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2603.28526 2026-03-31 quant-ph

Tunable Nonlocal ZZ Interaction for Remote Controlled-Z Gates Between Distributed Fixed-Frequency Qubits

Benzheng Yuan, Chaojie Zhang, Haoran He, Yangyang Fei, Chuanbing Han, Shuya Wang, Huihui Sun, Qing Mu, Bo Zhao, Fudong Liu, Weilong Wang, Zheng Shan

Comments 8 pages, 4figures

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英文摘要

Fault-tolerant quantum computing requires large-scale superconducting processors, yet monolithic architectures face increasing constraints from wiring density, crosstalk, and fabrication yield. Modular superconducting platforms offer a scalable alternative, but achieving high-fidelity entangling gates between distant modules remains a central challenge, particularly for highly coherent fixed-frequency qubits. Here, we propose a distributed hardware architecture designed to overcome this bottleneck by employing a pair of double-transmon couplers (DTCs). By synchronously controlling the two DTCs stationed at opposite ends of a macroscopic cable, our scheme strongly suppresses residual static inter-module coupling while enabling on-demand activation of a non-local cross-Kerr interaction with an on/off ratio exceeding $10^6$. Through comprehensive system-level numerical simulations incorporating realistic hardware parameters, we demonstrate that this mechanism can realize a remote controlled-Z (CZ) gate with a fidelity over 99.99\% between fixed-frequency transmons housed in separate packages interconnected by a 25 cm coaxial cable. These results establish a highly viable, hardware-efficient route toward high-performance distributed superconducting processors.

2603.28525 2026-03-31 quant-ph hep-ph hep-th

Quantized Dissipation from the Inverse-Square Anomaly in a Non-Hermitian Klein-Gordon Field

Mansour Haghighat, Ali Nouri

Comments 4 pages

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We construct an exactly solvable relativistic model that embeds the anomalous inverse-square interaction into a non-Hermitian Klein-Gordon field theory through a purely imaginary, scale-invariant scalar potential. The stationary field equation reduces to an inverse-square Schrodinger-type problem with a quadratic spectral parameter. Imposing a strictly outgoing boundary condition at the singularity-interpreted as irreversible absorption-selects a unique physical realization and converts the fall-to-the-center instability into a discrete, log-periodic spectrum of complex energies. The resulting decay rates exhibit universal geometric spacing, determined solely by the anomalous scaling exponent and insensitive to microscopic short-distance regularization. This structure defines an emergent kinematic energy scale that controls dissipative dynamics and provides a minimal analytic framework for studying scale anomaly, boundary-condition-induced non-Hermiticity, and quantized dissipation in relativistic open quantum systems.

2603.28523 2026-03-31 nlin.CD

Slow spectral dynamics of shot noise in the Kuramoto model: the role of microscopic regularity

S. Yu. Kirillov, V. V. Klinshov

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Finite-size effects in the Kuramoto model are known to induce collective fluctuations even below the critical coupling, where the thermodynamic limit predicts complete asynchrony. While the shot-noise approach developed in our recent work accurately describes the power spectrum of these fluctuations for random frequency sampling, the present study reveals that the microscopic realization of the frequency distribution plays a crucial role. We show that a deterministic (quasi-uniform) selection of natural frequencies from the same Lorentzian distribution leads to qualitatively different dynamics: the shot noise spectrum exhibits anomalously slow oscillatory behavior, manifesting as wave-like patterns in time-frequency representations. The period of these oscillations scales linearly with the system size and matches the frequency spacing between neighboring oscillators near the distribution center. Numerical simulations confirm that these slow spectral dynamics arise from resonant interactions facilitated by the regular frequency structure, which are absent for random sampling. Our findings demonstrate that identical integral frequency distributions do not guarantee equivalent collective dynamics, highlighting the necessity of accounting for the fine structure of microscopic parameters in finite-size populations.

2603.28521 2026-03-31 math.NA cs.NA

Quantum Enhanced Numerical Homogenization

Loïc Balazi, Matthias Deiml, Daniel Peterseim

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We propose a numerical homogenization method for scalar linear partial differential equations with rough coefficients, that integrates classical coarse-scale solvers with quantum subroutines for fine-scale corrections. Inspired by the Localized Orthogonal Decomposition, we employ quantum local problem solvers to capture fine-scale features efficiently. Crucially, the approach does not rely on the periodicity of the problem, and the integration of the quantum computation within a coarse model requires only selected measurements of the quantum representative volume elements, overcoming the information bottleneck of quantum interfaces that could eliminate the speed-up. We demonstrate that the local quantum solver can achieve solutions with sufficient accuracy, with a number of operations that scales only logarithmically with the fine-scale resolution, determined by the smallest length scale encoded in the diffusion coefficient. The potential of the approach is illustrated through two-dimensional test cases, using a classical simulation of the local quantum solver.

