Materials Science · Cross-listed from physics.app-ph
20 ps Non-Destructive Read and 1 ns Write Operations at <5 V in Ferroelectric HfO2/ZrO2 Non-Volatile Memories
Alexandre Baigol, Ruben Hamming-Green, Paul Uriarte Vicandi et al. (+8 more)
Achieving low-voltage, nanosecond multi-level programming and non-destructive read-out of ferroelectric non-volatile
memories (NVM) is critical for analog in-
memory computing architectures relying on ferroelectric capacitive devices (FeCap). We integrate HfO2/ZrO2 ferroelectric nanolayers concurrently in the BEOL of CMOS and on SiO2/Si, achieving nanosecond multilevel switching with programming voltages below 5 V. Partial ferroelectric switching enhances FeCap endurance above 1011 cycles, leading to MemCapacitance (MC) states with non-destructive read-out and 10-year retention. However, experiments reveal the collapse of the MC window for read frequencies above 1 MHz. To overcome this speed limit, we introduce a novel, non-destructive readout methodology. Using electrical pulses with widths down to 20 ps, below the RC time constant of the FeCaps, we enable measurement of the polarization-dependent leakage current, providing ultrafast and non-destructive read operations at only 14 fJ.
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All authors Alexandre Baigol, Ruben Hamming-Green, Paul Uriarte Vicandi, Jiajie Gao, Till Zellweger, Anwesha Panda, Alexandros Emboras, Miklós Csontos, Mathieu Luisier, Beatriz Noheda, Laura Bégon-Lours
Soft Condensed Matter · Cross-listed from physics.bio-ph
Bistability of cellular traction on strain-stiffening substrates
Irina Pi-Jaumà, Jaume Casademunt and Ricard Alert
To migrate,
cells exert traction forces on the extracellular
matrix (ECM) – a biopolymer network that often exhibits nonlinear strain-stiffening elasticity. Cellular tractions can therefore stiffen the ECM. At the same time,
cells exert stronger tractions on stiffer ECM. Here, we show theoretically that this traction-stiffness feedback can produce traction bistability and hysteresis. As a result, increasing either the ECM's nonlinear elasticity or cellular contractility leads to a discontinuous transition from low to high tractions. This traction jump might trigger collective
cell migration as the ECM stiffens, for example during development and tumor progression. Moreover, the bistable behavior might provide robustness to cellular traction forces when
cells migrate through mechanically heterogeneous environments.
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Superconductivity
Enhanced superconductivity in atomically thin noble metals: From quantum confinement to interface-induced Lifshitz transition
Chun-Jie Zhang, Bing Zhang, Yapeng Wu et al. (+2 more)
Unlocking superconductivity in intrinsically non-superconducting noble metals (Au, Ag, Cu) represents a fundamental challenge in low-dimensional physics. While
quantum confinement in the atomically thin limit is known to trigger emergent superconductivity, strategies to amplify this marginal effect to experimentally accessible temperatures remain a key open question. Using first-principles calculations, we establish a unified framework linking intrinsic confinement effects with interface engineering in noble metal films. We reveal that intrinsic superconductivity is element-specific: it is suppressed in Ag by a stiff
phonon spectrum, but emerges in trilayer Cu ($T_{\rm C} \approx 0.78$ K) and pentalayer Au ($0.63$ K) driven by confinement-induced density-of-states (DOS) enhancement and
phonon softening, respectively. In h-BN/Cu(111)
heterostructures, $T_{\rm C}$ is critically dictated by the interfacial stacking configuration. We identify the thermodynamically stable N-bonded interface as a reliable platform for accessible superconductivity ($T_{\rm C} \approx 3.23$ K), whereas manipulating the system into a metastable B-bonded configuration boosts $T_{\rm C}$ to $7.00$ K. This enhancement originates from a B-bonded-induced Lifshitz transition, where the
Fermi surface forms a tangential contact with the Brillouin zone boundary at the M point, enhancing electron-
phonon coupling beyond DOS effects. Our work unifies the understanding of intrinsic two-dimensional superconductivity with atomistic interface design, offering a blueprint for functionalizing noble metals as emergent
superconductors.
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All authors Chun-Jie Zhang, Bing Zhang, Yapeng Wu, Xiao-Ping Li, Lei Wang
Superconductivity
Chirality-Resolved Spectroscopy of Caroli-de Gennes-Matricon States in Multiband FeTe$_{1-x}$Se$_{x}$ Superconductors
T. Rõõm, A. Glezer Moshe, R. Nagarajan et al. (+4 more)
We employ terahertz Faraday magneto-optical spectroscopy to probe the relaxation dynamics of quantized helical Caroli-de Gennes-Matricon (CdGM) states in epitaxial FeTe$_{1-x}$Se$_x$ thin films, nodeless multiband
superconductors with short coherence lengths in the moderately clean limit. By exploiting polarization-selective optical transitions, we directly resolve the helicity and band origin of
vortex-core quasiparticles. We observe long-lived CdGM resonances with opposite circular polarizations for electron- and hole-like bands. This enables independent, band-resolved determination of quasiparticle lifetimes,
vortex masses, coherence lengths, and upper critical fields, and reveals their systematic
evolution with isovalent substitution. The results establish terahertz magneto-optics as a direct probe of helical
vortex-core excitations and provide dynamical evidence for multiband CdGM states in iron-based
superconductors.
