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2605.14711 2026-05-15 gr-qc

Black holes and neutron stars in massive Hellings-Nordtvedt theory

Zhe Luo, Liang Liang, Zhong-Xi Yu, Hong-Da Lyu, Shoulong Li, Hongwei Yu

AI总结 本文研究了质量型Hellings-Nordtvedt理论中黑洞和中子星的性质,该理论通过两个独立的耦合项将矢量场与曲率非最小耦合。作者分析了不同耦合情形下的渐近真空结构,发现只有在特定耦合下才能得到类似单极子的真空行为,并进一步在$A^2{\cal R}$耦合下得到了具有非平凡径向矢量场的施瓦茨希尔德度规。研究还计算了诺特质量,推导了太阳系限制,并构建了中子星模型,表明该理论框架在强场条件下能够产生与广义相对论显著不同的天体性质,同时仍符合弱场测试。

Comments 29 pages, 3 figures

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英文摘要

Hellings-Nordtvedt theory is a vector-tensor theory in which a vector field $A_μ$ is nonminimally coupled to curvature through two independent interactions $A^2{\cal R}$ and $A^μA^ν{\cal R}_{μν}$. When supplemented by a potential whose zero-energy minimum occurs at nonzero $A^2$, the restricted $A^μA^ν{\cal R}_{μν}$ sector is known to admit black-hole and neutron-star solutions with a monopole-like asymptotic vacuum structure. We examine whether this structure is a generic consequence of the nonzero vector vacuum or instead relies on the special Ricci-tensor coupling. By analyzing the field equations near spatial infinity, we show that the asymptotic vacuum condition is incompatible with generic nonzero values of both couplings and instead selects two allowed single-coupling sectors. The $A^μA^ν{\cal R}_{μν}$ sector reproduces the known monopole-like asymptotics, whereas the $A^2{\cal R}$ sector admits an asymptotically flat Schwarzschild metric with a nontrivial radial vector field. We further compute the Noether mass in the $A^2{\cal R}$ sector, derive the corresponding Solar-System constraints, and construct neutron-star configurations. Although the weak-field deviation is constrained to be small, neutron stars can still show appreciable departures from both general relativity and the Ricci-tensor-coupling sector in their masses, radii, and moments of inertia. Our results identify that the $A^2{\cal R}$ sector of massive Hellings-Nordtvedt theory as a viable and useful framework for studying strong-field compact objects with a nonzero vector vacuum while remaining compatible with weak-field tests.

2605.14706 2026-05-15 math.CO

On equidistribution theorem for plane partitions

Alimzhan Amanov, Damir Yeliussizov

AI总结 本文研究了有界平面分拆中两组统计量的等分布性质,分别为(体积,迹)和(角钩体积,角数)。作者通过不同的三维路径系统可视化方法,给出了严格的证明,并得到了一个平面分拆体积生成函数的新直观证明。此外,文章引入了一个新的统计量——共钩面积,并证明其在普通分拆中与面积统计量等分布。

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Journal ref
European Journal of Combinatorics 136 (2026), Article 104394
英文摘要

We prove equidistribution of two pairs of statistics on boxed plane partitions: (volume, trace) and (corner-hook volume, number of corners). The proof relies on different 3d visualizations of the corresponding non-intersecting path systems. In particular, we obtain a new visual proof for a volume generating function of plane partitions. We also introduce a new statistic called the cohook area on ordinary partitions, and prove that it is equidistributed with the area of partitions.

2605.14702 2026-05-15 math-ph cond-mat.soft math.MP physics.flu-dyn

Weakly nonlinear analysis of Hopf bifurcations in the elastohydrodynamics of Cosserat rods

Mohamed Warda

AI总结 本文研究了在粘性流体中由终端跟随力驱动的平面Cosserat杆的flutter不稳定性弱非线性饱和问题。通过多重尺度展开和非自共轭算子的伴随模态分析,推导出临界振荡模式的Stuart-Landau振幅方程,揭示了在临界力附近极限环振荡的形成机制。研究结果表明,系统经历超临界Hopf分岔,振荡振幅与偏离临界阈值的距离平方根成正比,为软体机器人在低雷诺数下的自持振动提供了理论解析依据。

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英文摘要

We study the weakly nonlinear saturation of the flutter instability of a planar Cosserat rod in a viscous fluid driven by a terminal follower force. This instability, established in our preceding work as a Hopf bifurcation of a non-self-adjoint linear operator, produces stable limit-cycle oscillations in the fully nonlinear overdamped dynamics. Here we derive an analytical description of the emergence of this limit cycle near threshold. Working close to the critical follower force, we perform a multiple-scale expansion about the compressed straight base state and systematically remove secular growth at higher orders. Solvability at cubic order, enforced using the adjoint eigenmode of the non-Hermitian operator, yields a Stuart-Landau amplitude equation for the critical oscillatory mode. The Landau coefficients are expressed as explicit inner products involving the critical eigenmode, its adjoint, and quadratic corrections. The resulting reduced theory predicts a supercritical Hopf bifurcation with a steady-state tip oscillation amplitude scaling as the square root of the distance from threshold. These predictions rationalize the near-threshold scaling observed in nonlinear simulations and provide an analytical normal form for the onset of self-sustained beating in pressure-driven soft robotic arms at low Reynolds number.

2605.14701 2026-05-15 math.LO

Nonembeddings of Combinatory Algebras

Patrick Lutz, Paul Shafer, Sebastiaan A. Terwijn

AI总结 在组合代数理论中,存在从克莱尼第二模型、范奥斯特恩模型到斯科特图模型之间的一系列嵌入关系。本文证明了这些嵌入关系均无法逆向成立,并进一步探讨了这些模型的有效版本及相对嵌入问题,解决了文献中提出的多个问题。

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英文摘要

In the theory of combinatorial algebras, there is a sequence of embeddings between Kleene's second model, van Oosten's model, and Scott's graph model. We prove that none of these embeddings can be reversed. We also prove nonembedding results for the effective versions of these models, and in addition we discuss relativized embeddings. This answers several questions from the literature.

