Soft Condensed Matter · Cross-listed from physics.flu-dyn
Soap Film Drainage Using a Centrifugal Thin Film Balance
Antoine Monier, Kévin Gutierrez, Cyrille Claudet et al. (+3 more)
Surface bubbles are an abundant source of aerosols, with important implications for
climate processes. In this context, we investigate the stability and thinning dynamics of soap films under effective
gravity fields. Experiments are performed using a centrifugal thin-film balance capable of generating accelerations from 0.2 up to 100 times standard
gravity, combined with thin-film interferometry to obtain time-resolved thickness maps. Across all experimental conditions, the drainage dynamics are shown to be governed by capillary suction and marginal regeneration-a mechanism in which thick regions of the film are continuously replaced by thin film elements (TFEs) formed at the meniscus. We consistently recover a thickness ratio of 0.8-0.9 between the TFEs and the adjacent film, in agreement with previous observations under standard
gravity. The measured thinning rates also follow the predicted scaling laws. We identified that effective
gravity has three distinct effects: (i) it induces a strong stretching of the initial film, extending well beyond the linear-elastic regime; (ii) it controls the meniscus size, and thereby the amplitude of the capillary suction and the drainage rate; and (iii) it reveals an inertia-to-viscous transition in the motion of TFEs within the film. These results are supported by theoretical modeling and highlight the robustness of marginal regeneration and capillary-driven drainage under extreme
gravity conditions.
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All authors Antoine Monier, Kévin Gutierrez, Cyrille Claudet, Franck Celestini, Christophe Brouzet, Christophe Raufaste
Materials Science
Self-induced marginality in plastically deformed crystals
Oguz Umut Salman, Aylin Ahadi and Lev Truskinovsky
Quasi-brittle plastic yielding is a salient feature of well-annealed glassy materials. Here we show that the same behavior is characteristic of perfect
crystals after they experience mechanically driven elastic instability leading to massive nucleation of dislocations. We argue that such 'preparation' effectively converts an atomic configuration from crystalline to quasi-amorphous. To understand the nature of the subsequent intermittent mechanical response we study a model 2D
crystal subjected to AQS driving and show that both pre- and post-yield dislocation avalanches exhibit power law statistics with similar exponents indicative of self-induced marginal stability.
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Strongly Correlated Electrons
Non-linear spin wave theory in the strong easy-axis limit of the triangular XXZ model
Achille Mauri, Siebe Roose and Frédéric Mila
Motivated by recent experimental studies, we investigate the spectrum of the nearest-neighbour triangular XXZ model within the $1/S$ expansion, in the limit in which the exchange couplings present a strong easy-axis anisotropy $J_{xy}/J_{zz} \ll 1$. We show that in the limit in which $1/S \to 0$ and $J_{xy} \to 0$ at fixed $V = J_{zz}/(S J_{xy})$, the triangular
spin model can be reduced to an effective
boson model with quartic interactions on the honeycomb
lattice. This effective model interpolates between a
spin-wave ($V \to 0$) and a strong-coupling limit ($V \to \infty$) and encodes in a simple framework the regimes discussed by Kleine~et al.~[Z. Phys. B Condens. Matter~86, 405 (1992);~87, 103 (1992)]. For zero field, the classical ground state of the model presents an accidental degeneracy, which can be traced to a simple
symmetry of the classical energy. The model thus offers a transparent realization of a theory with
quantum order-by-disorder and a pseudo-Goldstone mode. We analyze the spectrum at zero
magnetic field by calculating the self-energy at one-loop order. In the calculation, we introduce a self-consistent renormalization of the energy scale and of the pseudo-Goldstone energy gap; the latter renormalization is essential to remove infrared divergences in the on-shell corrections to the energy dispersion. Finally, we discuss qualitatively the structure of the one-loop corrections in comparison with the spectrum observed experimentally in K$_{2}$Co(SeO$_{3}$)$_{2}$.
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Strongly Correlated Electrons
Growth-Controlled Twinning and Magnetic Anisotropy in CeSb$_2$
Jan T. Weber, Kristin Kliemt, Sergey L. Bud'ko et al. (+2 more)
Cerium diantimonide (CeSb$_2$) is a layered heavy-
fermion Kondo
lattice material that hosts complex magnetism and pressure-induced superconductivity. The interpretation of its in-plane anisotropy has remained unsettled due to structural twinning, which superimposes orthogonal
magnetic responses. Here we combine controlled
crystal growth with magnetization and rotational magnetometry to disentangle the effects of twinning. Nearly untwinned high-quality single
crystals reveal the intrinsic in-plane anisotropy: The in-plane easy axis saturates at $M_{\text{easy}}(4~\text{T}) \approx 1.8~\mu_{\text{B}}$/Ce, while the in-plane hard axis magnetization is strongly suppressed, nearly linear, and comparable to the out-of-plane response. These results resolve long-standing discrepancies in reported
magnetic measurements, in which in-plane metamagnetic transition fields and saturation magnetization varied significantly across previous studies. Growth experiments demonstrate that avoiding the proposed $\alpha$-$\beta$ structural transition $-$ through Sb-rich flux and slower cooling $-$ systematically reduces twinning. However, powder X-ray diffraction and differential thermal analysis measurements show no clear evidence of a distinct $\beta$ phase. Our results establish a consistent
magnetic phase diagram and provide essential constraints for
crystal-electric field models, enabling a clearer understanding of the interplay between anisotropic magnetism and unconventional superconductivity in CeSb$_2$.