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All authors T. Rõõm, A. Glezer Moshe, R. Nagarajan, U. Nagel, Hee Taek Yi, Seongshik Oh, G. Blumberg
Quantum Gases
Two-mode collapse and revival of quantum coherent state in a tilted optical lattice
Chi-Kin Lai, Shengjie Jin, Yuanzhe Hu et al. (+6 more)
Collective dynamics is an important out-of-
equilibrium feature of
quantum coherent states and usually reflects the intrinsic properties of the state. Collapse and revival (CR) dynamics of phase coherence is a well-known example for bosonic coherent states, which is usually induced by applying a quench. Previous studies have shown that the CR frequency is governed solely by interactions, even in the presence of a tilt quench. However, whether such interaction-dominated oscillation is a universal feature remains unknown. In this work, we show that an ensemble of one-dimensional
bosons can undergo two-mode CR, with frequencies set by both the interaction and the tilt, particularly when the tilt is weaker than the interaction. The newly discovered tilt mode is enabled by tunneling between
lattice sites. When the two modes coexist, the amplitudes of both modes exhibit universal linear scaling for various tilts. These findings clarify the general features of CR dynamics in tilted
lattice models and the underlying mechanism, and provide deeper insight into collective dynamics in correlated systems.
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All authors Chi-Kin Lai, Shengjie Jin, Yuanzhe Hu, Zhongshu Hu, Fansu Wei, Congwen Li, Tianwei Zhou, Hepeng Yao, Xiaoji Zhou
Materials Science
Molecular neutron spectroscopy techniques applied to ceramics $\alpha$-SiC and $\beta$-Ga$_2$O$_3$
Adam J. Jackson, Svemir Rudić, Manh Duc Le et al. (+1 more)
Neutron spectroscopy is a powerful technique for determining the vibrational states of matter. Instruments with fixed geometry may measure inelastic scattering at a limited set of angles, producing a 1-D spectrum $S(\omega)$. Such measurements are usually simulated in a DOS-like semi-analytic incoherent approximation, well-established for study of bending/stretching modes in molecular
crystals. In this work we empirically test the simulation method for two ceramics with industrial electronic applications that act as "worst-case" systems. The
phonon scattering from $\alpha$-SiC and $\beta$-Ga$_2$O$_3$ is coherent, depends on momentum transfer $Q$ and sits in frequencies below the typical "fingerprint" range of molecular spectroscopy. Inelastic
neutron-scattering measurements of powders were performed with two contrasting spectrometers at cryogenic and elevated temperatures, and simulations performed using a variety of density-functional approximations. We find that for 1-D powder spectra from a compact instrument, the approximate simulations are easily comparable with experimental spectra and give similar results to a more computationally-intensive numerical sampling of the coherent spectrum. Given the success with these systems, the approximate method appears to be suitable for modelling inelastic
neutron scattering by harmonic
phonons of almost any powder sample with this technique. When a $Q$-resolved instrument is used to collect the 2-D dynamical structure factor $S(Q,\omega)$, numerical averaging is still required to capture
phonon features. Our simulations of inelastic scattering from $\alpha$-SiC in the 6H polytype using the PBEsol functional gave good agreement with the experiments. By contrast, the RSCAN functional gave the best agreement with the measured spectra of $\beta$-Ga$_2$O$_3$ and is recommended for future work on the
lattice dynamics of this material.
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All authors Adam J. Jackson, Svemir Rudić, Manh Duc Le, Sanghamitra Mukhopadhyay
Disordered Systems and Neural Networks · Cross-listed from cs.LG
Training a Predictive Coding Network on ImageNet using Equilibrium Propagation
Tugdual Kerjan, Rasmus Høier and Benjamin Scellier
Equilibrium Propagation (EP) is a physics-based training framework that has primarily been employed in energy-based models, including continuous Hopfield networks, nonlinear resistive networks and coupled phase oscillators. However, EP's practical applications have so far remained limited to relatively small-scale problems. Predictive coding networks (PCNs), another class of energy-based models rooted in computational neuroscience, are typically trained with a specialized
algorithm and have likewise not yet been demonstrated at large scale. In this work, we develop an EP-based training method for PCNs which combines the centered variant of EP with a novel equilibration scheme for PCNs. Using this approach, we train a 10-layer convolutional PCN (VGG10) on full-size ImageNet, achieving 13.23% test error rate on the top-5 classification task, close to the 12.2% backpropagation baseline. To our knowledge, this is the first demonstration of both PCNs and EP-based training at ImageNet scale. These results significantly extend the scalability of both approaches and suggest that the primary challenges in scaling EP in other physical systems may come more from the computational properties of these systems than from inherent limitations of the EP framework.