2605.14699 2026-05-15 math.AP math.CA math.FA

Bilinear embedding for divergence-form operators with first-order terms and negative potentials

Lorenzo Luciano Morelato, Andrea Poggio

AI总结 本文研究具有复系数、同时包含一阶项和负势的二阶散度型算子的双线性嵌入问题,拓展了Carbonaro和Dragičević在齐次情形下以及后续针对单一情形的研究成果。作者引入了一种统一的广义$p$-椭圆性条件,作为双线性不等式的自然前提,并提出一种基于序列的新方法,克服了传统Bellman-热方程方法在任意开集上的局限性。该研究进一步证明了$H^\infty$-微分算子在$L^p$空间上的有界性以及$L^p$-极大正则性,并展示了该条件对生成半群的$L^p$-收缩性和解析性的充分性。

Comments 56 pages

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英文摘要

This article establishes a bilinear embedding for second-order divergence-form operators with complex coefficients, characterized by the simultaneous presence of first-order terms and negative potentials. This work provides a further development of the theory initiated by Carbonaro and Dragičević for the homogeneous case, and recently extended by the second author to cases where first-order terms or negative potentials were treated in isolation. We work in the general setting of arbitrary open subsets of $\mathbb{R}^d$ under Dirichlet, Neumann, or mixed boundary conditions. Our main contribution is the introduction of a unified notion of generalized $p$-ellipticity that extends all its predecessors and serves as the natural condition for the bilinear inequality. Methodologically, we overcome the rigidity of the Bellman-heat method on arbitrary open subsets by introducing a novel sequence-based approach that unifies and simplifies the previous techniques. As fundamental applications, we prove the boundedness of the $H^\infty$-calculus on $L^p$ and establish $L^p$-maximal regularity. Moreover, we show that this generalized $p$-ellipticity provides a sufficient condition for the $L^p$-contractivity and $L^p$-analyticity of the generated semigroup.

2605.14697 2026-05-15 cond-mat.mtrl-sci quant-ph

Telecom-Wavelength-Compatible Quantum Information Transcription Using Nitrogen-Vacancy Centers

B. Göblyös, S. Kollarics, R. Kucsera, D. Plitt, K. Koltai, B. G. Márkus, L. Forró, F. Simon

AI总结 该研究利用金刚石中的氮-空位(NV)中心,探索了一种在电信波段兼容的量子信息读取方法。通过红外波段(约1042 nm)的光检测磁共振(ODMR)测量,研究人员直接观测到了与自旋状态相关的光信号变化,并揭示了其对磁场的依赖性。研究表明,NV中心的自旋信息可通过自旋选择性的系间窜越过程传递到红外单重态发射中,从而实现高保真度的光学读取。这一成果为构建无需主动频率转换的金刚石自旋量子比特与电信设备之间的高效接口提供了新途径。

Comments 6 pages, 4 figures, plus Supplementary Information

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英文摘要

Nitrogen-vacancy (NV) centers in diamond are a leading platform for solid-state quantum sensing and quantum information processing. While most optical studies rely on the visible fluorescence associated with the triplet transitions, the infrared singlet transition near $1042$ nm, which is typically considered dark within the singlet manifold of the NV optical cycle, provides an alternative optical channel. Here, we report wavelength-resolved optically detected magnetic resonance (ODMR) measurements of this infrared emission. We directly observe ODMR contrast in the $1042$ nm emission and analyze its dependence on the magnetic field. The field-dependent spectral dispersion of the ODMR signal demonstrates that the spin-state information encoded in the NV center is transcribed to the infrared singlet emission through the spin-selective intersystem crossing, in close analogy to the visible fluorescence readout. These results establish infrared ODMR as a high-fidelity optical readout pathway. Crucially, by extending spin-state transcription directly into the $1300-1600$ nm range, this work demonstrates a direct, conversion-free interface between diamond spin-qubits and standard telecommunication infrastructure, bypassing the efficiency bottlenecks of active frequency conversion and benefiting from the already well-developed technologies in this range of the electromagnetic spectrum.

2605.14695 2026-05-15 hep-th

A Tale of Two Orbits: Non-Simply Laced Mirror

Amihay Hanany, Deshuo Liu

AI总结 该论文研究了一个三维$\mathcal{N}=4$规范场论,其Higgs分支实现了$\mathfrak{sl}_n$最小nilpotent轨道的余切丛的仿射闭包,这一空间被识别为$\mathrm{U}(1)$超凯勒商空间。通过将$\mathrm{SU}(2)$ SQCD(带有$n+1$味)的味对称群中的$\mathrm{SO}(2)\cong\mathrm{U}(1)$子群规范化得到该理论。文章提出了一个非单李型磁性图,其Coulomb分支重现了相同的奇点,为包含非单李型图的镜像对提供了证据,并通过格子商和Hasse图逆变换进行了验证。

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英文摘要

A three-dimensional $\mathcal{N}=4$ gauge theory is constructed whose Higgs branch realizes the affine closure of the cotangent bundle of the minimal nilpotent orbit of $\mathfrak{sl}_n$. This space is a symplectic singularity recently identified by Fu and Liu as a $\mathrm{U}(1)$ hyperkähler quotient of the closure of the minimal nilpotent orbit of $\mathfrak{so}_{2n+2}$. The theory arises by gauging an $\mathrm{SO}(2)\cong\mathrm{U}(1)$ subgroup of the flavour symmetry of $\mathrm{SU}(2)$ SQCD with $n+1$ flavours. The Hilbert series is computed and the stratification is determined. A non-simply laced magnetic quiver is proposed whose Coulomb branch reproduces the same singularity. Evidence is thereby provided for a mirror pair involving a non-simply laced quiver, further tested through quiver subtraction and Hasse diagram inversion. A related $\mathbb{Z}_2$ quotient of the magnetic lattice is also analysed, and the exceptional behaviour in the case $n=2$, where $A_1 \cong C_1$, is explained. This construction provides a concrete example in which the Higgs-branch structure associated with a non-simply laced magnetic quiver can be inferred and validated through its mirror dual.

