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2605.00240 2026-05-04 cs.HC

Electrotactile Improves Thermal Referral

电触觉增强热传导

Wen Li, Rong Ni, Bozhi Tian, Pedro Lopes

AI总结 本文提出通过电触觉替代振动触觉改进热传导,提升冷感传达效率,减少触觉干扰,并增强VR中热场景的真实性,提供沉浸式多模态热体验设计指南。

Comments 12 Pages, 12 Figures

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AI中文摘要

电触觉增强热传导通过电触觉替代振动触觉改进热传导,提升冷感传达效率,减少触觉干扰,并增强VR中热场景的真实性,提供沉浸式多模态热体验设计指南。

英文摘要

Thermal referral enables thermal sensations in locations lacking thermal actuators--this is achieved using vibrotactile actuators to redirect a nearby thermal sensation to where a tactile sensation is applied. However, we found that its reliance on vibration introduces critical limitations: it struggles to produce cold referral, and the inherent strong tactile "buzz" makes it unsuitable for simulating non-contact thermal events, such as the chill of an open freezer in VR (in contrast to contact-based thermal events like touching the freezer's cold handle). To improve this, we propose a shift from vibrotactile to electrotactile-based thermal referral. We evaluated in two user studies--a psychophysics experiment (N=22) and a VR deployment (N=20)--where we contrasted electrotactile with vibrotactile-based thermal referral. Our results reveal key advantages of the electrotactile based thermal referral: (1) increases the referral rate for cold sensations; (2) increases thermal perception while minimizing tactile; and (3) improves realism across a range of VR thermal scenarios, specifically distinguishing between contact-based and non-contact thermal events. Finally, we provide design guidelines for choosing tactile cues to create immersive multimodal thermal experiences in VR.

2605.00239 2026-05-04 physics.med-ph

Resolution-Noise Characteristics of Common FDK Filter Kernels: A Practical Reference for Preclinical Cone-Beam Micro-CT

常见FDK滤波核的分辨率-噪声特性:预临床锥形束微CT的实用参考

Falk L Wiegmann, Nancy L Ford

AI总结 本文通过不同滤波核与截止频率组合,评估预临床微CT中FDK算法的分辨率与噪声特性,提供MTF、NPS和NPW d'的量化参考数据。

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AI中文摘要

ramp滤波核和截止频率是FDK算法的基本参数,决定了重建图像的分辨率和噪声特性。尽管其重要性,但系统评估其对预临床微CT任务导向图像质量的综合影响仍有限,许多研究未报告滤波器配置。我们使用GE eXplore CT 120扫描仪重建相同数据,采用四种滤波核(ramp、Shepp-Logan、cosine、Hamming)和四个截止频率(1.0、0.8、0.6和0.379×Nyquist,匹配探测器到体素大小比),评估十六种配置的MTF、NPS和NPW d'。对小鼠肺组织进行定性评估。在十六种配置中,MTF10从0.93到2.35 lp/mm,积分NPS从75,670到13,259 HU²,Rose标准交叉直径在ΔC=500 HU时从2.86到0.93 mm,在100 HU时从7.74到3.62 mm。本文以简洁的视觉和量化参考数据呈现,为选择FDK滤波参数的预临床锥形束CT组提供参考。

英文摘要

The ramp filter kernel and cutoff frequency are fundamental parameters of the Feldkamp-Davis-Kress (FDK) algorithm that determine the resolution and noise characteristics of the reconstructed image. Despite their importance, systematic evaluations of their combined effect on task-based image quality in preclinical micro-CT are scarce, and many studies do not report the filter configuration used. We reconstruct identical data from a GE eXplore CT 120 scanner using four filter kernels (ramp, Shepp-Logan, cosine, Hamming) at four cutoff frequencies (1.0, 0.8, 0.6, and $0.379\times$ Nyquist, matched to the detector-to-voxel size ratio) and evaluate each of the sixteen configurations using the modulation transfer function (MTF), noise power spectrum (NPS), and non-prewhitening detectability index (NPW $d'$). Qualitative assessment is performed on a mouse lung specimen. Across the sixteen configurations, $\mathrm{MTF}_{10}$ ranges from 0.93 to 2.35 lp/mm, integrated NPS from 75,670 to 13,259 $\mathrm{HU}^2$, and the Rose criterion crossing diameter from 2.86 to 0.93 mm at $ΔC = 500$ HU and from 7.74 to 3.62 mm at 100 HU. This note presents the data as a concise visual and quantitative reference for groups selecting FDK filter parameters for preclinical cone-beam CT.

2605.00235 2026-05-04 nlin.SI math-ph math.MP

Bilinear formalism for Schwarzian KP and Harry Dym hierarchies

双线性方法用于Schwarzian KP和Harry Dym层次结构

Vadim Prokofev, Anton Zabrodin

AI总结 本文通过双线性方法重新表述Schwarzian KP和Harry Dym层次结构,展示其与KPtau函数的关系,并讨论其与反演-达布变换的联系。

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AI中文摘要

我们考虑Schwarzian KP和Harry Dym层次结构在双线性方法框架下的表现,该方法在KP、修改KP、BKP、Toda格子等可积层次结构中广为人知。我们证明,类似于修改KP层次结构的双线性公式,Schwarzian KP可以重新表述为一个关于KPtau函数对的积分双线性方程,其中任何线性组合仍为KP层次结构的tau函数。Harry Dym层次结构则作为SchKP的Lax-Sato公式获得。此外,还讨论了SchKP层次结构与可积层次结构反演-达布变换的紧密联系,并展示了SchKP层次结构自然嵌入多组分KP层次结构。

英文摘要

We consider the Schwarzian KP and Harry Dym hierarchies in the framework of the bilinear formalism which is well known for such integrable hierarchies as KP, modified KP, BKP, Toda lattice and other. We show that, similarly to the bilinear formulation of the modified KP hierarchy, the Schwarzian KP can be reformulated as an integral bilinear equation for a pair of KP tau-functions with the property that any linear combination of them is again a tau function of the KP hierarchy. The Harry Dym hierarchy is then obtained as the Lax-Sato formulation of the SchKP one. The close connection with Backlund-Darboux transformations for integrable hierarchies is also discussed. Besides, it is shown that the SchKP hierarchy has a natural embedding into the multi-component KP hierarchy.

2605.00234 2026-05-04 physics.class-ph

A revisited time domain formulation of boundary integral equations for two-dimensional elastodynamics

二维弹性动力学边界积分方程时域公式的重新审视

Domenico Capuani

AI总结 本文提出一种用于二维瞬态弹性波传播问题的边界积分方程方法,通过三维积分恒等式获得时间依赖核,并假设每个时间步长内位移和应力线性变化,推导出隐式时间推进方案,用于求解边界面上瞬态压力作用下圆柱形空腔的解析解。

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AI中文摘要

本文提出了一种用于二维瞬态弹性波传播问题的边界积分方程(BIE)公式。基于三维积分恒等式,获得了二维边界积分方程的时间依赖核。假设每个时间步长内位移和应力呈线性变化,并推导出隐式时间推进方案。该公式用于求解边界面上瞬态压力作用下圆柱形空腔的解析解。

英文摘要

A boundary integral equation (BIE) formulation for 2-D transient elastic wave propagation problems is presented. On the basis of the three-dimensional integral identity, the time-dependent kernels for the two-dimensional boundary integral equation are obtained. A linear time variation of displacements and tractions is assumed over each time step and an implicit time marching scheme is deduced. The formulation is used to obtain an analytical solution for the cylindrical cavity under transient pressure at the boundary surface.

