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2605.30398 2026-06-01 gr-qc astro-ph.HE astro-ph.SR

Dark Energy Stars in Finch-Skea Spacetime with a Schwarzschild-(Anti)-de Sitter Exterior

Finch-Skea时空中具有Schwarzschild-(Anti)-de Sitter外部的暗能量星

Muhamad Ashraf Azman

AI总结 在爱因斯坦引力框架下,利用复杂度因子形式构造Finch-Skea时空中包含普通物质和暗能量的静态各向异性星体模型,并与外部Schwarzschild-(anti-)de Sitter时空光滑匹配,系统研究了宇宙常数对暗能量星结构和稳定性的影响。

Comments 24 pages, 5 figures

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AI中文摘要

在这项工作中,在爱因斯坦引力框架下系统研究了宇宙常数对Finch-Skea时空中暗能量星的影响。通过采用复杂度因子形式获得时间度量势,构造了由普通物质和暗能量组成的静态各向异性恒星构型。通过适当的边界条件,内部解与外部Schwarzschild-(anti-)de Sitter时空光滑匹配。详细研究了正负宇宙常数对致密星候选体Vela X-1的结构和稳定性的影响。结果表明,正的宇宙常数值产生更大、更不致密的构型,而负的宇宙常数值导致更致密、更紧凑的星体,具有更强的引力效应。在所有考虑的情况下,恒星内部的能量条件均得到满足。然而,足够大的宇宙常数值会引入对流体静力学平衡的偏离,并影响模型的因果和动力学稳定性行为。总体而言,结果表明宇宙常数在决定Finch-Skea时空中暗能量星的致密性、平衡和稳定性行为方面起着重要作用。

英文摘要

In this work, the effects of the cosmological constant on dark energy stars in Finch-Skea spacetime are systematically investigated within the framework of Einstein gravity. A static and anisotropic stellar configuration composed of ordinary matter and dark energy is constructed by employing the complexity factor formalism to obtain the temporal metric potential. The interior solution is smoothly matched to the exterior Schwarzschild-(anti-)de Sitter spacetime through appropriate boundary conditions. The influence of positive and negative cosmological constants on the structural and stability properties of the compact star candidate Vela X-1 is investigated in detail. The results show that positive values of the cosmological constant produce larger and less compact configurations, whereas negative values lead to denser and more compact stars with stronger gravitational effects. The energy conditions are satisfied throughout the stellar interior for all considered cases. However, sufficiently large values of the cosmological constant introduce deviations from hydrostatic equilibrium and affect the causal and dynamical stability behavior of the model. Overall, the results demonstrate that the cosmological constant plays an important role in determining the compactness, equilibrium and stability behavior of dark energy stars in Finch-Skea spacetime.

2605.30397 2026-06-01 math.CO math.AC

On Modular Invariants of Truncated Polynomial Rings

截断多项式环的模不变式

Hoang Le Xuan

AI总结 本文研究截断多项式环在模表示下的不变式,推广了Macdonald猜想并扩展了Stong-Tamagawa公式,同时探讨了抛物子群作用下的不变空间及delta算子的多项式性质。

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AI中文摘要

模不变理论是数学的一个分支,研究在群作用下不变的多项式函数的行为,特别是在正特征域上。总体而言,模不变理论是连接代数方法与组合和拓扑应用的重要纽带。基于现有文献,本本科学位论文旨在研究Macdonald(1992)、Lewis、Reiner和Stanton(2017)以及L. M. Ha、N. D. H. Hai和N. V. Nghia(2024)近期工作中出现的猜想和问题。特别地,我们陈述并证明了Macdonald(1992)猜想(7.25)的一个推广,从而扩展了Stong-Tamagawa公式,该公式是有限域上Schur函数的一个无基刻画。此外,我们考察了Lewis-Reiner-Stanton(2017)关于截断多项式代数在抛物子群作用下不变空间的猜想,以及Ha、Hai和Nghia(2024)对Borel子群的证明,并由此将研究扩展到幂幺群作用下的不变环。另外,我们考虑了delta算子——Ha、Hai和Nghia(2024)证明中使用的关键算子族——特别关注其多项式性质。

英文摘要

Modular Invariant Theory is a branch of mathematics that explores the behavior of polynomial functions invariant under group actions, particularly over fields with positive characteristic. Overall, modular invariant theory serves as a vital link connecting algebraic methods with combinatorial and topological applications. Based on the existing literature, this undergraduate thesis aims to investigate conjectures and problems emerging from the work of Macdonald (1992), and the recent work of Lewis, Reiner, and Stanton (2017), as well as subsequent developments by L. M. Ha, N. D. H. Hai, and N. V. Nghia (2024). In particular, we state and prove a generalization of Conjecture (7.25) by Macdonald (1992), leading to an extension of the Stong-Tamagawa formula, which is a basis-free characterization of Schur functions over finite fields. Besides, we examine conjectures by Lewis-Reiner-Stanton (2017) about invariant spaces of truncated polynomial algebras under the action of parabolic subgroups, and the proof for the Borel subgroups by Ha, Hai, and Nghia (2024), from which we extend the investigation to the invariant rings under the unipotent group's action. Additionally, we consider the delta operators-a pivotal family of operators used in the proof of Ha, Hai, and Nghia (2024)-with particular attention to their polynomiality properties.

2605.30395 2026-06-01 astro-ph.IM astro-ph.EP cond-mat.soft

Experiments on Settling of Granular and Cohesive Material in Low Gravity

低重力下颗粒和粘性材料沉降实验

Matthias Keulen, Timo Giese, Kolja Joeris, Jonathan Kollmer

AI总结 通过落塔实验模拟不同低重力条件,研究三种颗粒样品的沉降行为,发现体积增大、堆积密度降低,且细颗粒对重力变化最敏感,表明体积变化不仅取决于粒径还与粗糙度和均匀性有关。

Comments Submitted to Planetary Science Journal

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AI中文摘要

岩石天体(如行星或小行星)的表土通常在不同于地球的重力条件下沉降。颗粒材料的行为在不同重力下难以缩放。为了预测这些高度复杂的系统,其中颗粒间的粘性力可与重力相当,我们需要模拟和实验。我们在变化的低重力下对三种不同颗粒样品进行了沉降实验,并检查了它们的堆积密度。我们使用高精度线性平台在ZARM落塔提供的零$g$环境内人为诱导低重力,并观察样品的沉降。三种样品为:粒径$1 ext{-}200\,μ$m的细玄武岩、$2 ext{-}5\,$mm的粗玄武岩和$750 ext{-}1000\,μ$m的玻璃珠。人为重力为$150,\,250,\,500,\,750$和$1000\,$mm/s$^2$,因此范围从小行星重力到接近月球重力。我们观察到颗粒样品在较低重力下体积更大,因此堆积密度更低;我们还发现细玄武岩对重力变化最敏感,在$250\,$mm/s$^2$时体积增加$+19.6\,\%$,其次是粗玄武岩,在$150\,$mm/s$^2$时增加$+12.2\,\%$,而玻璃珠的堆积密度对重力变化最不敏感,在$250\,$mm/s$^2$时增加$+4.25\,\%$。通过这些实验,我们表明体积变化不仅取决于粒径,还取决于粗糙度和均匀性,我们提供了真实实验数据以验证理论工作,并强调了低重力环境中粘性力的作用。

英文摘要

The regolith of rocky bodies, such as planets or asteroids, generally settles under gravity conditions different from those of Earth. The behavior of granular material is not easily scalable for different gravities. To predict these highly complex systems where cohesive inter particle forces can be comparable to gravitational forces, we need simulations and experiments. We did experiments on settling of three different granular samples in varying reduced gravities and examined their packing densities. We used a high precision linear stage to artificially induce reduced gravities inside the zero $g$ environment provided by the ZARM drop tower and observe the settling of our samples. The three samples were fine basalt with particle diameters of $1\text{-}200\,μ$m, coarse basalt with $2\text{-}5\,$mm and glass beads with $750\text{-}1000\,μ$m. The artificial gravities were $150,\,250,\,500,\,750$ and $1000\,$mm/s$^2$ and therefore ranged from large asteroid gravity to almost moon gravity. We saw the granular samples have higher volumes in lower gravities and therefore lower packing densities, we also saw the fine basalt be the most sensitive to changes in gravity, up to $+19.6\,\%$ in volume for $250\,$mm/s$^2$, followed by the coarse basalt particles, up to $+12.2\,\%$ for $150\,$mm/s$^2$ and the glass beads packing density being the least sensitive to changes in gravity, up to $+4.25\,\%$ for $250\,$mm/s$^2$. With these experiments we show change in volume is not solely dependent of particle size but also roughness and uniformity, we provide real life experimental data to validate theoretical works and highlight the role of cohesive forces in low gravity environments.