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Strongly Correlated Electrons · Cross-listed from quant-ph
Fracton Topological Holography
Yu-Tao Hu, Jie-Yu Zhang and Peng Ye
Topological holography (TH), or SymTFT, realizes
symmetries and dualities of a
quantum system as boundary data of a topological bulk in one higher dimension. We formulate fracton topological holography (FTH), extending this mechanism from
liquid topological orders to fracton stabilizer codes. The construction is organized as a general four-stage framework: prepare the bulk model and compute its excitations, determine boundary data and admissible gapped top boundaries, identify the low-energy preserving operator
algebra together with its
symmetry, relation, and twist data, and then switch among top boundaries to compare the induced boundary descriptions. As a type-I example, we develop FTH for the X-cube model with smooth and rough top boundaries; for a minimal effective
Hamiltonian, both yield transverse-field plaquette Ising models, with exchanged subsystem
symmetry and twist data, and the boundary switch is implemented by a linear-depth local
unitary sequential
quantum circuit (SQC). As a type-II example, we formulate FTH for Haah's cubic code in the Laurent-
polynomial stabilizer formalism and analyze the natural $(Z)$ and $(X)$ top boundaries, which induce two two-dimensional
qubit systems related locally by exchanging generalized plaquette Ising and transverse-field terms and nonlocally by a
symmetry–relation duality. These results show that FTH is a genuine extension of TH to both type-I and type-II fracton orders. FTH therefore provides a concrete framework for organizing and understanding duality, with the prospect of offering a systematic route to new dualities.
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Materials Science
Reversible Superdense Ordering of Tetragonal Lithium in a Layered Material
Natalie L. Williams, Stephen D. Funni, Sihun Lee et al. (+14 more)
Understanding lithium (Li) ordering and dynamics is foundational in energy storage. X-ray based experimental methods do not simultaneously provide atomic structure information together with chemical composition and local bonding information for lithium in solids. Here we employ scanning transmission electron microscopy (STEM) and combine imaging, spectroscopy, and diffraction within a single experiment, to observe, in situ, an all-solid-state electrochemical
cell. By integrating
multimodal STEM with other complementary techniques, we report a complete mapping of lithium intercalation in a layered system, LaTe3. We identify three ordered phases of LixLaTe3 with x ranging from 1/3 to 3 with in-plane strain of up to 5%. At a very high lithium concentration of Li3LaTe3, we discover an unexpected three-layer, superdense lithium phase with tetragonal
symmetry occupying the van der Waals gap. This represents a new Li phase that is reversible. Our
multimodal approach thus enables complete tracking of lithium ordering and dynamics, important for next-generation energy storage applications.
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All authors Natalie L. Williams, Stephen D. Funni, Sihun Lee, Drake Niedzielski, Mingjia Fang, Josh Leeman, Ratnadwip Singha, Saif Siddique, Tyler Hendee, Shiyu Xu, Jeffrey Kaaret, Giovanni Sartorello, Nicole A. Benedek, Leslie M. Schoop, Lynden A. Archer, Tomás A. Arias, Judy J. Cha
Statistical Mechanics
Constraint-Enhanced Physical Search through Correlation Matching
Song-Ju Kim
Physical systems do not merely add noise to search processes; they impose constraints that generate structured correlations. We propose a principle of constraint-enhanced physical search in which temporal correlations in exploration are matched to constraint-induced spatial correlations in the update dynamics. Using a minimal tug-of-war bandit model (TOW), we show that a conservation law converts local observations into differential evidence across alternatives, while a temporally correlated drive controls the order of exploration. Search efficiency is improved not by stronger randomness or by maximal anti-correlation, but by matching the temporal correlation to the physical update scale that converts feedback into evidence. A scaling estimate identifies the update-noise-to-contrast ratio as the leading parameter that limits how strongly temporal anti-correlation can be used. The results suggest a general organizing principle for physical search: constraints and fluctuations can generate structured spatiotemporal correlations, and efficient exploration emerges when these correlations are matched to the update dynamics.
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Soft Condensed Matter
Kinetics of Droplet Cloaking and Wetting Ridge Growth on Lubricated Polymer Brushes
Antonio Torregrosa Abellán, Enqing Liu, Vincent Siekman et al. (+3 more)
We investigate the kinetics of wetting ridge growth and droplet cloaking on lubricant-infused
polymer brushes using a combination of experiments, molecular dynamics simulations, and theoretical modeling. We focus on three representative systems: DMSO-water on hexadecane-swollen PLMA (D-H), water on hexadecane-swollen PLMA (W-H), and water on PDMS (W-S). The dynamics are governed by the interplay between interfacial thermodynamics, brush elasticity, and transport of lubricant within the brush. Ridge growth is accompanied by the formation of depletion zones both beneath and outside the drop. This leads to a progressive slowdown governed by the need to transport lubricant through the brush. At sufficiently high swelling, we observe local separation of oil from the brush within the ridge, providing an additional mechanism for lubricant depletion. To rationalize these observations, we develop a continuum
diffusion model based on the free energy of the brush and its coupling to the contact line. The model quantitatively captures the growth of the wetting ridge at intermediate and late times, demonstrating that the kinetics are largely controlled by diffusive transport within the brush.
