical interface with a transparent and flexible numerical backend. FitED supports conventional peak profiles, including Gaussian, Lorentzian, Pseudo-Voigt, and exact area-normalized Voigt functions, as well as arbitrary user-defined analytical models for broader experimental applications. The software integrates local and global-search-assisted optimization strategies, automated model initialization, repeated stability testing, parameter-correlation analysis, and covariance-based propagation of uncertainty for derived quantities. By combining interactive usability with uncertainty-aware analysis and structured export of fitting results, FitED provides a practical platform for reproducible and interpretable fitting of experimental data. The software is intended to support both routine analysis and advanced model evaluation while preserving the parameter-level control required by experimental researchers.
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Disordered Systems and Neural Networks
Data-Driven Modelling to predict forest fire spread in the Patagonian region in Argentina
Lucas Becerra, Monica Malen Denham, Alejandro B. Kolton et al. (+1 more)
Wildfires are among the most severe disturbances affecting forest ecosystems, with over 50,000 hectares burned in Patagonia, Argentina, during 2025 alone. This study implements a Reaction-
Diffusion-Convection (RDC) model to simulate wildfire spread in the Steffen and Martin Lakes area, a region severely impacted by fires. By integrating high-resolution maps of slope, wind velocity, and vegetation, we conducted three computational experiments of increasing complexity to simulate fire propagation across heterogeneous landscapes. We employed a Genetic
Algorithm (GA) to recover reference model parameters by maximizing the spatial overlap between simulated and reference burned areas. Subsequently, parameter estimates were refined using XGBoost to improve accuracy. Results demonstrate that the GA accurately recovers reference parameters across all scenarios, while the XGBoost fine-tuning significantly enhances accuracy in simpler cases. This integrated framework offers a systematic approach for estimating difficult-to-measure wildfire parameters, demonstrating the potential of hybrid computational methods for wildfire modeling and forest management.
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All authors Lucas Becerra, Monica Malen Denham, Alejandro B. Kolton, Karina Laneri
Mesoscale and Nanoscale Physics · Cross-listed from quant-ph
Optically detected nuclear magnetic resonance of carbon-13 in bulk diamond
Maxwell D. Aiello, Janis Smits, Yaser Silani et al. (+13 more)
Precision measurements based on optically detected
nuclear magnetic resonance offer exquisite sensitivity to absolute shifts in
spin transition frequencies, with potential applications in fundamental physics experiments and inertial sensing. We investigate 13C
nuclear spins in diamond as a candidate system for solid-state implementations, which hold the promise for high-fidelity readout of large numbers of coherent
nuclear spins in millitesla or lower
magnetic fields. We demonstrate a technique that allows for both optical polarization and readout of large ensembles of ~10^{16} polarized
nuclear spins. Our method takes advantage of state-selective Landau-Zener transitions under microwave frequency sweeping, which bidirectionally transfer
spin polarization between Nitrogen-Vacancy (NV) electron
spins and remote 13C
nuclear spins. Using natural isotopic abundance diamonds with nitrogen densities of ~0.5-10 ppm, we perform optically-detected 13C Ramsey spectroscopy and realize a
nuclear-
spin-dependent fluorescence contrast exceeding 0.5% peak-to-peak. We observe
nuclear spin dephasing times T2*~2 ms that only modestly improve with homonuclear dipolar decoupling, indicating that they are limited by the longitudinal
spin relaxation of nearby NV electron
spins. We study the
magnetic field dependence of the optical readout and find comparable contrast and dephasing times for
magnetic fields in the range 8-20 mT. Our method can be interpreted as a type of repetitive readout, where each NV center optically reads out the
spin state of ~10^2
nuclei before
nuclear spins depolarize.
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All authors Maxwell D. Aiello, Janis Smits, Yaser Silani, Andris Berzins, David Lidsky, Bryan A. Richards, Amilcar Jeronimo Perez, Chandrasekhar Ramanathan, Sebastián C. Carrasco, Jabir Chathanathil, Michael Goerz, Vladimir S. Malinovsky, Dmitry Budker, Sean Lourette, Andrey Jarmola, Victor M. Acosta
Superconductivity
Demonstration of a fermion Quadrupling Condensate via Quantum Monte Carlo Simulation
Alexandru Golic, Egor Babaev and Johan Carlström
Fermionic condensation typically occurs via pairing. In recent decades, however, a fundamental question has emerged: whether alternative forms of order exist, such as condensates of
fermion quadruplets. These states–including “charge-4e"
superconductors and “charge-0" counterflow condensates–lie beyond the standard Bardeen-Cooper-Schrieffer framework, and require strong fluctuations and correlation effects that invalidate the BCS mean-field description. This makes the problem notoriously difficult to study numerically at a microscopic level, as it involves both strong interactions and the fermionic sign problem. Here, we present a microscopic fermionic model featuring correlated hopping that significantly mitigates the sign problem, enabling rigorous Monte-Carlo-based analysis. Using large-scale simulations, we demonstrate the existence of a
fermion-quadrupling condensate with a transition temperature comparable to the hopping energy scale. These results provide direct numerical evidence for quartic fermionic order in a microscopic system and suggest that these exotic states are also experimentally accessible in ultracold atomic gases.