2605.30390 2026-06-01 math-ph hep-th math.MP quant-ph

A Boundary--Residue Incidence Coalgebra for Associahedral Scattering Forms

Associahedral散射形式的边界-留数关联余代数

Ioannis P. Zois

AI总结 引入与正几何面偏序集相关的边界-留数关联余代数,并应用于associahedral散射形式,证明其记录树级标量振幅的嵌套平面因子化通道,并推广至圈级。

Comments 29 pages, 5 figures

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AI中文摘要

我们引入了一个与正几何的面偏序集相关的边界-留数关联余代数,并将其应用于associahedral散射形式。该构造的动机源于Feynman图上的Connes-Kreimer余积与规范形式的递归留数结构之间的类比。对于Stasheff associahedron \(K_n\),其面由\((n+1)\)边形的非交叉剖分索引,我们证明了关联余积记录了相应树级标量振幅的所有中间嵌套平面因子化通道。由剖分标记的面上的规范形式的留数分解为与所得子多边形相关的较低associahedron上规范形式的外积。我们明确地说明了五边形associahedron \(K_4\)(对应于五点平面标量振幅)的构造。然后我们提出了圈级扩展:每当平面圈被积函数由正几何表示时,associahedral面偏序集被相应圈几何的边界偏序集替代。单圈halohedron给出了一个具体的标量例子,而在非平面情形下,我们在对数奇点层上定义了关联余代数。最后,我们将边界-留数余代数与三角化或正则CW时空的胞腔关联余代数进行了比较。有限正则CW复形的面偏序集重构了其重心细分,从而重构了其底层多面体,而在正几何中,相同的关联机制组织了规范形式的留数。这建立了一个先关联的桥梁,连接了胞腔时空拓扑与正几何振幅因子化,而不假设度量或因果数据由拓扑决定。

英文摘要

We introduce a boundary--residue incidence coalgebra associated with the face poset of a positive geometry and apply it to associahedral scattering forms. The construction is motivated by the analogy between the Connes--Kreimer coproduct on Feynman graphs and the recursive residue structure of canonical forms. For the Stasheff associahedron \(K_n\), whose faces are indexed by non-crossing dissections of an \((n+1)\)-gon, we prove that the incidence coproduct records all intermediate nested planar factorisation channels of the corresponding tree-level scalar amplitude. The residue of the canonical form on a face labelled by a dissection factorises as the exterior product of canonical forms on the lower associahedra associated with the resulting subpolygons. We illustrate the construction explicitly for the pentagon associahedron \(K_4\), corresponding to the five-point planar scalar amplitude. We then formulate a loop-level extension: whenever a planar loop integrand is represented by a positive geometry, the associahedral face poset is replaced by the boundary poset of the corresponding loop geometry. The one-loop halohedron gives a concrete scalar example, while in the non-planar case we define the associated incidence coalgebra at the level of logarithmic singularity strata. Finally, we compare the boundary--residue coalgebra with the cellular incidence coalgebra of a triangulated or regular CW spacetime. The face poset of a finite regular CW complex reconstructs its barycentric subdivision, and hence its underlying polyhedron, while in positive geometry the same incidence mechanism organises canonical-form residues. This yields an incidence-first bridge between cellular spacetime topology and positive-geometric amplitude factorisation, without assuming that metric or causal data are determined by topology.

2605.30386 2026-06-01 physics.gen-ph

The Saddle Point of Everything

万物的鞍点

K. Sravan Kumar

AI总结 本文论证倒谐振子(鞍点)哈密顿量在物理系统普遍性,并指出其与量子引力中纯虚拟自旋2扇区的对偶关系,从而修正量子引力历史,导致非奇异宇宙、Starobinsky暴胀及CMB和原初引力波特征。

Comments 20 pages, 2 figures

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AI中文摘要

谐振子是稳定平衡的普遍哈密顿量。其对应物——倒谐振子(IHO)是不稳定平衡的哈密顿量:物理系统的鞍点。它出现在跨学科领域,从凝聚态、量子光学、量子化学到标准模型希格斯不稳定性以及引力视界附近的量子场论。其数学深度进一步体现在通过Berry-Keating哈密顿量与黎曼ζ函数非平凡零点的关联。值得注意的是,最近研究表明,IHO的对偶哈密顿量支配着四维中唯一幺正微扰可重整化量子引力理论的额外自旋2扇区,该扇区保持纯虚拟并在普朗克尺度正则化引力相互作用。本文论证鞍点的普遍物理学修正了放弃可重整性、唯一性和可预测性的量子引力方法的历史。其后果包括非奇异宇宙、Starobinsky暴胀,以及对大尺度CMB特征和原初引力波的可能影响。

英文摘要

The harmonic oscillator is the universal Hamiltonian of stable equilibrium. Its counterpart, the inverted harmonic oscillator (IHO), is the Hamiltonian of unstable equilibrium: the saddle point of physical systems. It appears across disciplines, from condensed matter, quantum optics, and quantum chemistry to the Standard Model Higgs instability and quantum field theory near gravitational horizons. Its mathematical depth is further reflected in its relation to the non-trivial zeros of the Riemann zeta function through the Berry-Keating Hamiltonian. Remarkably, a dual Hamiltonian to the IHO has recently been shown to govern the additional spin-2 sector of the unique unitary perturbatively renormalizable theory of quantum gravity in four dimensions, with that sector remaining purely virtual and regularizing gravitational interactions at the Planck scale. This paper argues that the universal physics of the saddle point course-corrects the history of quantum gravity approaches that abandoned renormalizability, uniqueness, and predictivity. Its consequences include a non-singular Universe, Starobinsky inflation, and possible implications for large-scale CMB features and primordial gravitational waves.

2605.30384 2026-06-01 astro-ph.IM astro-ph.GA

The EPS Research Astro-RAG Platform: A Unified Open-Science Infrastructure for Cross-Epoch Astrophysical Kinematic Analysis, LLM-Assisted Research Workflows, and Educational Outreach

EPS Research Astro-RAG平台:用于跨纪元天体物理运动学分析、LLM辅助研究工作流程和教育推广的统一开放科学基础设施

David C. Flynn

AI总结 提出一个开放科学平台,整合四个跨纪元天体物理语料库、120个可执行Jupyter笔记本示例,并利用LLM辅助检索增强生成(RAG)研究工作流程,通过ω运动学校正揭示从z=0到z~5的角速度符号反转。

Comments 5 pages, no figures, no tables. Platform release: four open astrophysical corpora (772 objects, z=0 to z~6), 120 verified Jupyter notebooks, QuickStart reproducibility pathway, and High-School Exploration Track. Zenodo DOIs: 10.5281/zenodo.19563417, 10.5281/zenodo.20320362, 10.5281/zenodo.19907765, 10.5281/zenodo.20369285. GitHub: github.com/eps-research/rag-corpus-series

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AI中文摘要

我们介绍了EPS Research Astro-RAG平台(v1.0),这是一个开放科学研究基础设施,提供四个机器可读的跨纪元天体物理语料库、120个经过验证的可执行Jupyter笔记本示例、一个QuickStart可重复性路径、一个教育性高中探索轨道,以及一个LLM辅助检索增强生成(RAG)研究工作流程路线图。该平台覆盖从本地宇宙(z=0)到接近再电离纪元(z~6)的整个可观测宇宙纪元,提供了首个统一的运动学数据集,在通用模式和分析框架下连接了HI 21cm旋转曲线、银河系球状星团动力学和高红移ALMA [CII]形态运动学。四个语料库共包含772个天体:438个HI示踪星系(统一HI旋转曲线语料库v7.0)、129个矮/不规则星系(矮/不规则HI语料库v1.0)、174个银河系球状星团(GC语料库v1.3.1)和31个z=4.26-5.68的恒星形成星系(高红移运动学语料库Z1)。统一HI语料库保留了凯斯西储大学SPARC数据库(Lelli等人2016)的完整保真度,包括所有测光分解成分和表面亮度轮廓,并补充了THINGS、LITTLE THINGS和WALLABY DR2数据。统一的科学框架是Flynn & Cannaliato(2025)的ω运动学校正,该校正揭示了边界点角速度ω从z=0的正值(SPARC平均值+7.06 ± 3.26 rad/Gyr)到z~5的负值(Z1中位数-13.05 rad/Gyr)的稳健符号反转,为未来的RAMSES宇宙学模拟提供了动机。所有语料库均以CC BY 4.0许可在Zenodo上发布,并带有永久DOI,平台存档于https://github.com/eps-research/rag-corpus-series(DOI: 10.5281/zenodo.20398430)。

英文摘要

We present the EPS Research Astro-RAG Platform (v1.0), an open-science research infrastructure providing four machine-readable, cross-epoch astrophysical corpora, 120 verified executable Jupyter notebook examples, a QuickStart reproducibility pathway, an educational High-School Exploration Track, and a roadmap for LLM-assisted retrieval-augmented generation (RAG) research workflows. The platform spans the full observable cosmic epoch from the local universe (z = 0) to the epoch approaching reionization (z ~ 6), providing the first unified kinematic dataset connecting HI 21cm rotation curves, Milky Way globular cluster dynamics, and high-redshift ALMA [CII] morpho-kinematics under a common schema and analysis framework. The four corpora contain 772 total objects: 438 HI-traced galaxies (Unified HI Rotation Curve Corpus v7.0), 129 dwarf/irregular galaxies (Dwarf/Irregular HI Corpus v1.0), 174 Milky Way globular clusters (GC Corpus v1.3.1), and 31 star-forming galaxies at z = 4.26-5.68 (High-z Kinematic Corpus Z1). The Unified HI corpus preserves the full fidelity of the Case Western Reserve University SPARC database (Lelli et al. 2016), including all photometric decomposition components and surface brightness profiles, augmented with THINGS, LITTLE THINGS, and WALLABY DR2 data. The unifying scientific framework is the omega kinematic correction of Flynn & Cannaliato (2025), which reveals a robust sign reversal in the boundary-point angular velocity omega from positive values at z = 0 (SPARC mean +7.06 +/- 3.26 rad/Gyr) to negative values at z ~ 5 (Z1 median -13.05 rad/Gyr), motivating future RAMSES cosmological simulations. All corpora are released under CC BY 4.0 at Zenodo with permanent DOIs, and the platform is archived at https://github.com/eps-research/rag-corpus-series (DOI: 10.5281/zenodo.20398430).