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All authors Antonio Torregrosa Abellán, Enqing Liu, Vincent Siekman, Frieder Mugele, Friederike Schmid, Rodrique G. M. Badr
Mesoscale and Nanoscale Physics
Ferroelectric-tunable quantum nonlinearity of chiral Bloch electrons in a moiré system
Zitian Pan, Jundong Zhu, Yu Hong et al. (+7 more)
Sliding ferroelectricity in van der Waals materials shows great potential for designing robust
memory devices. However, its thermodynamic behaviors and the coupling with certain
quantum effects remain largely unexplored. Here, we demonstrate ferroelectric control over
quantum nonlinear transport in a hexagonal boron nitride (hBN) encapsulated twisted double-
bilayer graphene moiré
heterostructure. The ferroelectricity is attributed to the presence of rhombohedral stacking in the top hBN, confirmed by both electrical transport and optical second harmonic generation (SHG) measurements. Remarkably, the polarization magnitude remains temperature-independent across 1.7-200 K, while nucleation time exhibits thermally activated behavior, decreasing with increasing temperature. Furthermore, we demonstrate a ferroelectric-switchable nonlinear
Hall effect, attributed to the
chiral scattering induced by Berry
curvature, with outstanding fatigue-resistant and nonvolatility, demonstrating direct coupling between sliding ferroelectricity and
quantum geometric properties. Our results establish sliding ferroelectrics as a platform for exploring electrically programmable Berry
curvature physics.
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All authors Zitian Pan, Jundong Zhu, Yu Hong, Jingwei Dong, Dongxia Shi, Kenji Watanabe, Takashi Taniguchi, Luojun Du, Wei Yang, Guangyu Zhang
Soft Condensed Matter
Multiscale Phase Separation in Chemophoretic Active Matter
Manisha Jhajhria, Subir K. Das and Snigdha Thakur
Nonreciprocal interactions in active matter provide interesting structure and dynamics. Here we investigate chemophoretic systems in which nonreciprocity arises from the asymmetric coupling between
agents: first species produces certain chemicals and the other phoretically responds to it. This leads to phase separation at varying scales. Our study uncovers a re-entrant steady-state phase diagram as the nature of the coupling changes from chemoattractive to chemorepulsive character. Chemoattraction provides sustained domain growth, leading to macrophase separation via cluster coalescence. Aggregation in the chemorepulsive case, on the other hand, leads to a steady-state situation that displays phase separation only at a microscale, owing to strong caging effect and frequent fragmentation. The overall far-from-steady-state dynamics is quantified via calculations of growth exponents, cluster transition
matrices, and mean-squared displacements.
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Disordered Systems and Neural Networks
Hierarchical crack patterns: Identification of crack generations
Yuri Yu. Tarasevich, Andrei S. Burmistrov and Andrei V. Eserkepov
Identifying crack generations from microscopic images of hierarchical crack patterns is challenging due to the lack of temporal information and sensitivity to image boundaries. Existing
algorithms often fragment individual cracks or lose stability when the observed fragment is shifted. We propose a method that reduces the classification problem to topological sorting of a directed acyclic graph (descendant$\to$parent), built from T-junctions and nearly collinear edges. Sequential removal of leaf vertices assigns generation numbers starting from the youngest. On 100 computer-generated networks, our method correctly classifies $\approx 70$% of cracks at a window size of only three mean edge lengths, whereas a conventional approach that starts from primary cracks drops nearly to zero. The classification is highly stable against reasonable shifts of image boundaries but remains limited to strictly hierarchical networks.
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Materials Science
Microscopic derivation of the microstretch theory for carbon nanotubes
Naoki Nishimura, Mamoru Matsuo and Takeo Kato
Twisted carbon nanotubes support
phonons involving not only torsion, naturally associated with microrotation, but also radial breathing, which requires a scalar stretch degree of freedom. We derive an effective microstretch theory for these modes starting from nonlinear elasticity on a cylindrical surface. By linearizing the equation of motion around a uniformly twisted
equilibrium configuration, we obtain the dynamical
matrix for the twisting, longitudinal, and radial-breathing modes. This
matrix coincides with that of a one-dimensional microstretch theory, and the corresponding elastic constants are expressed in terms of the Lamé constants, the nanotube radius, and the twist rate. The twist generates
chiral couplings in the effective theory, which hybridize the three modes and open an anticrossing in the
phonon dispersion. These results provide a microscopic basis for the microstretch description of
phonons in twisted carbon nanotubes and clarify how structural chirality enters the effective couplings.
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Strongly Correlated Electrons
Magnetic field effects on spin-split band and magnon transport in altermagnets and emergent compensated ferrimagnets
Kazushi Aoyama and Hikaru Kawamura
In altermagnets and fully compensated ferrimagnets, not only the electron band but also the
magnon band exhibits
spin splitting without net magnetization, which enables thermal activation of the
magnon spin current. Here, we theoretically investigate
magnetic field effects on the
magnon properties of these antiferromagnets in the presence of a weak easy-axis anisotropy which makes the collinear states robust against the
magnetic field. For the altermagnet and compensated ferrimagnet, we analyze a 2 sublattice order in the $J_1$-$J_2$-$J_2^\prime$ model on the square
lattice and a triple-${\bf Q}$ 12-sublattice order in the $J_1$-$J_3$ model on the kagome
lattice, respectively, each accompanied by $d$-wave and $s$-wave
spin splitting at zero field. It is shown that for positive (negative)
magnetic field $H$ whose energy scale is smaller than the anisotropy gap, the up- and down-
spin magnon bands are shifted to lower (higher) and higher (lower) energies, respectively, similarly to the Zeeman coupling in electron systems. In the altermagnet, with increasing field, the $d$-wave splitting tends to be deformed into the $s$-wave one, which is reflected as the change in the direction of the
spin current generated by thermal gradient. In the compensated ferrimagnet, the $s$-wave nature, i.e., the population imbalance between the up- and down-
spin magnons at $H=0$, can induce an asymmetric field dependence of the longitudinal
spin and thermal conductivities in a field-sweep process.