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All authors Jan T. Weber, Kristin Kliemt, Sergey L. Bud'ko, Paul C. Canfield, Cornelius Krellner
Disordered Systems and Neural Networks
High-Winding-Number Zero-Energy Edge States in Rhombohedral-Stacked Su-Schrieffer-Heeger Multilayers
Feng Lu, Ao Zhou, Shujie Cheng et al. (+1 more)
We study the topological properties of rhombohedral-stacked N-layer Su-Schrieffer-Heeger networks with interlayer coupling. We find that these systems exhibit $2N$-fold degenerate zero-energy edge states with winding number $W=N$, providing a direct route to high-winding-number topological phases where $W$ equals the layer number. Using effective
Hamiltonian theory and Zak phase calculations, we demonstrate that the winding number scales linearly with $N$ through a layer-by-layer topological amplification mechanism. We introduce the Wigner
entropy as a novel detection method for these edge states, showing that topological boundary states exhibit significantly enhanced Wigner
entropy compared to bulk states. Our results establish rhombohedral stacking as a systematic approach for engineering high-winding-number topological
insulators with potential applications in
quantum information processing.
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All authors Feng Lu, Ao Zhou, Shujie Cheng, Gao Xianlong
Materials Science
Excitonic shift current induced broadband THz pulse emission efficiency of layered MoS2 crystals
Neetesh Dhakar and Sunil Kumar
Following the ultrafast photoexcitation of a
semiconductor, it embodies competing dynamics among photocarriers, many-body transient states of highly energetic
excitons, and electron-hole
liquid. Here, we show that femtosecond optical pulse excitation induces transient excitonic shift current contributing to stronger THz emission from a single crystalline bulk MoS2 at low temperatures. The control of dominating excitonic shift current is elucidated from excitation density dependent experiments at varying temperatures. A strong decrease in the excitonic contribution beyond a critical fluence of 150microJ/cm^2 is observed at a very low temperature of 20K. This behavior suggests the formation of a new
quantum condensate, i.e., the electron-hole
liquid, in the regime when the
exciton density is overwhelmingly large that the average spacing between
exciton pairs is comparable to the
exciton radius. Furthermore, the
exciton density dependent THz emission at varying temperatures is consistent with the Varshni model and the
crystal Debye temperature of 260K.
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Statistical Mechanics
Coherence enhanced by detrained oscillators: Breaking $\pi$-reflection symmetry
Hyunsuk Hong, Jae Sung Lee and Hyunggyu Park
We study a generalized Kuramoto model in which each oscillator carries two coupled phase variables, representing a minimal swarmalator system. Assuming perfect correlation between the intrinsic frequencies associated with each phase variable, we identify a novel dynamic mode characterized by bounded oscillatory motion that breaks the $\pi$-reflection
symmetry. This
symmetry breaking enhances global coherence and gives rise to a non-trivial mixed state, marked by distinct degrees of ordering in each variable. Numerical simulations confirm our analytic predictions for the full phase diagram, including the nature of transition. Our results reveal a fundamental mechanism through which detrained (dynamic) oscillators can promote global synchronization, offering broad insights into coupled dynamical systems beyond the classical Kuramoto paradigm.
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Mesoscale and Nanoscale Physics
Carrier-envelope phase control of ultrafast photocurrents in layered MoS$_2$
Johannes Schmuck, Björn Sinz, Nina Pettinger et al. (+2 more)
We demonstrate carrier-envelope-phase (CEP)-controlled photocurrents in mono-, bi-, and tri-layer MoS$_2$ driven by few-cycle
laser pulses. The photocurrent in the two-terminal devices scales quadratically with the field amplitude, indicating perturbative carrier dynamics in the weak-field regime distinct from strong-field tunnelling. Our results extend light-field-sensitive current control from bulk dielectrics,
semiconductors, and
graphene to two-dimensional transition-metal dichalcogenides, highlighting their potential for electric-field sensitive optoelectronics.
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All authors Johannes Schmuck, Björn Sinz, Nina Pettinger, Sergey Zherebtsov, Alexander W. Holleitner
Mesoscale and Nanoscale Physics · Cross-listed from physics.app-ph
Second-Harmonic Magnetoacoustic Ultrasound from Magnetic Nanoparticles under Radiofrequency Electromagnetic Fields
R. Marqués-Gómez, J. Melchor, A.C. Moreno Maldonado et al. (+4 more)
We report experimental evidence of mechanical wave generation by
magnetic nanoparticles (MNPs) under radiofrequency electromagnetic fields (EMFs, 65mT, 800 kHz, at 100ms bursts) in the ultrasonic (US) frequency range. We developed an experimental setup to detect the second harmonic (SH) signal under isothermal conditions. This SH-US signal was observed only in samples containing MNPs and consequently originated from the EMF interaction on samples containing MNPs. These findings suggest that US generation due to magneto-acoustic interaction in the MNPs could be responsible for the
cell damage induced by EMF in
cells containing MNPs without increasing the temperature. Experiments performed on magnetically aligned MNP clusters in gelatin significantly enhance the amplitude of the SH signal compared to non-aligned samples. This phenomenon could pave the way for new theoretical and practical approaches as for 'in vivo' magnetoacoustics theragnostic.