2605.30382 2026-06-01 q-bio.PE q-bio.QM

On the Connection Between Differential Population Growth Rate and Epidemic Reproduction Numbers

关于差异种群增长率与流行病再生数之间联系的探讨

Hong Qin

AI总结 本文通过理论推导和实证分析(涵盖SARS-CoV-2和流感数据),建立了从基因组监测估计的差异种群增长率(DPGR)与流行病再生数(Rt)之间的数学联系,并验证了DPGR在预测变异株传播优势方面的有效性。

Comments 23 pages, 5 figures

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AI中文摘要

在大流行期间,公共卫生机构需要快速评估新的病毒变异株是否比现有谱系更具传播性。对于共同流行的变异株,相对适应性可以表示为选择系数,即从基因组监测估计的差异种群增长率(DPGR),或者,在附加假设下,表示为流行病再生数$R_t$的对比。我们证明DPGR估计的是成对的增长率差异。在指定的代际间隔模型下,该差异可以转化为再生数空间;在等世代时间SIR特例中,它简化为变异特异性$R_t$的缩放差异。相关的增长率对比也出现在多项逻辑和增长优势随机游走模型中,尽管这些方法在似然、平滑、先验和数据输入方面与DPGR不同。我们通过总计超过2200个匹配数据点的五项SARS-CoV-2和流感分析评估了该理论。当真实$R_t$已知时,SIR模拟恢复了预期的映射,回顾性SARS-CoV-2分析显示,在变异株占主导地位前43至65天,DPGR信号持续存在,在我们的分析中符号准确率为95%。DPGR在谱系三元组中近似可传递,对于选定的功能相似亚谱系接近零,并且在各国之间方向一致。这些结果通过一个假设明确的增长率桥梁,将基于序列计数的适应性估计与再生数对比联系起来。

英文摘要

During pandemics, public health agencies need to rapidly assess whether a new viral variant is more transmissible than existing lineages. For co-circulating variants, relative fitness can be expressed as a selective coefficient, as the differential population growth rate (DPGR) estimated from genomic surveillance, or, with additional assumptions, as a contrast in epidemic reproduction numbers $R_t$. We show that DPGR estimates a pairwise growth-rate difference. Under a specified generation-interval model, this difference can be transformed into reproduction-number space; in the equal-generation-time SIR special case, it reduces to a scaled difference in variant-specific $R_t$. Related growth-rate contrasts also appear in multinomial logistic and growth-advantage random-walk models, although those methods differ from DPGR in likelihood, smoothing, priors, and data inputs. We evaluate the theory across five SARS-CoV-2 and influenza analyses totaling more than 2,200 matched data points. SIR simulation recovers the expected mapping when the true $R_t$ is known, and retrospective SARS-CoV-2 analyses show sustained DPGR signals 43 to 65 days before variant dominance, with 95\% sign accuracy in our analysis. DPGR is approximately transitive across lineage triplets, near zero for selected functionally similar sublineages, and directionally consistent across countries. These results connect sequence-count-based fitness estimates to reproduction-number contrasts through an assumption-explicit growth-rate bridge.

2605.30378 2026-06-01 math.CV

Estimates of $Γ$-functions and their $\log{}$-derivatives

$\Gamma$ 函数及其 $\log{}$ 导数的估计

Miron Bekker, Boris Mityagin

AI总结 本文给出了 $\Gamma$ 函数的加权比值及其对数导数的下界,并应用于估计 Hardy 空间 $H^p({\mathbb C}_+)$ 中 Cesàro 算子相关算子的范数,其中 $1<p<\infty$。

Comments 11 pages, 2 figures

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AI中文摘要

我们给出了 $\Gamma$ 函数的加权比值及其对数导数的下界。然后我们将此结果应用于估计 Hardy 空间 $H^p({\mathbb C}_+)$($1<p<\infty$)中与 Cesàro 算子相关的算子的范数。

英文摘要

We provide a lower bound for a weighted ratio of $Γ-$functions and its $\log{}-$derivative. Then we apply this result to estimate the norm of the operator associated with the Cesáro operator in the Hardy space $H^p({\mathbb C}_+)$, $1<p<\infty$

2605.30377 2026-06-01 cs.AR cs.PF

FREESS: A Web-Based Educational Simulator for a RISC-V-Inspired Superscalar Processor with Tomasulo-Style Dynamic Scheduling

FREESS:一个基于Web的RISC-V启发超标量处理器教学模拟器,采用Tomasulo风格动态调度

Roberto Giorgi, Miquel Moretó Planas

AI总结 提出FREESS开源教学模拟器,通过周期级可视化展示RISC-V启发超标量处理器中Tomasulo风格的寄存器重命名、发射、执行、写回、提交及内存排序,支持运行时参数调整以比较不同超标量架构。

Comments RISC-V Summit Europe, Bologna, 8-12th June 2026

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AI中文摘要

FREESS(免费教育超标量模拟器)是一个开源教学环境,用于RISC-V启发的超标量处理器中的指令级并行性。它提供了Tomasulo风格机器中寄存器重命名、发射、执行、写回、提交和内存排序的紧凑、周期级视图。该模拟器在一个文本表示中展示了寄存器映射、空闲池、指令窗口、重排序缓冲区和加载/存储队列,因此硬件状态的演变可以在屏幕上跟踪并在纸上重现。运行时参数如发射宽度、队列大小和功能单元延迟可以轻松更改,从而能够直接比较不同的超标量组织。该工具已支持高级计算机体系结构教学约十五年,并在GitHub上公开可用。

英文摘要

FREESS (Free Educational Superscalar Simulator) is an open-source teaching environment for instruction-level parallelism in a RISC-V-inspired superscalar processor. It provides a compact, cycle-by-cycle view of register renaming, issue, execution, write-back, commit, and memory ordering in a Tomasulo-style machine. The simulator exposes the register map, free pool, instruction window, reorder buffer, and load/store queues in one textual representation, so the evolution of the hardware state can be followed on screen and reproduced on paper. Runtime parameters such as issue width, queue sizes, and functional-unit latencies can be changed easily, enabling direct comparison among alternative superscalar organizations. The tool has supported Advanced Computer Architecture teaching for about fifteen years and is publicly available on GitHub.

2605.30373 2026-06-01 cs.CG

Apple-Peel Unfolding in Three and Four Dimensions: Spiral and Zonal Selection Rules

三维和四维中的苹果皮展开:螺旋和带状选择规则

Takashi Yoshino, Supanut Chaidee

AI总结 本文定义了两种面选择规则(螺旋规则RS和带状规则RZ),系统评估了它们在柏拉图立体、阿基米德立体和正凸4-多胞体上的展开成功率,并提出了完美、可能和不可能的三分类,同时指出顺序成功与几何有效性是不同的概念。

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AI中文摘要

苹果皮展开是一种贪婪算法,它以螺旋顺序一次选择一个多面体(或多胞体)的面(或胞),生成类似于连续条带剥苹果皮的网。我们定义了两种面选择规则——RS(螺旋规则:最小有符号行列式,即最陡的顺时针转弯)和RZ(带状规则:沿剥皮轴的最大坐标)——并系统评估了它们在(i)五个柏拉图立体、(ii)十三个阿基米德立体和(iii)六个正凸4-多胞体上的展开成功率。一个主要贡献是将每个立体分为三类:\emph{完美}(每个起始对都产生完整网)、\emph{可能}(至少一对成功)和\emph{不可能}(没有一对成功),同时通过等变性论证表明面传递立体仅限于0/100%二分法。RZ在大多数情况下达到最高成功率;对于正4-多胞体,它是唯一在120-胞体上产生非零结果的规则,并取得了完美结果(1,440/1,440对)。我们注意到\emph{顺序成功}(完成贪婪遍历)和\emph{几何有效性}(3D实现中无自交)是不同的:每个120-胞体排序都产生自交的3D网,因此尽管有完美的排序结果,120-胞体有零个有效的3D网。600-胞体在所有测试规则下都是不可能的。

英文摘要

Apple-Peel Unfolding is a greedy algorithm that selects the faces (or cells) of a polyhedron (or polytope) one at a time in a spiral order, producing a net analogous to peeling an apple in a single continuous strip. We define two face-selection rules -- RS (Spiral rule: minimum signed determinant, i.e.\ sharpest clockwise turn) and RZ (Zonal rule: maximum coordinate along the peeling axis) -- and systematically evaluate their unfolding success rates on (i)~the five Platonic solids, (ii)~the thirteen Archimedean solids, and (iii)~the six regular convex 4-polytopes. A principal contribution is a three-way classification of each solid as \emph{Perfect} (every starting pair yields a complete net), \emph{Possible} (at least one pair succeeds), or \emph{Impossible} (no pair succeeds), together with an equivariance argument showing that face-transitive solids are confined to the $0/100\%$ dichotomy. RZ achieves the highest success rates in most cases; for the regular 4-polytopes it is the only rule yielding non-zero results for the 120-cell, where it achieves a Perfect result (1,440/1,440 pairs). We note that \emph{ordering success} (completing the greedy traversal) and \emph{geometric validity} (no self-intersection in the 3D realization) are distinct: every 120-cell ordering produces a self-intersecting 3D net, so the 120-cell has zero valid 3D nets despite its Perfect ordering result. The 600-cell is Impossible under all rules tested.

