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2602.14806 2026-06-03 math.DG

Minimizing the volume of globally hyperbolic anti-de Sitter 3-manifolds

最小化全局双曲反德西特3-流形的体积

Gabriele Mondello, Nicolas Tholozan

AI总结 本文证明最大全局双曲Cauchy紧致反德西特3-流形M的体积至少为π²|χ(M)|,且该最小值当且仅当M是Fuchsian时达到。

Comments 12 pages, identical to the version appeared online on Rendiconti di Matematica e delle sue Applicazioni (May 2026)

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AI中文摘要

在本文中,我们证明最大全局双曲Cauchy紧致反德西特3-流形M的体积至少为π²|χ(M)|,且该最小值当且仅当M是Fuchsian时达到。

英文摘要

In this paper we show that the volume of a maximal globally hyperbolic Cauchy-compact anti-de Sitter $3$-manifold $M$ is at least $π^2|χ(M)|$, and that this minimum value is attained if and only if $M$ is Fuchsian.

2511.19208 2026-06-03 cs.DC

Leader Election via Unique Sink Orientation

通过唯一源定向的领导者选举

Jérémie Chalopin, Maria Kokkou

AI总结 本文针对可拆卸图类,通过每边一位或每节点O(Δ)位的标签和局部约束,首次实现了领导者选举的局部可检查标记(LCL)表示,并给出将任意有限标签和局部约束转换为静默自稳定算法的通用方法。

Comments 21 pages, 5 figures

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AI中文摘要

局部可检查标记(LCL)是一个定义在有界度图上的分布式约束满足问题,它将有限输入标签集与有限输出标签集通过一组有限的可局部检查约束联系起来。在这项工作中,我们定义了编码两个经典问题(领导者选举和生成树构造)解的标签和局部约束。已知在任意图中使用常数大小标签无法将领导者选举表示为LCL。事实上,即使在环类上,也不存在用于领导者选举的有限标签集和局部约束。另一方面,存在用于树上领导者选举的有限标签集和局部约束。在这项工作中,我们证明在更大的可拆卸图类上也存在用于领导者选举的有限标签集和局部约束。我们的标签每边需要一位,或等价地每节点需要O(Δ)位(其中Δ是图中的最大度数),并且可在每个节点的1-邻域诱导的子图内检查。据我们所知,这是首个针对可拆卸图类的局部标记结果,可能突出了有助于为其他LCL问题设计标签和约束的结构性质。最后,我们提出一个通用转换,在假设Gouda公平调度器的情况下,通过仅添加一个额外状态,将任意有限标签集和局部约束转换为静默自稳定算法。这一转换可能具有独立意义。

英文摘要

A Locally Checkable Labeling (LCL) is a distributed constraint satisfaction problem defined on a bounded-degree graph that relates a finite set of input labels to a finite set of output labels through a finite set of locally checkable constraints. In this work we define labels and local constraints that encode solutions to two classical problems: leader election and spanning tree construction. It is known that leader election cannot be expressed as an LCL in arbitrary graphs using constant-size labels. In fact, it is known that there does not exist a finite set of labels and local constraints for leader election even for the class of rings. On the other hand, there exists a finite set of labels and local constraints characterizing leader election on trees. In this work, we prove that there exists a finite set of labels and local constraints for leader election also in the much larger class of dismantlable graphs. Our labels need one bit per edge or equivalently $O(Δ)$ bits per node (where $Δ$ is the maximum degree in the graph) and are checkable within the graph induced by the 1-neighborhood of each node. To the best of our knowledge, these are the first local labeling results tailored to dismantlable graphs, potentially highlighting structural properties useful for designing labels and constraints for additional LCL problems. Finally, we present a generic transformation that converts any finite set of labels and local constraints into a silent self-stabilizing algorithm by adding only one extra state, assuming a Gouda fair scheduler. This transformation may be of independent interest.

2602.13614 2026-06-03 cond-mat.mtrl-sci

Anisotropic Core-Shell Swift Heavy Ion Tracks in beta-Ga2O3

β-Ga2O3中各向异性核壳结构快重离子径迹

Huan He, Jiayu Liang, Shaowei He, Yanwen Zhang, Jiahui Zhang, Ziqi Cai, Tan Shi, Hang Zang, Flyura Djurabekova, Chaohui He, Junlei Zhao

