Soft Condensed Matter
A Minimal Theoretical Model for Morphodynamic Selection in Soft Matter Systems
Weihua Mu and Da Wang
Soft matter systems often display shape transitions, mode competition, and threshold-like dynamical responses driven by the coupling between mechanics, geometry, and biochemical or active fields. Here we present a minimal theoretical framework for describing such morphodynamic selection using a small number of physically interpretable order parameters. The model combines elastic relaxation, active driving, and nonlinear feedback, yielding distinct regimes corresponding to weak deformation, single-mode selection, and coupled shape transformation. We derive the governing equations, identify the relevant dimensionless control parameters, and show how the phase behavior can be organized in terms of threshold competition and effective coupling strengths. The framework provides a compact route for connecting analytical theory, numerical simulations, and experimentally observable shape dynamics in soft and biological matter.
Read the full abstract ▾
Quantum Physics
Partial-coherence weak measurement of polarization qubits with a temporal pointer: theory and experiment
Shane P. Gervais and Lambert Giner
Weak measurement has proven useful for metrology, for probing
quantum paradoxes, and for the direct measurement of
quantum states. Weak measurements of polarization
qubits with temporal pointers provide a direct route to weak-value characterization, including in regimes where the pointer is only partially coherent. We derive a closed-form expression for the post-selected temporal shift that interpolates between the incoherent and coherent (ideal) weak-measurement limits through a single parameter $\nu$, the pointer visibility. The expression is experimentally tested for a range of polarization states spanning three trajectories corresponding to rotations about the principal axes of the Poincaré sphere. Two of the trajectories provide parameter-free
benchmarks, with the real part of the weak value following $\cos^2\theta$ and $1/2$. In contrast, the weak value along the third trajectory is sensitive to incoherence and is well described by the single-parameter partial-coherence model, from which a reduced pointer visibility is obtained. Time shifts are extracted from the smoothed derivative of the pulse leading edge with internal calibration, reaching few-picosecond precision on 10 ns optical pulses using commercial components. The same apparatus also gives qualitative access to the imaginary quadrature through the frequency centroid, showing that temporal weak measurements remain accessible and quantitative in partially coherent pulsed systems.
Read the full abstract ▾
Exactly Solvable and Integrable Systems
Higher-order semi-rational solutions of the (2+1)-dimensional nonlocal multi-component Yajima–Oikawa system
Wenqiang Lu, Kelei Tian, Ying Xu et al. (+2 more)
Higher-order semi-rational solutions are constructed for the (2+1)-dimensional nonlocal multi-component Yajima-Oikawa system. This system is obtained from its local \(2M\)-component counterpart through a spatial-reflection reduction. Using Hirota's bilinear method and the Kadomtsev-Petviashvili hierarchy reduction, we derive a unified \(6\times6\) block Gram determinant. Its entries involve Schur
polynomials and exponential functions. The complex-conjugation and spatial-reflection reductions are imposed through algebraic constraints on the spectral parameters and determinant blocks, with the former ensuring a real-valued denominator tau function. Separate spectral parameter sets are assigned to the rational, breather, and dark-
soliton blocks. These solutions describe paired lumps or line rogue waves on breather, dark-
soliton, or combined backgrounds. Pure rational, breather, and dark-
soliton solutions follow by setting the appropriate block sizes to zero. Asymptotic analysis establishes the elastic interactions of the fundamental breather and dark-
soliton pairs and determines their position and phase shifts.
Read the full abstract ▾
All authors Wenqiang Lu, Kelei Tian, Ying Xu, Ge Yi, Xiaoming Zhu
Materials Science
Investigation on Thermal Stability of Epi-GeSn Directly on Si (001)
Tharundev V V, Dushyant Singh, Vigneshswari SR et al. (+3 more)
In this paper we investigate the structural properties and thermal stability of metastable Ge1-xSnx epilayers (~4.5 at.% Sn) grown directly on Si(001) substrates by high-resolution X-ray diffraction (HRXRD) and Raman spectroscopy. Our results demonstrate that both 70 and 140 nm films are fully relaxed, with the thicker film exhibiting a small tensile strain (+0.09%). The thermal stability of the
heterostructures was evaluated up to 813 K using temperature-dependent Raman spectroscopy and scanning electron microscopy. The surface-weighted Raman response (532 nm excitation) and surface morphology of the 70 nm film remain highly stable. In contrast, the 140 nm film undergoes severe degradation, characterized by significant attenuation and broadening of the Ge-Ge longitudinal optical
phonon mode, alongside enhanced surface Sn segregation. These findings demonstrate that the thermal stability of direct GeSn/Si
heterostructures is governed by the initial defect structure established during epitaxial growth, providing key design rules for understanding the fabrication of GeSn-based optoelectronic devices.