2605.30369 2026-06-01 astro-ph.HE astro-ph.IM gr-qc

Reconciling GW170817 and GW190814 with a Nonmonotonic Sound-Speed Equation of State

用非单调声速状态方程调和GW170817和GW190814

Marlon M. S. Mendes, Odilon Lourenço da Silva Filho, César H. Lenzi

AI总结 通过约束演化TOV发现管道(CETD)在广义相对论框架内找到结构化因果状态方程盆地,调和了GW170817和GW190814的张力。

Comments 4 pages, 2 figures, 1 table

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AI中文摘要

我们表明,GW170817-GW190814张力可以在广义相对论内通过一个结构化因果EoS盆地调和,该盆地由约束演化TOV发现管道(CETD)找到。该盆地包含约1.4×10^4个独特的EoS,其M_max = 2.3-2.8 M_sun,R_1.4 = 11.97-12.29 km,Lambda_1.4 <= 580,以及达到c_s^2/c^2 = 0.86-0.99的双峰声速。

英文摘要

We show that the GW170817-GW190814 tension can be reconciled within General Relativity by a structured causal EoS basin found with a Constrained Evolutionary TOV Discovery pipeline (CETD). The basin contains ~1.4x10^4 unique EoS with M_max = 2.3-2.8 M_sun, R_1.4 = 11.97-12.29 km, Lambda_1.4 <= 580, and double-peaked sound speeds reaching c_s^2/c^2 = 0.86-0.99.

2605.30360 2026-06-01 cs.DC stat.AP

Polynomial Histograms for Memory-Efficient Representation of Long-tailed System Distributions

多项式直方图用于长尾系统分布的内存高效表示

Murray Stokely, Tim Hesterberg, Arif Merchant, Nate Coehlo

AI总结 提出多项式直方图,通过在每个桶中标注矩信息,在相同存储成本下比传统直方图更有效地表示长尾分布,并应用于大规模生产系统的文件系统指标。

Comments 2014 Preprint

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AI中文摘要

分布式系统必须经常跟踪许多不同计算机上的多种性能指标。例如,某些操作的延迟分布可能针对计算机、用户和操作的大量组合进行计算。这些经验分布需要在单个软件组件上以最小代价收集,跨多个维度高效聚合,并以紧凑表示存储,用于各种下游数据分析应用。我们描述了一种针对分箱数据的信息损失度量,使我们能够优化不同直方图表示的信息损失成本。我们探索了多项式直方图的使用,其中直方图的每个桶都标注了该桶中底层分布的矩。将这些多项式直方图与使用相同存储成本用于额外桶而不是每个桶中标注的传统直方图进行比较。我们描述了这些技术在大规模生产系统的文件系统指标中的应用,并分析表征了多项式直方图何时以更低成本提供更多信息。

英文摘要

Distributed systems must frequently keep track of many different types of performance metrics across many different computers. For example, the latency distribution of certain operations may be computed for a large combination of computers, users, and operations. These empirical distributions need to be collected at minimal expense on the individual software components, efficiently aggregated across multiple dimensions, and stored in a compact representation for a variety of downstream data analysis applications. We describe an information loss metric for binned data that allows us to optimize cost of information loss from different histogram representations. We explore the use of polynomial histograms where each bin of a histogram is annotated with moments of the underlying distribution in that bin. These polynomial histograms are compared to traditional histograms using the same storage cost for additional bins instead of annotations in each bin. We describe an application of these techniques for file system metrics for a large production system, and analytically characterize when polynomial histograms offer more information at lower cost.

2605.30357 2026-06-01 cs.NI cond-mat.mtrl-sci

Emerging Trends in Intelligent Sensing

智能传感的新兴趋势

Ghazi Sarwat Syed

AI总结 本文探讨了人工智能、连接设备与高速移动网络推动下,传感器架构向边缘计算转变的趋势,并总结了关键架构与性能指标。

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AI中文摘要

人工智能、连接设备和高速移动网络的快速普及正在推动前所未有的计算需求,这对传统的传感器架构提出了挑战。本文探讨了向边缘计算的转变,即直接在数据源处执行计算,并强调了可能定义下一代智能传感器系统的关键架构和性能指标。

英文摘要

The rapid proliferation of artificial intelligence, connected devices, and high speed mobile networks is driving unprecedented computational demands that challenge traditional sensor architectures. This article explores the shift toward edge computing, where computation is performed directly at the data source, and highlights the key architectures and performance metrics that may define the next generation of intelligent sensor systems.

2605.30356 2026-06-01 cs.NI

CREWS: Collaborative Robust Edge WiFi Sensing with Asynchronous and Incomplete Observations

CREWS:具有异步和不完整观测的协作鲁棒边缘WiFi感知

Yinan Chen, Yang Zhou, Xiaoxia Huang, Pan Li

AI总结 提出CREWS框架,通过拓扑无关聚合器和感知延迟自适应重放机制,解决边缘WiFi感知中节点异步和数据不完整导致的鲁棒性问题,理论证明收敛性,实验表明在严重丢包和抖动下精度仅下降2.2个百分点。

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AI中文摘要

现有的协作WiFi感知系统依赖于完美的节点同步和完整的数据可用性。然而,实际边缘部署面临异构计算和网络中断,导致异步和不完整的特征。我们提出CREWS,一个鲁棒的协作感知框架,固有地抵抗这些网络波动。首先,CREWS采用拓扑无关聚合器,对输入特征的到达顺序和子集大小不变。其次,它不丢弃延迟观测,而是利用感知自适应重放机制。通过将滞后节点的陈旧特征视为系统诱导的难样本,CREWS将同步延迟转化为有益的训练正则化。我们从理论上证明了该架构的联合收敛性,并展示了重放如何限制偏差-方差权衡。大量评估和一个8节点异构硬件测试平台证明了其卓越的鲁棒性。在严重条件下,即50%的瞬时丢包率或分布外抖动,CREWS将精度下降限制在仅2.2个百分点,显著优于最先进的基线。

英文摘要

Existing collaborative WiFi sensing systems rely on perfect node synchronization and complete data availability. However, real-world edge deployments suffer from heterogeneous computing and network dropouts, leading to asynchronous and incomplete features. We propose CREWS, a robust collaborative sensing framework that inherently resists these network volatility. First, CREWS employs a topology-agnostic aggregator invariant to the arrival order and subset size of incoming features. Second, rather than discarding delayed observations, it utilizes a staleness-aware adaptive replay mechanism. By treating stale features from lagging nodes as system-induced hard samples, CREWS transforms synchronization delays into beneficial training regularization. We theoretically prove the joint convergence of this architecture and demonstrate how replay bounds the bias-variance trade-off. Extensive evaluations and an 8-node heterogeneous hardware testbed demonstrate its superior resilience. Under severe conditions i.e., 50\% transient dropout rate or out-of-distribution jitter, CREWS restricts accuracy degradation to merely 2.2 percentage points, substantially outperforming state-of-the-art baselines.

2605.28648 2026-06-01 math.NA cs.NA

Efficient and Accurate Model Order Reduction for Integral Electromagnetic Formulations in Fusion Device Transient Analysis Toward AI-Enabled Modeling

面向AI建模的聚变装置瞬态分析中积分电磁公式的高效精确模型降阶

Salvatore Ventre

AI总结 针对聚变装置中基于积分公式的瞬态电磁问题,提出一种结合小波时域压缩和源驱动Krylov投影的模型降阶策略,避免密集积分算子的重复求逆,实现大幅计算加速并保持精度,且成功应用于生成神经网络代理的训练数据。

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AI中文摘要

聚变装置中电磁瞬态的数值模拟对于分析等离子体稳定性和破坏性事件至关重要。然而,由于积分公式产生的大规模密集系统,计算需求仍然很高。本文提出了一种基于积分公式的瞬态电磁问题的模型降阶(MOR)策略。与基于算子的压缩技术(如$\mathcal{H}$-矩阵方法)不同,降阶空间直接从瞬态激励构建。与经典的基于快照和传递函数的MOR方法相比,所提出的公式在MOR基构造阶段避免了密集积分算子的重复显式求逆或分解。通过结合基于小波的时域压缩和源驱动Krylov投影,该方法生成了针对指定激励族动态可达响应定制的降阶模型。在各种等离子体事件和聚变相关场景上的数值验证证明了该策略的鲁棒性,在准确保持瞬态电磁响应的同时实现了显著的计算加速。最后,该方法成功应用于零场问题,高效生成神经网络代理的训练数据,为物理一致的AI驱动聚变建模做出贡献。

英文摘要

The numerical simulation of electromagnetic transients in fusion devices is essential for analyzing plasma stability and disruptive events. However, it remains computationally demanding due to the large-scale dense systems arising from integral formulations. This work proposes a model order reduction (MOR) strategy for transient electromagnetic problems based on integral formulations. Unlike operator-based compression techniques (such as $\mathcal{H}$-matrix approaches), the reduced space is constructed directly from the transient excitation. In contrast to classical snapshot- and transfer-function-based MOR approaches, the proposed formulation avoids repeated explicit inversions or factorizations of the dense integral operator during the MOR basis-construction stage. By combining wavelet-based temporal compression with source-driven Krylov projections, the method generates reduced models tailored to the dynamically reachable responses of the prescribed excitation families. Numerical validations on various plasma events and fusion-relevant scenarios demonstrate the robustness of the strategy, achieving substantial computational speedups while accurately preserving the transient electromagnetic response. Finally, the method is successfully applied to the null-field problem to efficiently generate training data for neural-network surrogates, contributing toward physics-consistent AI-enabled fusion modelling.