AI总结 本研究通过多尺度原子模拟,揭示了β-Ga2O3中快重离子辐照诱导的核壳结构径迹形成机制及各向异性恢复动力学。

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AI中文摘要

快重离子(SHI)辐照通过强烈的电子激发产生纳米级离子径迹,但在低对称性氧化物中,控制其形态和相稳定性的微观机制仍不清楚。本文采用多尺度原子模拟框架,研究单斜β-Ga2O3中SHI诱导径迹的形成和恢复,覆盖宽范围的电子能量损失(Se)和晶体取向。随着Se增加,识别出一系列不同的结构响应:(i)低Se时完全晶格恢复;(ii)中等Se时重结晶为亚稳态γ-Ga2O3相;(iii)高Se时形成核壳离子径迹,由非晶核和重结晶γ相壳层组成。尽管初始能量沉积本质上是各向同性的,但最终离子径迹形态表现出显著的晶体学各向异性,由取向依赖的恢复动力学控制。沿[010]方向的优异重结晶归因于其极高的弹性刚度。值得注意的是,垂直于(100)面的SHI辐照在低Se(≤10 keV/nm)时引起更严重的结构响应,但在较高Se时产生的残余离子径迹比其他取向更小。模拟的离子径迹尺寸与广泛Se值范围内的现有实验测量结果表现出极好的定量一致性。这些发现建立了β-Ga2O3中核壳径迹形成和各向异性恢复的统一原子尺度图像。

英文摘要

Swift heavy ion (SHI) irradiation generates nanoscale ion tracks through intense electronic excitation, yet the microscopic mechanisms governing their morphology and phase stability in low symmetry oxides remain poorly understood. Here, a multiscale atomistic simulation framework is used to investigate the formation and recovery of SHI-induced tracks in monoclinic $β$-Ga2O3 over a wide range of electronic energy losses (Se) and crystallographic orientations. A sequence of distinct structural responses is identified with increasing Se: (i) complete lattice recovery at low Se; (ii) recrystallization into a metastable $γ$-Ga2O3 phase at intermediate Se; and (iii) the formation of core-shell ion tracks at high Se, consisting of an amorphous core surrounded by a recrystallized $γ$-phase shell. Despite the essentially isotropic initial energy deposition, the final ion-track morphology exhibits pronounced crystallographic anisotropy, governed by orientation-dependent recovery dynamics. The superior recrystallization along the [010] direction is attributed to its exceptionally high elastic stiffness. Notably, SHI irradiation perpendicular to the (100) plane induces a more severe structural response at low Se ($\le$ 10 keV/nm), however, at higher Se, it yields a smaller residual ion track compared to the other orientations. The simulated ion-track sizes show excellent quantitative agreement with the available experimental measurements over a wide range of Se values. These findings establish a unified atomic-scale picture of core-shell track formation and anisotropic recovery in $β$-Ga2O3.

2508.04983 2026-06-03 cond-mat.stat-mech nlin.CD q-bio.NC

Kinetic energy in random recurrent neural networks

随机递归神经网络中的动能

Li-Ru Zhang, Haiping Huang

AI总结 本文通过动态平均场理论和数值模拟,研究随机递归神经网络中动能从零到正值的连续转变及其在混沌临界点附近的立方标度行为,并揭示混沌动力学与不稳定不动点的几何关系。

Comments 30 pages, 8 figures, revised manuscript to PRE

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AI中文摘要

当突触增益超过阈值时,大型随机递归神经网络中可能出现高维混沌动力学。最近的研究表明,神经活动的动能将混沌动力学与相空间中支持的不稳定不动点(平衡点)联系起来。在这里,我们通过结合动态平均场理论和大量数值模拟,研究了随机递归神经网络的动能中心性质。我们发现,平均动能从零连续转变为正值,发生在已知的耦合方差(突触增益)临界值处,并在临界点附近从上方表现出立方标度行为。这种标度行为得到了数值模拟的支持,并定量描述了混沌起始时动力学变化的速度以及混沌动力学远离不稳定不动点的程度。进一步通过理论计算了稳态活动分布,并从动能优化角度与有限尺寸系统的模拟进行了比较。还从几何角度分析了活动分布,揭示出尽管原始混沌动力学和动能的梯度动力学呈壳状结构,但它们在极角方向上分离良好。混沌流形上的轨迹长度可以从稳态动能推导出来,并分析了相关的稳态行为。

英文摘要

High-dimensional chaotic dynamics can emerge in a large random recurrent neural network when the synaptic gain crosses a threshold. Recent works showed that the kinetic energy of neural activity links the chaotic dynamics and the supporting unstable fixed points (equilibria) in the phase space. Here, we investigate the kinetic-energy-centric properties of random recurrent neural networks by combining dynamical mean-field theory with extensive numerical simulations. We find that the average kinetic energy shifts continuously from zero to a positive value at the known critical value of coupling variance (synaptic gain) and exhibits a cubic scaling behavior near the critical point from above. This scaling behavior is supported by numerical simulations and provides a quantitative characterization of how fast the dynamics change during the onset of chaos as well as how far the chaotic dynamics are away from the unstable fixed points. The steady-state activity distribution is further calculated by the theory and compared with simulations on finite-size systems from the kinetic-energy optimization perspective as well. The activity distribution is also analyzed in a geometric angle, revealing that although the original chaotic dynamics and the gradient dynamics of the kinetic energy are arranged in a shell-like structure, they are well separated in the polar direction. The trajectory length on the chaotic manifold can be derived from the stationary kinetic energy, and the associated stationary behavior is analyzed as well.