2603.28520 2026-03-31 math.PR math-ph math.MP

The Supercritical Loop O(1) and Random Current models: Uniqueness and Mixing

Ulrik Thinggaard Hansen, Frederik Ravn Klausen

Comments 30 pages, 3 figures

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Much recent rigorous study of the classical ferromagnetic Ising model has been powered by its graphical representations, such as the random current and loop O(1) model (high temperature expansion). In this paper, we prove uniqueness of Gibbs measures and exponential ratio weak mixing for the loop O(1) and random current models corresponding to the supercritical Ising model on the hypercubic lattice $\Z^d$ in any dimension $d \geq 2$. The main technical innovation is to establish unique crossing events for conditional random-cluster measures by a delicate exploration coupling of Pisztora's coarse-graining method across scales. The results generalise to $q$-flow models and have natural applications for gradient measures of $\Z/q\mathbb{Z}$-gauge theories.

2603.28519 2026-03-31 quant-ph physics.optics

Photon-triplets for quantum optics generated by a phase-matched third-order difference-frequency mixing in a KTiOPO4 bulk crystal pumped at 532 nm

Gaspar Mougin-Trichon, Veronique Boutou, Corinne Felix, David Jegouso, Benoit Boulanger

Comments 4 pages, 1 table, 5 figures

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We report implementation and modelling of an efficient photon-triplets generation experiment based on a difference-frequency-mixing of two picosecond beams at 532 nm and 1491 nm in a type II phase-matched KTP crystal. The photon-triplets flux was measured as a function of the energy of the two incident beams using a coincidence protocol. A maximal flux of 11.6 photon-triplets per second was achieved. These experimental data were satisfactorily described by a semiclassical model based on the quantum fluctuations of vacuum and the classical equations of nonlinear optics.

2603.28517 2026-03-31 hep-lat hep-ex hep-ph

Heavy-Meson Bag Parameters using Gradient Flow

Matthew Black, Robert V. Harlander, Jonas T. Kohnen, Fabian Lange, Antonio Rago, Andrea Shindler, Oliver Witzel

Comments 37 pages, 18 figures, 7 tables, 2 ancillary files

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We demonstrate the use of the gradient flow combined with the short flow-time expansion (GF+SFTX) as a renormalization procedure for four-quark operator matrix elements and associated bag parameters relevant to neutral heavy-meson mixing ($ΔQ=2$) and heavy-meson lifetimes ($ΔQ=0$). Using six RBC/UKQCD 2+1-flavor domain-wall fermion ensembles, we calculate for a charm-strange system with physical quark masses flowed bag parameters and match them to the $\overline{\text{MS}}$ scheme using perturbative SFTX coefficients up to next-to-next-to-leading order in QCD. We employ a multi-scale matching strategy and a renormalization-group improved flow-time evolution which allows for a reliable estimate of systematic uncertainties. For a fictitious neutral $D_s$ meson, we obtain the $ΔQ=2$ $\overline{\text{MS}}$ bag parameter ${\cal B}^{\overline{\text{MS}}}_1(3\,{\rm GeV})=0.7673(123)$, consistent with existing short-distance $D^0$ mixing determinations. For the $ΔQ=0$ lifetime-ratio operator basis, we find the $\overline{\text{MS}}$ results $B^{\overline{\text{MS}}}_1(3\,{\rm GeV})=1.0524(97)$, $B^{\overline{\text{MS}}}_2(3\,{\rm GeV})=0.9621(71)$, $ε^{\overline{\text{MS}}}_1(3\,{\rm GeV})=-0.2275(76)$, and $ε^{\overline{\text{MS}}}_2(3\,{\rm GeV})=-0.0005(8)$. We provide conversion formulae to re-express these results for an arbitrary choice of evanescent operators. These results demonstrate that GF+SFTX can deliver precise determinations of dimension-six four-quark operators and establish a framework for future lattice computations including more complex operator bases, where the challenge of power-divergent mixing is shifted to the continuum and handled in the SFTX.