2605.00232 2026-05-04 hep-ex hep-ph

Cosmic Ray Physics with the KM3NeT Telescopes

利用KM3NeT望远镜进行宇宙射线物理研究

Brían Ó Fearraigh

AI总结 KM3NeT望远镜通过探测海水中的切连科夫辐射,研究大气μ子通量,解决宇宙射线实验中的μ子谜题,并用于探测器校准和系统误差约束。

Comments Contribution to the 2026 Very High Energy Phenomena in the Universe session of the 60th Rencontres de Moriond

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AI中文摘要

KM3NeT研究基础设施利用光电倍增管对大量海水进行仪器化,以探测由中微子相互作用产物激发的切连科夫辐射,以及由穿透海水的宇宙射线μ子激发的切连科夫辐射。KM3NeT/ARCA和KM3NeT/ORCA探测器分别位于地中海不同深度,具有不同的光电探测元件扩展性和密度。尽管各自独立运行,两者整体提供广泛的大气μ子通量能量覆盖。通过分析这些大气μ子,KM3NeT望远镜可以进行多种物理研究。利用KM3NeT/ORCA探测器前六个探测单元的数据,已对大气μ子中微子通量进行了测量。同时,最近的`Daemonflux'大气轻子模型已被纳入KM3NeT大气μ子束蒙特卡洛事件生成器。这显著缓解了宇宙射线实验中被称为`μ子谜题'的系统性问题,并对KM3NeT的大气μ子数据进行了全面描述。这些大气μ子还用于探测器校准,并约束探测器的系统误差,如仪器化海水的光学特性。本文概述了这些主题及其他宇宙射线分析。

英文摘要

The KM3NeT research infrastructure instruments a large volume of seawater using photomultiplier tubes, which are sensitive to the Cherenkov radiation stimulated by the products of neutrino interactions in the water, as well as that stimulated by atmospheric muons which penetrate the sea depths. The KM3NeT/ARCA and KM3NeT/ORCA detectors are situated at different depths in the Mediterranean Sea, with different extension and densities of the photo-detection elements. Although operating independently, taken as a whole the two detectors provide a wide energy coverage for the atmospheric muons flux. Through the detection and analysis of these atmospheric muons, a variety of physics studies are possible with the KM3NeT telescope. A measurement of the atmospheric muon neutrino flux has been carried out with data from the initial six detection units of the KM3NeT/ORCA detector. Relatedly to the atmospheric muon flux, the recent atmospheric lepton model `Daemonflux' has been incorporated into the KM3NeT Monte Carlo event generator for atmospheric muon bundles. This has resulted in a stark alleviation of the atmospheric muon data-Monte Carlo simulation discrepancy - a systemic issue in cosmic ray experiments referred to as the `Muon Puzzle' - and a comprehensive description of the atmospheric muon data in KM3NeT. These atmospheric muons are also used in the calibration of the detectors, as well as constraining systematic uncertainties in the detectors such as the optical properties of the instrumented seawater. An overview of these topics, and other cosmic ray analyses, is presented.

2605.00231 2026-05-04 eess.SY cs.SY

An Annual Quasi-Static Time-Series Simulation Framework for Enhanced Transmission System Expansion Planning

一种用于增强输电系统扩展规划的年度准静态时间序列模拟框架

Hussein Suprême, Martin de Montigny, Kevin-R. Sorto-Ventura, Hind Chit Dirani, Mouhamadou Makhtar Dione, Nicolas Compas

AI总结 本文提出一种年度准静态时间序列模拟框架,用于应对分布式能源资源、变量可再生能源和新兴技术带来的挑战,通过高分辨率全年建模揭示灵活性机会和运营约束,提升输电系统扩展规划的鲁棒性。

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AI中文摘要

随着分布式能源资源(DERs)、变量可再生能源和新兴技术的日益整合,传输系统扩展规划(TSEP)面临新的挑战。传统基于快照的确定性方法无法捕捉现代电力系统的时间动态和运营约束。本文介绍了一种年度准静态时间序列模拟(AQSTSS)框架,能够实现高分辨率的全年传输系统建模,包含详细的设备行为、控制策略和DER交互。通过模拟系统性能在所有季节和运行条件下,AQSTSS揭示了静态方法所忽略的灵活性机会和运营约束。应用于水电站魁北克2035/2036电网,该框架在高风能和电动汽车渗透率下揭示了关键洞察。它还集成了一个能源存储控制策略,旨在缓解风能波动并支持电网可靠性。此外,AQSTSS有助于评估在极端天气和负载变化等不同场景下的系统韧性。模拟结果强调了将规划与运营现实对齐的重要性,以确保安全、高效和面向未来的电网发展。总体而言,所提出的框架通过弥合长期规划与实时运营需求之间的差距,增强了TSEP的鲁棒性。

英文摘要

The increasing integration of distributed energy resources (DERs), variable renewable energy sources, and emerging technologies presents new challenges for transmission system expansion planning (TSEP). Traditional snapshot-based and deterministic approaches are inadequate for capturing the temporal dynamics and operational constraints of modern power systems. This paper introduces an annual quasi-static time-series simulation (AQSTSS) framework that enables high-resolution, year-round modeling of transmission systems, incorporating detailed equipment behavior, control strategies, and DER interactions. By simulating system performance across all seasons and operating conditions, AQSTSS uncovers flexibility opportunities and operational constraints that static methods overlook. Applied to Hydro-Québec's projected 2035/2036 grid, the framework reveals critical insights under high wind and electric vehicle penetration. It also integrates an energy storage control strategy designed to mitigate wind variability and support grid reliability. Furthermore, AQSTSS facilitates the assessment of system resilience under diverse scenarios, including extreme weather and load variability. The simulation results underscore the importance of aligning planning with operational realities to ensure secure, efficient, and future-ready grid development. Overall, the proposed framework enhances the robustness of TSEP by bridging the gap between long-term planning and real-time operational needs.

2605.00230 2026-05-04 physics.optics

Percolation with coupled lasers: effect of non-linearities on the phase transition

光子耦合中的渗流:非线性对相变的影响

Simon Mahler, Nikita Stroev, Mahmoud Abu Rmilah, Asher Friesem, Nir Davidson

AI总结 本文通过光子耦合平台研究渗流现象,发现非线性效应改变激光站点的有效行为和渗流相变性质。

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AI中文摘要

受调控实验研究渗流的挑战性限制,由于难以调节站点连通性、隔离局部相互作用和缓解有限尺寸效应。在本工作中,我们通过耦合激光平台研究渗流,其中连通性、相互作用强度和系统大小均可控制。使用100个激光的正方形阵列,具有天文数字的可能聚类配置数,我们显示渗流聚类的出现对应于激光之间相位锁定的起始。我们还发现,渗流概率随站点占据概率的变化经历类似二级相变,具有与经典理论预测一致的阈值。令人惊讶的是,我们发现低泵浦水平下,放大模式竞争(非线性区域)改变了激光站点的有效行为,并改变了渗流相变的性质。实验结果通过具有连接规则的经典渗流理论模型进行解释。

英文摘要

Controlled experimental studies of percolation are challenging due to difficulties in tuning site connectivity, isolating local interactions, and mitigating finite-size effects. In this work, we experimentally investigate percolation with a platform of coupled lasers, where connectivity, interaction strength, and system size can be controlled. Using a square array of 100 lasers with astronomical number of possible cluster configurations, we show that the emergence of a percolating cluster corresponds to the onset of phase locking among the lasers. We also show that the percolation probability undergoes a second-order alike transition as a function of the site-occupation probability, with a threshold consistent with classical theoretical predictions. Surprisingly, we find that at low pump level, amplified mode competition (nonlinear regime) alters the effective behavior of the lasing sites and modify the nature of the percolation transition. The experimental results are interpreted by the means of a theoretical toy model with connectivity rules to the classical percolation.

2605.00228 2026-05-04 math-ph math.AP math.MP

Classical limit of the Pauli-Fierz dynamics

泡利-费尔兹动力学的经典极限

Lucas Jougla, Nikolai Leopold

AI总结 研究泡利-费尔兹哈密顿量生成的薛定谔演化在普朗克常数趋近于零的经典极限下的行为,推导牛顿-麦克斯韦方程作为有效动力学近似,并提供收敛速率的显式估计。

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AI中文摘要

我们研究由泡利-费尔兹哈密顿量生成的薛定谔演化,该模型用于非相对论量子电动力学,在普朗克常数趋近于零的经典极限下。在此 regime,我们严格推导出经典电动力学的牛顿-麦克斯韦方程作为有效动力学近似,近似时间演化。我们的结果通过另一种推导方式补充了先前工作,提供了收敛速率的显式估计,证明了对于特殊初始数据类的近似有效性。

英文摘要

We study the Schrödinger evolution generated by the Pauli-Fierz Hamiltonian, a model for nonrelativistic quantum electrodynamics, in the classical limit $\hbar \rightarrow 0$. In this regime, we rigorously derive the Newton-Maxwell equations of classical electrodynamics as effective dynamics approximating the time evolution. Our result complements prior work by an alternative derivation that provides explicit estimates on the rate of convergence, justifying the validity of the approximation for a special class of initial data.