Read the full abstract ▾
All authors Tharundev V V, Dushyant Singh, Vigneshswari SR, Subha Maity, Prince Rathor, Krista R Khiangte
Computational Physics
Chi Zhang, Hefeng Wang and Hua Xiang
We present a mass-weighted meshless formulation for the shifted incompressible
lattice Boltzmann method (LBM) whose streaming step is exactly
unitary, combining with the Carleman
embedding. In traditional meshless LBM, on a scattered node set the semi-Lagrangian streaming step is an interpolation, which is not
unitary; a generic block encoding of this
matrix therefore requires a normalization proportional to its sparsity and logarithmically many ancillas. To overcome the non-unitarity, we instead express the interpolation as the exponential exp(a Dx + b Dy) of mimetic derivative operators. Endowing each node with its Voronoi mass and applying a mass-weighted similarity transform renders these derivative operators skew-Hermitian by enforcing moment constraints together with low-wave number trigonometric differentiation conditions, so that the interpolation becomes exactly
unitary. Such unitarization of interpolation leave the local collision step unchanged up to a rescaling of its quadratic term, where the same weights define the amplitude encoding of the distribution functions. For quasi-uniform node sets, the mass-weighting diagonal remains within a unit-order normalization that degrades only mildly as the Carleman truncation order grows, thereby mitigating the cost of block encoding. Numerical experiments on the Taylor Green
vortex confirm that the method reproduces the full meshless LBM, with the velocity error decreasing as the Carleman order increases.
Read the full abstract ▾
Quantum Physics
A complete classification of operator controllability for closed three-level quantum systems driven by a single control
Sergey Kuznetsov and Alexander Pechen
In this work, we study operator controllability of finite-dimensional closed
quantum systems driven by a single coherent control. Two general Lie-algebraic results on controllability of such systems are proved. The first gives sufficient conditions under which controllability of the system is preserved when controlled energy-level shifts are added. The second gives a sufficient basis-element condition under which the dynamical Lie
algebra contains $\mathfrak{su}(N)$ and the system is therefore operator controllable. These results, together with known controllability conditions, are applied to obtain a complete classification of operator controllability of all three-level
quantum systems in terms of their free and interaction
Hamiltonian matrix elements. This classification covers all combinations of energy-level and level-spacing degeneracies, two or three allowed transitions, as well as the presence or absence of controlled energy-level shifts, and gives necessary and sufficient conditions for operator controllability in each case.
Read the full abstract ▾
Atmospheric and Oceanic Physics
Clarifying tipping terminology
Niklas Boers, Robert E. Kopp, Peter Ashwin et al. (+21 more)
The notion of tipping points and related terminology have so far had inconsistent and sometimes confusing definitions in both scientific and popular literature. While it is difficult for the scientific community to align popular usage of the term tipping point with a precise definition, technical usage of related terms would benefit from greater consistency and rigor. Toward this end, we offer a systematic set of terms to clarify formal communication around potential tipping dynamics, with focus on examples from Earth system dynamics.
Read the full abstract ▾
All authors Niklas Boers, Robert E. Kopp, Peter Ashwin, Sebastian Bathiany, Maya Ben-Yami, Reyk Börner, Jofre Carnicer, Henk Dijkstra, Thomas L. Frölicher, Michael Ghil, Elisabeth Gilmore, Gabriele C.Hegerl, Laura Jackson, Shipra Jain, David Lapola, Timothy M. Lenton, Valerio Lucarini, Teng Liu, Virna L. Meccia, Andreas Morr, Anastasia Romanou, Thomas F. Stocker, Shuting Yang, Cunde Xiao
High Energy Physics (Theory)
Charged Deformation of a Hairy Black Brane: Perturbative Solution and Thermodynamics
Sangheon Yun
We study electrically charged black branes in four-dimensional Einstein-Maxwell-scalar theory with Maxwell coupling $Z(\phi)=e^{3\phi/\sqrt7}$, whose potential has an AdS$_4$ fixed point only in the infrared. For nonzero hair parameter $\alpha$ the scalar grows logarithmically at large radius and the geometry is not asymptotically AdS, so the holographic dictionary is a working assumption. With the scale-invariant multi-trace boundary condition of the neutral branes, giving conformal thermodynamics, we work to second order in the charge, obtaining the Maxwell field and susceptibility in closed form, plus the thermodynamics, condensate, incoherent conductivity and cumulant ratio $T^2\chi_4/\chi_2=6c(\alpha)<0$ for all $\alpha$ considered. Independent perturbative computations and first-law closed forms agree within $4\times10^{-6}$; nonlinear solutions reproduce second-order results to $1.2\times10^{-5}$ and $c$ to $6\times10^{-4}$. They are locally thermodynamically stable where constructed, and the pressure is analytic in $(\mu_Q/T)^2$ near zero density. No regular extremal horizon exists at finite scalar value, and $\rho/s<\sqrt{21}/(2\pi)$ exactly. The extremal limit is an AdS$_2\times\mathbb R^2$ throat where the scalar grows as $\ln\ln(1/u)$ in the AdS$_2$ radial coordinate $u$; the bound is saturated there, and extremal values are approached as powers of $1/\ln(\mu_Q/T)$. With a Dirichlet condition on the scalar source, the same solutions describe a non-conformal theory with scale $\Lambda$, whose charged branes exist only below $T_{\max}(\mu_Q)$, which falls from $0.194\Lambda$ at zero density to zero at $\mu_Q=0.506\Lambda$. This boundary is a diffusive instability where the charge susceptibility diverges at nonzero density, and the bulk viscosity violates Buchel's bound at all densities. Quasinormal modes with the normalizable large-radius condition reproduce its hydrodynamics.