2605.28245 2026-06-01 physics.flu-dyn

Data-efficient semi-supervised learning for flow estimation using unlabelled probe data

利用未标记探针数据的高效数据半监督流估计方法

Junwei Chen, Marco Raiola, Stefano Discetti

AI总结 提出一种结合简单平流模型时间推进和半监督学习的框架,利用未标记探针数据增强PIV训练集,通过两个神经网络预测POD模态时间系数及其导数,提高速度场重建精度和压力估计可靠性。

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AI中文摘要

从粒子图像测速(PIV)估计时间分辨的速度和压力场仍然具有挑战性,因为其在许多应用中时间分辨率有限。将快照PIV与高频探针数据相结合的数据驱动方法在重建对流主导流动的流动力学方面显示出巨大潜力;然而,它们通常仅利用与PIV帧直接同步的探针测量值,而忽略了在快照之间获取的大量仅探针数据。在这项工作中,我们提出一个框架,通过时间推进一个简单的平流模型来丰富原始PIV训练数据集,然后通过半监督学习策略利用未标记的探针数据。训练两个神经网络分别预测流场的本征正交分解(POD)模态的时间系数及其时间导数。未标记的探针样本被用来强制时间一致性并扩展流场景的覆盖范围,超出快照PIV捕获的范围,这对于获得压力场重建所需的物理一致的时间梯度至关重要。进一步采用最小二乘正则化步骤来协调预测并强制时间系数及其导数之间的一致性。该方法在合成湍流通道流数据和机翼尾流的实验PIV测量上进行了验证。结果表明,结合未标记的探针数据显著提高了速度重建的准确性和时间平滑性,从而通过纳维-斯托克斯方程获得更可靠的压力估计,而不增加实验成本。

英文摘要

Estimating time-resolved velocity and pressure fields from Particle Image Velocimetry (PIV) remains challenging due to its limited temporal resolution in many applications. Data-driven approaches that combine snapshot PIV with high-frequency probe data have shown great promise in reconstructing the flow dynamics for advection-dominated flows; however, they typically exploit only the probe measurements directly synchronized with the PIV frames, leaving a large volume of probe-only data acquired between snapshots unused. In this work, we propose a framework that enriches the original PIV training dataset by time-marching a simple advection model and then exploits unlabelled probe data through a semi-supervised learning strategy. Two neural networks are trained to predict the temporal coefficients of Proper Orthogonal Decomposition (POD) modes of the flow fields, and their temporal derivatives, respectively. Unlabelled probe samples are leveraged to enforce temporal consistency and expand the coverage of flow scenarios beyond those captured by snapshot PIV, which is crucial for obtaining physically consistent temporal gradients required for pressure field reconstruction. A least-squares regularization step is further employed to reconcile the predictions and enforce consistency between temporal coefficients and their derivatives. The proposed approach is validated on both synthetic turbulent channel flow data and experimental PIV measurements of an airfoil wake. Results demonstrate that incorporating unlabelled probe data significantly improves the accuracy and temporal smoothness of velocity reconstruction, leading to more reliable pressure estimation via the Navier-Stokes equations, without increasing the experimental cost.

2605.28194 2026-06-01 math.PR math.AP

Delayed Blow-up in 3D Fluids via Pseudo-transport Noise

通过伪输运噪声实现三维流体的延迟爆破

Shuaijie Jiao, Marco Romito

AI总结 研究伪输运噪声驱动的流体动力学方程,通过参数a控制小尺度噪声行为,证明噪声以高概率延迟三维欧拉和纳维-斯托克斯方程的潜在爆破。

Comments 51 pages

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AI中文摘要

我们建立了由伪输运噪声驱动的流体动力学方程的标度极限结果。噪声在小尺度上的行为由参数a控制。这扩展了Flandoli和Luo (2020)以及Galeati (2020)的先前结果,在我们的设定中对应于a=0。根据a的值,我们证明噪声以高概率延迟了三维欧拉和纳维-斯托克斯(NS)方程的潜在爆破。

英文摘要

We establish scaling limit results for fluid dynamics equations driven by pseudo-transport noise. The behaviour of noise at small scales is governed by a parameter a. This extends previous results by Flandoli and Luo (2020) and Galeati (2020), which correspond to a=0 in our setting. Depending on the value of a, we prove that the noise delays the potential blow-up of both the 3D Euler and Navier-Stokes (NS) equations with high probability.

2605.28175 2026-06-01 cs.IR

Mixture-of-Experts Knowledge Graph Retrieval-Augmented Generation for Multi-Agent LLM-based Recommendation

基于混合专家知识图谱检索增强生成的多智能体LLM推荐系统

Shijie Wang, Chengyi Liu, Yujuan Ding, Shanru Lin, See-Kiong Ng, Xu Xin, Wenqi Fan

AI总结 提出MixRAGRec框架,通过混合专家检索、知识偏好对齐和对比学习增强推荐,解决KG-RAG中检索粒度单一、结构信息丢失和端到端学习困难问题。

Comments Accepted by KDD 2026 Research Track

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AI中文摘要

大型语言模型(LLM)最近因其理解用户意图和项目语义的能力而被用于推荐。然而,基于LLM的推荐系统通常依赖参数化知识,并面临知识过时的问题,这促使知识图谱检索增强生成(KG-RAG)将推荐建立在结构化、最新的知识图谱上。尽管有前景,但推荐中的有效KG-RAG面临巨大挑战。首先,用户查询的复杂性不同,需要不同粒度的KG知识,而现有方法采用一刀切的检索策略,导致简单查询过度检索和复杂查询检索不足。此外,用KG知识增强LLM需要将图结构数据转换为线性文本,这可能引入噪声并导致结构信息丢失。而且,检索粒度的选择缺乏直接监督,必须在对齐和下游利用后从最终推荐中推断,使得查询感知检索难以端到端学习。为解决这些问题,我们提出MixRAGRec,一个用于KG-RAG推荐的多智能体协作框架。MixRAGRec集成了混合专家检索智能体(将每个查询路由到不同粒度的KG检索专家)、知识偏好对齐智能体(将结构化知识转换为LLM友好的自然语言)以及对比学习增强的推荐智能体(通过对比偏好反馈训练)。值得注意的是,我们引入混合专家多智能体策略优化(MMAPO)来在统一目标下训练三个智能体。在真实数据集上的大量实验证明了我们框架的有效性。

英文摘要

Large language models (LLMs) have recently been adopted for recommendations due to their ability to understand user intent and item semantics. However, LLM-based recommender systems often rely on parametric knowledge and suffer from outdated knowledge, motivating knowledge graph retrieval-augmented generation (KG-RAG) to ground recommendations on structured, up-to-date KGs. Despite this promise, effective KG-RAG in recommendations faces great challenges. First, users' queries vary in complexity and require KG knowledge at different granularities, whereas existing methods adopt a one-size-fits-all retrieval strategy, leading to over-retrieval for simple queries and under-retrieval for complex ones. In addition, augmenting LLMs with KG knowledge requires translating graph-structured data into linear text, which may introduce noise and cause structural information loss. Moreover, the selection of retrieval granularity lacks direct supervision and must be inferred from the final recommendation after alignment and downstream utilization, making query-aware retrieval hard to learn end-to-end. To address these issues, we propose MixRAGRec, a cooperative multi-agent framework for KG-RAG recommendations. MixRAGRec integrates a Mixture-of-Experts Retrieval Agent that routes each query to a KG retrieval expert with different granularities, a Knowledge Preference Alignment Agent that converts structured knowledge into LLM-friendly natural language, and a Contrastive Learning-reinforced Recommendation Agent trained with contrastive preference feedback. Notably, we introduce Mixture-of-Experts Multi-Agent Policy Optimization (MMAPO) to train three agents under a unified objective. Extensive experiments on real-world datasets demonstrate the effectiveness of our framework.