2603.28516 2026-03-31 hep-ph hep-ex hep-lat

Bag Parameters for Heavy Meson Lifetimes

Matthew Black, Robert V. Harlander, Jonas T. Kohnen, Fabian Lange, Antonio Rago, Andrea Shindler, Oliver Witzel

Comments 8 pages, 3 figures, 2 tables

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We calculate the dimension-six $ΔQ=0$ four-quark matrix elements describing heavy-meson lifetime ratios using the gradient flow with its short flow-time expansion as a renormalization procedure. On six RBC/UKQCD 2+1-flavor domain-wall fermion ensembles, we determine flowed bag parameters for physical charm and strange quarks and match to the $\overline{\text{MS}}$ scheme with perturbative short flow-time expansion coefficients through next-to-next-to-leading order (NNLO). A multi-scale matching procedure using renormalization-group running improves the extrapolation to zero flow time. For the operators relevant to $τ(D_s)/τ(D^0)$ at the SU(3)$_{\rm F}$ symmetric point, we obtain $B_1^{\overline{\text{MS}}}(3\,{\rm GeV})=1.0524(97)$,$B_2^{\overline{\text{MS}}}(3\,{\rm GeV})=0.9621(70)$, $ε_1^{\overline{\text{MS}}}(3\,{\rm GeV})=-0.2275(76)$, and $ε_2^{\overline{\text{MS}}}(3\,{\rm GeV})=-0.0005(8)$ using a specific choice of evanescent operators. This is the first lattice-QCD determination of $ΔQ=0$ four-quark operators with a full error budget. It opens the path towards higher-precision predictions of heavy-meson lifetimes and similar quantities exhibiting operator mixing under renormalization.

2603.28514 2026-03-31 math.AP math.CA math.DS nlin.PS nlin.SI

Stability of periodic waves in the model with intensity--dependent dispersion

Fábio Natali, Dmitry E. Pelinovsky, Shuoyang Wang

Comments 38 pages

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We study standing periodic waves modeled by the nonlinear Schrodinger equation with the intensity-dependent dispersion coefficient. Spatial periodic profiles are smooth if the frequency of the standing waves is below the limiting frequency, for which the profiles become peaked (piecewise continuously differentiable with a finite jump of the first derivative). We prove that there exist two families of the periodic waves with smooth profiles separated by a homoclinic orbit and the period function (the energy-to-period mapping) is monotonically increasing for the family inside the homoclinic orbit and decreasing for the family outside the homoclinic orbit. This property allows us to derive a sharp criterion for the energetic stability of such standing periodic waves under time evolution if the perturbations are periodic with the same period for both families and, additionally, for the family outside the homoclinic orbit, spatially odd with respect to the half-period. By numerically approximating the sharp stability criterion, we show that both families are energetically stable for small frequencies but become unstable when the frequency approaches the limiting frequency of the peaked waves.

2603.28513 2026-03-31 physics.plasm-ph physics.comp-ph

The FreeGSNKE Pulse Design Tool (FPDT): a computational framework for evolutive plasma scenario and control design

K. Pentland, N. C. Amorisco, A. Ross, P. Cavestany, T. Nunn, A. Agnello, G. K. Holt, G. McArdle, C. Vincent, J. Buchanan, S. J. P. Pamela

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We present the FreeGSNKE Pulse Design Tool (FPDT), an open-source, Python-based computational framework that enables in silico testing and predictive design of tokamak plasma scenarios and control strategies. The FPDT couples the FreeGSNKE evolutive equilibrium solver with a virtual Plasma Control System (PCS) containing modular and customisable controllers. Given a set of user-defined waveforms and control parameters, the virtual PCS uses feedback and feedforward control to modulate plasma current, position, and shape, while adhering to machine safety limits on poloidal field coil currents and voltages. The resulting framework allows simulation of the controlled dynamic evolution of plasma equilibria, along with the currents in both active poloidal field coils and passive conducting structures, under the assumption of axisymmetry. The FPDT can be used to develop plasma scenarios, test control schemes, calibrate control parameters, and perform uncertainty quantification studies, thereby reducing iterative and expensive experimental testing on a physical tokamak. The FPDT is machine-agnostic and can be customised to implement different control algorithms tailored to the specific tokamak of interest. Here, we outline the overall framework and validate its performance on plasma discharges on the MAST Upgrade tokamak in the `flat-top' phase. We demonstrate excellent quantitative agreement between the FPDT simulations, the desired control waveforms, and the experimental shot data. With this extension to the FreeGSNKE open-source suite of codes we aim to encourage more reproducible and collaborative research in plasma modelling and control.