2605.00223 2026-05-04 astro-ph.GA

Extinction law and stellar mass in the Nuclear Bulge from kinematically-selected red clump stars

银河核球中红巨星星团星的运动学选择与恒星质量

Á. Valenzuela Navarro, M. Zoccali, E. Valenti, R. Contreras Ramos, A. Rojas-Arriagada, A. Luna, R. Albarracín, C. Gallart, J. Olivares Carvajal, F. Gran, C. Salvo-Guajardo, G. Nandakumar, A. Renzini

AI总结 通过运动学选择红巨星星团星研究银河核球的消光定律和恒星质量,发现消光比和恒星密度分布,验证了之前的研究结果。

Comments 17 pages, 11 figures, accepted for publication in A&A

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AI中文摘要

银河系核球中的恒星群体为理解星系形成过程提供了关键线索,并作为外部星系核球形成的近邻类比。然而,该区域的详细研究受到极端且高度变化的星际消光严重阻碍,遮蔽了恒星的固有性质并阻碍了准确的恒星质量确定。我们的目标是测量核球方向的消光定律并估计其恒星密度。我们开发了一种通过运动学选择属于该区域的红巨星星团星来确定核球方向的消光定律的方法。我们创建了一个高空间分辨率的消光图,并通过完整性校正的红巨星星团星计数计算恒星质量,该计数基于经验测量进行缩放。我们发现总消光比为A_K/E_H-K=1.259±0.074,消光比为A_H/A_K=1.794±0.046,与先前研究一致。高空间分辨率的消光图显示了清晰的纤维状结构,并在巨分子云G0.253+0.016(即Brick)上显示出消光梯度。通过恒星计数,我们测得核球的恒星质量为12.2±2.6×10^8 M_太阳,与其他质量估计一致。

英文摘要

The Nuclear Bulge of the Milky Way harbors stellar populations that provide crucial insights into galaxy formation processes and serve as a nearby analog for understanding bulge formation in external galaxies. However, detailed studies of this region are severely hampered by extreme and highly variable interstellar extinction, which obscures the intrinsic stellar properties and impedes accurate stellar mass determinations. Our goal is to measure the extinction law towards the Nuclear Bulge and to estimate its stellar density. We developed a method to determine the extinction law towards the Nuclear Bulge by kinematically selecting red clump stars belonging to this region. We created a high-spatial resolution reddening map, and computed stellar mass with completeness-corrected red clump star counts, scaled from empirical measurements. We find a total-to-selective extinction ratio of $\mathrm{A_K/{E_{H-K}} = 1.259 \pm 0.074}$, and an extinction ratio of $\mathrm{A_H/A_K = 1.794 \pm 0.046}$, which are consistent with previous works. The high-spatial resolution reddening map shows clear filamentary structures, and a gradient in the extinction over the giant molecular cloud G0.253+0.016 (i.e., the Brick). From the star counts, we measured a stellar mass of $\mathrm{12.2~\pm2.6\times10^8~M_{\odot}}$ for the Nuclear Bulge, in agreement with other mass estimates.

2605.00221 2026-05-04 cond-mat.mtrl-sci

Dilute Zn alloying in biodegradable Mg wires: microstructure, mechanical performance, and degradation behavior

稀释锌合金化在可降解镁丝中的应用:微结构、机械性能和降解行为

Jiří Ryjáček, Leonard Hlodák, Jiří Liška, Jan Pinc, Tomáš Herma, Karel Tesař

AI总结 研究稀释锌含量对镁合金丝微结构、机械性能和降解行为的影响,发现锌含量对晶粒尺寸和力学性能影响有限,但低锌合金表现出明显的屈服点。

Comments 29 pages, 9 figures

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AI中文摘要

稀释镁-锌合金丝在可降解小骨固定中具有重要应用价值,因为镁的降解可支持骨相关过程,而低锌含量可能提供生物益处而不影响生物相容性。本研究评估了低于室温溶解度极限的锌含量对用于可吸收植入物的镁-锌合金丝的影响。通过单步直接热挤压制备了镁-0.4Zn、镁-0.6Zn、镁-0.8Zn和镁-1.5Zn合金,通过相关微结构分析、拉伸测试、弯曲实验和体外降解进行表征。所有合金均获得了再结晶细等轴晶粒尺寸(5.0-5.9 μm),并表现出最高抗拉强度(246-256 MPa)和延伸率(23-28 %)。在这些细丝中,锌含量对晶粒尺寸、抗拉性能和弯曲行为影响有限,尽管低锌合金表现出明显的尖锐屈服点。弯曲主要由挤压织构控制,并通过孪生和反孪生保持可逆塑性。模拟体液导致在7天内快速局部降解和机械完整性丧失,而生物更相关的DMEM基培养基更好地反映了预期的体内响应。这些发现支持稀释镁-锌丝作为未来可吸收骨固定设备开发的简单材料平台。

英文摘要

Dilute Mg-Zn wires are of great interest for biodegradable small-bone fixation, as magnesium degradation can support bone-related processes, while low zinc additions may provide biological benefits without compromising biocompatibility. In this work, the influence of Zn content below the room-temperature solubility limit was assessed in Mg-Zn wires intended for resorbable implant applications. Mg-0.4Zn, Mg-0.6Zn, Mg-0.8Zn, and Mg-1.5Zn alloys were processed by single-step direct hot extrusion into thin wires and characterized by correlative microstructural analysis, tensile testing, bending experiments, and in vitro degradation. All compositions achieved a recrystallized fine equiaxed grain size of 5.0-5.9 um and exhibited ultimate tensile strengths of 246-256 MPa with elongations of 23-28 %. In these thin wires, Zn content had only a limited effect on grain size, tensile properties, and bending behavior, although lower-Zn alloys showed a pronounced sharp yield point. Bending was governed mainly by extrusion texture and preserved reversible plasticity through twinning and detwinning. Simulated body fluid caused rapid localized degradation and loss of mechanical integrity within 7 days, while the biologically more relevant DMEM-based medium better reflected the expected in vivo response. Together, these findings support dilute Mg-Zn wires as a simple material platform for the development of future resorbable bone fixation devices.

2605.00220 2026-05-04 cs.DS

The Impact of Approximation on Algorithmic Progress

近似对算法进步的影响

Jeffery Li, Jayson Lynch, Liva Olina, Cecilia Chen, Andrew Lucas, Neil Thompson

AI总结 本文调查了计算机科学中最重要的118个算法问题,量化了近似在历史中带来的收益与权衡,发现仅约20%的问题受益于近似,但那些有良好近似算法的问题计算速度显著提升。

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AI中文摘要

在几乎所有学科中,科学计算都受到计算成本和速度的限制。例如,旅行商问题的最优算法在处理百万规模实例时需要数个世纪。面对这种限制,人们倾向于寻找新算法或并行化现有算法,但许多算法已达到理论最优,且并行化往往不可能或成本过高。自20世纪60年代起,计算机科学家探索了另一种解决方案:允许解有少量误差(即近似)。本文回顾了118个最重要的计算机科学算法问题,量化了近似在历史中发现的收益和权衡。总体而言,仅约20%的问题受益于近似。然而,那些有良好近似算法的问题在计算速度上可以显著提升,而对精度的影响很小。例如,四分之一的计算不可行问题(例如需要指数时间计算的问题)有多项式时间近似算法。近似还增加了能在线性时间内运行的算法数量23%,为大数据领域开辟了新的计算机会。本文还揭示了AI进步应预期的内容,其中近似是深度学习的核心。

英文摘要

In nearly every discipline, scientific computations are limited by the cost and speed of computation. For example, the best-known exact algorithms for the canonical Traveling Salesman Problem would take centuries to run on an instance of size 1 million. A natural response to such limits is to try to find new algorithms or to parallelize existing ones, but many algorithms are already at their theoretically-optimal level and parallelization is often impossible or prohibitively expensive. Starting in the 1960's, computer scientists pursued another solution: allowing solutions to have a small amount of error (i.e. approximating them). In this paper, we survey 118 of the most important algorithm problems in computer science, quantifying the gains and tradeoffs from approximation that have been discovered over the history of the field. Overall, only $\approx$20\% of problems have benefited from approximation. However, those with good approximate algorithms can be dramatically faster to compute with little cost to accuracy. For example, a quarter of computationally intractable problems (e.g. those that take exponential time to compute) have polynomial time approximate algorithms. Approximation also increases the number of algorithms that can run in linear time by 23\%, opening up new computational opportunities for those working in the big data regime. This work also sheds light on what should be expected from progress in AI, where approximation is at the heart of how deep learning works.