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Statistical Mechanics
Predicting the conditions for observing the Mpemba effect
Yue Liu, Tan Van Vu, Raphaël Chétrite et al. (+2 more)
The Mpemba effect, a counterintuitive phenomenon where a hotter system relaxes faster than a colder one, has been widely observed in various nonequilibrium systems. Despite this progress, the fundamental structural features of the energy landscape required for its emergence remain a subject of debate. In this study, we investigate the conditions for the Mpemba effect within one-dimensional overdamped Langevin dynamics. We classify the potential landscapes based on the presence of single or double wells, their
symmetry properties, and the existence of walls. We establish that the existence of the effect is primarily driven by the presence of boundaries, either hard or soft, rather than the specific internal structure of the potential landscape, such as metastability or the number of minima. By employing a spectral decomposition of the Fokker-Planck operator, we analyze the behavior of the first nontrivial eigenmode and demonstrate that its derivative acts as a Dirac delta peak in the low-temperature regime. This helps us elucidate the mechanism underlying the Mpemba effect: it appears as the interplay between this behavior and the initial population dynamics in a non-trivial way induced by the presence of the wall. Our analysis provides a unified classification across single- and double-well potentials, highlighting the crucial role of boundary conditions and asymmetry. Furthermore, we demonstrate that this framework allows for the engineering of potential landscapes capable of producing multistage Mpemba transitions.
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All authors Yue Liu, Tan Van Vu, Raphaël Chétrite, Frédéric van Wijland, Hisao Hayakawa
Quantum Gases
Populating topologically protected edge states of a Chern insulator with the cold-atom elevator scheme and measurements
Toke Marstrand Pontoppidan Lindhard and Anne E. B. Nielsen
Two-dimensional Chern
insulators support topologically protected,
chiral edge currents, and these can be detected in experiments with ultracold atoms in optical
lattices. It has previously been shown that one can populate a selected group of edge states of a Chern
insulator by transferring particles from a reservoir. Here, we numerically investigate the effect of performing an instantaneous, projective measurement on the reservoir before the reservoir is discarded. In this way, the final state of the system is pure and described by a wavefunction. We also show that quite likely measurement outcomes can help to increase the final number or percentage of particles in the
chiral edge states through postselection. Without the measurement step, the physics can be described in terms of single-particle physics. The measurement significantly complicates the description. By appropriately rewriting the analytical expressions, we show that measurement probabilities, expectation values, averages of expectation values, and purity can nevertheless be computed from the state before the measurement in a way that scales only linearly with the number of
lattice sites for a fixed number of particles. This enables us to investigate a setup with, for instance, 14 particles and 198
lattice sites numerically. The approach applies generally to noninteracting, fermionic models that conserve the number of particles.
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Mesoscale and Nanoscale Physics
Epitaxial $\mathrm{Co_2MnSi}$ with intrinsic magnetocrystalline anisotropy as a route to bias-field-free nonlinear half-metal magnonics at the nanoscale
Anna Maria Friedel, Jaafar Ghanbaja, Björn Heinz et al. (+5 more)
Half-metallic Heusler compounds like $\mathrm{Co_2MnSi}$ allow to bridge magnonic and spintronic functionality for hybrid unconventional computing approaches with sought-after properties like 100%
spin polarization and associated low Gilbert damping $\alpha\leq 10^{-3}$. However, the desirable material parameters are inherently tied to the
crystal lattice with a particularly critical dependence on structural order in $\mathrm{Co_2MnSi}$. To date, the successful fabrication of nanoscale devices with robust structural integrity remains yet a challenge, and consequently the impact of the material parameters on the resulting nonlinear
spin-wave dynamics remains largely unexplored. Here, we report on a study of linear and nonlinear
spin-wave dynamics in transversally magnetized $\mathrm{Co_2MnSi}$ waveguides with impeccable crystalline ordering. We show that epitaxial, $\mathrm{L2}_1$-ordered $\mathrm{Co_2MnSi}$ exhibits an intrinsic cubic anisotropy with first- and second-order contributions, stabilizing a magnetization
alignment along the
crystal $\langle110\rangle$ directions. We confirm the implication of an unaffected
crystal structure resulting in preserved
magnetic properties in the patterned structures. Herein, the persistent magnetocrystalline anisotropy reshapes the
spin-wave dispersion which yields a first-order nonlinear instability suppression range extending over several GHz - even for vanishing bias fields. Moreover, the intrinsic magnetocrystalline anisotropy can be exploited to counteract shape demagnetization for a stabilized low bias field operation in the favourable Damon-Eshbach geometry with high group velocities and decay lengths. Together with the proven half-
metallicity and ultralow Gilbert damping, this research establishes $\mathrm{Co_2MnSi}$ as a robust, scalable platform towards bias-field-free nonlinear half-metal magnonics.