2605.17540 2026-06-01 cs.DS

One-Shot Klein Cutting Planes for Lipschitz Geodesically Convex Optimization in Hyperbolic Space

双曲空间中Lipschitz测地凸优化的一次性Klein切割平面法

Yutong Zhang, Yaoran Yang, Yifan Zhu, Wentao Zhang

AI总结 针对双曲空间上Lipschitz测地凸优化问题,提出一种一次性Klein切割平面方法,通过将黎曼子梯度半空间转化为精确欧几里得中心切割,实现与曲率无关的加性精度依赖,并给出显式的Oracle调用次数上界。

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AI中文摘要

受Criscitiello、Martínez-Rubio和Boumal在COLT 2023上提出的关于Hadamard流形上Lipschitz测地凸优化的确定性一阶方法的开放问题启发,我们研究双曲空间\[ \HH^d_{-\kappaC^2} =\{X\in\R^{d+1}:\ipL{X}{X}=-1,\ X_0>0\}, \qquad \ip{U}{V}_X=\kappaC^{-2}\ipL{U}{V}. \] 对于每个测地凸的$M$-Lipschitz函数\[ f:\bar B_{\HH}(x_0,r)\to\R,\qquad s=\kappaC r, \] 我们给出一种一次性Klein切割平面方法,返回一个查询点$\hat x$,使得\[ f(\hat x)-\min_{\bar B_{\HH}(x_0,r)}f\le \eps Mr \] 在最多\[ \left\lceil 2d(d+1)\log\!\left(\frac{16\sinh s\cosh s}{s\eps}\right) \right\rceil \] 次Oracle调用后成立。对于$d\ge2$,每次定位步骤花费$O(d^2)$次算术运算;对于$d=1$,区间变体给出相同的Oracle界。因此\[ N=O\bigl(d^2(s+\log(e/\eps))\bigr) =O\bigl(d^2\zeta_s\log(e/\eps)\bigr), \qquad \zeta_s=s/\tanh s . \] 与COLT问题相关的常曲率构造相比,这将链式曲率-精度依赖替换为加性依赖。证明不依赖于Klein拉回函数的凸性(通常仅为拟凸)。相反,每个黎曼子梯度半空间成为精确的欧几里得中心切割:对于$\theta=\kappaC\dist(X,Y)$,\[ \ip{g}{\log_XY}_X =\frac{\theta}{\kappaC^2\sinh\theta}\ipL{g}{Y}, \] 且在$X$处的切性将$\ipL{g}{Y}\le0$转化为\[ \gbar^{\mathsf T}(u-c)\le0,\qquad u=\Phi(Y),\ c=\Phi(X). \] 因此一个固定的欧几里得椭球定位双曲球,曲率仅通过\[ \log\!\left(\frac{\sinh s\cosh s}{s\eps}\right) =\log(1/\eps)+2s-\log(4s)+O(e^{-4s}) \] 进入。一般的Hadamard流形问题仍然开放。

英文摘要

Motivated by the COLT 2023 open problem of Criscitiello, Martínez-Rubio, and Boumal on deterministic first-order methods for Lipschitz geodesically convex optimization on Hadamard manifolds, we study hyperbolic space \[ \HH^d_{-\kappaC^2} =\{X\in\R^{d+1}:\ipL{X}{X}=-1,\ X_0>0\}, \qquad \ip{U}{V}_X=\kappaC^{-2}\ipL{U}{V}. \] For every geodesically convex $M$-Lipschitz function \[ f:\bar B_{\HH}(x_0,r)\to\R,\qquad s=\kappaC r, \] we give a one-shot Klein cutting-plane method returning a queried point $\hat x$ such that \[ f(\hat x)-\min_{\bar B_{\HH}(x_0,r)}f\le \eps Mr \] after at most \[ \left\lceil 2d(d+1)\log\!\left(\frac{16\sinh s\cosh s}{s\eps}\right) \right\rceil \] oracle calls. For $d\ge2$, each localization step costs $O(d^2)$ arithmetic operations; for $d=1$, an interval variant gives the same oracle bound. Hence \[ N=O\bigl(d^2(s+\log(e/\eps))\bigr) =O\bigl(d^2ζ_s\log(e/\eps)\bigr), \qquad ζ_s=s/\tanh s . \] Compared with the constant-curvature construction associated with the COLT problem, this replaces chained curvature--accuracy dependence by additive dependence. The proof does not rely on convexity of the Klein pullback, which is generally only quasiconvex. Instead, every Riemannian subgradient halfspace becomes an exact Euclidean central cut: for $θ=\kappaC\dist(X,Y)$, \[ \ip{g}{\log_XY}_X =\fracθ{\kappaC^2\sinhθ}\ipL{g}{Y}, \] and tangency at $X$ converts $\ipL{g}{Y}\le0$ into \[ \gbar^{\mathsf T}(u-c)\le0,\qquad u=Φ(Y),\ c=Φ(X). \] Thus one fixed Euclidean ellipsoid localizes the hyperbolic ball, and curvature enters only through \[ \log\!\left(\frac{\sinh s\cosh s}{s\eps}\right) =\log(1/\eps)+2s-\log(4s)+O(e^{-4s}). \] The general Hadamard-manifold problem remains open.

2605.27907 2026-06-01 quant-ph cond-mat.stat-mech

Geometry near rank-changing points on the mixed-state manifold: Bures metric, conical singularities, and Lindblad dynamics

混合态流形上秩变化点附近的几何:Bures度量、锥形奇点与Lindblad动力学

Yu-Huan Huang, Xu-Yang Hou, Hao Guo, Chih-Chun Chien

AI总结 本文阐明了密度矩阵秩变化点附近量子态空间的Bures度量,揭示了两能级系统与高维系统的对比行为,并展示了锥形几何导致的曲率奇点及Lindblad演化构造。

Comments 19 pages, 8 figures, submitted

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AI中文摘要

我们阐明了密度矩阵秩变化点附近量子态空间的Bures度量,并展示了两能级($N=2$)系统与高维系统的对比行为。由于$N=2$时存在光滑的纯态边界,我们证明了表观度量发散仅仅是坐标伪影,并给出了三个Lindblad过程,它们在秩变化点附近表现出定性不同的演化,包括测地线逼近、幂律标度和纯态逃逸律。对于高维($N\ge 3$)系统,秩变化点附近的几何有根本不同。在密度矩阵及其向纯态逼近的适当限制下,Bures度量退化为以纯态为锥顶的锥形度量。这种锥形几何导致真实的曲率奇点:二维锥在锥顶附近呈现狄拉克δ函数曲率,而高维锥则显示曲率向锥顶的幂律发散。我们给出了具有锥形奇点的$N=3$系统Lindblad演化的构造,并讨论了其对未来实验和理论研究的可能影响。

英文摘要

We elucidate the Bures metric in quantum state space near a rank-changing point of the density matrix and show contrasting behavior for two-level ($N=2$) systems versus higher-level systems. Due to the smooth pure-state boundary for $N=2$, we prove the apparent metric divergences to be merely coordinate artifacts and present three Lindblad processes exhibiting qualitatively different evolution near rank-changing points, showing geodesic approach, power-law scaling, and pure-state escape law. For higher-dimensional ($N\ge 3$) systems, the geometry near a rank-changing point differs fundamentally. Under suitable restrictions of the density matrix and its approach towards a pure state, the Bures metric reduces to a conical metric with the pure state at the cone tip. Such a conic geometry leads to genuine curvature singularities: A two-dimensional cone exhibits a Dirac delta-function curvature near the tip while a higher-dimensional cone shows a power-law divergence of the curvature towards the cone tip. A construction of Lindblad evolution for $N=3$ systems with conic singularities is presented, along with possible implications for future experimental and theoretical research.

2605.27753 2026-06-01 eess.SP

Decoupled Delay-Doppler and Angle Estimation in BD-RIS Sensing via Nested Tucker Decomposition

基于嵌套Tucker分解的BD-RIS感知中解耦延迟-多普勒与角度估计

Kenneth Benício, André L. F. de Almeida, Fazal-E-Asim, Bruno Sokal, Behrooz Makki, Gabor Fodor, A. Lee Swindlehurst

AI总结 针对组连接BD-RIS辅助单站网络中的单目标定位,提出NTFE算法,通过嵌套Tucker张量分解解耦延迟-多普勒与角度域,实现两步参数估计并提升感知性能。

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AI中文摘要

我们研究了具有K个元件组的组连接超对角线可重构智能表面(BD-RIS)辅助单站网络中的单目标定位。我们提出了一种嵌套张量分解与估计(NTFE)算法,该算法将接收信号建模为三阶嵌套Tucker张量,从而解耦延迟-多普勒和角度域。由此产生的两步过程估计目标承载张量因子,然后使用子空间和闭式步骤提取其他物理参数。我们还分析了可辨识性和唯一性条件。仿真表明,NTFE利用了组连接BD-RIS结构,并且优于最先进的感知基准。

英文摘要

We study single-target localization in a group-connected beyond-diagonal reconfigurable intelligent surface (BD-RIS)-assisted monostatic network with K element groups. We propose a Nested Tensor Factorization and Estimation (NTFE) algorithm that models the received signal as a 3rd-order nested Tucker tensor, decoupling the delay-Doppler and angle domains. The resulting two-stage procedure estimates the target-bearing tensor factors and then extracts the other physical parameters using subspace and closed-form steps. We also analyze identifiability and uniqueness conditions. Simulations show that NTFE exploits the group-connected BD-RIS structure and outperforms state-of-the-art sensing benchmarks.