2605.14693 2026-05-15 astro-ph.GA

Discovery of a Compact Hub-Filament System in G286.21+0.17 with JWST and ALMA: Insights into Protocluster Formation and Competitive Accretion

L. K. Dewangan, N. K. Bhadari, Ram K. Yadav, A. K. Maity, O. R. Jadhav, Kee-Tae Kim, Paul F. Goldsmith, A. Saha, Dana Alina, Chang Won Lee, Saurabh Sharma, Tie Liu, Patricio Sanhueza, Tapas Baug, E. Sharma, Fengwei Xu, Ariful Hoque, James O. Chibueze, Dana Makarova, Wenyu Jiao

AI总结 本文利用JWST近红外成像和ALMA的H¹³CO⁺观测,研究了大质量原星团G286.21+0.17中的致密枢纽-丝状结构系统,揭示了一个由多个汇聚丝状结构和原恒星喷流组成的紧凑系统。研究发现,丝状结构的质量吸积率和核心密度分布支持竞争吸积机制,并表明原星团形成可能受到丝状结构吸积和恒星反馈的共同调控。

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英文摘要

We present a multi-wavelength study of the massive protocluster G286.21+0.17 (G286) using \emph{JWST} near-infrared imaging and ALMA H$^{13}$CO$^{+}$(1--0) observations. The \emph{JWST} images uncover a compact ($\sim$0.5 pc) hub-filament system (HFS), comprising a dense central hub connected by at least four converging filaments seen in absorption, along with multiple H$_2$ protostellar jets/outflows. The hub hosts dense core G286c1. The H$^{13}$CO$^{+}$ emission confirms this HFS over [$-$19.2, $-$16.4]~km~s$^{-1}$. The \emph{JWST} images further trace prominent photodissociation regions around the H\,{\sc ii}~region~A, powered by a B-type star. The radial distribution of ALMAGAL 1.38 mm core properties reveals steep power-law slopes toward the hub center. Within the inner hub (r < 8'', $\sim0.1$~pc), the core number density follows $ρ~[\rm pc^{-2}] \propto r^{-2.4\pm0.5}$, the surface density scales as $Σ~[\rm g~cm^{-2}] \propto r^{-1.0\pm0.2}$, and the enclosed core mass varies as $M_{\rm core}~[M_{\odot}] \propto r^{-1.2\pm0.2}$, while core diameters remain approximately constant ($D_{\rm core}~[\rm AU] \propto r^{-0.1\pm0.1}$). These trends, along with filament mass accretion rates of $7\times10^{-6}$--$1.8\times10^{-4}$~$M_\odot$~yr$^{-1}$, support a competitive accretion scenario in which gravitational focusing enhances core growth toward the hub center. Filament linewidths increase from tail/outer-region to head/hub-region, consistent with gravity-driven turbulence. However, the absence of a preferred alignment between velocity gradients and gravitational force directions may indicate a dynamically evolved system. The HFS likely formed through large-scale gas layer interactions and compression by the adjacent H\,{\sc ii} region. Overall, star formation in G286 appears regulated by filamentary accretion, competitive core growth in the hub, and stellar feedback.

2605.14691 2026-05-15 quant-ph

Decoherence of $q-$Deformed Photon Added Coherent State

Amit Das, Sobhan Sounda

AI总结 本文研究了在耗散环境中 $q$-形变光子附加相干态的退相干行为,采用 $q$-形变作为非线性函数来描述形变谐振子系统。通过调节形变参数,发现 $q$-形变光子附加相干态(DPACS)相比标准谐振子系统表现出更强的非经典特性和抗退相干能力。研究还分析了DPACS在光子损耗环境下的非经典性质和纠缠特性。

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英文摘要

In this study, we explore the behavior of photon added coherent states in a deformed harmonic oscillator subjected to dissipative decoherence. We use $q-$deformation as our nonlinear function to model our system. By adjusting the deformation parameter, we show that $q-$deformed photon added coherent state (DPACS) exhibit greater nonclassicality and resilience to decoherence compared to those of a standard harmonic oscillator. Additionally, we investigate the nonclassical properties and entanglement of DPACS under decoherence induced by interaction with a dissipative photon-loss environment.

2605.14688 2026-05-15 eess.SY cs.SY

Dynamic Event-Triggered Control of Discrete-Time Nonlinear Systems based on Difference-Algebraic Representations

Vitoriano Casas, Gabriela Reis, Pedro Henrique Coutinho, Iury Bessa, Rodrigo Araújo

AI总结 本文研究了基于差分代数表示(DAR)的离散时间非线性系统的动态事件触发控制问题,提出了一种基于增益调度控制器的方法。该方法将系统非线性特性以及事件触发采样引起的异步项纳入控制律和触发函数设计中,从而推导出一种更为宽松的协同设计条件,用于同时设计增益调度控制律和动态触发机制,以保证闭环系统的渐近稳定性。此外,还通过优化问题减少了事件触发次数并扩大了闭环系统的吸引域估计,数值例子验证了方法的有效性。

Comments Accepted to the IFAC World Congress 2026

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英文摘要

This paper addresses the dynamic event-triggered control for a class of discrete-time nonlinear systems described by a difference-algebraic representation (DAR), using a gain-scheduled controller. An outstanding aspect of the proposed method is the incorporation of information about the system's nonlinearities into the control law and the trigger function. The proposed event-triggered mechanism also incorporates information on the asynchronous terms induced by the event-based sampling. All these ingredients enable the derivation of a less conservative co-design condition for the simultaneous design of the gain-scheduled control law and the dynamic triggering mechanism to ensure the asymptotic stability of the closed-loop system. An estimate of the region of attraction of the origin of the closed-loop system is obtained to guarantee the closed-loop system's operation within the domain of validity of the DAR. Then, an optimization problem is formulated to reduce the number of events and enlarge the estimated region of attraction. Finally, the effectiveness of the proposed condition is illustrated by a numerical example.