Read the full abstract ▾
General Relativity and Quantum Cosmology
Quantum Energy Inequalities with a twist: rotating frames along stationary worldlines
Christopher J. Fewster and Daniel Lomax Ford
The energy densities of the quantised scalar and electromagnetic fields need not be positive, but their averages along timelike worldlines are constrained by
Quantum Energy Inequalities (QEIs) that hold in flat and curved spacetimes for arbitrary Hadamard
quantum field states. However the general QEI bound is not easy to compute in closed form. Here, we compute closed form expressions for the massless scalar and electromagnetic fields along stationary worldlines in Minkowski spacetime. These worldlines are solutions to the four-dimensional Frenet-Serret equations with constant
curvature invariants and include inertial, uniformly linearly accelerated, and uniformly rotating worldlines as special cases. The QEI bound depends on a choice of tetrad along the worldline, and we compute it for any tetrad with constant angular velocity relative to the Frenet-Serret tetrad. Optimising over the angular velocity, we show that the tightest electromagnetic QEI bound occurs when the tetrad is invariant under Fermi-Walker tetrads. Surprisingly, the Fermi-Walker tetrad does not produce the tightest QEI bound for massless scalar fields, and we investigate the optimal bound both analytically and numerically. Our results and methodology significantly improve on those in [CJ Fewster & J Thompson, Class.
Quantum Grav. 40 (2023) 175008], in which only Frenet-Serret tetrads were considered for massless scalar fields.
Read the full abstract ▾
High Energy Astrophysical Phenomena
A GeV Gamma-Ray Spectral Excess in the Fermi Blazar 4FGL J0136.5+3906
Shi-Ju Kang, Yue Yin, Yong-Gang Zheng et al. (+2 more)
We report the detection of a $\sim${{19}} GeV gamma-ray spectral excess (peak energy in observer frame) at $\sim$5.7$\sigma$ significance (3 degrees of freedom, without correction for trials and the look-elsewhere effect) in the Fermi-LAT data of the blazar 4FGL J0136.5$+$3906, based on $\sim${17} years of observations. The excess manifests as a distinct bump-like feature in the 100 MeV$-$1 TeV spectrum, with a flux of $\sim$3.6$\rm \times10^{-10}~ph~cm^{-2}~s^{-1}$. No similar feature is detected in nearby sources or background regions. The origin of this signal cannot be explained by standard blazar emission models and remains unknown. This Letter presents the observational finding without providing a definitive physical interpretation.
Read the full abstract ▾
All authors Shi-Ju Kang, Yue Yin, Yong-Gang Zheng, Qingwen Wu, Junhui Fan
Disordered Systems and Neural Networks · Cross-listed from q-bio.NC
Full Lyapunov Spectra of Random Neural Networks, Part I: Finite-Time and Asymptotic Theory
Haoyu Albert Wang and Wei P. Dai
We develop a dynamical mean-field framework for the full finite-time and stationary asymptotic Lyapunov spectra of random recurrent neural networks. At finite observation time, an exact log-determinant representation of tangent-propagator singular values leads to a closed-contour
matrix Dyson equation for the smoothed spectral tail. In the stationary setting, a cocycle representation yields an operator equation for the asymptotic cumulative spectrum. Both formulations retain complete local gain histories and the repeated action of quenched connectivity. Direct singular-value calculations and network QR spectra support the predictions in the regimes examined, with sampling uncertainty and numerical cutoffs assessed separately. The stationary equation also recovers the known maximal exponent, and controlled gain-history replay illustrates how temporal correlations redistribute instability. This work was carried out in collaboration with ChatGPT 5.6 Sol. Toward the end of preparation we became aware of David G. Clark's contemporaneous work, Lyapunov spectrum of random neural networks[arXiv:2610.12426], which reports overlapping mean-field results for the full Lyapunov spectrum using a cavity approach.
Read the full abstract ▾
Instrumentation and Detectors
Development of high-resolution timing technique in the past 25 years
Jerry Vavra
This paper reviews recent progress in high-resolution timing, rate capability, and aging performance of particle detectors in the context of developments over the past 25 years. It focuses on MCP, SiPM, LGAD, 3D silicon, and SiEM detectors and compares their performance with that of gaseous timing detectors. In addition, preliminary results from a simplified simulation program, Mini-TCAD, are presented, indicating that hexagonal 3D silicon
cells may provide better drift-time uniformity and timing resolution than square
cells.