2605.27151 2026-06-01 cond-mat.mtrl-sci

Identifying and designing altermagnetic crystals in real space

实空间中识别与设计交变磁晶体

Ying Chen, Qiushi Huang, Yu Wu, Xiaolan Yan, Su-Huai Wei

AI总结 提出基于实空间对称性判据,通过分析非磁母体结构操作对自旋子晶格的置换来识别交变磁体,并通过第一性原理计算验证。

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AI中文摘要

交变磁性是一种补偿磁相,其特征是零净磁化和交换驱动的自旋分裂。然而,在共线反铁磁体中识别交变磁体通常需要完整的磁空间群或自旋群分析,这并不直观。这里我们基于宿主非磁结构的晶体学操作如何置换两个相反自旋子晶格,制定了一个简单的实空间判据。为简单起见,我们关注磁原胞与宿主非磁晶体学原胞一致的共线补偿反铁磁体。在此类中,除非存在交换两个相反自旋子晶格的反演型操作,否则通常允许交变磁自旋分裂。对代表性非中心对称和中心对称材料的第一性原理计算证明了该判据。类似的规则也可应用于低维晶体或准晶体。我们的工作将交变磁性的识别简化为透明的实空间对称性测试,并为发现交变磁晶体提供了实用途径。

英文摘要

Altermagnetism is a compensated magnetic phase characterized by zero net magnetization and exchange-driven spin splitting. However, identifying altermagnets among collinear antiferromagnets usually requires full magnetic-space-group or spin-group analysis, which is not intuitive. Here we formulate a simple real-space criterion based on how the crystallographic operations of the host nonmagnetic structure permute the two opposite-spin sublattices. For simplicity, we focus on collinear compensated antiferromagnets whose magnetic primitive cell coincides with the host nonmagnetic crystallographic primitive cell. In this class, altermagnetic spin splitting is generally allowed unless an inversion-type operation exists that exchanges the two opposite-spin sublattices. First-principles calculations on representative noncentrosymmetric and centrosymmetric materials demonstrate this criterion. Similar rules can also be applied to low-dimensional crystals or quasicrystals. Our work reduces the identification of altermagnetism to a transparent real-space symmetry test and provides a practical route for discovering altermagnetic crystals.

2605.27107 2026-06-01 physics.pop-ph gr-qc hep-th

A gentle introduction to the cosmological multiverse

宇宙学多重宇宙的温和介绍

Oliver Janssen

AI总结 本文面向艺术家读者,通过介绍广义相对论和宇宙常数,引出宇宙常数难题,并探讨多重宇宙如何解决该问题,同时指出永恒暴胀的测量问题。

Comments Adapted transcript, translated to English, of a 30-minute talk given on October 3, 2024 at the arts and science workshop "La Mixtape du Multivers" (La Grange Center, Université de Lausanne) during the "Journées de recherche interdisciplinaires". Translations to Spanish, French, Dutch, Italian, German, Russian, Chinese, Arabic and Hindi (by Claude) are available as ancillary files

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AI中文摘要

我们面向艺术家读者,介绍宇宙学多重宇宙。我们讨论广义相对论——现代引力理论——以及宇宙常数,它被广泛认为负责观测到的宇宙加速膨胀。然后我们转向宇宙常数带来的一个大难题,并最终探讨多重宇宙如何解决这个难题。然而,天下没有免费的午餐:多重宇宙可以变得任意大和古老。在永恒加速的宇宙中做出明确预测的未解决问题被称为永恒暴胀的测量问题。

英文摘要

We give an introduction to the cosmological multiverse, aimed at an audience of artists. We discuss general relativity -- our modern theory of gravity -- and the cosmological constant, which is widely believed to be responsible for the observed accelerated expansion of the universe. We then turn to a big puzzle that the cosmological constant poses, and, eventually, how the multiverse could solve this puzzle. There's no such thing as a free lunch, however: the multiverse can become arbitrarily large and old. The unsolved problem of making unambiguous predictions for observations in eternally accelerating universes is known as the measure problem of eternal inflation.

2605.26709 2026-06-01 math.CA math.FA

On a fundamental barrier of the Wirtinger criterion for Gabor systems with odd functions

关于奇函数Gabor系统的Wirtinger准则的一个基本障碍

Markus Faulhuber

AI总结 本文证明Wirtinger准则无法用于研究第一Hermite函数的框架集猜想,且对于奇函数,无法确定密度小于2的框架集区域。

Comments 6 pages, 17 references, to appear in "Results in Applied Mathematics"

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Journal ref
Results in Applied Mathematics, 30:100719, 2026
AI中文摘要

我们证明Wirtinger准则不能用于研究第一Hermite函数的框架集猜想。更一般地,对于奇函数,它无法确定密度小于2的框架集区域。

英文摘要

We show that the Wirtinger criterion cannot be used to investigate the frame set conjecture for the first Hermite function. More generally, for odd functions, it cannot determine regions of the frame set with density less than 2.

2605.26707 2026-06-01 math.CO

Sum of the $k$ Largest Eigenvalues of Symmetric Matrices: Theory and Applications

对称矩阵的 $k$ 个最大特征值之和:理论与应用

Shaowei Sun, Yaping Min, Kinkar Chandra Das

AI总结 本文建立了对称矩阵的 $k$ 个最大特征值之和的新上界,改进了Mohar的相关界,并证明了对几乎所有图,Brouwer猜想在小$k$情况下成立。

Comments 30 pages

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AI中文摘要

本文建立了对称矩阵的 $k$ 个最大特征值之和的新上界。当应用于图的邻接矩阵时,我们的结果改进了 Mohar [On the sum of k largest eigenvalues of graphs and symmetric matrices, J. Combin. Theory Ser. B 99 (2009) 306--313] 的一个相关界。此外,对于拉普拉斯矩阵,我们证明了著名的 Brouwer 猜想 [Spectra of Graphs, Springer, New York, 2012] 对几乎所有图的小 $k$ 值成立,从而朝着完全解决该猜想迈出了重要一步。

英文摘要

This paper establishes new upper bounds for the sum of the $k$ largest eigenvalues of symmetric matrices. When applied to the adjacency matrix of a graph, our results improve upon a related bound due to Mohar {\bf [On the sum of k largest eigenvalues of graphs and symmetric matrices, J. Combin. Theory Ser. B 99 (2009) 306--313]}. Furthermore, in the case of the Laplacian matrix, we prove that the well-known Brouwer's conjecture {\bf [Spectra of Graphs, Springer, New York, 2012]} holds for small values of $k$ for almost all graphs, thereby taking a significant step toward its complete resolution.

2605.26528 2026-06-01 quant-ph

Crosstalk In Contemporary Quantum Devices

当代量子器件中的串扰

Spiro Gicev, Ben Harper, Haiyue Kang, Muhammad Usman, Martin Sevior

AI总结 本文全面综述了量子计算中串扰噪声的物理起源、缓解方法及安全漏洞,涵盖所有主要量子平台。

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AI中文摘要

串扰噪声源于量子器件中抑制个体可寻址性或引起量子比特间意外相互作用的现象。它被广泛认为是量子计算平台在超过一两个量子比特规模运行时需要解决的主要问题之一。尽管如此,在描述量子器件性能(包括器件基准测试和单个算法执行)时,对串扰的详细讨论往往被忽略。此外,虽然所有量子平台都存在串扰的可能性,但不同平台之间串扰的机制和严重程度差异很大,增加了理解和研究不熟悉量子平台的入门门槛。虽然以往的工作侧重于理论形式或特定平台的细节,但在这篇综述文章中,我们提供了来自量子计算文献中跨一系列物理系统的串扰全面概述,重点关注物理起源、缓解方法和已知的相关安全漏洞。我们描述了所有主要量子计算平台的多种串扰机制,这些机制通常通过器件设计、调谐和缓解技术隐含地解决。我们还观察到关于安全影响的研究正在加速,但仍有多条进一步探索的途径,特别是对于非超导系统。总之,这篇综述为有兴趣理解和解决现代量子计算系统中串扰现象带来的挑战的研究人员和行业工程师提供了一个全面的入门点。

英文摘要

Crosstalk noise derives from phenomena in quantum devices which inhibit individual addressability or cause unintended interactions among qubits. It is widely considered one of the major problems to be solved for a quantum computing platform to operate at scales beyond one or two qubits. Despite this, detailed discussion of crosstalk is often neglected when quantum device performance is described both in the context of device benchmarking and individual algorithm execution. Additionally, while the potential for crosstalk exists in all quantum platforms, the mechanisms and severity of crosstalk between platforms varies significantly, increasing the barrier of entry associated with understanding and performing research on unfamiliar quantum platforms. While previous work focused on theoretical formalism or platform specific details, in this review article, we provide a comprehensive overview of crosstalk from quantum computing literature across a range of physical systems focusing on physical origins, methods of mitigation and known consequential security vulnerabilities. We describe multiple crosstalk mechanisms for all major quantum computing platforms, which are usually implicitly addressed through device design, tuning, and mitigation techniques. We also observe accelerating research regarding security implications, however with multiple avenues for further exploration, especially for non-superconducting systems. Together, this review provides a comprehensive entry point for researchers and industry engineers interested in understanding and addressing the challenges arising from crosstalk phenomena in modern quantum computing systems.