2605.14687 2026-05-15 physics.chem-ph cond-mat.quant-gas cond-mat.stat-mech

Generalized Suzuki-Chin Factorization in Bosonic Path Integral Molecular Dynamics

Jacob Higer, Barak Hirshberg

AI总结 本文研究了广义Suzuki-Chin分解在玻色子路径积分分子动力学(PIMD)中的应用,提出该方法可提升玻色子体系平衡平均值的收敛速度,且无需改变现有的二次标度算法。该方法通过引入一个重加权因子实现,不影响原始采样过程,适用于谐振子势和正弦势等体系,并在多种温度范围内展现出约2至4倍的收敛加速效果,计算代价较低。

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英文摘要

Modern implementations of path integral molecular dynamics (PIMD) simulations of distinguishable particles frequently make use of high order factorization schemes for the Boltzmann operator to expedite convergence of equilibrium averages. Among these methods is the generalized Suzuki-Chin factorization (GSF), which is accurate up to fourth order in the imaginary-time step. In this work, we show that the GSF decomposition of the Boltzmann operator is applicable to bosonic PIMD, and results in an improved convergence of estimators. In particular, we show that the recently developed quadratic scaling bosonic PIMD need not change when using the GSF. The GSF scheme is implemented as a re-weighting factor for observables, without affecting the sampling generated by the standard, second-order, primitive factorization. We study the effect of this factorization for bosons in a harmonic trap and a sinusoidal potential. We also assess the effectiveness of GSF in calculating fermionic expectation values for harmonically-trapped atoms. In all these cases, we find that the GSF speeds up convergence with the Trotter number by a factor of $\sim 2-4$ across a wide temperature range, at only a modest computational cost.

2605.14684 2026-05-15 hep-th gr-qc hep-ph

QCD axion from broken scale symmetry

Georgios K. Karananas, Mikhail Shaposhnikov

AI总结 本文研究了如何从破缺的标度对称性中产生QCD轴子,并提出通过标度对称性的伪Nambu-Goldstone玻色子——稀释子(dilaton)来实现一个自洽的非紧致轴子宇宙学模型。该方法满足非周期场、高于暴胀尺度的有效场论以及对势能的小非QCD贡献等关键条件,从而能够及时触发域墙塌缩。这一研究为轴子暗物质的理论构建提供了新的视角和可能的解决方案。

Comments 19 pages, 2 figures

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英文摘要

A consistent non-compact axion cosmology requires a non-periodic field, an effective field theory valid sufficiently above the inflationary scale, and a small non-QCD contribution to the potential that tilts the axionic vacuum landscape in order to trigger a timely domain-wall collapse. All conditions can be met by the dilaton -- the pseudo-Nambu-Goldstone boson of spontaneously broken approximate scale invariance.

2605.14682 2026-05-15 math.CO

Combinatorial study of the q-Catalan triangle and its generalizations

Youssouf Wirdane

AI总结 本文研究了q-Catalan三角形及其推广的组合性质,定义了满足特定递推关系的q-Catalan数C_{n,k}(q),并给出了其通过七类组合对象的解释,包括模式避免排列、Dyck路径、二进制词和三角剖分等。文章引入了镜像多项式C-tilde_{n,k}(q),并提出了其对偶递推关系和共逆序统计解释,同时拓展了q,p-Catalan三角形及多变量推广,为环状q-模拟提供了基础。

Comments 10 pages. First paper of the W-series (W0-W5). HAL: hal-05549275

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英文摘要

We announce a series of results on the combinatorial study of the q-Catalan triangle (C_{n,k}(q)), defined by C_{n,0}(q)=q^{n(n-1)/2} and C_{n,k}(q)=C_{n,k-1}(q)+q^{n-k-1}C_{n-1,k}(q). We establish combinatorial interpretations via a universal combinatorial family of seven components: four families of pattern-avoiding permutations weighted by inversion or co-inversion statistics, Dyck paths, binary words and triangulations. We introduce the mirror polynomial C-tilde_{n,k}(q)=q^{n(n-1)/2}C_{n,k}(q^{-1}), prove its dual recurrence and co-inversion interpretation. The q,p-Catalan triangle and a multivariate generalization opening the way to cyclotomic q-analogues are introduced. Theorems on the q-Catalan triangle via 312-avoiding permutations and the mirror recurrence are proved completely here. This is the first paper of series W0-W5 on classical and q-deformed interpretations of the Catalan triangle.

2605.14681 2026-05-15 math.PR math-ph math.MP

Lower bound on the mixing time of $p$-spin glasses

Anouar Kouraich, Simone Warzel

AI总结 本文研究了$p$-自旋玻璃模型中Glauber动力学的混合时间下界,证明在逆温度大于常数乘以$\ln(p)/p$时,混合时间随$p$增大呈指数级增长。研究通过高斯分解分析能量景观,并建立瓶颈界来证明该下界。这一结果揭示了$p$-自旋玻璃在高逆温度下动力学行为的缓慢特性,为理解复杂系统中的弛豫过程提供了理论依据。

Comments 9 pages, 1 figure

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英文摘要

We show that Glauber dynamics for $ p$-spin glass mixes exponentially slowly at inverse temperatures larger than a constant times $ \ln (p)/p $ for large enough $ p $. This is done by analyzing the energy landscape using Gaussian decompositions and establishing a bottleneck bound.

2605.14680 2026-05-15 q-bio.NC

Are cortical microcircuits optimized for information flux? -- A simulation-based reverse engineering study

Claus Metzner, Ali Ghebleh, Karin Prebeck, Achim Schilling, Andreas Maier, Thomas Kinfe, Patrick Krauss

AI总结 该研究探讨了皮层微柱等生物神经网络是否通过特定结构优化信息流。通过构建一个简化的皮层第5层网络模型,研究发现外围网络能够显著增强核心网络的信息流动。分析表明,外围网络通过引入有效偏置和随机波动,使核心神经元进入更高熵的运行状态,并避免陷入固定点或振荡吸引子,从而提升信息处理能力。这一发现对理解生物神经回路功能及设计人工递归系统具有重要意义。

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A sufficiently large information flux in recurrent neural networks, quantified by the mutual information between successive network states, is considered a prerequisite for rich information processing capabilities. This raises the question of whether biological neural networks, such as cortical microcolumns, may be structurally organized to enhance information flux. To investigate this possibility, we study a simplified model of the cortical layer 5 architecture, in which a densely and strongly interconnected core population is embedded within a larger supporting network. Surprisingly, we find that the embedding network exerts a pronounced flux-enhancing effect on the core dynamics. Systematic reverse-engineering analyses reveal that the embedding network provides two key contributions: first, it generates effective biases that shift core neurons into a higher-entropy operating regime; second, it supplies stochastic fluctuations that prevent the network from becoming trapped in simple fixed-point or oscillatory attractors through the mechanism of Recurrence Resonance. We further show that the information flux can be increased even beyond the biologically embedded case by applying individually optimized biases to the core neurons, and that these biases can emerge from a simple self-organization principle. Our findings are relevant both for the functional interpretation of biological neural circuits and for the design of artificial recurrent systems such as reservoir computers.