Read the full abstract ▾
Physics and Society · Cross-listed from q-bio.PE
Multilateral governance of invasive alien species management: An ecological-economic model with Allee effect
Raouf Boucekkine, Weihua Ruan and Ullrika Sahlin
Invasive alien species (IAS) generate substantial ecological and economic damages that often transcend political boundaries, creating strong incentives for coordinated management. We develop a two-region ecological-economic model of IAS control that integrates prevention and eradication measures with population dynamics characterized by logistic growth and an Allee effect. We derive analytical results on the interaction between ecological thresholds and strategic behaviour and compare outcomes under cooperation (central planner) and non-cooperation (open loop Nash
equilibrium and Markovian Nash
equilibrium). We show that, under realistic control costs, neither prevention nor eradication can eliminate invasive populations in finite time, and complete prevention of cross-border spread is generally not optimal. In the absence of an Allee effect, the zero-population
equilibrium is unstable, implying long-run persistence of the invasive species. By contrast, the presence of an Allee effect fundamentally alters system dynamics by making extinction locally stable and creating a basin of attraction within which eradication becomes feasible. This finding highlights the economic significance of ecological thresholds and demonstrates how delays in management can shift populations beyond critical levels, after which eradication is unlikely regardless of subsequent control efforts. Numerical simulations further show that cooperative management expands the set of initial conditions leading to eradication and consistently reduces aggregate social costs relative to decentralized management. The results provide a formal rationale for rapid intervention, precautionary regulation, and stronger multilateral cooperation in IAS management, particularly in jurisdictions such as the European Union where listing and control actions may be delayed pending evidence of harm.
Read the full abstract ▾
General Relativity and Quantum Cosmology
Analytic Electromagnetic Effective Source for Geodesic Orbit in Schwarzschild Spacetime
Xuchen Lu, Yungui Gong, Bokai Zhang et al. (+2 more)
Self-force effects are essential for accurately describing the motion of small bodies in curved spacetime. The effective-source approach privides a promising route to higher-order self-force calculations. In this paper, we construct analytic electromagnetic effective source for geodesic motion in Schwarzschild spacetime. An angular completion and a tetrad decomposition express the vector-harmonic puncture modes as finite sums of scalar modes. We derive the coupling coefficients for both parity sectors and obtain the effective sources from the Maxwell mode equations. The point-particle delta contribution cancels, and representative eccentric-orbit results show finite mode sources near the particle. These expressions provide the source terms for future $1+1$-dimensional residual-field calculations.
Read the full abstract ▾
All authors Xuchen Lu, Yungui Gong, Bokai Zhang, Chao Zhang, Wenting Zhou
Materials Science
Pressure-Driven Evolution of the Physical Properties of Layered Y2GaB and Y2InB MAB Phases: A Comparative First-Principles Study
M. Rabi Us Sani Shapon, Md. Asif Afzal, Jubair Hossan Abir et al. (+2 more)
MAB phases are nanolaminated ternary borides in which strong in-plane M-B bonds and weaker interlayer interactions drive their distinctive stability and functionality. Hydrostatic pressure offers a direct route to tune the in-plane and interlayer interactions that govern the stability and functionality of layered Y2GaB and Y2InB borides. Here, first-principles calculations are used to compare their structural, elastic, thermophysical, electronic, bonding, optical, and vibrational responses from 0 to 20 GPa. Elastic criteria show that Y2GaB is stable at 0, 5, and 10 GPa, whereas Y2InB is stable only at ambient pressure. Within the stable Y2GaB range, compression increases the elastic moduli, acoustic velocities, Debye temperature, and
lattice thermal conductivity while reducing the elastic anisotropy. Both compounds are multiband metals and
spin-orbit coupling modifies local dispersions without opening a gap. Y2GaB retains nine Fermi-surface sheets from 0 to 10 GPa, whereas Y2InB has eight at ambient pressure, with no pressure-induced topological reconstruction. Charge-density and overlap analyses indicate mixed ionic-covalent Y-B bonding within a delocalized metallic background. Optical parameters are anisotropic. Unit-
cell phonon spectra contain positive frequencies at 0 and 10 GPa, although expanded-supercell calculations reveal low-frequency sensitivity. These results establish mechanically viable pressure windows and clarify substitution-driven structure-property relationships for these borides.
Read the full abstract ▾
All authors M. Rabi Us Sani Shapon, Md. Asif Afzal, Jubair Hossan Abir, Raihana Shams Islam, Saleh Hasan Naqib
Materials Science
Spiral Edge States in Topological 2D Sb2Te3 Crystals
Timothy Carlson, Daniel Lazega, Scott McGuire et al. (+7 more)
This work explores the edge state conduction properties of twinned and spiraled, 2D Sb2Te3 topological
insulator crystals. We show the structure supports spatially continuous edge states within two spiral and knotted edge conduction channels. The channels are connected through a topological defect. This geometry introduces boundary conditions into the 2D
crystal that modifies the edge state dispersion. Using a combination of low loss Electron Energy Loss Spectroscopy,
Magnetic Force Microscopy and traditional carrier transport measurements we identify a distinct excitation at 0.155 eV in the spiral that seems to be related to two isolated states within the gap. This state is localized to the
crystal edges. The modification of edge state bands using manipulation of a systems
quantum geometry may open new avenues for the use of 2D topological systems.