2603.28511 2026-03-31 cond-mat.soft physics.flu-dyn

Bubbles in highly porous media: Clogging and unclogging at constrictions

J. M. P. Beunen, T. Lappan, P. Malgaretti, O. Aouane, K. Eckert, J. Harting

Comments 17 pages, 8 figures

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Gas bubble transport through highly porous transport layers (PTLs) is a key process in electrochemical devices such as proton exchange membrane water electrolyzers, where bubbles generated at catalyst surfaces must migrate through complex porous networks. To understand this process, we focus on model systems, namely the motion of single, paired and multiple bubbles in capillaries and study these by combining analytical modeling, three-dimensional color-gradient lattice Boltzmann simulations, and X-ray radiography. For single bubbles, we derive an analytical expression for the critical Bond number separating passage from clogging and show that, in the low deformation regime, it accurately predicts this transition in circular capillaries. Extending the study to bubble pairs, we uncover additional clogging and unclogging pathways, including hydrodynamic unclogging driven by pressure buildup in the interbubble film, and coalescence-induced clogging and unclogging. By mapping our results as functions of confinement ratio and Bond number, we define distinct dynamical regimes that control bubble passage. Experiments on bubble chains rising through highly porous nickel foams confirm the predicted clogging and unclogging mechanisms.

2603.28510 2026-03-31 math.CO math.NT math.RT

Zeros in the character table of the symmetric group

Sarah Peluse, Kannan Soundararajan

Comments 12 pages

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Computations of Miller and Scheinerman suggest that the vast majority of the zeros appearing in the character table of the symmetric group are of a certain special type. While we cannot prove this, we resolve a conjecture arising in their paper concerning these zeros, and address a related question of Stanley.

2603.28506 2026-03-31 quant-ph

Open-System Adiabatic Quantum Search under Dephasing

Afaf El Kalai, Peter J. Eder, Christian B. Mendl

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Adiabatic quantum algorithms must evolve slowly enough to suppress non-adiabatic transitions while remaining fast enough to be practical. In open systems, this trade-off is reshaped by decoherence. For Hamiltonians subject to dephasing Lindbladians, Avron et al. [1] showed that a unique timetable exists that maximizes the fidelity with a target state. This optimal schedule is characterized by a constant tunneling rate along the adiabatic path. In this work, we revisit their analysis and apply it to the adiabatic Grover search framework, obtaining closed-form expressions for the optimal evolution schedule, the minimum runtime, and the resulting achievable fidelity. Moreover, by invoking an energy-time uncertainty argument, we identify a critical dephasing threshold, beyond which further noise-assisted acceleration is prohibited, thereby defining the physically realizable boundaries for dephasing-based adiabatic quantum search protocols.

2603.28505 2026-03-31 physics.ins-det hep-ex nucl-ex

Process Development and First Cryogenic Operation of Compact Germanium Ring-Contact HPGe Prototypes

Kunming Dong, Shasika Panamaldeniya, Dongming Mei

Comments 27 pages, 12 figures and 3 tables

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Rare-event experiments such as LEGEND-1000 require high-purity germanium (HPGe) detectors with excellent energy resolution, low electronic noise, and scalable low-background packaging. The germanium ring-contact (GeRC) concept addresses this need through a recessed ring-and-groove electrode geometry intended to preserve point-contact-like low-capacitance signal formation in larger crystals. However, reliable GeRC fabrication has remained unproven because the non-planar groove geometry complicates machining, surface recovery, conformal passivation, and especially the eventual formation of a robust lithium-diffused outer contact. We report the fabrication and first cryogenic operation of two compact n-type GeRC process-validation prototypes produced from in-house HPGe crystals at the University of South Dakota. An optimized workflow was developed for core drilling, groove cutting, non-planar polishing, conformal amorphous-germanium (a-Ge) encapsulation, Al patterning, and GeRC-specific cryogenic mounting. Two independent sputtering systems were used to test whether the thin-film sequence remains operable across substantially different deposition environments. At 77~K, both devices biased stably, showed an inferred depletion onset near 340~V from a pulser-based capacitance proxy consistent with electrostatic modeling, and produced identifiable full-energy peaks from $^{241}\mathrm{Am}$ and $^{137}\mathrm{Cs}$. These results establish a proof-of-principle process and readout baseline for geometry-specific GeRC development. They do not yet constitute a deployment-ready large-mass GeRC technology, but they define the foundation for the next step: integrating conformal lithium-paint deposition and controlled diffusion on the ring-and-groove topology.