2605.14677 2026-05-15 eess.IV

An Attention-Enhanced Network with Joint Dehazing and Retinex-Based Enhancement for Underwater Images

Sahana Ray, Bibhabasu Debnath, Sanjay Ghosh

AI总结 本文针对水下图像因光的吸收、散射和悬浮颗粒导致的能见度下降问题,提出了一种包含去雾和Retinex增强的三阶段网络ADR,通过扩展水下成像模型并结合注意力机制的U-Net++进行优化,有效提升了水下图像的质量。实验表明,该方法在多个基准数据集上的表现优于现有先进方法。

Comments 6 pages, 3 figures, 4 tables; accepted for the IEEE ICIP 2026 conference

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英文摘要

Underwater images suffer from severe wavelength-dependent light absorption and scattering, and turbidity due to suspended particles, degrading visual quality for applications in autonomous underwater vehicles (AUVs), marine biology, archaeology, and offshore infrastructure inspection. Classical IFM inadequately capture nonlinear underwater light behavior, while purely data-driven methods lack physical interpretability. This paper proposes a three-stage network named ADR, that extends the underwater image formation model with additional terms to perform underwater dehazing, followed by Retinex-based enhancement and attention-enabled U-Net++ refinement. Experiments on UIEB and UFO-120 benchmark datasets demonstrate competitive performance with state-of-the-art methods.

2605.14676 2026-05-15 physics.optics

Boosting Sensing Performance through Near-Field Engineering in Low-Q Metasurfaces

José Antonio Álvarez-Sanchis, Luis Manuel Máñez-Espina, Teresa Mengual Chuliá, Amadeu Griol, Ana Díaz-Rubio

AI总结 本文研究了如何通过近场工程提升低品质因数介质超表面的传感性能。不同于传统依赖高品质因数共振结构的方法,作者提出利用设计的低品质因数模式增强电磁近场分布,从而提高传感灵敏度和检测性能。研究表明,通过对倏逝模式的近场工程,可以在不依赖超高品质因数共振的情况下显著提升传感效果,为超表面传感提供了新的设计思路。

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英文摘要

Dielectric metasurfaces have introduced a new paradigm for substance detection by exploiting their resonant properties to enhance light-matter interaction. This enhancement can be used for sensing either through refractive index changes or through absorption-based mechanisms. Most works focus on high-quality factor resonators, aiming to increase field confinement in the vicinity of the resonant structure to improve sensitivity. In this work, we explore an alternative approach based on low-quality factor, fully dielectric metasurfaces, with engineered modes to enhance near-field concentration. We investigate different topologies that, despite their low-quality factors, achieve sensitivity and detection performance beyond what is typically reported for low-Q structures in the literature. This improvement is enabled by near-field engineering of the evanescent modes, allowing us to control the spatial distribution of the electromagnetic field and maximize its overlap with the analyte. Our results show that careful mode engineering provides a powerful strategy to boost sensing performance without relying on ultra-high-Q resonances.

2605.14675 2026-05-15 cs.SE

Agentic AI in Industry: Adoption Level and Deployment Barriers

Spyridon Alvanakis Apostolou, Jan Bosch, Helena Holmström Olsson

AI总结 本文研究了工业领域中智能代理AI系统的采用现状及部署障碍。通过对12家不同规模和行业的公司中16位从业者的定性访谈,研究发现大多数企业仍处于初级采用阶段,仅少数具备较高级别的多智能体协同能力。研究揭示了企业在将高级AI能力集成到生产流程时面临的主要障碍,包括大语言模型上下文窗口限制、对专有编程语言支持不足、非确定性与资质标准的冲突以及数据保密问题,这些问题共同导致了能力验证与实际部署之间的显著差距。

Comments 16 pages

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英文摘要

Agentic AI systems are entering software engineering workflows, yet empirical evidence on how industrial organizations actually adopt them remains sparse. We present a qualitative interview study with sixteen practitioners across twelve companies of varying size and domain. This study characterizes the current agentic AI adoption state of these companies, employing a six-level maturity framework adapted from established AI-driven organizations. The findings reveal that seven companies operate at Level~1 (AI Assistants), four companies at Level~2 (AI Compensators), and only one in Level~3 (Multi-Agent Orchestration), with large and safety-regulated organizations among the most advanced adopters. The primary finding is a capability-deployment verification gap, four companies demonstrated higher-level experimental AI capabilities but cannot integrate them into production workflows because adequate output verification mechanisms are absent, leaving human-in-the-loop as the only trusted verification mechanism. This gap is shaped by four recurring barriers: context window of LLMs constraints especially when diverse knowledge aggregation is needed, under-performance on proprietary programming languages and protocols, non-determinism incompatible with qualification standards, and data confidentiality concerns. Two interdependent dimensions of this gap emerge from these findings (information asymmetry and qualification absence) framing a core open problem for industrial agentic integration.

2605.14674 2026-05-15 nucl-th

Fourth order correlation of baryon number and electric charge as a better magnetometer of QCD

Shijun Mao, Shuai Yang, Sicheng Lin, Xinran Yang, Guoyun Shao, Wen-Chao Zhang

AI总结 本文研究了在有限温度、磁场和零夸克化学势条件下,重子数、电荷和奇异数的四阶关联,以探讨其作为QCD磁强计的潜力。研究基于三味夸克PNJL模型,考虑了有无反磁催化效应的情况,发现四阶关联 $χ^{BQ}_{31}$ 在手征恢复相变时对磁场的敏感性优于其他二阶和四阶关联,可作为更有效的QCD磁强计。

Comments 12 pages, 10 figures, 1 table. arXiv admin note: text overlap with arXiv:2504.14532

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英文摘要

This work focuses on the fourth order correlations $χ^{BQ}_{31}$, $χ^{QB}_{31}$, $χ^{BQ}_{22}$, $χ^{BS}_{31}$, $χ^{SB}_{31}$, $χ^{BS}_{22}$, $χ^{QS}_{31}$, $χ^{SQ}_{31}$, $χ^{QS}_{22}$, $χ^{BQS}_{211}$, $χ^{QBS}_{211}$, $χ^{SBQ}_{211}$ of baryon number $B$, electric charge $Q$ and strangeness $S$ at finite temperature, magnetic field and vanishing quark chemical potential. The study is carried out in the framework of a three-flavor PNJL model, considering both cases with and without inverse magnetic catalysis effect. We find that, fourth order correlations $χ^{BQ}_{31}$ at chiral restoration phase transition is more sensitive to the magnetic field than other second order and fourth order correlations and fluctuations, and can be served as a more effective magnetometer of QCD.