Read the full abstract ▾
All authors Timothy Carlson, Daniel Lazega, Scott McGuire, Mihirangi Medahinne, Motahhare Mirhosseini, Gabriel Marcus, ChaoChao Dun, Maria Kolesnik-Gray, Vojislav Krstic, David Carroll
Computational Physics · Cross-listed from math.NA
A single LU~factorization approach to model reduction for linear system families with a quadratic matrix pencil
Mikhail A. Botchev, Leonid Knizhnerman, Nikolai L. Zamarashkin et al. (+1 more)
To solve a family of large linear systems where the system
matrix depends on the family parameter quadratically, we propose a new solution approach. Our method employs the derivatives of solutions with respect to the parameter. It turns out that the accumulated solution derivatives of increasing order, evaluated at a single specially chosen parameter value, provide successively better approximations to solution subspaces for the whole linear system family. We show that the derivatives can be computed by a recurrence, involving, at each step, solving a linear system with the same
matrix. Constructing an orthonormal basis for the subspace spanned by the derivatives then leads to an efficient solver where just a single (sparse) LU factorization (or a single preconditioner setup in an iterative scheme) suffices to solve the whole linear system family. We call the new method ODB (orthonormal derivative basis method). As shown in numerical tests, compared to conventional solution methods, the ODB method allows to drastically reduce computational costs.
Read the full abstract ▾
All authors Mikhail A. Botchev, Leonid Knizhnerman, Nikolai L. Zamarashkin, Dmitry A. Zheltkov
Mathematical Physics · Cross-listed from math.PR
Overlap distributions under the Gibbs measure of a Haar model of $\log|\zeta|$ on and near the critical line
Frédéric Ouimet
We study the Gibbs measure of $H(h) = \Re\sum_{p^{j} \leq X}U_{p}^{j}/(j p^{j(\sigma + i h)})$, a random field modeling large values of the log-modulus of the Riemann zeta function on and near the critical line, where the $U_{p}$ are independent and uniformly distributed on the complex unit circle. Writing $t = \log \log T$, the cutoff $X$ and real part $\sigma$ may vary with $T$ subject to $T^{1/t^{\Phi}} \leq X \leq T^{1/t^{\phi}}$ and $0 \leq \sigma - 1/2 \leq C_{\sigma}t^{\Phi}/\log T$, for fixed $\Phi \geq \phi > 1/2$ and $C_{\sigma} > 0$. On $I_{\theta} = [ - (\log T)^{\theta},(\log T)^{\theta}]$, define the Gibbs measure $G_{\beta,\sigma,T}^{\mathrm{H}}(\mathrm{d}h) := e^{\beta H(h)}\mathrm{d}h/\int_{I_{\theta}}e^{\beta H(h')}\mathrm{d}h'$. For every fixed $\theta > - 1$ and inverse temperature $\beta > 0$, the limiting joint distributions of correlations (overlaps) among points sampled from this measure are determined after averaging over the Haar phases. At and below $\beta_{c}(\theta) = 2\sqrt{1 + (\theta \vee 0)}$, the limiting two-overlap distribution is concentrated at $q_{0} = |\theta \wedge 0|$. Above this threshold, it assigns masses $\beta_{c}(\theta)/\beta$ and $1 - \beta_{c}(\theta)/\beta$ to $q_{0}$ and $1$, respectively, and the limiting joint overlap distribution is described by a Poisson-Dirichlet process of parameter $\beta_{c}(\theta)/\beta$. Approximate Ghirlanda-Guerra identities are shown to hold uniformly for bounded deterministic functions of the sampled positions. This paper is the first in a series devoted to extending these results to $\log|\zeta|$ near the critical line.
Read the full abstract ▾
Computational Physics
FDTD Model of Noise Pollution from an AI Data Center
Gavin Buxton
The sudden growth in AI data centers is raising numerous environmental concerns. Low-frequency noise pollution is a concern for local residents, that may not just be an annoyance but also carry significant health impacts. An FDTD model of sound propagation over the topography near an AI data center is presented. The topography plays a large role in the level of noise pollution, with areas of sudden elevation on either side of the river near the AI data center more susceptible to high noise levels, while areas further afield largely protected from noise pollution by the topography. Understanding the role that topography plays in noise pollution, and capturing the noise pollution in specific topographies, can help identify areas where noise mitigation strategies might be best employed.
Read the full abstract ▾
Materials Science
Pressure-transferable universal machine-learning potentials: the WBM-MatPES benchmark and Tuga-FF
Pierre-Paul De Breuck, Thalis H. B. da Silva, Antoine Loew et al. (+2 more)
Universal machine-learning interatomic potentials hold the promise to replace costly ab initio calculations in materials science workflows. However, the accuracy and transferability of current models are limited by the availability of training data. We release WBM-MatPES, a
dataset of 182 thousand structures recomputed with consistent MatPES settings, together with two reference convex hulls of different depths and test sets at six pressures up to 150 GPa. These
datasets reproduce a realistic discovery workflow and allow potentials to be ranked systematically at this level of theory, similar to the Matbench Discovery leaderboard at the Materials Project settings. In this
benchmark, five published MatPES potentials agree within 12 meV/atom at 25 GPa, yet their errors increase dramatically to 0.4-5 eV/atom at 150 GPa. To address this limitation, we develop Tuga-FF, a graph
transformer trained on
datasets spanning ambient and high-pressure configurations alike. Tuga-FF is the most accurate model in the
benchmark at ambient pressure, with an energy error of 13.6 meV/atom, and maintains an error of just 21 meV/atom at 150 GPa. We believe this
benchmark will encourage the community to train higher-accuracy models and generate richer
datasets, advancing machine-learned interatomic potentials as a whole.