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All authors R. Marqués-Gómez, J. Melchor, A.C. Moreno Maldonado, C. Marquina, G. Goya, M. R. Ibarra, G. Rus
Soft Condensed Matter
Prediction of the three-phase coexistence line of the ethane hydrate from molecular simulation
Paula Gómez-Álvarez, Miguel J. Torrejón, Jesús Algaba et al. (+1 more)
We investigate the three-phase coexistence line of ethane (C$_2$H$_6$) hydrate through molecular dynamics simulations using the direct coexistence approach. In this framework, C$_2$H$_6$ sI hydrate, aqueous, and pure guest phases are constructed within a single simulation box, allowing us to monitor their mutual stability. From the temporal
evolution of the potential energy, we identify the
equilibrium temperature (T$_3$) at which all three phases coexist, across pressures ranging from 1000 to 4000 bar, in accordance with available experimental data. Simulations are performed with the GROMACS package (version 2016, double precision) in the $NPT$ ensemble. Water and C$_2$H$_6$ molecules are represented using the TIP4P/Ice and TraPPE-UA models, respectively, while unlike non-bonded interactions are computed with the Lorentz-Berthelot combining rule. Dispersive Lennard-Jones and Coulomb interactions are truncated at 1.6 nm, with long-range Coulombic contributions treated via Particle-Mesh Ewald summation. The predicted three-phase coexistence line shows excellent agreement with experimental measurements within the investigated pressure range. These results demonstrate the suitability of the direct coexistence methodology, combined with established molecular models, for reproducing hydrate dissociation behavior in systems that have received little prior computational
attention.
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All authors Paula Gómez-Álvarez, Miguel J. Torrejón, Jesús Algaba, Felipe J. Blas
Materials Science
Suppression of magnetism in Co$_3$Sn$_2$S$_2$ under external pressure
A. Chmeruk, D. Jones, R. Balducci et al. (+13 more)
The ability to control the
magnetic state provides a powerful means to tune the underlying band
topology, enabling transitions between distinct electronic phases and the emergence of novel
quantum phenomena. In this work, we address the
evolution of
ferromagnetic state upon applying external pressures up to 10.8~GPa using a combined experimental and theoretical study. The standard ab initio Density Functional Theory computation including ionic relaxations grossly overestimates the unit
cell magnetization as a function of pressure. In our theoretical analysis we identify two possible mechanisms to remedy this shortcoming. Matching the experimental observations is achieved by a
symmetry-preserving adjustment of the sulfur atoms position within the unit
cell. Alternatively, we explore various combinations of the exchange and correlation parts of the effective potential which reproduce the experimental magnetization, the structural parameters and the measured optical conductivity spectra. Thus, the pressure-dependent behavior of magnetization demands a careful theoretical treatment and analysis of theoretical and experimental data.
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All authors A. Chmeruk, D. Jones, R. Balducci, J. Ebad-Allah, F. Beiuşeanu, F. Schilberth, M. A. Kassem, U. Schade, A. Veber, L. Puskar, Y. Tabata, T. Waki, H. Nakamura, C. A. Kuntscher, A. Östlin, L. Chioncel
Materials Science
On the Role of Interlayer Electrons on the Frictional Behavior of Two-Dimensional Electrides
Jingcheng Qi, Giuliana Materzanini, Gian-Marco Rignanese et al. (+2 more)
Friction accounts for up to 30% of global energy consumption, underscoring the urgent need for superlubricity in advanced materials. Two-dimensional (2D) electrides are layered materials with cationic layers separated by 2D confined electrons that act as anions. This study reveals the unique frictional properties of these compounds and the underlying mechanisms. We establish that interlayer friction correlates with the cationic charges and sliding-induced charge redistribution. Remarkably, the 2D electride Ba2N stands out for its lower interlayer friction than
graphene, despite its stronger interlayer adhesion, defying conventional tribological understanding. This anomalous behavior arises from electron redistribution as the dominant energy dissipation pathway. Combining ab initio calculations and deep potential molecular dynamics (DPMD) simulations, we show that incommensurate twisted interfaces (2{\deg} < {\theta} < 58{\deg}) in Ba2N achieve structural superlubricity by suppressing out-of-plane buckling and energy corrugation. Notably, a critical normal load of 2.3 GPa enables barrier-free sliding in commensurate Ba2N ({\theta} = 0{\deg}), with an ultralow shear-to-load ratio of 0.001, suggesting the potential for superlubricity. Moreover, electron doping effectively reduces interlayer friction by controllably modulating stacking energies in 2D electrides. These findings establish 2D electrides as a transformative platform for energy-efficient tribology, enabling scalable superlubricity through twist engineering, load adaptation, or electrostatic gating. Our work advances the fundamental understanding of electron-mediated friction, with Ba2N serving a model system for cost-effective, high-performance material design.