2605.14673 2026-05-15 cond-mat.mes-hall cond-mat.mtrl-sci

Compositional and Magnetic Characterisation of Oblique Co and Fe Nanowire Structures Fabricated Using Focused Electron Beam Induced Deposition

Aurys Silinga, Keir Edgar, Stephen McVitie, Kayla Fallon, András Kovács, Rafal E. Dunin-Borkowski, Trevor P. Almeida

AI总结 该研究利用聚焦电子束诱导沉积(FEBID)技术制备了具有悬空结构的钴(Co)和铁(Fe)纳米线,并系统研究了其组成和磁性特性随生长角度的变化。通过电子能量损失谱和离轴电子全息术,发现随着生长角度增大,纳米线中的金属含量逐渐降低,且该变化可通过调节电子束参数进行调控。研究为优化FEBID工艺以实现均匀的磁性纳米结构提供了重要参考。

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英文摘要

Focused electron beam induced deposition (FEBID) is an additive manufacturing technique uniquely suited for fabricating nanoscale 3D prototypes for a range of applications, including spintronic devices. However, the variation of growth dynamics associated with electron beam translation and sample interaction volumes results in structures with non-uniform composition when fabricating intricate 3D geometries. Herein, we measure changes in atomic composition and corresponding changes in magnetic induction in 3D ferromagnetic nanostructures with overhanging elements, e.g. bridges or arches. To investigate the effects of electron beam translation, we fabricated 41 Co and Fe nanowire (NW) structures with growth angle relative to the optic axis varying from 0° to 90°. The (scanning) transmission electron microscopy techniques of electron energy loss spectroscopy and off-axis electron holography were performed to map the NW elemental composition and magnetic induction as a function of NW growth angle. Comparison of the results reveals a reduction in metal content with increased oblique growth angle in FEBID NWs. The magnitude of metal content reduction can be tuned by controlling electron beam parameters, and ferromagnetic NWs with approximately equal metal content at growth angles from 0° to 60° were fabricated by using the lowest viable electron beam voltage and the highest viable beam current to reduce the interaction volume and increase the metal content, respectively.

2605.14670 2026-05-15 physics.geo-ph gr-qc

Laboratory rivers extremize friction and are cosmological analogues

Valerio Faraoni, Nikki Veilleux

AI总结 本研究发现,在浅水近似下,实验室河流的横截面轮廓满足一个微分方程,该方程在形式上等同于支配反德西特宇宙演化的弗里德曼方程。通过这一宇宙学类比,研究提出了一个反直觉的拉格朗日量来描述河流横向轮廓,并指出使对应作用量极值化等价于使河底摩擦力和能量耗散率极值化。进一步分析表明,这一极值是一个极大值。

Comments 8 pages, LaTeX

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英文摘要

In the shallow water approximation, the cross-sectional profiles of laboratory rivers satisfy a differential equation here shown to be formally the Friedmann equation of cosmology ruling the evolution of Anti-de Sitter universe. The ensuing cosmic analogy provides a counterintuitive Lagrangian for the transverse river profile. Extremizing the corresponding action corresponds to extremizing the friction force on the river bottom and the energy dissipation rate. Analysis of the second variation establishes that this extremum is a maximum.

2605.14669 2026-05-15 math.CA

Darboux-type formula for Jacobi biorthogonal polynomials

Zhaofeng Lin, Kai Wang, Zhanhang Zheng

AI总结 本文研究雅可比双正交多项式的渐进行为,提出了一种基于最速下降法的Darboux型公式。通过构造合适的积分路径并应用Rodrigues公式,推导出该公式,并证明在正交情形下该结果退化为经典的Darboux公式,拓展了传统Darboux公式的适用范围。

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英文摘要

In this paper, we study the asymptotic behavior of Jacobi biorthogonal polynomials. A Darboux-type formula is established using the method of steepest descent. In the proof, we construct an appropriate contour to apply the Rodrigues formula. Our result reduces to the classical Darboux formula in the orthogonal case.

2605.14668 2026-05-15 hep-th gr-qc

$α'$ corrections to self-dual gravitational instantons

José Luis V. Cerdeira, Cristóbal Corral, Tomás Ortín

AI总结 本文研究了四维Cano--Ruipérez作用量下自对偶引力瞬子的$α'$修正,该作用量源自异质弦有效作用量在$\mathbb{T}^6$紧致化后的截断与场重定义。研究发现,自对偶曲率空间的度规不受修正影响,但其标量场和轴子场由于与高斯-博内和庞特里亚金密度的耦合而发生修正。作者推导了Gibbons--Hawking多瞬子解的标量和轴子场的一般修正形式,并给出了欧几里得Taub--NUT和Eguchi--Hanson空间的具体表达式,同时构造了定义良好变分原理所需的边界项,并证明在$α'$一阶下欧几里得Eguchi--Hanson瞬子的总作用量无修正。

Comments LaTeX, 32 pages, no figures

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英文摘要

We study the $α'$ corrections to self-dual gravitational instantons in the context of the four-dimensional Cano--Ruipérez action, which can be obtained by the compactification of the Bergshoeff--de Roo heterotic string effective action on $\mathbb{T}^{6}$ followed by a truncation and a field redefinition. We show that the metric of spaces of self-dual curvature does not receive any corrections, but their (initially trivial) dilaton and axion fields do, owing to their couplings to Gauss--Bonnet and Pontrjagin densities. We find the generic form of the corrections of the dilaton and axion fields for the Gibbons--Hawking multi-instanton solutions and their explicit form for the particular cases of the Euclidean Taub--NUT and Eguchi--Hanson spaces. We construct the boundary terms required to define a well-posed Dirichlet variational principle in the Euclidean Cano--Ruipérez theory, including the contributions associated with the Gauss--Bonnet and Pontrjagin terms. The boundary terms are normalized for asymptotically-locally-Euclidean solutions, and we evaluate with them the Euclidean action of the $α'$-corrected Eguchi--Hanson instanton showing that the total action receives no corrections to first order in $α'$. We also show that, at zeroth order in $α'$, one can construct Euclidean solutions similar to the string theory D-instanton with non-trivial dilaton and axion on the background of a self-dual purely gravitational instanton which remains unmodified. We also compute the $α'$ corrections to these solutions.