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All authors Anna Maria Friedel, Jaafar Ghanbaja, Björn Heinz, Moritz Bechberger, Sylvie Migot, Sébastien Petit-Watelot, Stéphane Andrieu, Philipp Pirro
Disordered Systems and Neural Networks · Cross-listed from stat.ME
Modeling Discrete Data with High-Order Vector Potts Models
Aaron De Clercq, Merijn Moody and Clélia de Mulatier
Modeling high-dimensional data is challenging, yet essential to understanding many complex systems. Maximum
entropy models such as Ising and Potts models have been used extensively to capture pairwise interactions from correlation patterns in data, allowing to infer graphical representations of complex systems from observations (e.g., from
protein sequences or neural population activity). Recently, there has been growing interest in modeling higher-order correlation patterns involving simultaneously three or more variables. While progress has been made in binary data with high-order Ising models, we extend this framework to the more general case of discrete data. We introduce q-state
spin models, a complete family of maximum
entropy models that generalize the vector Potts model to include long-range and arbitrary high-order interactions. In the pairwise case, our models allow for more diverse interaction types compared to the standard vector Potts model. We discuss their statistical interpretation with examples and relate them to discrete
Fourier analysis. Using a loop expansion of the partition function, we show that the statistical properties of
spin models are fully captured by the algebraic structure of their interactions. We define gauge transformations under which this structure, and thus the partition function, remains invariant. Models equivalent under gauge transformations can be seen as different representations of the same abstract statistical model, despite generally having interactions of different orders, extending results from the binary case. For practical application to data analysis, we focus on a subset of models known in the binary case as Minimally Complex Models, generalizing them to discrete data. We obtain a closed-form expression for the marginal likelihood of these models, enabling fast model selection. We illustrate their use with simple real-world examples.
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Strongly Correlated Electrons
Criticality and Quench Dynamics at the Anderson Transition of a Chern Insulator
Lara Ulčakar, Jernej Mravlje, Gal Lemut et al. (+1 more)
We study the critical properties of the topological Anderson phase transition in a strongly disordered Chern
insulator, separating the topological phase from a trivial Anderson
insulator. We show that the transition is characterized by a non-zero electrical conductance and by the emergence of a critical length scale in the real-space profile of the local Chern marker. From this, we extract the correlation-length and the dynamical critical exponents, which are consistent with those of non-interacting models of the integer
quantum Hall effect. We then ramp the disorder strength across the transition and study the ensuing dynamics. In contrast to clean topological systems, we find that the excitation density does not follow the Kibble-Zurek scaling. The non-
equilibrium length scale associated with the local Chern marker is decoupled from the generation of excitations. For studied system sizes, we find it to be close to the Kibble-Zurek prediction for the topological-to-trivial quench, while it deviates from it for the reverse direction.
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All authors Lara Ulčakar, Jernej Mravlje, Gal Lemut, Tomaž Rejec
Materials Science
Quantum annealing for materials
Alfredo Fiorentino and Nicola Marzari
Finding the global minimum of a potential energy surface is a fundamental challenge in materials science, with applications ranging from
protein folding to cluster physics and, more broadly, to systems in which the number of (meta)stable configurations grows prohibitively large. In recent decades,
quantum annealing (QA) has emerged as a promising global optimization strategy, exploiting
quantum fluctuations in contrast to the thermal fluctuations that drive its classical counterpart. Here, we introduce a novel implementation of QA based on path-integral molecular dynamics, an efficient and well-established framework for sampling the
quantum nuclear density without the need to manipulate many-body wavefunctions explicitly. While retaining the flexibility and simplicity of molecular dynamics simulations, this
quantum-annealing protocol delivers strong performance across a wide range of atomic systems, simulated by either empirical force fields or machine-learning interatomic potentials. The method can be used either as a global optimizer of the potential-energy surface, or as a
quantum-informed structure-search strategy in which
nuclear quantum effects are included directly in the optimization workflow – a feature particularly relevant for materials such as high-pressure hydrides.
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Quantum Gases
Drag-induced skin effect in a Bose-Fermi mixture
Wenjie Liu, Yee Sin Ang, Ching Hua Lee et al. (+1 more)
The non-Hermitian skin effect (NHSE) represents one of the most distinctive phenomena in non-Hermitian physics. Here, we uncover a new drag-induced NHSE mechanism in interacting Bose–
Fermi mixtures where only
bosons, but not
fermions, experience asymmetric hopping.We show that strong Bose–
Fermi interactions enable
fermions to inherit boundary accumulation through correlated bound states.The interplay of interactions,
quantum statistics, and non-Hermitian dynamics gives rise to an interaction-induced blockade mechanism, leading to highly asymmetric fermionic transport.We demonstrate that the drag-induced NHSE is dynamically stable and propose a feasible realization in ultracold Bose–
Fermi mixtures with Floquet-engineered asymmetric tunneling.Our results establish a qualitatively distinct route to the NHSE, where non-Hermitian localization is not generated by direct nonreciprocal hopping of the localized particles themselves, but emerges through the interaction-mediated transfer of non-Hermitian dynamics between different
quantum species. This mechanism further provides a potential route toward species-selective control of localization and transport in hybrid
quantum matter.