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Statistical Mechanics
Graph theoretic derivation of mutual linearity for transient probabilities and hitting time distributions in Markov networks
Julian B. Voits and Ulrich S. Schwarz
For irreducible, time-homogeneous Markov networks, mutual linearity has recently been established for both occupation probabilities and network currents in the stationary regime as well as in the non-stationary regime in Laplace space. The derivation of this property for the stationary distribution utilized the Markov chain tree
theorem, which also allows for an explicit combinatorial expression of the response ratios under variation of a single transition rate. The extension of this result was proven at the trajectory level by employing the Doob Meyer decomposition. By employing the all-minors
matrix-tree
theorem, we show that this property also follows from a graph theoretic formulation and derive explicit combinatorial expressions for the non-stationary response ratios. The stationary result follows as the long time limit. We also show that the small-time asymptotics are entirely determined by minimal path distances in the underlying graph. Finally we use the graph theoretic approach to prove that mutual linearity also extends to hitting time densities.
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Strongly Correlated Electrons
Criticality on Rényi Defects at (2+1)$D$ O(3) Quantum Critical Points
Yanzhang Zhu, Zhe Wang, Meng Cheng et al. (+1 more)
At a
quantum critical point, the universal scaling behavior of Rényi
entanglement entropy is controlled by the universality class of the codimension-two Rényi (or conical) defects in the infrared theory. In this work we perform a systematic study of critical correlations along Rényi defect lines in (2+1)$D$
quantum spin models realizing
quantum phase transitions described by the O(3) Wilson-Fisher universality class, using large-scale
quantum Monte Carlo simulations. We present numerical evidence that, for a fixed Rényi index $n$, there exist multiple Rényi defect universality classes, with distinct critical exponents for the O(3) order parameter on the defect. These universality classes are realized by choosing microscopically different
entanglement cuts in
lattice models, which we classify as ordinary, special and extraordinary according to their relation to surface criticality. For the extraordinary
entanglement cut, we further find evidence for a phase transition on the defect as a function of the Rényi index. Our results highlight the key role of defect universality classes in determining the universal scaling of Rényi
entropy, and provide a framework for understanding the previously observed dependence of Rényi
entropy scaling on microscopic
lattice details.
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All authors Yanzhang Zhu, Zhe Wang, Meng Cheng, Zheng Yan
Quantum Gases · Cross-listed from quant-ph
Nonreciprocity-enriched steady phases in open quantum systems
Ding Gu, Zhanpeng Fu and Zhong Wang
Nonreciprocity can profoundly alter the spectra and dynamics of open
quantum systems, yet its impact on the long-time steady-state phases of matter has remained largely unexplored. Here we show that the interplay of nonreciprocity,
symmetry defects, and spatial boundaries can generate phases beyond the standard spontaneous-
symmetry-breaking paradigm. We demonstrate this mechanism by showing that sufficiently strong nonreciprocity turns boundaries into sources and drains of
symmetry defects, while simultaneously endowing these defects with
chiral dynamics in the bulk. As a result, the conventional uniform
symmetry-broken state gives way to a domain-wall traveling-wave phase, in which
symmetry defects form a persistent
chiral wave. We showcase this mechanism in a bosonic model with \(Z_{2}\)
symmetry, where periodic boundary conditions support only the conventional symmetric and
symmetry-broken phases, whereas open boundary conditions allow the traveling-wave phase. We further show that even in the absence of
symmetry breaking, the steady state can exhibit anomalous
chiral relaxation: owing to the non-Hermitian skin effect in the stability
matrix, local fluctuations are chirally amplified as they approach a boundary, where they eventually decay. Combining mean-field theory with truncated Wigner simulations, we characterize these phases, analyze the order parameter and Goldstone-mode fluctuations of the traveling-wave phase, and confirm its existence in three spatial dimensions.