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All authors Jingcheng Qi, Giuliana Materzanini, Gian-Marco Rignanese, Maria Clelia Righi, Junjie Wang
Soft Condensed Matter
(Dis-)appearance of liquid-liquid phase transitions in a heterogeneous activated patchy particle model and experiment
Furio Surfaro, Peixuan Liang, Hadra Banks et al. (+3 more)
The ion-activated patchy particle model is an important theoretical framework to investigate the phase behaviour of globular
proteins in the presence of multivalent ions. In this work, we study and highlight the influence of patch heterogeneity on the extension, appearance and disappearance of the
liquid-
liquid coexistence region of the phase diagram. We demonstrate that within this model the binding energy between salt ions and patches of different type is a key factor in determining the phase behavior. Specifically, we show under which conditions
liquid-
liquid phase separation (LLPS) in these systems can appear or disappear for varying binding energy and ion-mediated attraction energy between ion-occupied and unoccupied patches. In particular we address the influence of the patch type dependence of these energies on the (dis)appearance of LLPS. These results rationalize our new results on ion-dependent
liquid-
liquid phase separation in solutions of bovine serum albumine with trivalent cations. In comparison with models with non-activated patches, where the gas-
liquid transition disappears when the number of patches approaches two, we find the complementary mechanism that ions may shift the attractions from stronger to weaker patches (with an accompanying disappearance of the transition), if their binding energy to the patches changes. The results have implications for the understanding of charge-driven LLPS in biological systems and its suppression.
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All authors Furio Surfaro, Peixuan Liang, Hadra Banks, Fajun Zhang, Frank Schreiber, Martin Oettel
Statistical Mechanics · Cross-listed from quant-ph
Mixed-state phase structure of gauge-Higgs subsystem codes under logical-preserving decoherence
Yoshihito Kuno and Ikuo Ichinose
Some of
lattice-gauge-theory models, in particular gauge-
Higgs model (GHM), can be regarded and work as a subsystem code. This work studies the effect of local-gauge-symmetric decoherence on the GHM from the perspective of the subsystem code. We clarify the global phase diagram of the subsystem code. In particular, the decoherence induces an unconventional critical mixed state, where the logical information is preserved but the rest of the system exhibits mixed state criticality. For a fixed point, the decohered subsystem code is understood by the “gauging out" prescription. By mapping the GHM to the toric code subject to decoherence, we can understand the properties of the subsystem code. We further discuss and investigate the robustness of the logical space of the subsystem code. Although this kind of subsystem code can be produced by using any bulk mixed state in the GHM, its robustness is a subtle problem due to the mixed critical gauge
qubits. We consider some specific
unitary for examining the robustness of the stored
quantum information. For dynamical
unitary perturbations described by interactions between the logical
qubit and gauge
qubits, the deformation of the subsystem code drastically depends on the initial mixed state of the gauge
qubits.
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Soft Condensed Matter
Confinement-induced collective motion in suspensions of run-and-tumble particles
José Martín-Roca, Daniel Escobar Ortiz, Chantal Valeriani et al. (+1 more)
Collective motion is ubiquitous in active systems at all length and time scales. The mechanisms behind such collective motion usually are
alignment interactions between active particles, effective
alignment after collisions between
agents or
symmetry-breaking fluctuations induced by passive species in active suspensions. In this article, we introduce a new type of collective motion in the shape of a traveling band induced purely by confinement, where no explicit or effective
alignment are prescribed among active
agents. We study a suspension of run-and-tumble particles confined in microchannels comprising asymmetric boundaries: one flat wall and one array of funnel-like obstacles. We study the phase behavior of the confined active suspension upon changes in the packing fraction and the persistence length to define the stability region of the traveling band. We characterize the traveling band structurally and dynamically and study its stability with respect to the tilt angle of the obstacles. Lastly, we describe the mechanism of motion of the band, which resembles the tracked locomotion of some heavy vehicles like tractors, finding that a counter-flux of active particles in the lower part of the band, explained in terms of source-sink and vacancy
diffusion mechanisms, is the facilitator of the traveling band and sustains its motion. We name this new collective phenomenon confinement-induced tracked locomotion
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All authors José Martín-Roca, Daniel Escobar Ortiz, Chantal Valeriani, Horacio Serna
Mesoscale and Nanoscale Physics · Cross-listed from quant-ph
Coherence in the Leak and Storage Kurtosis control Ergotropy in Quantum Batteries
Bitap Raj Thakuria, Trishna Kalita, Manash Jyoti Sarmah et al. (+1 more)
We introduce a cavity-coupled finite
quantum system which can act as a
quantum battery by harnessing noise induced coherences. We apply the methodology of full counting statistics to capture higher-order fluctuations of quanta exchange in the storage station. Together with the thermodynamic parameters, the fluctuations constitute a training platform for unsupervised as well as supervised learning models in predicting ergotropy. We identify a minimal predictive feature set from the battery's operating parameters that can classify the ergotropy into different regimes with great accuracy.Our results show that the usual
quantum and thermodynamic variables are inadequate for the purpose of identifying high ergotropy regimes in isolation. Rather, it is the kurtosis of quanta exchange in the storage and the noise-induced coherence in the leakage mode that become the dominant quantities in controlling the magnitude of ergotropy.