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All authors Wenjie Liu, Yee Sin Ang, Ching Hua Lee, Yi Qin
Disordered Systems and Neural Networks · Cross-listed from quant-ph
Spectral theory of energy-selective quantum search with Ising Hamiltonian phase oracles
A. S. Plyashechnik, A. A. Zhukov, A. V. Lebedev et al. (+1 more)
We develop an exact spectral-response theory for the Grover-type iterate \(W_T=D_\xi\exp(-\mathrm{i} T H)\), in which the
evolution generated by a diagonal Ising
Hamiltonian is used directly as a continuous phase oracle. An energy-grouped recurrence and its generating-function solution show how the empirical characteristic function determines the position, width, height, and saturation time of an energy-selective resonance. For an annealed Gaussian density of states, a high-density-tail resonance containing \(M\) configurations is reached after \(\Theta(\sqrt{2^n/M})\) oracle calls with success probability \(\Theta(1)\), giving a quadratic query improvement over independent uniform sampling with classical energy evaluation. For correlated random Ising spectra, overlap-dependent covariances lead to a realization-dependent resonance shift with root-mean-square scale \(O(n^{-3})\), parametrically larger than the resonance width, and can also reduce the peak height. The shift is both an algorithmic detuning and a coherent probe of sample-specific spectral fluctuations whose ensemble statistics reflect the Ising overlap structure. Spectral symmetrization and iterative calibration can remove or compensate the resonance-center displacement for prescribed-energy targeting. We also clarify the relation to designed spectral filters and the precision and coherence requirements of this asymptotic primitive.
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All authors A. S. Plyashechnik, A. A. Zhukov, A. V. Lebedev, W. V. Pogosov
Soft Condensed Matter
In vivo measurements of fascia lata effective mechanics combined to a memory fiber recruitment viscoelastic modeling approach
Franck Germain and Thomas Gibaud
The fascia lata plays a central role in force transmission and body mechanics, yet its in vivo mechanical behavior remains poorly characterized. Existing approaches – shear wave elastography and direct force measurements alike – share a fundamental limitation: none simultaneously captures both the elastic and viscous components of fascial mechanics within a single experiment. The primary aim of this study is therefore to develop an experimental and modeling framework that enables the reproducible measurement of the effective viscoelastic properties of the fascia lata in vivo. To this end, we combine controlled ramp-relaxation experiments on the human fascia lata with a constitutive model that integrates fiber recruitment and dual-timescale viscoelastic relaxation. We emphasize that this is an effective model: rather than describing intrinsic local material properties, it characterizes the mechanical response of the fascia lata complex including its coupling to the hip-thigh musculoskeletal system under controlled loading conditions. The model captures both the nonlinear stiffening during elongation and the dual decay of force during relaxation, using a minimal set of physically interpretable parameters. Repeated trials demonstrate good reproducibility, with parameter variability within 10%. Our results support the view that fascia lata behaves as a hierarchical, hydrated composite whose macroscopic mechanical response emerges from the coupled effects of collagen
alignment,
matrix viscoelasticity, and fluid flow. This work provides a quantitative foundation for future in vivo investigations into how training, rehabilitation, or aging influence the
evolution of fascial mechanical properties.
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Mesoscale and Nanoscale Physics
Spin-wave phase modulation using magnetic domain walls in dipolarly coupled structures for non-volatile magnonic computation
Hanadi Mortada, Philipp Pirro and Alexandre Abbass Hamadeh
A controllable phase shifter is a key component for
spin-wave-based logic and information processing devices. Here, we propose a domain-wall-position-controlled
spin-wave phase shifter that exploits dipolar coupling between two closely spaced waveguides to enable continuous phase tuning over a range approaching 360degrees while keeping the
spin-wave amplitude constant. Using micromagnetic simulations, we model a bias-free hybrid structure composed of a nanoscale waveguide magnetostatically coupled to a half-ring-shaped structure both made from bismuth-doped yttrium iron garnet with strong perpendicular
magnetic anisotropy. Displacing a domain wall in the half-ring modulates the dispersion relation in the adjacent straight waveguide due to the changed magnetostatic interaction, providing a compact and dynamically reconfigurable phase-shifting mechanism. This approach offers precise and non-volatile control over
spin-wave propagation and is compatible with energy-efficient magnonic logic architectures.
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Materials Science
Role of Characteristic Length Scale in Interface Graphitization-Induced Wear Resistance of Diamond and Amorphous Carbon
WenLiang Shi, YanYu Zhang, WenZheng Liao et al. (+4 more)
The
evolution of interfacial atomic structures critically influences the friction and wear behavior of carbon-based materials. However, how the characteristic length scale of friction-induced sp\textsuperscript{2} reconstruction governs macroscopic wear remains poorly understood, particularly for diamond and amorphous carbon where the interfacial graphitization modes differ fundamentally. In this work, we develop a machine learning potential for these carbon systems and investigate the structural
evolution at interfaces in both diamond/diamond and amorphous/amorphous carbon systems using molecular dynamics simulations. Our results reveal distinct atomic-scale characteristics of graphitization at the two interfaces. Diamond interfaces develop a laterally continuous sp\textsuperscript{2} reconstruction layer with a characteristic length of 30–45~Å, while amorphous carbon interfaces form only fully isolated sp\textsuperscript{2} patches of 8–12~Å. This disparity in characteristic length scale determines the density of weakly bonded interfacial atoms left outside the reconstruction layer, thereby directly dictating the macroscopic wear rate. Based on these insights, we propose a strategy to regulate friction-induced graphitization in diamond coatings by protecting specific crystallographic orientations, such as the (111) close-packed planes. This work bridges the gap between atomic-scale interfacial structure and macroscopic tribological performance, offering mechanistic guidelines for the rational design of wear-resistant carbon-based coatings.