2603.28504 2026-03-31 astro-ph.SR astro-ph.IM

JW-VL: A Vision-Language Model for Solar Physics

Mingfu Shao, Hui Wang, Liyue Tong, Yuyang Li, Cunshi Wang, Jiaben Lin, Suo Liu, Haiqing Xu, Yin Zhang, Jing Huang

Comments 16 Pages,8figures

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Vision-Language Models (VLMs) have achieved breakthrough progress in general knowledge domains, yet adaptation to specialized scientific fields remains challenging due to multimodal representation shifts and the limited integration of domain-specific knowledge. To address the limitations of general-purpose VLMs when applied to solar physics image recognition, analysis, and reasoning, we propose JinWu Vision-Language (JW-VL), a fine-tuned foundation model tailored for solar physics. The model integrates multi-wavelength observational data from both space-based and ground-based telescopes, encompassing representative spectral bands spanning the photosphere, chromosphere, and corona. Built upon a cross-modal alignment knowledge distillation framework, JW-VL learns a joint visual-semantic embedding that enables end-to-end modeling from raw solar observational data to downstream tasks, including solar image recognition, solar activity analysis via image-based question answering, and optical character recognition (OCR), while also supporting the construction of a multi-band, cross-instrument solar image benchmark dataset. Furthermore, as a demonstration of interdisciplinary applicability, we developed a "Daily Solar Activity Reports" agent comprising core modules for solar activity level assessment, significant active region characterization, magnetic field complexity analysis, potential space weather impact assessment, and identifying active regions for targeted observation. While JW-VL may not yet meet the rigorous, high-precision demands of operational solar physics, it bridges raw observations and diverse downstream tasks, establishing a valuable methodological framework for applying multimodal deep learning to the field.

2603.28500 2026-03-31 math.GR

Monoids generated by projections

Matthew Fayers

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We define and explore semireflection monoids on a finite-dimensional vector space. These are monoids generated by semireflections: linear maps fixing a subspace of codimension 1. We mostly focus on the case of projection monoids (where the generating semireflections are non-invertible). After exploring some general theory, we give some important examples, and give classification results for projection monoids on $\mathbb C^2$ and $\mathbb R^3$. We then briefly introduce affine projection monoids.

2603.28496 2026-03-31 gr-qc

Asymptotic Solutions of Radiating Stars

R. S. Bogadi, G. Leon, M. Govender, K. S. Govinder, S. Maharaj, A. Paliathanasis

Comments 11 pages, 2 figures, to appear in Gen. Rel. Grav

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We investigate the evolution of the surface of radiating stars by studying the asymptotic behaviour of exact solutions initiated via the stationary boundary condition. This boundary condition leads to a master equation in the form of a second-order nonlinear differential equation that describes the evolution of the scale factor. We examine this master equation by introducing a set of dimensionless dynamical variables, motivated by similar approaches in cosmological settings. We derive the stationary points of the system in the presence of charge and a cosmological constant. Furthermore, we construct criteria for the initial conditions in order that the asymptotic limit approaches a static geometry.

2603.28490 2026-03-31 cond-mat.supr-con

Bogoliubov flat bands in twisted layered materials

Keiji Yada, Yuri Fukaya, Yukio Tanaka

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Flat bands have attracted considerable interest in condensed matter physics because they provide a fertile platform for realizing strongly correlated and topological quantum phases. To date, however, most studies have focused on flat bands in normal-state electronic structures, such as those found in graphene and transition metal dichalcogenides. In this work, we investigate the emergence of flat bands in the superconducting Bogoliubov quasiparticle spectrum of twisted layered $d$-wave superconductors. We show that when the superconducting order parameter is odd under the in-plane $\mathrm{C}_2$ rotation, Bogoliubov flat bands can be engineered in the vicinity of the rotation axis. By analyzing a low-energy effective Hamiltonian, we demonstrate that the Berry connection of single layer system provides a clear criterion for the formation of the Bogoliubov flat bands. Our results establish a new paradigm of superconducting twistronics, in which the twist angle acts as a powerful tuning parameter for designing gapless flat-band superconductors.

2603.28489 2026-03-31 eess.IV

Video Generation Models as World Models: Efficient Paradigms, Architectures and Algorithms

Muyang He, Hanzhong Guo, Junxiong Lin, Yizhou Yu

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The rapid evolution of video generation has enabled models to simulate complex physical dynamics and long-horizon causalities, positioning them as potential world simulators. However, a critical gap still remains between the theoretical capacity for world simulation and the heavy computational costs of spatiotemporal modeling. To address this, we comprehensively and systematically review video generation frameworks and techniques that consider efficiency as a crucial requirement for practical world modeling. We introduce a novel taxonomy in three dimensions: efficient modeling paradigms, efficient network architectures, and efficient inference algorithms. We further show that bridging this efficiency gap directly empowers interactive applications such as autonomous driving, embodied AI, and game simulation. Finally, we identify emerging research frontiers in efficient video-based world modeling, arguing that efficiency is a fundamental prerequisite for evolving video generators into general-purpose, real-time, and robust world simulators.