2605.26378 2026-06-01 physics.atom-ph

Parity non-conservation in isotope chain of tin

锡同位素链中的宇称不守恒

V. A. Dzuba, V. V. Flambaum, D. DeMille, Jianwei Wang, Geoffrey Zheng

AI总结 计算Sn基态5p^2组态内所有磁偶极跃迁的宇称不守恒振幅,发现^1S_0-^3P_1跃迁振幅最大,提出高精度测量方法,并利用同位素比值消除原子结构因子,研究中子皮对同位素比值的影响,表明Sn同位素链的PNC测量可灵敏探测新物理。

Comments 8 pages, 8 tables

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AI中文摘要

我们计算了Sn基态$5p^2$组态内所有磁偶极(M1)跃迁的宇称不守恒(PNC)振幅。在所考虑的跃迁中,$^1$S$_0$-$^3$P$_1$跃迁具有最大的PNC振幅,并且似乎是实验中最有希望的候选者。我们还讨论了一种测量方法,该方法能够在该跃迁的PNC测量中实现前所未有的高精度。我们认为最稳健的测试应基于不同同位素的PNC振幅之比,因为原子结构因子在这样的比值中很大程度上被抵消。我们利用Sn的现有核数据研究了中子皮对这些同位素比值的影响,并表明与中子皮相关的不确定性可以降低到相对于PNC效应同位素变化的$10^{-3}$水平。我们的结果表明,沿Sn同位素链的PNC测量提供了一种现实且灵敏的新物理探针。

英文摘要

We calculate parity non-conservation (PNC) amplitudes for all magnetic-dipole (M1) transitions within the ground $5p^2$ configuration of Sn. Among the transitions considered, the $^1$S$_0$-$^3$P$_1$ transition has the largest PNC amplitude and appears to be the most promising candidate for experiment. We also discuss a measurement method capable of achieving unprecedentedly high precision in a measurement of PNC in this transition. We argue that the most robust test should be based on ratios of PNC amplitudes for different isotopes, since the atomic-structure factor largely cancels in such ratios. We study the effect of the neutron skin on these isotope ratios using available nuclear data for Sn and show that the uncertainty associated with the neutron skin can be reduced to the $10^{-3}$ level relative to the isotopic variation of the PNC effect. Our results indicate that PNC measurements along a chain of Sn isotopes offer a realistic and sensitive probe of new physics.

2605.26309 2026-06-01 cs.HC cs.CY cs.SI

Visual Matters: Connecting Aesthetic Appeal and Production Quality of Photos, Infographics and Data Visualizations to Credibility of Social Media Posts

视觉问题:将照片、信息图和数据可视化的美学吸引力和制作质量与社交媒体帖子的可信度联系起来

Salman Khawar, Yingdan Lu, Yilang Peng, Jiyoung Yeon, Cuihua Shen

AI总结 本研究基于处理流畅性理论,通过实验比较照片、信息图、数据可视化和纯文本帖子,发现视觉帖子(尤其是照片和信息图)比纯文本帖子更可信,美学吸引力通过处理流畅性部分中介提升可信度,而制作质量无显著影响。

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AI中文摘要

视觉内容的迅速普及引发了关于不同视觉格式和特征如何塑造感知可信度的基本问题。基于处理流畅性理论,本研究考察了视觉如何影响可信度判断。我们聚焦于三种流行格式——照片、信息图和数据可视化——将它们与纯文本帖子进行比较,并测试了两种视觉特征——美学吸引力和制作质量——通过处理流畅性作为中介机制对可信度的影响。通过一项包含1200名美国参与者的预注册实验,我们发现视觉帖子通常被认为比纯文本帖子更可信,但这种可信度优势仅适用于照片和信息图,而不适用于数据可视化。美学吸引力增加了感知可信度,部分由处理流畅性中介,而制作质量在各类格式中对可信度无显著影响。这些发现区分了视觉格式,推进了视觉特征的概念化,并确定了处理流畅性作为跨多模态情境理论化可信度的关键机制。

英文摘要

The rapid proliferation of visual content raises fundamental questions about how different visual formats and features shape perceived credibility. Drawing on processing fluency theory, this research examines how visuals shape credibility judgments. We focus on three popular formats-photos, infographics, and data visualizations-comparing them to text-only posts, and test how two visual features, aesthetic appeal and production quality, influence credibility through processing fluency as a mediating mechanism. Through a preregistered experiment with 1200 US participants, we found that visual posts are generally perceived as more credible than text-only posts but this credibility advantage only applies to photos and infographics, not to data visualizations. Aesthetic appeal increases perceived credibility, partially mediated by processing fluency, while production quality had no significant effect on credibility across formats. These findings differentiate visual formats, advance conceptualizations of visual features, and identify processing fluency as a key mechanism for theorizing credibility across multimodal contexts.

2605.26140 2026-06-01 astro-ph.IM astro-ph.EP astro-ph.SR

The role of the Hubble Space Telescope in advancing our understanding of atmospheric escape in exoplanets

哈勃太空望远镜在推进系外行星大气逃逸理解中的作用

Leonardo A. Dos Santos, Arika Egan, Kevin France, Eric Gaidos, Antonio García Muñoz, R. O. Parke Loyd, Keighley Rockcliffe, Mercedes López-Morales, P. Christian Schneider, Arif Solmaz, Michael Zhang, Vladimir S. Airapetian, Munazza K. Alam, Laura N. R. do Amaral, Tommi Koskinen, Seth Redfield, Jake D. Turner

AI总结 本文回顾哈勃太空望远镜紫外能力在探测系外行星流体动力学大气逃逸及测量质量损失率方面的关键作用,并讨论未来十年所需观测与仪器模式以推进行星演化和宜居性研究。

Comments 8 pages, 2 figures; this article is a response to the call for white papers by STScI on "Building a Roadmap for Hubble science into the 2030s."

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AI中文摘要

行星大气的一个重要演化途径是逃逸到太空,这一过程在地球和火星上已被研究了几十年,最近也在系外行星中展开研究。一个特别重要的机制是流体动力学逃逸,其中大气质量以高速度在碰撞流体外流中逃离行星。这一过程被部分用于解释太阳系内外岩石行星的早期演化,以及系外行星人口统计的关键方面。流体动力学逃逸在太阳系行星中并未发生,因此我们进行此类观测的唯一选择是通过系外行星。哈勃太空望远镜的紫外能力对于探测流体动力学逃逸、测量一系列行星系统的质量损失率以及识别宜居世界观测站巡天的目标至关重要。我们在此讨论未来十年继续研究系外行星大气逃逸所需的观测类型和仪器模式,以及如何推进我们对行星演化和宜居性的理解。

英文摘要

An important evolutionary pathway for planetary atmospheres is escape to space, which has been studied on Earth and Mars for several decades and more recently in exoplanets. A particularly important regime is the hydrodynamic escape, wherein atmospheric mass escapes the planet at high rates in a collisional fluid outflow. This process is used to partly explain the early evolution of rocky planets in and out of the Solar System, as well as key aspects of exoplanet demographics. Hydrodynamic escape is not occurring in the Solar System planets, so our only option for such observations is through exoplanets. The ultraviolet (UV) capabilities of the Hubble Space Telescope (HST) are fundamental to detect hydrodynamic escape and measure the resulting mass-loss rates for a range of planetary systems and to identify targets for surveys with the Habitable Worlds Observatory. We discuss here what kinds of observations and instrument modes are necessary to continue studying atmospheric escape in exoplanets for the next decade, as well as how to advance our understanding of planetary evolution and habitability.

2605.25361 2026-06-01 physics.chem-ph

An Efficient On-the-Fly Nonadiabatic Coupling Framework Integrated into CP2K

集成到CP2K中的高效即时非绝热耦合框架

Xiaoke He, Hsiao-Yi Tsai, Ziwei Chai, Junwen Yin, Zhongfei Xu, Li-Min Liu

AI总结 通过在CP2K中直接实现非绝热耦合模块,结合高斯与平面波方法和相位校正方案,实现了大规模体系的高效非绝热分子动力学模拟。

Comments 16 pages of main text, 4 figures. Includes 5 pages of Supporting Information

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AI中文摘要

非绝热分子动力学(NAMD)广泛用于描述热电子弛豫和非辐射复合过程,但高计算成本限制了其在大超胞中的应用。本文在CP2K中直接实现了一个非绝热耦合(NAC)模块,使得在从头算分子动力学过程中可以即时计算NAC。与依赖外部NAMD程序和电子结构代码接口的传统方法不同,这种集成简化了工作流程。结合CP2K固有的高斯与平面波(GPW)方法,实现了大规模体系的高效NAC计算。为确保数值稳定性,引入了一种相位校正方案以消除波函数相位的不一致性。晶体并五苯中热电子弛豫的基准计算与先前研究一致,而有/无相位校正的模拟结果显示出显著差异,证实了相位校正的必要性。在更大并五苯超胞上的模拟进一步证明了该实现用于大规模NAMD模拟的能力。

英文摘要

Nonadiabatic molecular dynamics (NAMD) is widely used to describe hot electron relaxation and nonradiative recombination processes, but high computational costs limit its application to large supercells. Here, we implement a nonadiabatic coupling (NAC) module directly into CP2K, enabling on-the-fly NAC calculation during ab-initio molecular dynamics. Unlike conventional approaches relying on interfaces between external NAMD programs and electronic structure codes, this integration streamlines the workflow. Combined with CP2K's inherent Gaussian and Plane Waves (GPW) method, it achieves efficient NAC calculations for large-scale systems. To ensure numerical stability, a phase correction scheme is introduced to remove inconsistencies of wavefunction phases. Benchmark calculations of hot electron relaxation in crystalline pentacene agree with previous studies, while the results of simulations with and without phase correction show significant difference, confirming the necessity of the phase correction. Simulations on larger pentacene supercells further demonstrate the capability of this implementation for large-scale NAMD simulations.