2605.00217 2026-05-04 math.AG

On logarithmic Poisson cohomology of a degenerate Poisson bivector in affine plane

关于退化Poisson双矢量在仿射平面中的对数Poisson上同调

Kamtila Kari, Iskamlé Bruno, Diekouam Fotso Luc Éméry, Tcheka Calvin

AI总结 本文研究了退化双矢量的古典Poisson上同调与对数Poisson上同调的同构性,通过确定对数Hamilton算子和上同调复形计算相关上同调不变量。

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AI中文摘要

在本文中,我们证明对于给定的退化双矢量π=y^n∂_x∧∂_y(n>1),沿理想I=y^nF[x,y]的古典Poisson上同调群和对数Poisson上同调群在每一度数上都是同构的。这一结果源于对数Hamilton算子和对数Poisson上同调复形的确定,以计算与π相关的上同调不变量。F是特征为0的域。

英文摘要

In this paper, we show that for a given degenerate bivector $π= y^n\partial_x \wedge \partial_y$ with $n>1$, the classical Poisson cohomology group and the logarithmic Poisson cohomology group along the ideal $\mathcal{I}=y^n\mathbb{F}[x,y] $ are isomorphics in every dégrée. This result follows from determination of the logarithmic Hamiltonian operator and the logarithmic Poisson cochain complexe in order to compute the cohomological invariants associated to $π$. $\mathbb{F}$ is the field of characteristic 0.

2605.00216 2026-05-04 stat.ME

Simplicity Above Elegance: Another Look at the Asymptotically Correct Standardization of Snijders

简洁胜于优雅:对Snijders标准化的另类审视

Sandip Sinharay

AI总结 本文通过另类推导重新审视Snijders提出的渐近正确标准化方法,得出更简洁的公式及对lz*统计量的理论解释,解释了相关模拟结果。

Comments 34 pages, 5 figures. This version is the corrected version of the published article. Due to the correction, the content in pages 7-12 of this document differs substantially from that in the journal version

Journal ref Jour. Ed. Behav. Stat. (2026)

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AI中文摘要

在教育和心理测量中,人适应统计量广泛用于检测异常响应模式。Snijders(2001)为一类此类统计量提出了渐近正确的标准化方法。本文提供了该标准化的另一种推导方法。推导过程带来了多个优势,包括更简单的公式以及对几种人适应统计量(包括lz*统计量)的更简洁描述,并为Snijders(2001)和van Krimpen-Stoop及Meijer(1999)等报告的模拟结果提供了理论解释。

英文摘要

Person-fit statistics are widely used to detect aberrant response patterns in educational and psychological measurement. Snijders (2001) suggested an asymptotically correct standardization for a broad class of such statistics. This paper presents an alternative derivation of this standardization. The derivation yields several advantages including a simpler formula and simpler description of several person-fit statistics including the lz* statistic (van Krimpen-Stoop & Meijer, 1999) and a theoretical explanation of simulation findings reported by Snijders (2001) and van Krimpen-Stoop and Meijer (1999), among others.

2605.00215 2026-05-04 eess.SP

Multi-Objective Adaptive Beamforming Using Partial Knowledge of Dynamic Dielectric Media for Non-Invasive Microwave Hyperthermia

多目标自适应波束成形利用动态介电介质的部分知识用于非侵入式微波热疗

Ahona Bhattacharyya, Tessa Haldes, Jeffrey A. Nanzer, Susan C. Hagness

AI总结 本文研究了非侵入式微波热疗中多目标自适应波束成形设计策略,旨在在介电特性变化时维持目标区域的聚焦功率沉积并减少其他区域的意外加热。通过线性约束最小功率算法和FDTD仿真评估了波束成形效果。

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AI中文摘要

我们研究了非侵入式微波热疗中的多目标自适应波束成形设计策略。我们的重点是解决在介电特性变化条件下维持目标区域的聚焦功率沉积并减少其他区域的意外加热的挑战。加热过程会导致介质介电特性变化,这会降低静态权重波束成形器的有效性。典型的热疗波束成形器设计利用MRI或微波断层扫描获得的患者特异性高分辨率介电图计算天线波束成形权重,但此过程耗时且难以实时进行。本文探讨了在变化的介电条件下在各种不均匀介质中微波热疗的有效性,旨在指导未来自适应实时微波热疗技术的设计。我们旨在通过选择性吸收电磁波,在2.5 GHz载频下获得约45°C的温度以引起细胞凋亡,同时通过放置空洞以避免治疗区域外的意外加热。我们研究了线性约束最小功率(LCMP)算法在近场多目标波束成形中的有效性,并检查了有限差分时域(FDTD)仿真在简单解析模型和解剖学真实数值乳腺假体上的功率密度。为了全面了解波束成形器的效果,我们评估了模型在简单均质情况、异质情况和MRI衍生的假体乳腺模型中的热图。

英文摘要

We investigate multi-objective adaptive beamformer design strategies for non-invasive microwave hyperthermia. Our focus is to address the challenges of maintaining focused power deposition in desired locations while reducing unwanted heating elsewhere under conditions of changing dielectric properties. The process of heating the media causes changes in the dielectric properties of the media, which can degrade the effectiveness beamformers with static weights. Typical hyperthermic beamformer designs calculate antenna beamforming weights using patient-specific high resolution dielectric maps obtained by MRI or microwave tomography, however this process is time consuming and difficult to perform in real-time. In this work, we explore the efficacy of microwave hyperthermia in various inhomogeneous media under changing dielectric conditions, with the goal of informing the design of future adaptive real-time microwave hyperthermia techniques. We aim to achieve cell apoptosis by obtaining temperatures of $\sim$ 45 $^\circ\text{C}$ through selective absorption of electromagnetic wave focusing at a 2.5 GHz carrier frequency with little to no knowledge of the changes in the dielectric media and simultaneously place nulls to avoid unwanted heating outside of the treatment zone. We investigate the effectiveness of the linear constrained minimum power (LCMP) algorithm for near-field multi-objective beamforming and examine the power density obtained from finite-difference time-domain (FDTD) simulations on simple analytical models and anatomically realistic numerical breast phantoms. To gain a comprehensive knowledge of the efficacy of the beamformer we evaluate the resulting thermal maps of the models in simple homogeneous cases, heterogeneous cases and MRI-derived phantom breast models.

2605.00214 2026-05-04 quant-ph physics.optics

Generation of Tunable Entanglement from Thin-Film Lithium Niobate

从薄膜锂铌酸盐生成可调谐纠缠

Saniya Shinde, Maximilian A. Weissflog, Shaun Lung, Elkin A. Santos, Jinyong Ma, Tongmiao Fan, Anna Fedotova, Sina Saravi, Andrey A. Sukhorukov, Frank Setzpfandt

AI总结 本文提出一种基于薄膜锂铌酸盐的极化纠缠光子对源,利用其三重旋转晶体对称性实现可调谐纠缠生成,无需额外光学元件,兼容现有制备技术。

Comments 7 pages, 4 figures

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AI中文摘要

纠缠光子对在量子成像、通信和计算等现代技术中起着重要作用。传统光子对源通常基于体非线性晶体中的自发参量下转换。最近的研究也展示了从过渡金属二硫化物薄膜中生成纠缠光子对,但这些材料不广泛可用且不兼容现有制造能力。我们提出了一种新的薄膜锂铌酸盐源,可在通信波长下生成极化纠缠光子对,无需额外光学元件即可生成纠缠,并利用现有锂铌酸盐制造技术进行应用。我们通过锂铌酸盐的三重旋转晶体对称性演示了可调谐纠缠生成,根据泵浦光的偏振态可生成不同的最大纠缠贝尔态或完全分离态。

英文摘要

Entangled photon pairs play a major role in various modern technologies such as quantum imaging, communication, and computing. Conventional photon-pair sources are often based on spontaneous parametric down-conversion in bulk nonlinear crystals. Recent advances have also shown entangled photon-pairs from transition metal dichalcogenide thin-films, however, these materials are not widely available and are not compatible with existing fabrication capabilities. We present a new thin-film lithium niobate source of polarization-entangled photon pairs at the telecom wavelength that requires no additional optical elements for entanglement generation and allows for easy application using the existing lithium niobate fabrication technologies. We demonstrate tunable entanglement generation using the three-fold rotational crystal symmetry of lithium niobate, allowing the generation of different maximally entangled Bell states or completely separable states depending on the polarization of the pump beam.