Read the full abstract ▾
All authors Pierre-Paul De Breuck, Thalis H. B. da Silva, Antoine Loew, Silvana Botti, Miguel A. L. Marques
Computational Physics · Cross-listed from math.NA
Are implicit schemes needed in adaptive time stepping for PDEs?
Mikhail A. Botchev
Implicit time integration is the standard way to overcome the tight CFL time step restriction when solving nonstationary PDEs numerically. However, within an adaptive time accurate integration, the time step size selection is governed not only by stability but also by accuracy requirements. Therefore, an eligible question to ask is: is (unconditionally) stable implicit time stepping really needed if the time step is restricted by accuracy considerations anyway? And how much do we then lose (in terms of the time step size) when switching from the expensive implicit time stepping to stabilized explicit schemes? An answer to this question is also important because such a switch is often done when solving large scale nonstationary PDEs on massively parallel computers. This paper attempts to answer these questions by numerical tests for two particular adaptive time accurate settings: (i)~nonstationary convection-
diffusion equations and (ii)~nonlinear heat equations.
Read the full abstract ▾
Cosmology and Nongalactic Astrophysics
TDCOSMO 2026: new insights on the Hubble tension from strong lensing time delays
TDCOSMO Collaboration, Simon Birrer, Michele Cappellari et al. (+26 more)
We discuss the measurement of the Hubble constant ($H_0$) in flat $\Lambda$ cold dark matter cosmology based on the blind hierarchical analysis of 11 multiply-imaged
quasars (hereafter the TDCOSMO-2026 sample) and described in greater detail in a companion paper. In addition to the time delays, we use lens models based on high-resolution imaging from the Hubble Space
Telescope (HST) and from the James Webb Space
Telescope (JWST), analyzed jointly with axisymmetric dynamical models based on JWST-NIRSpec, VLT-MUSE, and Keck-KCWI spectroscopy. Our primary result $H_0=71.1^{+2.4}_{-2.3}$ km.s$^{-1}$.Mpc$^{-1}$ is based on the TDCOSMO-2026 sample, in combination with $\Omega_{\rm m}$ constraints from the DES-Dovekie
supernova (SN)
dataset. Our 3% precision accounts for the mass-sheet degeneracy. Importantly, our measurement is independent of the local distance ladder (LDL). Among individual late-universe probes, only the traditional LDL is more precise. We discuss our result in the context of the Hubble tension, the difference between $H_0$ measured in the late universe and the prediction based on early-universe probes such as the
cosmic microwave background (CMB). We construct combinations of independent late-universe probes and show that the tension with the Planck CMB prediction is robust to excluding any one of the methods based on Type-Ia
Supernovae, Cepheids, or the Tip of the Red Giant Branch. For example, we construct a 'no-SN' $H_0$ measurement, by replacing the DES-Dovekie constraint on $\Omega_{\rm m}$ with that from DESI baryon acoustic oscillations, and then combining TDCOSMO-2026 with independent non-SN late-universe probes. This 'no-SN' late-universe probe is in 3.7$\sigma$ tension with Planck. Even after completely excluding the LDL, the tension with Planck persists at the 2.7$\sigma$ level.
Read the full abstract ▾
All authors TDCOSMO Collaboration, Simon Birrer, Michele Cappellari, Frédéric Courbin, Christopher D. Fassnacht, Pierre Fleury, Joshua A. Frieman, Aymeric Galan, Xiang-Yu Huang, Daniel P. Johnson, Sanjana Khanolkar, Shawn Knabel, Hrvoje Krizic, Martin Millon, Takahiro Morishita, Veronica Motta, Pritom Mozumdar, Eric Paic, Hadrien Paugnat, Allan G. Schweinfurth, Anowar J. Shajib, William Sheu, Dominique Sluse, Massimo Stiavelli, Sherry H. Suyu, Tommaso Treu, Felipe Urcelay, Devon M. Williams, Kenneth C. Wong
Optics
Ultra-low-loss Ta2O5 waveguide for integrated nonlinear photonics
Xiaotong Zhang, Shuxuan Guo, Ruixuan Yi et al. (+8 more)
Integrated nonlinear photonics demands waveguides that simultaneously offer ultra-low-loss, relatively strong nonlinearity, and tight mode confinement. Tantalum pentoxide (Ta2O5) is attractive for this purpose because it combines a broad transparency window, relatively strong third-order nonlinearity, and favorable thick-film growth characteristics. In tightly confined Ta2O5 waveguides, however, enhanced interaction between the optical mode and etched sidewalls makes scattering loss an important limitation for achieving high Q anomalous-dispersion resonators. Here, we mitigate this confinement-scattering trade-off in pure Ta2O5 waveguides using a fabrication flow based on the Damascene concept. The resulting microring resonators (MRRs) with a cross-section of 1.6 {\mu}m x 0.85 {\mu}m exhibit intrinsic quality factors exceeding 4.0 x 106, corresponding to propagation losses below 10 dB/m, while maintaining anomalous dispersion suitable for bright dissipative Kerr
soliton operation. Using these resonators, we generate a coherent bright single-
soliton microcomb with a repetition rate of 108.32 GHz. Under optimized dual-pump operating conditions, the platform further exhibits an experimentally accessible single-
soliton window spanning 7.5 GHz, indicating a large detuning tolerance for
soliton operation; this broad operating window is consistent with the relatively weak thermo-optic response of Ta2O5. Thermal-bistability analysis further indicates that the residual scattering loss is comparable to the material-absorption loss, rather than dominating the loss budget. These results demonstrate that low optical loss, tight mode confinement, and dispersion engineering suitable for
soliton formation can be jointly achieved in a pure Ta2O5 platform, providing an ultra-low-loss platform foundation for integrated nonlinear photonic devices and more complex chip-scale nonlinear photonic systems.