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All authors Bitap Raj Thakuria, Trishna Kalita, Manash Jyoti Sarmah, Himangshu Prabal Goswami
Materials Science
Non-destructive 3D characterization of microtextured regions in the bulk of Ti-6Al-4V alloy
Mads Carlsen, Xiaohan Zeng, Haixing Fang et al. (+4 more)
In this study we present spatially resolved texture and orientation maps from a cube-shaped sample of Ti-6Al-4V
alloy, reconstructed by means of texture
tomography (TT). Unlike grain resolved 3DXRD techniques which require "spotty" diffraction patterns, TT can reconstruct local (voxelized) orientation distribution function (ODFs) from continuous diffraction patterns collected in a 3D scanning procedure. Reconstructions of the same sample, scanned in two different settings and subsequent EBSD analysis parallel to one of the sample faces show excellent mutual agreement and validate the single-axis data collection and reconstruction procedure for this class of materials. The reconstruction reveals the presence and the 3D shape of several micro-textured regions, showing a sharp unimodal texture of the $\alpha$-phase with a clear link of the orientation and spatial
alignment of these zones to the rolling, transverse and normal directions of the rolled material.
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All authors Mads Carlsen, Xiaohan Zeng, Haixing Fang, Moritz Frewein, Tilman A. Grünewald, Joao Quinta da Fonseca, Wolfgang Ludwig
Mesoscale and Nanoscale Physics
Localization transitions in an open quasiperiodic ladder
Suparna Sarkar, Soumya Satpathi and Swapan K. Pati
We investigate localization transition in an open quasiperiodic ladder where the quasiperiodicity is described by the Aubry-André-Harper model. While previous studies have shown that higher-order hopping or constrained quasiperiodic potentials can induce a mixed-phase zone in one dimension, we demonstrate that the dissipation can induce mixed phase zone in a one dimensional nearest-neighbor system without imposing any explicit constraints on the quasiperiodic potential or hopping parameter. Our approach exploits an exact correspondence between the eigenspectrum of the Liouvillian superoperator and that of the non-Hermitian
Hamiltonian, valid for quadratic fermionic systems under linear dissipation. Using third quantization approach within Majorana fermionic representation, we analyze two dissipation configurations: alternating gain and loss at every site, and at alternate sites under balanced and imbalanced conditions. By computing the inverse and normalized participation ratios, we show that dissipation can drive the system into three distinct phases: delocalizd, mixed, and localized. Notably, the mixed-phase zone is absent for balanced dissipation at every site but emerges upon introducing imbalance, while for alternate site dissipation it appears in both balanced and imbalanced cases. Furthermore, the critical points and the width of the mixed-phase window can be selectively tuned by varying the dissipation strength. These findings reveal that the dissipation plays a decisive role in reshaping localization transitions in quasiperiodic systems, offering new insight into the interplay between non-Hermitian effects and quasiperiodic order.
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Materials Science
Attosecond-resolved coherent control of zone-folded acoustic phonons in silicon carbide
Hiromu Matsumoto, Tsukasa Maruhashi, Yosuke Kayanuma et al. (+3 more)
Zone-folded acoustic
phonons (6 THz) in 4H silicon carbide (SiC) have been coherently excited using a femtosecond near-infrared pulse and measured through transient reflectivity with a pump and probe protocol. Their amplitude is coherently controlled with 300-attoseconds precision and the results show interference fringe patterns due to electronic and
phonon interference. The results are well reproduced by a model calculation with two electronic and
phonon levels and an impulsive stimulated Raman process. Using the model, we obtain the analytical form of the coherent control scheme at an off-resonant condition.
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All authors Hiromu Matsumoto, Tsukasa Maruhashi, Yosuke Kayanuma, Yadong Han, Jianbo Hu, Kazutaka G. Nakamura
Materials Science
Tuning Stability of AB3-Type Alloys by Suppressing Magnetism
Hung Ba Tran, Toyoto Sato, Ryuhei Sato et al. (+3 more)
Hydrogen is a promising clean energy carrier, yet effective and reversible storage remains challenging. AB3-type intermetallic
alloys are promising for solid-state hydrogen storage due to intermediate thermodynamic stability and rapid hydrogen uptake. Optimizing stability and gravimetric density is hindered by competing thermodynamic and
magnetic effects. Here, we analyze AB3 compounds (A = Ca, Y, Mg; B = Co, Ni) and ternary
alloys CaxYyMg1-x-yB3 using first-principles calculations and Monte Carlo simulations. We find a direct correlation between formation energy and total
magnetic moment that dictates
alloy stability, explaining the trade-off in hydrogen storage. In Co-rich systems with large
lattice volumes, formation energy rises with magnetization, showing magnetism as the dominant factor. Mg-rich compositions achieve high gravimetric densities, but strong magnetism destabilizes the system, requiring Y substitution to suppress
magnetic moments. Replacing Co with Ni weakens magnetism: YNi3 is nonmagnetic, while CaNi3 and MgNi3 are weakly polarized, allowing thermodynamic stability across compositions. Notably, CaMg2Ni9 combines high theoretical capacity (3.32 wt%) with good reversibility. Mg-rich Ni-based
alloys are predicted to offer negative formation energies with the highest gravimetric densities (up to 3.40 wt%). These results show that controlling magnetism via transition-metal substitution is key to overcoming the stability-capacity trade-off in AB3 hydrogen storage materials.