2605.00213 2026-05-04 math.FA

Composition-differentiation operators on weighted Dirichlet spaces

加权狄利克雷空间上的复合-微分算子

Anirban Sen, Somdatta Barik, Kallol paul

AI总结 研究加权狄利克雷空间上复合-微分算子的有界性、紧性和希尔伯特-施图姆算子性质,通过诱导映射的广义内维连纳计数函数的渐进行为估计本质范数,并给出特定诱导映射的范数估计及示例。

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AI中文摘要

我们刻画了加权狄利克雷空间上的有界、紧致和希尔伯特-施图姆复合-微分算子。本质范数通过涉及诱导映射广义内维连纳计数函数的渐进行为来估计。给出了特定诱导映射的范数估计,并提供了示例以展示结果的应用性。

英文摘要

We characterize bounded, compact, and Hilbert-Schmidt composition-differentiation operators on weighted Dirichlet spaces. The essential norm is estimated via the asymptotic behavior of a function that involves the generalized Nevanlinna counting function of the inducing map. Norm estimates for particular inducing maps are given, and examples are provided to demonstrate the applicability of the results.

2605.00212 2026-05-04 math.OC cs.NA math.AP math.NA physics.comp-ph

Structure-Preserving Optimal Control of Maxwell's Equations with Applications to Source Cloaking

保持结构的Maxwell方程最优控制及其在源伪装中的应用

Harbir Antil, Yaw Owusu-Agyemang, Rohit Khandelwal, Jimmie Adriazola, Denis Ridzal

AI总结 本文提出保持结构的Maxwell方程最优控制框架,结合Nédélec和Raviart--Thomas有限元与Crank--Nicolson时间步进,实现能量守恒和弱解收敛,并通过数值实验验证源伪装模型问题的优越性。

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AI中文摘要

我们开发了一个保持结构的求解框架,用于时间依赖Maxwell方程的最优控制。基于正则性理论,首先分析了一个耦合Nédélec和Raviart--Thomas有限元与Crank--Nicolson时间步进的前向求解器。该求解器保持de~Rham结构,强制离散高斯定律,精确满足每时间步的能量平衡,并在低正则性假设下收敛到弱解。为控制Maxwell系统,我们将在安培定律中加入空间-时间电流密度的旋度作为源。旋度形式实现了电荷守恒而无需辅助约束。我们证明了控制到状态映射的正则性和连续性,导出了伴随系统和跟踪型目标泛函的梯度表示,并提出了继承前向求解器结构保持性的离散优化方案。我们的离散站定条件与连续对应条件一致,离散最优控制在网格和时间细化下收敛到连续最优解。我们通过数值求解一系列源伪装模型问题,展示了最优控制公式和理论发展的优势。

英文摘要

We develop a structure-preserving solution framework for the optimal control of the time-dependent Maxwell's equations. Building on a well-posedness theory for a weak form of the forward problem, we first analyze a forward solver that couples Nédélec and Raviart--Thomas finite elements with Crank--Nicolson time stepping. The solver preserves the de~Rham structure, enforces a discrete Gauss law, exactly satisfies a per-time-step energy balance, and converges to the weak solution under low regularity assumptions on the problem data, which are dictated by the optimal control setting. To control the Maxwell system, we add the curl of a space-time current density as a source to Ampére's law. The curl form yields charge conservation without auxiliary constraints. We prove the well-posedness and continuity of the control-to-state map, derive the adjoint system and a gradient representation for a tracking-type objective functional, and formulate a discrete optimization scheme that inherits structure preservation from the forward solver. Our discrete stationarity conditions are consistent with their continuous counterparts, and the discrete optimal controls converge, with mesh and time refinements, to the continuous optima. We demonstrate the merits of our optimal control formulation and the theoretical developments by numerically solving a series of source-cloaking model problems.

2605.00211 2026-05-04 cond-mat.str-el

Quantized Collective Fluctuations in Correlated Fermion Systems

量子集体波动在关联费米子系统中的量化

S. S. Onuchin, Ya. S. Lyakhova, L. D. Silakov, A. N. Rubtsov

AI总结 本文提出量子FLF方法,用于高效表征单个玻色子模的贡献,通过计算格林函数、总能量和反铁磁磁化率,验证了低频玻色子模对集成可观测量的影响。

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AI中文摘要

费米子系统中的集体激发在决定其物理性质中起关键作用。一个重要挑战是开发高效的理论方法来描述这些激发及其与费米子自由度的耦合。在本文中,我们重新审视了在波动局部场(FLF)方法框架内量化单个玻色子模对关联费米子系统可观测性质的贡献的问题。尽管该方法中的辅助场先前仅被视为经典,我们提出了系统扩展方法,称为量子FLF(Q-FLF),该方法纳入了选定的玻色子马尔可夫频率,从而使其适用于描述量子集体波动。作为测试平台,我们将该方法应用于半填充分子一维海夫链,并计算格林函数、总能量和反铁磁磁化率。我们的结果表明,所提出的方法能够高效且选择性地表征单个玻色子模的贡献。特别是,低马尔可夫频率被发现对总能量和反铁磁磁化率等集成可观测量有定量影响。同时,准确描述单粒子性质需要包括更高频率的玻色子模。

英文摘要

Collective excitations in fermionic systems play a crucial role in determining their physical properties. An important challenge is to develop efficient theoretical approaches for describing these excitations and their coupling to fermionic degrees of freedom. In this work, we revisit the problem of quantifying the contributions of individual bosonic modes of collective fluctuations to observable properties of correlated fermion systems within the framework of the Fluctuating Local Field (FLF) method. Whereas the auxiliary field in this method was previously considered only classically, we formulate its systematic extension termed Quantum FLF (Q-FLF) that incorporates selected bosonic Matsubara modes, thus tailoring it to description of quantum collective fluctuations. As a testbed, we apply the approach to a half-filled one-dimensional Hubbard chain and compute the Green's function, the total energy, and the antiferromagnetic susceptibility. Our results demonstrate that the proposed scheme enables an efficient and selective characterization of the contributions of individual bosonic modes. In particular, low Matsubara frequencies are found to have a quantitative impact on integrated observables such as total energy and antiferromagnetic susceptibility. At the same time, an accurate description of single-particle properties requires inclusion of higher-frequency bosonic modes.

2605.00210 2026-05-04 eess.SY cs.SY

Distributed Observer Design for Discrete-Time LTI Systems via Jordan Canonical Form

基于约当标准型的离散时间线性时不变系统分布式观测器设计

Giulio Fattore, Maria Elena Valcher, Rui Gao, Guang-Hong Yang

AI总结 本文基于Gao与Yang(2025)框架,利用系统矩阵的约当标准型设计两种分布式估计方案,确保局部估计渐近收敛至真实系统状态。两种方法均通过李恩伯格观测器重构本地可检测的状态分量,并采用共识机制估计不可直接检测的分量。

Comments This manuscript is an extended version of the paper accepted for presentation at ECC 2026 and is currently under review for potential publication in Automatica

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AI中文摘要

本文基于Gao与Yang(2025)框架,利用系统矩阵的约当标准型设计两种分布式估计方案,确保局部估计渐近收敛至真实系统状态。两种方法均通过李恩伯格观测器重构本地可检测的状态分量,并采用共识机制估计不可直接检测的分量。

英文摘要

This paper addresses the problem of distributed state estimation for discrete-time linear time-invariant systems. Building on the framework proposed in Gao & Yang (2025), we exploit the Jordan canonical form of the system matrix to develop two distributed estimation schemes that ensure asymptotic convergence of local estimates to the true system state. In both approaches, each node reconstructs the components of the state that are locally detectable for it via a Luenberger observer, while employing a consensus-based mechanism to estimate the components that are not directly detectable. The first scheme relies on local observers whose dimension matches that of the original state vector; however, its applicability requires the satisfaction of a large set of inequalities. The second scheme, in contrast, can be implemented under less restrictive conditions, but results in observers of increased (augmented) order. For both methods, we derive necessary and sufficient conditions - expressed in terms of the eigenvalues of the system matrix and certain submatrices of the communication network Laplacian - that guarantee the existence of a distributed observer achieving asymptotically accurate estimation. Compared to Gao & Yang (2025), the proposed approaches offer greater flexibility in the selection of coupling gains and impose less stringent solvability conditions.