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Quantum Gases · Cross-listed from quant-ph
Scalable spin-nematic squeezing in multi-level dipole-interacting Rydberg atom arrays
Sakshi Bahamnia and Thomas Bilitewski
We study the generation of metrologically useful
entanglement in a three-level (
spin-1) system naturally realized in arrays of dipole-interacting Rydberg atoms confined in optical tweezers. In the
spin-quadrupolar operator basis, the interaction
Hamiltonian decomposes into effective SU(2) subspaces, within which quench dynamics from product initial states generate scalable
spin-nematic squeezing. For symmetric interactions, we identify a mapping to effective one-axis twisting within bright and dark
manifolds and demonstrate that the squeezing parameter scales as $\xi^{2}\propto N^{-2/3}$ ($\xi^{2}\propto N^{-0.5}$) with system size for all-to-all (two-dimensional dipolar) couplings. In both cases the
quantum Fisher information reaches $F_Q\propto N^{2}$. For antisymmetric interactions supplemented by a microwave drive we find a distinct two-axis countertwisting mechanism. This results in squeezing $\xi^{2}\propto N^{-0.7}$ for all-to-all interactions and moderate squeezing for dipolar interactions in 2D. Our results constitute a first theoretical step beyond the well-studied
qubit setting toward scalable
entanglement generation in qudit systems with dipolar interactions, directly relevant to current Rydberg tweezer experiments.
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Statistical Mechanics · Cross-listed from quant-ph
Graph-theory measures capture weak ergodicity breaking on large quantum systems
Heiko Georg Menzler, Rafał Świętek, Mari Carmen Bañuls et al. (+1 more)
We study the onset of weak ergodicity violations in closed
quantum many-body systems and focus on cases in which they occur through a transition that is controlled by a model parameter, a scenario called a weak ergodicity-breaking transition. This situation is realized in the Rosenzweig-Porter model and the
quantum sun model, which we investigate here. Our analysis is based on representing
quantum systems in Fock space and examining the short-time dynamics of density autocorrelation functions. From these, we extract proxies for decay rates for each individual basis state. As a first main result, we show that the distribution of such decay rates captures known weak ergodicity-breaking transitions in both models. As a second main result, we establish a connection between the decay rates of density autocorrelations and graph-theoretical measures. Concretely, we demonstrate that moments of the distribution of the recently introduced graph-energy centrality also detect the weak ergodicity transitions, which is inherited from the behavior of the decay rates. While most numerical tools are limited to small system sizes, the quantities studied in our work can be calculated analytically for large systems of many hundreds of sites and in some cases, even in the thermodynamic limit.
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All authors Heiko Georg Menzler, Rafał Świętek, Mari Carmen Bañuls, Fabian Heidrich-Meisner
Disordered Systems and Neural Networks
Locality versus Fock-space structure in East-type models
Achilleas Lazarides
Local kinetic constraints in
quantum many-body systems can generate slow dynamics or complete many-body localisation. Here we focus on a modification of the
quantum East model: Inspired by random
matrix theory, we randomise the connectivity in Fock space (rendering it nonlocal in real space) while preserving its organisation into neighbouring magnetisation sectors. We find that there is still a transition between two distinct phases, one delocalised and the other localised. We conclude that, for East-type constrained models, the essential ingredient is the structure of the graph in Fock space rather than
geometric locality of
spin flips.
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Statistical Mechanics · Cross-listed from quant-ph
A Unified Framework for Locally Stable Phases
Zhi Li, Raz Firanko and Timothy H. Hsieh
We propose a unifying framework for characterizing pure and mixed state phases of matter across
equilibrium, non
equilibrium, and metastable regimes. We introduce the concept of locally stable states, defined by the operational property that any local operation (including post selection) can be reversed by a local channel. We prove that local stability is equivalent to a state being short range correlated, defined by the decay of both correlations and conditional mutual information. We demonstrate that these properties are invariant under locally reversible channels, thus defining locally stable phases. Furthermore, we prove that local stability implies both the decay of a family of nonlinear correlators, including the fidelity correlator, and the decay of correlations in the canonical purification, thus bridging the gap between mixed and pure states. Along the way, we establish two results which may be of independent interest: we show that post-selection on locally stable (short range correlated) states can be implemented via local channels and that
quantum Markov chains can be characterized by the local computability of nonlinear observables.
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Quantum Gases
Observation of Vinen turbulence during far-from-equilibrium Bose-Einstein condensation
Sebastian J. Morris, Martin Gazo, Simon M. Fischer et al. (+5 more)
Relaxation of far-from-
equilibrium quantum fluids, intimately related to the emergence of long-range order, is theoretically associated with the decay of a turbulent isotropic tangle of
vortex lines. We observe and study such decaying
quantum turbulence in a homogeneous 3D atomic Bose gas. Using matter-wave techniques to magnify the gas density distribution, and then imaging a thin slice of the magnified cloud, we observe imprints of randomly oriented
vortex lines and measure the
vortex line-length density $\mathcal{L}$. The observed decay of $\mathcal{L}$ agrees with the prediction for Vinen `ultraquantum'
turbulence. Although our weakly interacting gases are highly compressible, their large-scale dynamics are consistent with the behavior of an incompressible hydrodynamic fluid, with the decay of $\mathcal{L}$ not depending on the strength of the interatomic interactions and being similar to that in the strongly interacting superfluid helium.