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All authors Hung Ba Tran, Toyoto Sato, Ryuhei Sato, Hiroyuki Saitoh, Shin-ichi Orimo, Hao Li
Soft Condensed Matter
Algebraic to exponential decay of spatial correlations in one-dimensional and confined hard-core fluids: A Laplace-pole analysis
Ana M. Montero and Andrés Santos
We derive the asymptotic behavior of the radial distribution function $g(x)$ for one-dimensional (1D) hard-rod systems and related quasi-one-dimensional geometries at high packing fractions using Laplace transform techniques and pole analysis. By identifying the poles and residues of the Laplace transform in the limit of small void fraction, we obtain compact representations of $g(x)$ in terms of the Jacobi
elliptic theta function $\theta_3$. This formulation naturally captures the two regimes governing the oscillatory decay toward unity: an intermediate algebraic decay and a long-distance exponential decay, consistent with previous results for the Tonks gas. Our approach provides a unified framework that (i) expresses $g(x)$ in a single well-tabulated special function, (ii) links spatial correlations directly to the pole structure in complex Laplace space, offering clear physical insight into decay rates and oscillation frequencies, and (iii) generalizes straightforwardly to 1D binary mixtures and confined hard-disk systems, where direct Gaussian decompositions are cumbersome. The equivalence between the theta-function representation and the Gaussian superposition of Bouzar and Messina [Phys. Rev. E 112, L042105 (2025)] is established via the Poisson summation formula, highlighting the versatility and conceptual advantages of the Laplace-pole framework.
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Materials Science
Implementation and application of a DFT$+U$$+V$ approach within the all-electron FLAPW method
Wejdan Beida, Gustav Bihlmayer, Christoph Friedrich et al. (+3 more)
We present an implementation of the density-functional theory DFT$+U$$+V$ formalism within the all-electron full-potential linearized augmented-plane-wave (FLAPW) method as implemented in the FLEUR code. The DFT$+U$$+V$ formalism extends DFT, supplemented by the onsite Coulomb interaction $U$, to address local correlation effects in localized states by incorporating intersite Coulomb interaction terms $V$. It holds promise for improving charge and bond disproportionation, charge and orbital ordering, charge density wave formation, charge transfer, and the intersite correlation resulting from hybridization between states of neighboring sites in a solid. $U$ and $V$ parameters are obtained from first principles using the constrained random-phase approximation (cRPA) employing two different atom basis representations to project the screened Coulomb interaction: the Wannier and the muffin-tin basis functions. We investigate in detail the impact of the $V$ term for typical covalently bonded materials like
graphene, for bulk
semiconductors such as silicon and germanium, and for charge-transfer
insulators like NiO. Our results demonstrate an improvement in accuracy of specific properties across these systems, providing a framework for describing materials with different interaction regimes. We compare our DFT$+U$$+V$ results using our cRPA parameter sets with (i) previous DFT$+U$$+V$ calculation employing pseudopotential approximations, (ii) with experimental results and (iii) with our $GW$ results.
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All authors Wejdan Beida, Gustav Bihlmayer, Christoph Friedrich, Gregor Michalicek, Daniel Wortmann, Stefan Blügel
Mesoscale and Nanoscale Physics
High and Magnetic-field-dependent Surface Carriers Mobility in 3D Topological Insulators without Bulk States
M. V. Pugachev, A. E. Borisov, A. V. Shupletsov et al. (+3 more)
By applying the conventional two-
liquid model to the magnetoresistivity tensor, we reveal a record-high carrier mobility for surface states in tetradymite topological
insulators ($\sim$ 20000 cm$^2$/Vs) in both bulk
crystals and thin flakes of Sn-Bi$_{1.1}$Sb$_{0.9}$Te$_2$S. Bulk
crystals of this 3D topological
insulator exhibit a transition from bulk to surface-dominated conductivity below 100 K, whereas in thin flakes, bulk conductivity is suppressed at even higher temperatures. Our data therefore suggest that a key ingredient for elevated mobility is the absence of bulk carriers at the
Fermi level. A fingerprint of the high-mobility carriers, i.e a steep low-field magnetoresistance along with a strong
Hall effect nonlinearity below 1 T, signifies the presence of at least two surface-related carrier species, even when bulk states are frozen out. To explain the magnetoresistance and the
Hall effect in a wider range of
magnetic fields ($>1$ T), one must assume that the carrier mobility drops with the field. The influence of Zeeman splitting on mobility and the contribution of anomalous
Hall conductivity provide a much better description of the magnetoresistance and the nonlinearity of the
Hall coefficient. Our data call for a revision of the surface state mobility in 3D topological
insulators.