2603.28487 2026-03-31 math.GT

On Legendrian Thurston-Bennequin-symmetrical graphs

Trung Chau, Tanushree Shah

Comments Commenmts are welcome

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This article reviews the development of Legendrian graph theory in the standard contact 3-sphere ($S^3, ξ_{std}$). We provide a generalized criterion under which the total Thurston-Bennequin invariant of a Legendrian graph (sum of tb of all cycles of the Legendrian graph) can be computed from the tb of its smaller cycles. We verify this criterion for graphs with up to 9 vertices and construct infinite families of examples where it holds. We also present examples demonstrating that each condition in the criterion is necessary. Notably, the graphs satisfying this criterion exhibit a high degree of symmetry.

2603.28486 2026-03-31 quant-ph cond-mat.str-el

Emergent-Coupling-Based Ansatz Evaluated on a Superconducting Quantum Processor

Alina Joch, Kevin Lively, Benedikt Fauseweh

Comments 12 pages, 5 figures

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The performance of the variational quantum eigensolver depends critically on the choice of ansatz. In this work, we experimentally evaluate the emergent-coupling-based ansatz (ECBA), a physically motivated variational ansatz for disordered systems. The ECBA is based on a renormalization (semi-)group approach to determine the dominant effective couplings, resulting in shallow circuits that capture the essential long-range entanglement structure while balancing local correlations. We implement the ECBA on superconducting quantum processors and benchmark it on disordered Heisenberg chain models. Using classically pre-optimized parameters and error mitigation techniques, we study systems of up to 30 qubits and observe an experimental relative energy accuracy of 96.47% for the largest system. Furthermore, we find that the ECBA can be efficiently embedded on hardware with two-dimensional square-lattice connectivity. We compare to commonly used hardware efficient ansätze and observe that the ECBA achieves significantly higher accuracy at a similar gate count.

2603.28485 2026-03-31 math.CO math.NT

On Generalizations of Maiorana-McFarland and $\mathcal{PS}_{ap}$ Functions

Sezel Alkan, Nurdagül Anbar, Athina Avrantini, Erroxe Etxabarri-Alberdi, Tekgül Kalaycı, Beatrice Toesca

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We study generalizations of two classical primary constructions of Boolean bent functions, namely the Maiorana-McFarland ($MM$) class and the (Desarguesian) partial spread ($\mathcal{PS}_{ap}$) class. The construction of bent functions lying outside the completed $MM$ class has attracted considerable attention in recent years. In this direction, we construct families of generalized Maiorana--McFarland bent functions that are not equivalent to any function in the classical $MM$ or $\mathcal{PS}_{ap}$ classes, and hence lie outside their completed classes. As a second contribution, we investigate the decomposition of generalized $\mathcal{PS}_{ap}$ functions. We prove that when the degree is sufficiently small relative to the size of the underlying finite field, such functions do not, in general, admit a decomposition into bent or semibent functions. Consequently, they cannot be obtained from known secondary constructions based on concatenation. Finally, we present a secondary construction of Boolean bent functions arising from the concatenation of components of vectorial generalized $\mathcal{PS}_{ap}$ functions. Our constructions and proofs rely on classical results concerning second-order derivatives of bent functions and their duals. In addition, we employ methods from the theory of algebraic curves and their function fields.

2603.28484 2026-03-31 math.OC

On the Convergence of Proximal Algorithms for Weakly-convex Min-max Optimization

Guido Tapia-Riera, Camille Castera, Nicolas Papadakis

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We study alternating first-order algorithms with no inner loops for solving nonconvex-strongly-concave min-max problems. We show the convergence of the alternating gradient descent--ascent algorithm method by proposing a substantially simplified proof compared to previous ones. It allows us to enlarge the set of admissible step-sizes. Building on this general reformulation, we also prove the convergence of a doubly proximal algorithm in the weakly convex-strongly concave setting. Finally, we show how this new result opens the way to new applications of min-max optimization algorithms for solving regularized imaging inverse problems with neural networks in a plug-and-play manner.

2603.28483 2026-03-31 math.LO

The Grothendieck ring of a non-divisible ordered abelian group is trivial

Blaise Boissonneau, Mathias Stout, Floris Vermeulen

Comments 5 pages, comments welcome

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We consider the model-theoretic Grothendieck ring of definable sets in ordered abelian groups. It is well-known that $\mathrm{K} \mathbb{Q} \cong \mathbb{Z}[T]/(T^2 + T)$ and $\mathrm{K} \mathbb{Z} =0$, but surprisingly little is known about other cases. We present a short computation which shows that they all collapse: $\mathrm{K} G = 0$, unless $G$ is divisible.