2605.00209 2026-05-04 cs.DC

Replication in Graph Partitioning and Scheduling Problems

图划分与调度问题中的复制

Pál András Papp, Toni Böhnlein, A. N. Yzelman

AI总结 研究复制对图划分和调度问题的影响,通过理论分析和实验验证,发现复制能显著提高图划分的近似难度,但对调度复杂性影响较小,实验显示复制可降低成本17%-65%甚至消除通信需求。

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AI中文摘要

高效并行执行复杂计算需要在处理器间平衡负载同时最小化通信。这种权衡通常通过图划分或DAG调度问题来捕捉。大多数工作假设节点只能分配给一个处理器,但实际中在多个处理器上复制操作可能有益:仅小幅增加计算成本,但显著减少通信需求。本文旨在全面分析复制对划分和调度问题的影响。理论上,图划分问题在近似复杂性上显著更难,而调度问题影响较小。实验上,分析复制在各种真实应用图中的成本降低。对于超图划分,使用整数线性规划(ILP)公式比较最优成本;实验显示复制可平均降低成本17%-65%,甚至在某些情况下完全消除通信需求。对于DAG调度,使用ILP在较小图上进行分析,并开发适用于更大负载的复杂启发式方法。实验显示复制可平均降低成本11.61%-23.13%,甚至在某些情况下降低58.17%。

英文摘要

The efficient parallel execution of complex computations requires balancing the workload across processors while minimizing the communication between them. This inherent trade-off is often captured by graph partitioning or DAG scheduling problems. For the sake of model simplicity, most works on these problems assume that nodes can be assigned to only a single processor. However, in reality, replicating an operation on several processors can easily be beneficial: it may increase the computational costs only by a small amount, while significantly reducing the communication requirements. Our goal is to provide a comprehensive analysis of the impact of replication on partitioning and scheduling problems. On the theoretical side, we show that for graph partitioning, replication makes the problem significantly harder in terms of approximation complexity, whereas for scheduling, its impact on complexity seems less prominent. On the experimental side, we conduct a thorough analysis of the cost reduction obtainable by replication, on a wide range of graphs from real-world applications. For hypergraph partitioning, we use Integer Linear Programming (ILP) formulations to compare the optimal costs; our experiments show that replication can reduce the cost by 17%-65% on average, or even entirely remove the need for communication in some cases. For DAG scheduling, we similarly use ILPs on smaller graphs, and develop a sophisticated heuristic that is also applicable to much larger workloads. Our experiments here demonstrate a mean cost reduction of 11.61%-23.13% with replication, or even up to 58.17% in some cases.

2605.00208 2026-05-04 astro-ph.CO

Correspondence between a decaying dark matter sector scenario and scalar field model

衰变暗物质领域与标量场模型之间的对应关系

Gilberto Aguilar-Pérez, Deryan Alvarado, Miguel Cruz, Estefany Ruíz-Ramos, Joel Saavedra

AI总结 研究通过统一标量场方法建模衰变暗物质领域,发现物理可行性迫使暗能量方程状态进入 phantom 域,并通过复数场景映射获得超轻质量标量场,形成统一暗流体。

Comments 28 pages, 4 figures

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AI中文摘要

我们探讨了通过统一标量场方法建模衰变暗物质领域的理论可行性。利用弗里德曼约束的精确解析解,我们将流体现象学映射到标量场势能上。我们的分析表明,物理可行性,特别是存在明确的势能最小值,不可避免地迫使暗能量方程状态进入 phantom 域。为解决晚期时间的动能病态,我们提出将框架重新解释为复数场景,将虚数转变映射到 $U(1)$ 相位的角动力学。这种映射自然产生超轻质量标量场 $m_ϕ\sim 10^{-33} \ \text{eV}$,将模型归类为统一暗流体。最后,我们采用动态方法研究非最小耦合的影响,证明 phantom 主导时期在该宇宙学场景中充当稳定的晚期时间宇宙吸引子。

英文摘要

We explore the theoretical viability of modeling a decaying dark matter sector through a unified scalar field approach. Using exact analytical solutions of the Friedmann constraints, we map the fluid phenomenology onto a scalar field potential. Our analysis reveals that physical viability, specifically the existence of a well-defined potential minimum; inevitably forces the dark energy equation of state into the phantom domain. To resolve the kinetic pathologies at late times, we propose reinterpreting the framework within a complex scenario, mapping the imaginary transition to the angular dynamics of a $U(1)$ phase. This mapping naturally yields an ultra-light mass scale of $m_ϕ\sim 10^{-33} \ \text{eV}$, classifying the model as a unified dark fluid. Finally, we employ a dynamical approach to study the effects of non-minimal coupling, proving that the phantom-dominated epoch acts as a stable, late-time cosmic attractor in this kind of cosmological scenario.

2605.00207 2026-05-04 cond-mat.stat-mech math.PR

Activated random walk exhibits self-organized criticality

激活随机游走表现出自组织临界性

Christopher Hoffman, Tobias Johnson, Matthew Junge, Josh Meisel

AI总结 本文证明了一维激活随机游走模型能快速达到稳态,产生幂律坍塌并具有与固定能量模型相同的临界密度,首次证实了自组织临界性的理论预测。

Comments 12 pages; rigorous proofs of Theorems 1 and 2 can be found in arXiv:2406.01731 and arXiv:2501.17938, respectively

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AI中文摘要

为了解释自然界中幂律和分形的普遍性,Bak、Tang和Wiesenfeld提出了系统自组织到临界状态的简单条件。Dickman、Muñoz、Vespignani和Zapperi提出自组织临界状态与对应固定能量模型的传统相变临界状态一致。尽管该理论在过去五十年中被广泛应用,但尚未有数学模型被证明表现出所推测的行为。事实上,最初提出的阿贝尔沙堆模型由于混合缓慢而表现出非普遍性。本文首次证明了一维激活随机游走模型能快速达到稳态,产生幂律坍塌并具有与固定能量版本相同的临界密度。

英文摘要

To explain the ubiquity of power laws and fractals in nature, Bak, Tang, and Wiesenfeld formulated simple conditions for a system to self-organize into a critical state. Dickman, Muñoz, Vespignani, and Zapperi postulated that the self-organized critical state matches the critical state in corresponding fixed-energy models undergoing traditional phase transitions. Although the theory has been applied broadly over the past five decades, no mathematical model has been proven to exhibit the conjectured behavior. Indeed, the originally proposed abelian sandpile model displays nonuniversal behavior stemming from its slow mixing. Marking the first result of its kind, we prove that the 1-d activated random walk model mixes quickly into a stationary state with power-law avalanches and limiting critical density that equals the critical value for the fixed-energy version.