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All authors M. V. Pugachev, A. E. Borisov, A. V. Shupletsov, V. O. Sakhin, E. F. Kukovitsky, A. Yu. Kuntsevich
Mesoscale and Nanoscale Physics
Angular Patterns of Photoluminescence in Quantum Dot Spherical Superparticles Mediated by Whispering-Gallery Modes
Yu. E. Geints
Quantum dot superparticles are a specific class of metamaterials created through the self-assembly of nanometer
semiconductor quantum dots into organized micro-scale structures, such as microspheres. Superparticles exhibit unique optical, chemical, and electronic properties. These properties are not merely the sum of the constituent
quantum dots but rather bear the signature of the collective behavior of the nanoscale building blocks. In particular, assembling an ensemble of
quantum dots into a super-sphere allows them to function as a single, high-quality optical resonator. This structure efficiently confines the emission from the pump-excited
quantum dots via whispering gallery modes. The emissive properties of such a superparticle resonator remain an area of active investigation. Using numerical simulation, we study the angular structure of the photoluminescence from superparticles of various sizes and architectures formed from CdS
quantum dots. We show that, in general, the angular distribution of the SP emission is characterized by strong asymmetry, with a maximum in the backward direction relative to the incident pump beam. In contrast, this asymmetry is virtually absent in the forward and side-scattering directions. The excitation of resonant modes in the superparticle enhances the emission intensity and reduces the degree of its backward asymmetry. Furthermore, coating the CdS
quantum dot particle with a silicon dioxide layer increases the probability of exciting field resonances in such a core-shell superparticle.
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Soft Condensed Matter
Persistently Non-Gaussian Metastable Liquids
Vinay Vaibhav, Tamoghna Das and Suman Dutta
Particles undergoing Fickian
diffusion within smooth energy landscapes exhibit Gaussian statistics. However, this Gaussian behavior is often elusive in complex
liquids, where particle dynamics within spontaneously fluctuating or spatio-temporally heterogeneous environments lead to a breakdown of ergodicity and time-reversal
symmetry. This is usually caused by extreme particle movements or sudden dynamical arrest. Such situations are prevalent in dense metastable
liquids exhibiting slow flow or cooperative movements, facilitated by cage-breaking. We investigate the dynamics of glassy systems driven by either thermal, external, or environmental fluctuations. Despite their differences, our findings reveal that particle motion is universally affected by large deviations, resulting in non-Gaussian tails persisting over multiple decades in time. We further discuss the underlying dynamical aspects.
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Soft Condensed Matter
Mesoscopic Correlations in Aqueous Alkylamine Mixtures Between Molecular and Micro Emulsions
Aurelien Perera
Understanding how molecular correlations give rise to mesoscale organization is central to the physics of complex fluids such as hydrogen-bonded mixtures. In this work, we develop a mesoscale bridge formalism that connects the site-site Ornstein-Zernike (SSOZ) framework to the field theoretical Teubner-Strey (TS) approach. This bridge highlights how local orientational correlations, typically lost in the SSOZ closure, reemerge as effective long-range components at the mesoscale. The resulting theory provides a unified description of density fluctuations spanning molecular to mesoscopic length scales. The approach is illustrated using X-ray scattering spectra from simulated and experimental hydrogen-bonded fluids, showing that the TS representation captures the essential features of the mesoscale structure. Beyond this specific application, the proposed formalism offers a general route to interpret the structural crossover between microscopic interactions and collective mesoscale organization in complex fluids, including aqueous and amphiphilic systems.
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Mesoscale and Nanoscale Physics
Gradient flow and Bogomolny bounds for quantum metric actions
T. Fukui
We formulate gradient flow dynamics generated by two natural actions of the
quantum metric for an isolated set of Bloch bands. Specializing to two spatial dimensions, we derive Bogomolny-type lower bounds that relate these actions to the Chern number and show that the bounds are saturated by (anti-)holomorphic projector configurations. Along the flows, the actions decrease monotonically while the Chern number is conserved, giving a constructive route to simplify models within a fixed topological phase toward canonical, low-complexity representatives.