2603.28482 2026-03-31 cond-mat.mes-hall

Resonant-enhanced tunneling electroresistance in sliding ferroelectric tunnel junctions

Ruixue Wang, Jiangang Chen, Er Pan, Wunan Wang, Zefen Li, Fan Yang, Hongmiao Zhou, Zhaoren Xie, Qing Liu, Xiao Luo, Junhao Chu, Wenwu Li, Fucai Liu

Comments 12 pages, 4 figures

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The escalating demand for memory scaling requires switching mechanisms that remain reliable at atomic thickness while operating with minimal energy consumption. Sliding ferroelectricity provides a promising platform for this challenge: the spontaneous interfacial polarization emerging at superlubric, atomically thin van der Waals interfaces endows exceptional fatigue resistance, ultrafast switching and ultralow coercive fields. Nevertheless, the intrinsically weak polarization of sliding ferroelectrics limits the available signal window, necessitating new physical mechanisms that can transduce subtle polarization variations into pronounced resistance contrasts. Here, we address this challenge by introducing momentum-conserving resonant tunneling between lattice-aligned graphene electrodes. The resulting resonant sliding ferroelectric tunnel junction achieves a tunneling electroresistance (TER) ratio of up to 225.65%, substantially exceeding that of conventional sliding ferroelectric tunnel junctions. In addition, the device delivers a tunable TER ratio, multistate programmability, high current density, robust endurance with a small coefficient of variation (<0.69%), fast switching (20 ns), low switching energy (310 fJ), and low read voltage (<0.2 V). Collectively, these results establish a unique role for sliding ferroelectricity in bridging the gap of memory technology between performance and miniaturization, and open a new pathway toward next-generation nonvolatile memory technologies.

2603.28479 2026-03-31 math.DG math.AP

Comparison methods for semilinear elliptic problems on Riemannian manifolds with a Ricci lower bound

José M. Espinar, Fernán González-Ibáñez, Diego A. Marín

Comments 42 pages, 5 figures

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In the first part of the article we develop a comparison method for positive solutions of the semilinear Dirichlet problem $Δu+f(u)=0$ on domains $Ω\subset \mathcal M^n$ of a Riemannian manifold $(\mathcal{M}^n,g)$ with a Ricci lower bound $\operatorname{Ric}_g\ge (n-1)k\,g$. Assuming admissibility and structural conditions on $f$, we prove a sharp pointwise gradient comparison, with a rigid characterization of the equality case. As applications, we derive an explicit isoperimetric-type inequality and a quantitative hot-spot localization estimate under natural convexity assumptions. In the second part, on $\mathbb S^n$ we show that isoparametric foliations produce non-rotational $f$-extremal domains, and that these examples descend to smooth quotients under free isometric actions preserving the foliation.

2603.28478 2026-03-31 cs.CE

Physics-Enforced Neural Ordinary Differential Equation for Chemical Kinetics Optimization in Reaction-Diffusion Systems

Feixue Cai, Hua Zhou, Zhuyin Ren

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Calibrating chemical kinetics in a reaction-diffusion system is challenging because of complex dynamics governed by tightly coupled chemistry and transport, while experimental observations are often sparse and noisy. We propose a physics consistent diffusion-chemistry coupled neural ordinary differential equation (Diff-Chem Neural ODE) that embeds Arrhenius-structured reaction neurons into a fully differentiable streamline formulation and explicitly accounts for diffusion coupling. This design enables direct gradient-based analysis of kinetic parameters without sampling-based pretraining. We validate this method on burner-stabilized flat and stagnation reacting flows using mechanisms spanning different stiffness ranges. The proposed method reproduces species profiles with near-reference accuracy, whereas a pure chemistry Neural ODE that neglects diffusion coupling may misplace ignition and generate an incorrect thin reaction zone. Diff-Chem Neural ODE is more robust than pure chemistry Neural ODE and provides substantial speedups for gradient evaluation compared with fully discretized computations. In kinetics refinement, optimizing only a limited set of "primal" species reduces the loss by over 98% and simultaneously recovers unobserved variables, demonstrating physically consistent global control. Finally, tests with 1-20% noise in the objective show stable convergence without local overfitting, supporting its applicability under noisy measurements.