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All authors WenLiang Shi, YanYu Zhang, WenZheng Liao, Kai Xu, HongYu Wu, ZhiCheng Zhong, KeKe Chang
Materials Science
Unconventional crystallization pathway bypassing the intermediate cubic phase in phase-change superlattices
Bai-Qian Wang, Nian-Ke Chen, Yao-Jie Wang et al. (+5 more)
The Ge-Sb-Te (GST) superlattice phase-change material is a promising candidate for overcoming the high power-consumption of phase-change
memory (PCM). However, the working mechanism of the superlattice PCM remains controversial. Partial amorphization, which is currently considered the most plausible mechanism, remains hotly debated: how does the partially amorphized GST recrystallize into its superlattice phase instead of the conventionally expected cubic phase? Here, we address this issue using large-scale molecular dynamics simulations enabled by a machine-learning interatomic potential. Starting from a partially melted GST superlattice, we demonstrate that the residual crystalline regions serve as
nuclei, enabling the amorphous GST to recrystallize directly into the superlattice phase without passing through the intermediate cubic phase. Moreover, the recrystallized phase is not an ideal superlattice, but rather a structurally ordered and chemically disordered defective superlattice characterized by anti-site defects and stacking faults. The defective superlattice region is also more susceptible to melting than the defect-free superlattice, and thereby can act as the active region of the PCM device. These results help to clarify the longstanding debates concerning the mechanism of superlattice-based PCM.
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All authors Bai-Qian Wang, Nian-Ke Chen, Yao-Jie Wang, Jia Sun, Yu-Ting Huang, Ming Xu, Shengbai Zhang, Xian-Bin Li
Statistical Mechanics
A proof of an identity for the critical exponents of jamming
Giorgio Parisi and Francesco Zamponi
Within the full replica-
symmetry-breaking (fullRSB) solution of dense hard spheres in infinite dimension, Charbonneau, Kurchan, Parisi, Urbani, and Zamponi (CKPUZ; J.Stat.Mech.P10009, 2014) introduced three critical exponents $a$, $b$, $c$ governing the matching region of the fullRSB profile near the jamming transition. These exponents satisfy two scaling relations. The first, $b=(1+c)/2$, was established analytically by the
diffusion-drift balance in the scaling ansatz. The second, $a+b=1$, was observed numerically to arbitrary precision but could not be proven. The exponents $a,b,c$ of the scaling fullRSB ansatz are related to the physical exponents $\alpha, \theta, \kappa$ that control the gap, force, and overlap distributions by the relations $\alpha=a/b$, $\theta=(c-a)/(b-c)$, $\kappa=c+1$. Crucially, the relation $a+b=1$ yields the scaling relations $\alpha=1/(2+\theta)$ and $\kappa=2-2/(3+\theta)$ predicted on independent grounds by the mechanical-marginal-stability arguments of Wyart and collaborators. Here, we give an analytic proof of the identity $a+b=1$ from the scaling fullRSB equations. The proof was obtained through interaction with Claude (Sonnet 4.6 and Opus 4.7) and verified by us.
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Materials Science
Stress-triggered atomic explosion of trapped hydrogen initiates crack nucleation
Liang Gao, Thomas Schwarz-Selinger, Martin Balden et al. (+6 more)
Hydrogen embrittlement (HE) has persisted for more than a century as one of the most intractable problems in materials science. The prevailing view1 that diffusive H governs embrittlement has fostered the widespread assumption that H trapping at
crystal defects mitigates HE. Here we overturn this conventional paradigm. Using
plasma/ion irradiation of tungsten, we decouple – for the first time – H-induced crack nucleation from subsequent cavity propagation, and reveal nucleation as a two-stage mechanochemical fracture instability enabled by trapped H in the absence of diffusive H. In the first stage, H accumulation to a critical occupancy at dislocation cores acts as a chemical fuse, collapsing the local cohesive strength to a threshold at which infinitesimal external loads can trigger atomic decohesion. This bond rupture instantaneously enables the second stage: confined recombination of atomic hydrogen into molecular form. The abrupt release of chemical energy within an atomically restricted volume generates a transient inflation pressure that drives a dynamic, brittle jump to an internal macroscopic cavity. By separating mechanical decohesion triggering from energetic crack driving, our results provide a deterministic framework for the onset of H-induced crack nucleation under low-stress conditions. Furthermore, we place experimentally the classical H-enhanced decohesion model on an atomistic foundation and elevate it from phenomenology to prediction. Finally, by shifting the focus from experimentally elusive diffusive H to directly measurable trapped H, this work reframes HE as a deterministic, quantifiable instability, establishing a new paradigm for understanding and mitigating H-induced failure in high-strength metals.
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All authors Liang Gao, Thomas Schwarz-Selinger, Martin Balden, Cong Li, Peter Manz, Wolfgang Jacob, Rudolf Neu, Christian Linsmeier, GuangHong Lu