2605.00204 2026-05-04 math.FA

Range characterization of the weighted divergent beam and cone integral transforms

加权发散束和锥积分变换的范围特性

Fatma Terzioglu, Lili Yan

AI总结 本文研究了加权发散束和锥积分变换的范围特性,通过将变换分解为k-加权发散束变换和球面截面变换,推导出两种几何结构下的范围条件,包括凸集顶点和平面探测器两种情况。

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AI中文摘要

我们建立了将函数映射到锥面加权积分的积分变换的范围特性,或数据一致性条件。我们考虑了两种不同的锥顶几何结构,导致数学上不同的范围条件。我们使用术语'锥形Radon变换'表示顶点集是$\mathbb{R}^n$中的有界凸子集,包括未知函数的支持集。第二种几何结构受Compton相机成像启发:顶点集表示平面探测器位置且与辐射密度支持集分离。我们称相应的变换为'Compton变换'。我们的方法基于将变换分解为k-加权发散束变换和球面截面变换。在有界凸顶点几何中,发散束部分的范围由高阶传输边界值问题描述,如Derevtsov、Volkov和Schuster研究的。在平面探测器几何中,我们推导出k-加权发散束变换的范围条件,扩展了Clackdoyle和Desbat的平面锥束一致性条件。将这些结果与球面截面变换的范围特性结合,得出两种变换的完整范围描述。

英文摘要

We establish range characterizations, or data consistency conditions, for an integral transform that maps a function to its weighted integrals over conical surfaces in $\mathbb{R}^n$. We consider two different geometries for the cone vertices, which lead to mathematically distinct range conditions. We use the term \emph{conical Radon transform} when the vertex set is a bounded convex subset of $\mathbb{R}^n$ including support of the unknown function. The second geometry is motivated by Compton camera imaging: the vertex set represents planar detector locations and is disjoint from the support of the radiation density. We refer to the corresponding transform as the \emph{Compton transform}. Our approach is based on a factorization into the $k$-weighted divergent beam transform and the spherical section transform. In the bounded convex vertex geometry, the range of the divergent beam component is described by a higher-order transport boundary-value problem, as studied by Derevtsov, Volkov, and Schuster \cite{Derevtsov2021}. In the planar detector geometry, we derive range conditions for the $k$-weighted divergent beam transform that generalize the planar cone-beam consistency conditions of Clackdoyle and Desbat \cite{ClackdoyleDesbat2013}. Combining these results with the range characterization of the spherical section transform yields complete range descriptions for both the $k$-weighted conical Radon transform and the $k$-weighted Compton transform.

2605.00203 2026-05-04 hep-th gr-qc hep-ph

Topological charges and confined-deconfined phase transition in holography

拓扑电荷与反德西特空间中的受限-非受限相变

Nelson R. F. Braga, William S. Cunha

AI总结 本文通过AdS/QCD模型研究反德西特空间中引入能量尺度对拓扑类的影响,揭示受限与非受限相变及霍金-彭脱相变机制。

Comments 31 pages and 7 figures

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AI中文摘要

近年来,许多关于黑洞性质的拓扑描述工作在文献中出现。特别是,在这一框架中,黑洞对应于扩展(非壳)参数空间中的拓扑缺陷,具有关联的总拓扑电荷。在 gauge/gravity 对偶中,从受限到非受限相的转变被映射为引力侧黑洞相的主导。本文利用广义AdS/QCD模型表明,在反德西特空间中引入能量尺度会导致拓扑类的变化。这种修改对应于受限和非受限相之间由有限临界温度下的霍金-彭脱相变分隔。

英文摘要

In recent years, many interesting works providing a topological description for black hole (BH) properties have appeared in the literature. In particular, in this framework BHs correspond to topological defects in an enlarged (off-shell) parameter space, with an associated total topological charge. In gauge/gravity duality the transition from the confined to the deconfined phase is mapped into the dominance of a BH phase in the gravity side. Here we show, using a holographic AdS/QCD model, that the introduction of an energy scale in anti-de Sitter (AdS) space results in a change in the topological class. Such a modification corresponds to the existence of confined and deconfined phases, separated by a Hawking Page transition at a finite critical temperature.

2605.00202 2026-05-04 cond-mat.mes-hall

Observation of single antiferromagnetic magnon modes in the tunnelling transistors of spin-1/2 Kitaev system a-RuCl3

观察单反铁磁磁子模式在spin-1/2 Kitaev系统a-RuCl3隧道晶体管中的特性

Servet Ozdemir, Mikhail Kashchenko, Kostya S. Novoselov

AI总结 研究a-RuCl3薄膜在室温下的n型半导体性质及低温下反铁磁序的单磁子模式,为量子自旋液体态的电子特性研究提供实验基础。

Comments 13 pages, 10 figures

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AI中文摘要

已知在低温下经历Mott-Hubbard转变的小间隙室温半导体a-RuCl3是实现量子自旋液体态的最有希望的候选材料,可能在量子计算中有应用。尽管已被广泛研究,但以范德华异质结构形式的电子研究主要局限于石墨烯临近效应。本文报告了对a-RuCl3薄膜的平面和隧道电子性质的系统研究,发现其在室温下具有n型半导体性质,在120K以下表现出Mott绝缘体特性。在部分先前研究的基础上,我们聚焦于三层厚的薄膜,并在低于奈尔温度7-14.5 K时观察到一些非弹性散射特征,其中部分我们归因于单磁子模式。我们相信本研究通过电学手段证实了在原子薄薄膜极限下,已观察到的连续谱中保持的低温bulk zigzag反铁磁序及其单磁子模式。实验进展可能为未来在zigzag反铁磁序附近量子自旋液体态的电子特性研究以及a-RuCl3中Majorona激发的隧道晶体管研究提供一步。

英文摘要

The small gap room temperature semiconductor a-RuCl3 which is known to undergo a Mott-Hubbard transition at low temperatures, is one of the most promising candidates for realisation of an exotic matter form, the quantum spin liquid state, which may have applications in quantum computing. Although being extensively investigated by neutron scattering techniques, electronic study of this system in form of van der Waals heterostructures has been limited to mainly graphene proximity. Here we report a systematic study of planar and tunnelling electronic properties of a -RuCl3 films, where we observe an n-type semiconducting property of a -RuCl3 films at room temperature, with a Mott insulator nature onset below 120K. In constant some of the previous studies, we focus on films of three-layer thickness and below and we find inelastic scattering features, below the Neel temperature of 7-14.5 K, some of which we attribute to single magnon modes. We believe our study electrically confirms preserved low temperature signatures of the bulk zigzag antiferromagnetic order and its single magnon modes within the previously observed continuum in atomically thin film limit. The experimental progress could be a step for future electronic characterisation of quantum spin liquid state in the vicinity of the zigzag antiferromagnetic order as well as the Majorona excitations in a-RuCl3 in tunnelling transistors.

2605.00196 2026-05-04 stat.ME math.PR math.ST q-fin.ST stat.TH

Modeling Stock Returns and Volatility Using Bivariate Gamma Generalized Laplace Law

基于双变量伽马广义拉普拉斯定律的股票收益与波动建模

Tomasz J. Kozubowski, Andrey Sarantsev, James A. Spiker

AI总结 本文提出双变量伽马广义拉普拉斯分布模型,通过最大似然估计简化估计过程,并展示其在金融数据中的应用。

Comments 25 pages, 2 figures. Keywords: Financial modeling, Generalized Laplace distribution, Maximum likelihood estimation, Normal mean-variance mixture, Variance-gamma distribution

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AI中文摘要

我们考虑了方差-伽马(广义非对称拉普拉斯)分布的推广,定义为正态均值-方差混合分布,其中混合分布为伽马分布。虽然该模型通常在单变量情况下研究,但我们假设伽马混合变量与主变量同时观测,从而形成双变量框架。在此设定下,最大似然估计显著简化,类似于经典线性回归。我们推导了所得到估计量的显式表达式。对于某些参数配置,估计量表现出非标准收敛速率,超过通常的平方根速率。最后,我们通过分析几个主要指数的股票指数回报和相关波动性,展示了该模型在金融领域的应用。

英文摘要

We consider a generalization of the variance-gamma (generalized asymmetric Laplace) distribution, defined as a normal mean - variance mixture with a gamma mixing distribution. While this model is typically studied in the univariate setting, we assume that the gamma mixing variable is observed alongside the primary variable, resulting in a bivariate framework. In this setting, maximum likelihood estimation becomes significantly simpler than in the standard univariate case, reducing to a form of classical linear regression. We derive explicit expressions for the resulting estimators. For certain parameter configurations, the estimators exhibit nonstandard convergence rates, exceeding the usual square-root rate. Finally, we illustrate the applicability of this model in financial contexts by analyzing stock index returns and associated volatility for several major indices.