Read the full abstract ▾
All authors Xiaotong Zhang, Shuxuan Guo, Ruixuan Yi, Zheze Shi, Like Shui, Long Huang, Leiran Wang, Yang Wang, Junling Qu, Wenfu Zhang, Xuetao Gan
Soft Condensed Matter
A Higher-Order Stroh Framework for Weakly Nonlinear Post-Bifurcation Analysis
Shiyuan Deng, Han Ye, Yafei Wang et al. (+8 more)
Linear stability analysis predicts the onset of wrinkling, while weakly nonlinear analysis determines whether the bifurcation is supercritical or subcritical through the sign of the cubic amplitude coefficient. When this coefficient vanishes, higher-order terms are needed. In this paper, we develop a higher-order Stroh framework for weakly nonlinear post-bifurcation analysis of finitely deformed elastic solids. For each nonzero harmonic, the same base-state Stroh operator is retained at every order, with nonlinear source terms assembled from lower-order fields to account for geometry, constitutive laws and constraints. This recursive structure, together with Fredholm solvability conditions, enables us to derive cubic, quintic and higher-order amplitude equations. Here, we demonstrate the power of this framework by analysing wrinkling in an incompressible neo-Hookean film bonded to an exponentially graded substrate. The results recover established linear instability
benchmarks and the supercritical-subcritical transition in the homogeneous-substrate limit. For graded substrates, the cubic coefficient vanishes on a surface in the parameter space of modulus ratio and substrate gradation. On this surface, the quintic coefficient takes both signs, corresponding to supercritical and subcritical bifurcations. These regions are separated by a curve along which the quintic coefficient also vanishes. Determining the branch direction along this curve requires higher-order terms, which can be calculated within the same framework.
Read the full abstract ▾
All authors Shiyuan Deng, Han Ye, Yafei Wang, Lizichen Chen, Alain Goriely, Yibin Fu, Weiqiu Chen, Chaofeng Lü, Michel Destrade, Kecheng Li, Yangkun Du
Strongly Correlated Electrons
Emergent one-dimensional Bloch oscillations in coupled Ising layers
E. S. Ma and Z. Song
Bloch oscillations typically arise in periodic systems subjected to a constant force generated by a potential gradient. Here, we study domain-wall dynamics in coupled Ising layers under asymmetric longitudinal fields. The interlayer coupling is of Heisenberg type and acts as an effective transverse coupling in the emergent pseudospin representation. We show that the rung pseudospin structure gives rise to kinetic constraints, restricting the many-body dynamics to an emergent one-dimensional quasiparticle subspace within the original two-dimensional system. Furthermore, the imbalance between the longitudinal fields of the two layers induces an effective linear potential for the emergent domain-wall excitations, leading to their confinement between two oppositely polarized ferromagnetic domains. Remarkably, the resulting Wannier–Stark ladder of domain-wall excitations gives rise to Bloch oscillations in the absence of a conventional tilted potential, revealing a distinct mechanism for coherent
quantum dynamics. Numerical simulations of time-dependent observables confirm the analytical predictions.
Read the full abstract ▾
High Energy Physics (Experiment)
Exploring Collective Effects in Small Collision Systems via Light-Flavour Particle Production in High-Multiplicity pp Collisions at $\sqrt{s}=$ 13 TeV in ALICE
Rajendra Nath Patra for the ALICE Collaboration
High-multiplicity pp and p-Pb collisions show signatures of radial and anisotropic flow, as well as the enhanced production of strange
hadrons. These observations resemble phenomena seen in heavy-ion collisions, where a
quark-gluon
plasma (QGP) is formed, although their origin in small systems remains under discussion. This contribution presents ALICE Run 2 results on light-flavour
hadron ($\pi$, K, p) production in high-multiplicity (HM) pp collisions at $\sqrt{s}=13$ TeV, where the charged-particle multiplicity reaches values comparable to peripheral or semi-peripheral Pb-Pb collisions. The multiplicity dependence of $\pi$, K, and p transverse momentum spectra, $p_{\rm T}$-differential and $p_{\rm T}$-integrated particle ratios, and mean transverse momenta ($\langle p_{\rm T}\rangle$) is presented and compared with published results from other collision systems and energies, as well as with PYTHIA 8 and EPOS4 model calculations.