2603.28477 2026-03-31 math.AP

A convergence result for the master operator

Wenxiong Chen, Yahong Guo, Congming Li, Yugao Ouyang

Comments 27 pages

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英文摘要

In this paper, we establish a convergence result for the fully fractional heat operator $\ma{s}$, also known as the master operator, stated as follows: \[\mbox{If\ }u_i\to u\ \mbox{in}\ C^{2,1}_{x,t,loc}(\R^n\times\R),\ \mbox{then}\ \ma{s} u_i\to \ma{s}u-b\ \mbox{a.e. in}\ \R^n\times\R,\] for some nonnegative constant $b$. This result addresses a fundamental question in the blow-up and rescaling analysis, which are essential for establishing a priori estimates for solutions of master equations. Additionally, we present examples demonstrating that in certain cases, the constant $b$ can indeed be positive. This highlights a key distinction between nonlocal and local operators: for a local heat operator, such as $\partial_t - \lap$, it is well-known that $b \equiv 0$.

2603.28472 2026-03-31 astro-ph.SR astro-ph.GA

Period-Luminosity Relations, projection factor and radii of Anomalous Cepheids

Piotr Wielgórski, Grzegorz Pietrzyński, Wolfgang Gieren, Bartlomiej Zgirski, Weronika Narloch, Gergely Hajdu, Jesper Storm, Nicolas Nardetto, Pierre Kervella, Bogumił Pilecki, Marek Górski, Radosław Smolec, Ricardo Salinas, Dariusz Graczyk, Vincent Hocdé, Paulina Karczmarek, Monica Taormina, Wojciech Pych, Henryka Netzel, Rolf Chini, Klaus Hodapp, Mikołaj Kałuszyński, Francisco Pozo Nuñez, Krzysztof Kotysz, Dawid Moździerski, Przemysław Mikołajczyk, Piotr Kołaczek-Szymański

Comments Accepted for publication in Astronomy and Astrophysics

详情
英文摘要

Anomalous Cepheids are radially pulsating stars observed in dwarf galaxies, the Galactic bulge and halo, and globular clusters. Similarly to other radially pulsating stars, they can be used as distance indicators through their Period-Luminosity Relations (PLRs) and the geometrical Baade-Wesselink (BW) method. We aim to calibrate the zero-point of the distance scale of Anomalous Cepheids using nearby representatives of this class of pulsating stars. We collected optical and near-infrared photometry and spectra for a sample of nearby Anomalous Cepheids with twotelescopes located at the Rolf Chini Cerro Murphy Observatory and optical telescopes offered by the Las Cumbres Observatory, and with instruments hosted and operated by the European Southern Observatory. Using parallaxesmeasured by the Gaia space mission and mean magnitudes from our new photometry, we calibrate the zero-point of the PLRs in Johnson B, V, 2MASS J, H, KS , and Pan-STARRS g, r, i passbands and selected Wesenheit indices. Using the surface brightness-colour relation version of the BW technique, we also determined the projection factors and mean radii of three nearby Anomalous Cepheids. Precision of the measured zero-points is at the level of 0.04-0.05mag and their systematic uncertainty is estimated to about 0.1mag. We used our zero-points and literature photometry of the Large Magellanic Cloud Anomalous Cepheids to measure the distance modulus of this galaxy and obtained a value of 18.454$\pm$0.045(statistical) mag, in a very good agreement with the most accurate value from eclipsing binaries. The obtained projection factors are 1.38$\pm$0.13, 1.59$\pm$0.21 and 1.35$\pm$0.14 for V716 Oph, XX Vir and UY Eri, respectively. The radii measured for V716 Oph and UY Eri are in agreement with the period-radius relation obtained from the Large Magellanic Cloud Anomalous Cepheids.

2603.28471 2026-03-31 quant-ph

$1/N^2$ Precision Interferometry with Collectively Enhanced Atomic Mirror

Yuan Liu, Ke-Mi Xu, Hong-Bo Sun, Linhan Lin

Comments 6 pages, 3 figures

详情
英文摘要

Quantum metrology exploits quantum resources to enhance measurement precision beyond the classical limit. Conventional protocols normally rely on the preparation of delicate quantum states to acquire these resources, posing a major challenge for scaling and robustness. Here we introduce a paradigm that circumvents this requirement with a collectively enhanced quantum mirror (CEAM), i.e., a mesoscopic array of $N$ atoms coupled to a semi-infinite waveguide. When injecting single photons into the waveguide and estimating the CEAM-boundary distance from the reflection phase, a $1/N^2$ precision scaling can be obtained, which surpasses the Heisenberg limit. In this protocol, the quantum resource stems from the cooperative optical response, requiring no entangled state preparation. Our scheme is robust against positional and coupling disorder, offering a practical route to ultra-sensitive quantum metrology in integrated photonic systems.