2605.14663 2026-05-15 math.OC math.PR stat.ML

Optimal Asymptotic Rates for (Stochastic) Gradient Descent under the Local PL-Condition: A Geometric Approach

Sebastian Kassing, Thomas Kruse

AI总结 本文研究了梯度下降和随机梯度下降在满足Polyak-Lojasiewicz (PL)条件的$C^2$函数下的局部收敛行为,特别考虑了由过参数化神经网络引发的乘法梯度噪声模型。通过几何视角解释PL条件,作者证明了一个简洁而令人惊讶的结论:即使在非凸设置下,(S)GD的渐近收敛速度仍与强凸二次函数的收敛速度一致。这一结果揭示了SGD在非凸优化中具有与凸问题相似的最优渐近收敛速率。

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Stochastic gradient descent (SGD) has been studied extensively over the past decades due to its simplicity and broad applicability in machine learning. In this work, we analyze the local behavior of gradient descent and stochastic gradient descent for minimizing $C^2$-functions that satisfy the Polyak-Lojasiewicz (PL) inequality and under a multiplicative gradient noise model motivated by overparameterized neural networks. Using a geometric interpretation of the PL-condition, we prove a simple yet surprising fact: in this possibly non-convex setting, the asymptotic convergence rate of (S)GD matches the rate obtained for strongly convex quadratics.

2605.14658 2026-05-15 gr-qc

Static spherically symmetric Kundt vacuum solutions of higher-derivative gravities

Breno L. Giacchini, Ivan Kolář, Vojtěch Pravda, Alena Pravdová

AI总结 本文研究了具有宇宙学常数的二次引力和六阶导数引力理论中静态球对称的Kundt真空解。通过分析不同耦合常数下的解的结构,作者在二次引力中得到了所有满足特定条件的解,并利用Frobenius方法研究了特殊情形下的幂级数解;在六阶导数引力中,则重点展示了多种闭合形式解,并分析了可能的Frobenius解族。此外,作者还构造了在这些背景下传播的精确引力波解,指出在高阶引力理论中,适当选择耦合常数可以得到全局光滑的引力波解,与爱因斯坦引力中引力波必然伴随奇点的情况形成对比。

Comments 34 pages

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We study static spherically symmetric Kundt solutions to the vacuum field equations of quadratic gravity with a cosmological constant, as well as specific models of six-derivative gravity. In quadratic gravity, we identify all solutions for coupling constants satisfying ${α\neq3β}$, while the case ${α=3β}$ is studied using the Frobenius method, where we derive the recurrence relations for the power series. In contrast, in six-derivative gravity, we focus on selected models to illustrate the variety of closed-form solutions; we also analyze possible indicial families of Frobenius solutions. For all solutions, we analyze curvature singularities and their accessibility to geodesic observers. We then construct exact gravitational-wave solutions propagating on some of these backgrounds in quadratic and six-derivative gravity. It is known that in Einstein gravity, gravitational waves on the Nariai background unavoidably contain singularities, which are interpreted as physical sources generating these gravitational waves. In contrast, in addition to singular solutions, for appropriate values of the coupling constants, higher-order gravities allow for globally smooth solutions representing gravitational waves.

2605.14657 2026-05-15 gr-qc astro-ph.CO hep-th

Parametrization of the primordial power spectrum in loop quantum cosmology

Almudena Guillén, Kai Langer, Guillermo A. Mena Marugán, Niklas Rodenbücher, Antonio Vicente-Becerril

AI总结 本文研究了循环量子宇宙学中预暴胀反弹阶段对宇宙扰动角功率谱的影响,提出了一种新的原初功率谱参数化方法,该方法不仅包含标准宇宙学中的慢滚参数和宇宙学参数,还引入了反弹阶段的物理特性,如反弹时期的e-folds数和能量密度抑制尺度。该参数化方法基于NO-AHD真空选择,避免了原初真空状态的不确定性,并在高阶多极项上与Planck数据吻合良好,表现出优于标准ΛCDM模型的拟合效果。

Comments 22 pages, 7 figures

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英文摘要

We investigate the imprints on the angular power spectra of cosmological perturbations of a pre-inflationary bounce phase, as described by the hybrid and dressed metric approaches to loop quantum cosmology. For this purpose, we derive a new parametrization of the primordial power spectrum at the end of the inflationary regime. Apart from slow-roll coefficients and cosmological parameters that are present in the standard cosmological scenario without quantum modifications, this parametrization additionally depends only on pre-inflationary physics. More specifically, we find a dependence on the number of e-folds during the bounce epoch and on a characteristic suppression scale which, given the e-folds accumulated during cosmic evolution, is determined by the energy density at the bounce. Recall that this density depends on the Immirzi parameter and the area gap known from LQG. This leads to a robust and accurate parametrization of the primordial power spectrum. Since in pre-inflationary scenarios there is no preferred vacuum state, we adopt the NO-AHD proposal, which selects a vacuum that is optimally adapted to the background dynamics and yields a non-oscillatory primordial power spectrum. With this choice, we show that the tensor-to-scalar ratio in both quantization approaches coincides with its expression in the standard $Λ$CDM model when the observed scales are not much smaller than the power-suppressed region. Computing also the angular power spectrum, we find that, for a total cosmic expansion of about 140 e-folds, both the hybrid and the dressed metric approaches exhibit excellent agreement with Planck data at high multipoles, while apparently improving the fit with respect to $Λ$CDM for low multipole numbers.