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All authors Sebastian J. Morris, Martin Gazo, Simon M. Fischer, Haoyu Zhang, Christopher J. Ho, Nigel R. Cooper, Christoph Eigen, Zoran Hadzibabic
Superconductivity
Enhancement of superconducting stiffness in hybrid superconducting-metallic bilayers
J. E. Ebot, Lorenzo Pizzino, Sam Mardazad et al. (+3 more)
Boosting superconductivity by metallic reservoirs is the essence of Kivelson's
bilayer proposal. One layer provides pairing to the electrons, while the weakly coupled metal provides additional phase coherence to those pairs by mediating extended-range pair-pair coupling. Demonstrating significant and unambiguous performance gains with strong-coupling methods for such set-ups had been difficult. In the present work, we study these systems doped away from half-filling, corresponding to a partially
spin-polarized 1D Anderson- or Kondo-
lattice. We show that this breaks the coexistence of dominant superconducting and density-density correlations decisively in favour or the former. Consequently, we provide evidence that in this doped regime, superconducting near-long-range order is not precluded by a small charge-gap in the thermodynamic limit, as we have recently shown to be the case at half-filling [J. E. Ebot et al., Phys. Rev. B 113, 174530 (2026)]. We study the complex manner in which the enhancement of superconductivity in the pairing layer depends on the parameters of the metal, and especially that both pairing-limited and stiffness-limited regimes may appear in these systems. In addition to superconducting
bilayers, our results are relevant, via a particle-hole transformation, for heavy-
fermion Kondo-
lattice materials in
magnetic fields, as we provide previously lacking insight on the competition between
antiferromagnetic and easy-plane magnetism, as well as a route for comprehensive indirect tests of Kivelson's
bilayer proposal well beyond previous capabilities.
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All authors J. E. Ebot, Lorenzo Pizzino, Sam Mardazad, Johannes S. Hofmann, Thierry Giamarchi, Adrian Kantian
Mesoscale and Nanoscale Physics
Intrinsic anomalous thermal hall effect as a signature of quantum metric in d-wave altermagnets
Rishi G. Gopalakrishnan, Srimayi Korrapati and Sumanta Tewari
We investigate the intrinsic anomalous thermal
Hall effect in d-wave altermagnets, where a transverse heat current is generated by a longitudinal temperature gradient in the absence of a
magnetic field, with the leading response proportional to $(\nabla T)^3$. In these systems, the intrinsic Berry
curvature-driven linear and thermal
quantum-metric-driven second-order anomalous thermal
Hall currents vanish as a consequence of crystalline
symmetry. We show that the first nonvanishing contribution arises at third order in the temperature gradient and is governed by a nonlinear thermal Berry-connection polarizability, a quantity introduced in this work. Our analysis reveals a distinctive angular dependence of the anomalous thermal
Hall conductance as the applied thermal gradient is rotated with respect to the
crystal axes. We also find characteristic temperature and chemical-potential dependences that can be tested experimentally. These results identify unique
quantum geometry-induced thermal responses and establish altermagnets as a promising platform for exploring intrinsic (i.e., scattering-time-independent)
geometric transport phenomena.
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Materials Science
Uniaxial strain-driven ferroelastic domain control in LaAlO3
Matthias Roeper, Robin Buschbeck, Jakob Wetzel et al. (+15 more)
Multiferroic domain walls in functional
oxides exhibit properties distinct from the bulk and are increasingly exploited as active elements in nanoelectronic and photonic devices. Deterministic control of domain populations has typically remained limited to local control, or removal with temperature. Here we demonstrate continuous, reversible manipulation of the ferroelastic domain structure in single-
crystal LaAlO$_3$ using in-situ uniaxial strain. Combining atomic force microscopy, X-ray diffraction, and Raman spectroscopy with first-principles calculations we map the complete microscopic
evolution of the twin domain population through the strain-driven transition from the rhombohedral $R\bar{3}c$ ground state toward the predicted orthorhombic $Fmmm$ phase. Applied strains below $0.5\%$ produce pronounced surface flattening and large-scale domain reorganisation, establishing uniaxial strain as a technically accessible control parameter for ferroelastic domain engineering. These results open a route to active, real-time programming of domain architectures in LaAlO$_3$-based
heterostructures, with implications for strain-tunable superconducting interfaces, nanoscale
phonon-polariton optics, and ultrafast
lattice control.
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All authors Matthias Roeper, Robin Buschbeck, Jakob Wetzel, Tobias Ritschel, Anna-Lena Hofmann, Vladyslav Kovtunovych, Mike N. Pionteck, Javier Taboada-Gutiérrez, Alexey B. Kuzmenko, Martina Basini, Vivek Unikandanunni, Iuliia Kiseleva, Jochen Geck, Susanne C. Kehr, Maximilian Lederer, Simone Sanna, Lukas M. Eng, Samuel D. Seddon