Read the full abstract ▾
Strongly Correlated Electrons · Cross-listed from math.QA
Lifts of symmetries to minimal nondegenerate extensions are unique up to fermion attachment
Ran Luo and Jiahua Tian
Gauging
fermion parity in a $(2+1)$-dimensional fermionic topological order requires lifting its
symmetries to the resulting bosonic theory. We give a direct tensor-categorical proof that, for a slightly degenerate braided fusion category $\mathcal{C}$ and a fixed minimal nondegenerate extension ${\cal E}$, the restriction homomorphism $r\colon\operatorname{Aut}_{\mathrm{LR}}(\mathcal{E})\to \operatorname{Aut}_{\mathrm{LR}}(\mathcal{C})$ on classes of complex-linear locality-respecting (LR) braided autoequivalences is surjective with central kernel $\mathbb{Z}/2$, generated by
fermion attachment. Thus each
symmetry class has exactly two LR lift classes, related by attaching the
fermion to every
vortex. We apply graded Morita theory to reduce the kernel to two module types on the
vortex sector, corresponding to tensoring with the
vacuum or the
fermion. We then prove relative rigidity to show that each type determines a unique LR class, which are distinguished by fermionic self-braiding even when their actions on simple-object labels coincide. We prove surjectivity by extending graph
algebras in $\mathcal{C}^{\mathrm{rev}}\boxtimes\mathcal{C}$ to Lagrangian
algebras in $\mathcal{E}^{\mathrm{rev}}\boxtimes\mathcal{E}$. Our results require neither unitarity nor a ribbon structure. We illustrate the lifting ambiguity in the Laughlin state, the $SO(3)_3$ theory and the Ising topological order.
Read the full abstract ▾
Classical Physics
On some nonlinear extensions to Maxwell's electrodynamics
Bertrand Berche and Ernesto Medina
Soon after Maxwell's celebrated synthesis of electrodynamics, the discovery of the electron raised fundamental questions about the nature and structure of elementary particles. The picture of a small, rigid, charged body of finite radius faced the difficulty of introducing non-electromagnetic forces or stresses to prevent the charge from dispersing, an assumption that was increasingly regarded as unsatisfactory. The alternative description in terms of a point charge was no more satisfactory, because its electromagnetic self-energy diverges. From the early twentieth century onward, several authors therefore explored modifications of Maxwell's theory, with nonlinear electrodynamics emerging as a particularly natural and radical possibility. In this paper, we revisit at the undergraduate level some of the nonlinear theories proposed in this context and explore their ability to address the classical self-energy problem of charged particles.
Read the full abstract ▾
Data Analysis and Statistics · Cross-listed from cs.NI
Stackelberg Game with Multi-Agent Transformer for ISRS-Aware Resource Re-optimization in Multi-Band Optical Networks
Jiaxin Liu, Rentao Gu, Miao Zhu et al. (+3 more)
The rapid expansion of generative AI is driving computing infrastructures toward interconnected AI data centers. Multi-band optical networks have become the backbone of such connectivity. To accommodate increasingly dynamic traffic demands, these networks require continual resource re-optimization to improve resource utilization and reduce service blocking. However, multi-band transmission amplifies inter-channel stimulated Raman scattering(ISRS), inducing nonlinear coupling among services. This coupling complicates re-optimization, as local adjustments perturb the global power profile, creating interdependent optimization decisions across services. Moreover, the nonlinear interactions vary with the subset of services selected for re-optimization, and inappropriate selection may reduce re-optimization effectiveness or diminish achievable benefits. To address these challenges, we propose a Stackelberg Game with Multi-
Agent Transformer (SG-MAT) approach for ISRS-aware resource re-optimization. SG-MAT employs a leader-follower structure, in which the MAT-based follower models nonlinear coupling and generates coordinated channel reallocations, feeding the utilization improvements to the leader. Using this feedback, the leader identifies critical service subsets, approximating a Stackelberg
equilibrium to guide global decisions and enabling consistent and efficient re-optimization. Simulation results show that SG-MAT achieves the highest utilization improvement and reduces the blocking ratio by approximately 30% under moderate traffic loads, with computational complexity comparable to
benchmarks.
Read the full abstract ▾
All authors Jiaxin Liu, Rentao Gu, Miao Zhu, Zeguang Zou, Hui Li, Yuefeng Ji
Instrumentation and Methods for Astrophysics
From Sky to Science: Time Domain Astronomy with the ILMT Survey
Kuntal Misra, Bhavya Ailawadhi, Talat Akhunov et al. (+10 more)
The PyLMT transient detection pipeline has been operational since November 2023 and has detected $\sim$10,000 transients and variable objects in ILMT images in near real time. The survey has enabled the discovery and characterisation of a range of bright and faint optical transients. The detected population spans a broad diversity of astrophysical phenomena, including
supernovae, variable
stars, active galactic
nuclei (AGN) variability, and Solar System objects such as asteroids and comets. We provide a concise overview of the detection of a variety of transient and variable classes identified with the ILMT, emphasising the survey's potential contributions to a broad class of astrophysical sources. We highlight representative science cases, including
supernovae, AGNs, variable
stars, and asteroids, to demonstrate the scientific potential of the ILMT survey.
Read the full abstract ▾
All authors Kuntal Misra, Bhavya Ailawadhi, Talat Akhunov, Monalisa Dubey, Naveen Dukiya, Sara Filali, Paul Hickson, Priyanshi Kumari, Gokul Singh Mehra, Vibhore Negi, Kumar Pranshu, Jean Surdej, Sarvesh Kumar Yadav