2605.14656 2026-05-15 quant-ph

Blind Quantum Computation on a Modular Superconducting Processor

Yongxin Song, Johannes Knörzer, Kieran Dalton, Andreas Wallraff, Jean-Claude Besse

AI总结 本文研究了在模块化超导量子处理器上实现盲量子计算的问题,提出了一种基于测量的盲量子计算协议,使得客户端能够在不泄露任务或结果信息的情况下执行量子算法。实验中使用由两个模块组成的超导处理器,服务器生成二维簇态并发送给客户端,客户端仅通过自适应单量子比特旋转和测量实现通用量子门操作,并演示了三量子比特的德沃夏克算法。该工作验证了盲量子计算在超导电路架构中的可行性,为未来实现中等规模的盲量子协议奠定了基础。

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英文摘要

Current cloud-based quantum processors offer access to advanced hardware hosted on a remote server, but do not guarantee data or algorithm privacy. Blind quantum computation provides information-theoretic privacy by enabling a client to execute an algorithm without disclosing information about either the task or the final result. Here, we execute a measurement-based blind quantum computation protocol on a superconducting processor comprising two flip-chip-bonded modules, one acting as a server and the other as a client. The server generates a two-dimensional cluster state and forwards it to the client. Using this resource, the client implements a universal gate set with only adaptive single-qubit rotations and measurements. To illustrate this approach, we execute a three-qubit instance of the Deutsch-Jozsa algorithm. We analyze the server's quantum state after each rotation of a measurement-based single-qubit gate to verify that negligible information about the computation is revealed to the server, consistent with the one-way flow of information that guarantees blindness. This proof-of-principle demonstration establishes key elements of blind quantum computation in superconducting-circuit architectures, indicating that intermediate-scale implementations of blind protocols may become feasible with realistic near-term improvements in gate fidelities.

2605.14655 2026-05-15 cs.DC

Malleable Molecular Dynamics Simulations with GROMACS and DMR

Petter Sandås, Sergio Iserte, Íñigo Aréjula-Aísa, Berk Hess, Antonio J. Peña

AI总结 本文研究了如何通过动态资源管理提高分子动力学模拟的计算效率,提出将DMR中间件集成到GROMACS中,实现基于通信效率的进程动态调整。该方法结合了GROMACS原生的检查点/重启机制,能够在负载波动时自动调整MPI进程数量,从而减少资源空闲和排队等待时间。实验在MareNostrum~5超级计算机上验证,结果显示该方法在处理突发性工作负载时能有效降低节点小时成本并提升计算效率。

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英文摘要

Static resource allocations in high-performance computing (HPC) lead to inefficiencies for time-varying workloads, causing idle resources, queue delays, and higher node-hour costs. The Dynamic Management of Resources (DMR) middleware enables MPI process malleability in Slurm via a simple API decoupled from scheduler internals. In this work, we integrate DMR into the GROMACS molecular dynamics engine to obtain a malleable variant that can dynamically adapt its MPI process count by combining communication-efficiency-aware reconfiguration with GROMACS' native checkpoint/restart mechanism. We evaluate this design on the MareNostrum~5 supercomputer, comparing dynamic runs against static executions and quantifying reconfiguration overheads, time-to-solution, and node-hour savings for bursty GROMACS workloads.

2605.14653 2026-05-15 physics.optics

Programmable Non-Hermitian Synchronization of Light on a Silicon Photonic Processor

Ze-Sheng Xu, Nan Cheng, Mohammed S. Elmusrati, Rohan Yadgirkar, Andrea Cataldo, Rui Wen, Govind Krishna, Jun Gao, Ali W. Elshaari

AI总结 该研究利用硅光子处理器实现了一种可编程的非厄米同步机制,通过设计非厄米耗散矩阵,使任意多模光场同步到具有相等模强度和全局锁定相位的集体状态。研究展示了耗散率和总光功率的独立可编程性,为经典和量子光子技术提供了可重构的片上同步新途径。

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英文摘要

Synchronization is a pervasive collective phenomenon underlying the firing of neurons, the beating of the heart, and the coherent emission of lasers. Across these systems, dissipation plays an organizing role, suppressing microscopic differences and steering coupled units toward a common macroscopic order. Here we harness engineered non-Hermitian dissipation to synchronize light directly in the optical domain. Implementing non Hermitian transition matrices on a silicon photonic processor, we drive arbitrary multimode optical fields toward a unique collective state with equal modal intensities and a globally locked phase, a process we call dissipation-induced phase synchronization. The synchronization rate and total optical power throughput are independently programmable, enabling control over the dissipative dynamics without compromising reconfigurability. These results recast dissipation as a functional resource and open a route to reconfigurable on-chip synchronization for classical and quantum photonic technologies.

2605.14652 2026-05-15 hep-lat

Extraction of spectral densities from lattice correlators: decoupling signal from noise

Alessandro Lupo, Nazario Tantalo

AI总结 本文研究了如何从欧几里得关联函数中提取平滑谱密度的问题,提出了一种不依赖Backus-Gilbert正则化的方法。该方法基于对解的分解,发现对统计噪声贡献最大的项对谱密度中心值的贡献最小,从而可通过截断求和来抑制噪声、保留信号。该方法既可以作为独立处理手段,也可用于补充Backus-Gilbert方法中的稳定性分析。

Comments 14 pages, 14 figures

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英文摘要

We expand the treatment of the problem of the extraction of smeared spectral densities from Euclidean correlators introduced in [Phys. Rev. D 99, 094508], providing an alternative which does not rely on the Backus-Gilbert regularization. This is possible due to the observation that the solution can be decomposed into a sum of terms, in the spirit of the singular value decomposition, where those with the largest contribution to the statistical noise happen to contribute the least to the central value of the smeared spectral density. The analysis of the systematics of the inverse problem is then shifted to finding the optimal truncation of such summation, so that the signal is saturated before the noise explodes. We scrutinise the performance and systematics of this approach either as a standalone procedure, or to complement the stability analysis required to extrapolate the unbiased result in the Backus-Gilbert regulated version of the solution.