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Mesoscale and Nanoscale Physics · Cross-listed from physics.optics
Silicon-photonic optomechanical magnetometer
Fernando Gottardo, Benjamin J. Carey, Nathaniel Bawden et al. (+7 more)
Optomechanical sensors enable exquisitely sensitive force measurements, with emerging applications across
quantum technologies, standards, fundamental science, and engineering. Magnetometry is among the most promising applications, where chip-scale optomechanical sensors offer high sensitivity without the cryogenics or
magnetic shielding required by competing technologies. However, lack of compatibility with integrated photonics and electronics has posed a major barrier. Here we introduce silicon-on-
insulator optomechanical magnetometers to address this barrier. A new post-release lithography process enables high-quality metallisation of released mechanical structures, overcoming the incompatibility between silicon-on-
insulator fabrication and functional
magnetic films. This allows us to employ photonic-
crystal cavities that enhance motion-to-optical signal transduction by over an order of magnitude. The resulting devices achieve
magnetic field sensitivity of 800 pT Hz^-1/2, three orders of magnitude beyond previous waveguide-integrated designs. The advances we report provide a path towards high-performance, room temperature and chip-integrated magnetometers for applications ranging from biomedical imaging and
navigation to resource exploration.
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All authors Fernando Gottardo, Benjamin J. Carey, Nathaniel Bawden, Glen I. Harris, Hamish Greenall, Erick Romero, Douglas Bulla, James S. Bennett, Scott Foster, Warwick P. Bowen
Materials Science
Inhomogeneous dynamic state in the double trillium lattice antiferromagnet KBaFe$_2$(PO$_4$)$_3$
S. J. Sebastian, S. S. Islam, R. Kolay et al. (+11 more)
The three-dimensional (3D) magnet KBaFe$_2$(PO$_4$)$_3$ hosts a double-trillium
lattice of Fe$^{3+}$ (
spin, $S=5/2$) ions offering a prototypical platform to study the frustration induced effects in 3D. Through magnetization, specific heat, $^{31}$P
nuclear magnetic resonance (NMR), and
muon spin relaxation ($\mu$SR) experiments, supported by first principles calculations, we uncover an unconventional ground state. Despite strong
antiferromagnetic interactions with a large Curie-Weiss temperature $\theta_{\rm CW} = -70(2)$ K, no
magnetic long-range order is observed down to 30 mK. Below $T^{\ast}\simeq 3.5$ K, the NMR linewidth becomes nearly field-independent and the
spin-
spin relaxation rate $1/T_2$ saturates, accompanied by an inhomogeneous distribution of transverse
nuclear magnetization $M_{xy}$. The latter indicates the emergence of short-range dynamical correlations, which was further corroborated by a robust and field-insensitive broad maximum in specific heat. In $\mu$SR, we detect neither a static internal field nor
spin freezing; instead the relaxation remains dynamic and is best described by two coexisting dynamic relaxation channels: a dominant fast (sporadic) channel and a slower Markovian component. Their differing weights and fluctuation rates suggest microscopic inhomogeneity in
spin dynamics. Altogether, KBaFe$_2$(PO$_4$)$_3$ exemplifies a rare high-
spin stochiometric 3D antiferromagnet that evades ordering and instead fosters a mosaic of
spin dynamics driven by strong
geometric frustration intrinsic to the trillium
lattice.
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All authors S. J. Sebastian, S. S. Islam, R. Kolay, S. Mohanty, Q. P. Ding, Y. Skourski, J. Sichelschmidt, M. Baenitz, Jonas A. Krieger, T. J. Hicken, H. Luetkens, A. A. Tsirlin, Y. Furukawa, R. Nath
Other Condensed Matter
A Dual-Memory Ferroelectric Transistor Emulating Synaptic Metaplasticity for High-Speed Reservoir Computing
Yifan Wang, Muhammad Sakib Shahriar, Salma Soliman et al. (+6 more)
The exponential growth of edge artificial intelligence demands material-focused solutions to overcome energy consumption and latency limitations when processing real-time temporal data. Physical reservoir computing (PRC) offers an energy-efficient paradigm but faces challenges due to limited device scalability and reconfigurability. Additionally, reservoir and readout layers require
memory of different timescales, short-term and long-term respectively - a material challenge hindering CMOS-compatible implementations. This work demonstrates a CMOS-compatible ferroelectric transistor using hafnium-zirconium-
oxide (HZO) and silicon, enabling dual-
memory operation. This system exhibits non-volatile long-term
memory (LTM) from ferroelectric HZO polarization and volatile short-term
memory (STM) from engineered non-quasi-static (NQS) channel-charge relaxation driven by gate-source/drain overlap capacitance. Ferroelectric polarization acts as non-volatile programming of volatile dynamics: by modulating threshold voltage, the ferroelectric state deterministically switches the NQS time constant and computational behavior between paired-pulse facilitation (PPF) and depression (PPD). This establishes a generalizable material-design principle applicable to diverse ferroelectric-
semiconductor heterostructures, extending beyond silicon to
oxide semiconductors and heterogeneously-integrated systems. The device solves second-order nonlinear tasks with 3.69 x 10^-3 normalized error using only 16 reservoir states - ~5x reduction - achieving 20 us response time (~1000x faster) and 1.5 x 10^-7 J energy consumption, providing an immediately manufacturable pathway for neuromorphic hardware and energy-efficient edge intelligence.
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All authors Yifan Wang, Muhammad Sakib Shahriar, Salma Soliman, Noah Vaillancourt, Lance Fernandes, Andrea Padovani, Asif Islam Khan, Md Sakib Hasan, Raisul Islam