2605.00194 2026-05-04 cs.FL cs.DM math.CO math.PR

The speed of convergence in greedy Galois games

贪心哥德尔游戏中收敛速度的研究

Jeffrey Shallit

AI总结 研究贪心哥德尔游戏中,当成功概率趋近于零时,射击序列收敛速度问题,采用数学分析确定收敛速率。

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AI中文摘要

2013年,Cooper和Dutle发明了一个对战场景,Alice和Bob互相射击直到一方被击中。每次射击成功的概率为固定值p(0 < p < 1)。射击顺序由贪心算法决定,每一步将射击分配给当前成功概率较小的玩家。Cooper和Dutle观察到当p趋近于零时,射击序列收敛到无限Thue-Morse序列t,但未解决收敛速度问题。本文确定了该收敛速度。

英文摘要

In 2013 Cooper and Dutle invented a dueling scenario where Alice and Bob shoot at each other until one is hit. Each shot is successful with some fixed probability $p$, $0 < p < 1$. The shooting order is given by a greedy algorithm, where at each step a shot is assigned to the player whose current probability of success is smaller. Cooper and Dutle observed that as $p \rightarrow 0$, the resulting sequence of shots (by Alice or Bob) converges to the infinite Thue-Morse sequence t, but left the speed of convergence as an open problem. In this note we determine the speed of this convergence.

2605.00192 2026-05-04 cs.LO math.CO

Model Checking for Low Monodimensionality Fragments of CMSO on Topological-Minor-Free Graph Classes

针对拓扑极小图类的CMSO低单维碎片的模型检查

Ignasi Sau, Nicole Schirrmacher, Sebastian Siebertz, Giannos Stamoulis, Dimitrios M. Thilikos, Alexandre Vigny

AI总结 本文提出了一种基于低单维性的CMSO碎片,证明其在拓扑极小图类上具有固定参数可解性,扩展了逻辑元定理到拓扑极小图类。

Comments An extended abstract of this paper has been accepted to LICS 2026

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AI中文摘要

算法元定理通过将逻辑可表达性与结构图性质联系起来,解释了大规模计算问题的可处理性。尽管扩展的一阶逻辑如FO+dp在排除固定拓扑极小图类上具有高效的模型检查,但此前对更丰富的CMSO碎片的类似结果尚不清楚。我们进一步发展了Sau等人[SODA 2025]的框架,通过注释图参数来碎片化CMSO,限制集合量化到满足有界结构条件的顶点集。遵循这种方法,我们识别出一种CMSO碎片,即只允许量化低单维性集合的碎片,该碎片扩展了若干已知逻辑,并证明此碎片增强后,通过不相交路径谓词进行模型检查在拓扑极小图类上是固定参数可解的。此类类本质上限定了该逻辑在子图闭类上的可处理性。作为结果,我们的结果将已知的算法元定理从一阶逻辑扩展到了拓扑极小图类设置。

英文摘要

Algorithmic meta-theorems explain the tractability of large classes of computational problems by linking logical expressibility with structural graph properties. While extensions of first-order logic such as FO+dp admit efficient model checking on graph classes excluding a fixed topological minor, comparable results for richer fragments of CMSO were previously unknown. We further develop the framework of Sau, Stamoulis, and Thilikos [SODA 2025] for fragmenting CMSO via annotated graph parameters, which restrict set quantification to vertex sets satisfying bounded structural conditions. Following this approach, we identify a fragment of CMSO, namely the one defined by allowing quantification only over sets having what we call low monodimensionality, that generalizes several previously-known logics and we show that model checking for this fragment, enhanced with the disjoint-paths predicate, is fixed-parameter tractable on topological-minor-free graph classes. Such classes essentially delimit the tractability for this logic on subgraph-closed classes. As a consequence, our results lift several known algorithmic meta-theorems beyond first-order logic to the topological-minor-free setting.

2605.00191 2026-05-04 cs.SE

What Characterizes a Software Leader? Identifying Leadership Practices from Practitioners Social Media

什么是软件领导力的特征?从从业者社交媒体中识别领导力实践

Murilo Coelho, Denivan Campos, Mariana Maia Bezerra, Matheus Paixao, Allysson Allex Araujo, Savio Freire

AI总结 本文通过分析116篇开发者文章,识别并分类软件领导者感知的领导力实践,发现领导力主要与管理及人际实践相关,而非技术能力。

Comments International Conference on Evaluation and Assessment in Software Engineering (EASE), 2026

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AI中文摘要

背景:领导力在管理学和敏捷软件开发中已被广泛研究;然而,先前研究主要关注正式角色和预定义的领导模型,对软件从业者在日常实践中如何体验和展示领导力缺乏深入洞察。目标:本文旨在根据从业者专业经验,识别并分类领导力实践。方法:我们对Dev.to在线社区上116篇从业者撰写的文章进行了内容分析。文章被系统收集、筛选和编码,最终提取、相关性分析和分类领导力实践,基于从业者叙述。结果:我们识别出103项软件项目领导者的实践,区分了推荐和不推荐的实践。这些实践被分为五个类别:人员管理与开发、流程与执行、专业与个人成长、沟通与表达以及战略视野。最常推荐的实践包括培养和实践人际技能、管理和委托团队工作、以及实践和发展管理技能,而微观管理、反生产力的工作模式和反生产力的沟通风格则成为最频繁不推荐的实践。所有实践都被组织成一个概念图。结论:研究发现,软件领导力主要与管理及人际实践相关,而非技术能力。所得的概念图总结了这些实践,可作为理解软件开发情境中领导力的参考。

英文摘要

Context: Leadership has been extensively studied in management and agile software development; however, prior research predominantly focuses on formal roles and predefined leadership models, offering limited insight into how leadership is experienced and demonstrated by software practitioners in everyday practice. Objective: Our goal is to identify and categorize leadership practices as perceived and reported by software development practitioners based on their professional experiences. Method: We conducted a content analysis of 116 practitioner-authored articles published on the Dev.to online community. Articles were systematically collected, screened, and coded, resulting in the extraction, correlation analysis and categorization of leadership practices grounded in practitioners narratives. Results: We identified 103 practices for software project leaders, distinguished between recommended and discouraged ones. These practices were organized into five categories: People Management & Development, Processes & Execution, Professional & Personal Growth, Communication & Articulation and Strategic Vision. The most recurrent recommended practices include Cultivating & Practicing Interpersonal Skills, Managing & Delegating Team Work, and Practicing & Developing Managerial Skills, whereas Micromanagement, Counterproductive Work Patterns, and Counterproductive Communication Styles emerged as the most frequent discouraged practices. We organized all practices into a conceptual map. Conclusion: The findings indicate that software leadership is mainly associated with managerial and interpersonal practices rather than technical expertise. The resulting conceptual map summarizes these practices and can serve as a reference for understanding leadership in software development contexts.

2605.00190 2026-05-04 math.DS

Characterisation of Stability for Interval Translation Maps

区间翻译映射的稳定性刻画

Kostiantyn Drach, Leon Staresinic, Sebastian van Strien

AI总结 本文研究了区间翻译映射的稳定性,提出并证明了稳定性与'无临界连接'和'匹配'两个动态性质的关系,为一般ITM的稳定性理论奠定基础。

Comments arXiv admin note: substantial text overlap with arXiv:2411.14312

详情
AI中文摘要

区间翻译映射(ITM)是在有限划分$I_1, \ldots, I_r$的区间$I$上定义的分段翻译$T \colon I \to I$。与经典区间交换变换(IET)不同,我们不要求这些子区间的像互不相交;特别地,ITM不假定是双射的。因此,ITM为IET提供了一个自然的非可逆推广。本文提出了适用于一般区间翻译映射的适当稳定性概念,并证明了稳定性可由两个动态自然性质'无临界连接'和'匹配'来刻画。这一结果可视为一般ITM稳定性理论的基础步骤。

英文摘要

An interval translation map (ITM) is a piece-wise translation $T \colon I \to I$ defined on a finite partition $I_1, \ldots, I_r$ of an interval $I$ into $r \ge 2$ subintervals. In contrast to classical interval exchange transformations (IETs), we do not require that the images of these subintervals are disjoint; in particular, ITMs are not assumed to be bijective. Thus, ITMs provide a natural non-invertible generalisation of IETs. In this paper, we formulate an appropriate notion of stability for general interval translation mappings and prove a characterisation of stability in terms of two dynamically natural properties called the Absence of Critical Connections and Matching. This result can be viewed as the foundational step towards the stability theory of general ITMs.