2602.12339 2026-06-03 hep-th cond-mat.str-el gr-qc quant-ph

Magic and Wormholes in the Sachdev-Ye-Kitaev Model

Sachdev-Ye-Kitaev模型中的魔法与虫洞

Valérie Bettaque, Brian Swingle

AI总结 本文通过路径积分技术研究SYK模型热态中费米子弦期望值的统计性质,发现混沌情况下为高斯随机变量,可积情况下非高斯,并利用这些结果研究热态的魔法度量,同时在低温下通过引力对偶定量重现结果,其中方差与由算子弦对偶的粒子稳定的虫洞几何相关。

Comments 71 pages, 21 figures, prepared for JHEP submission, comments welcome

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AI中文摘要

任何量子态完全由一组完备厄米算符的期望值确定。对于Majorana费米子系统,如Sachdev-Ye-Kitaev (SYK)模型,这组可观测量可以取为所有可能的Majorana费米子算子弦。热态中这些费米子弦的期望值依赖于指定SYK哈密顿量的微观耦合,且具有不规则性,我们直接使用路径积分技术在热力学极限下研究其统计性质。当底层SYK哈密顿量是混沌的时,我们发现这些期望值可以很好地建模为均值为零、方差可计算的实高斯随机变量。相反,对于SYK的可积变体,我们发现期望值实际上是非高斯的。然后,我们利用这些结果研究SYK热态中的魔法度量,包括魔法的鲁棒性和稳定子Rényi熵。我们还展示了在混沌情况下,足够低温时我们的结果可以通过对偶引力计算定量重现。在这个对偶引力模型中,特定微观算子弦的方差与一个由算子弦对偶的粒子稳定的虫洞几何相关。因此,我们的结果为研究随机性、虫洞和封闭宇宙之间的关系,以及量子魔法的全息对偶,提供了一个具体且定量的框架。

英文摘要

Any quantum state is fully specified by the expectation values of a complete set of Hermitian operators. For a system of Majorana fermions, such as the Sachdev-Ye-Kitaev (SYK) model, this set of observables can be taken to be all possible strings of Majorana fermion operators. The expectation values of these fermion strings in a thermal state depend erratically on the microscopic couplings that specify the SYK Hamiltonian, and we study their statistical properties directly in the thermodynamic limit using path integral techniques. When the underlying SYK Hamiltonian is chaotic, we find that these expectation values are well-modeled as real Gaussian random variables with zero mean and a variance that we compute. In contrast, for the integrable variant of SYK, we find that the expectation values are actually non-Gaussian. We then use these results to study measures of magic in the SYK thermal state, including the robustness of magic and the stabilizer Rényi entropy. We also show that our results can be quantitatively reproduced with a dual gravity calculation in the chaotic case at sufficiently low temperature. In this dual gravity model the variance of a given microscopic operator string is related to a wormhole geometry stabilized by a massive particle which is dual to the operator string. Our results thus provide a concrete and quantitative setting in which to study the relationship between randomness, wormholes and closed universes, as well as a holographic dual of quantum magic.

2504.11761 2026-06-03 stat.CO

Delayed Acceptance Markov Chain Monte Carlo for Robust Bayesian Analysis

延迟接受马尔可夫链蒙特卡罗方法用于稳健贝叶斯分析

Masahiro Tanaka

AI总结 提出延迟接受MCMC算法,通过两阶段筛选减少大协方差矩阵计算,在准贝叶斯推断中实现效率翻倍。

Journal ref In: Ferreira, D., von Rosen, D., Limnios, N., Ferreira, S. (eds) Mathematics for Industrial Applications. ICoMS 2025. Springer Proceedings in Mathematics & Statistics, vol 537

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AI中文摘要

本研究引入了一种计算高效的算法——延迟接受马尔可夫链蒙特卡罗(DA-MCMC),旨在改进准贝叶斯推断中的后验模拟。准贝叶斯方法不需要完全指定概率模型,但由于需要评估大协方差矩阵的逆和行列式,通常计算成本高昂。DA-MCMC通过采用两阶段过程解决这一挑战:在第一阶段,使用近似后验筛选提议;在第二阶段,基于精确目标后验做出最终接受或拒绝决定。这减少了对昂贵矩阵计算的需求,从而在不牺牲准确性的情况下提高效率。我们通过合成数据和真实数据的应用证明了DA-MCMC的有效性。结果表明,尽管DA-MCMC每次迭代的有效样本量略低于标准MCMC,但它在每秒有效样本量方面取得了显著改进,效率大约翻倍。这使得DA-MCMC特别适用于后验模拟计算密集的情况。因此,DA-MCMC算法为准贝叶斯推断的计算效率提供了显著进步,使其成为稳健贝叶斯分析的宝贵工具。

英文摘要

This study introduces a computationally efficient algorithm, delayed acceptance Markov chain Monte Carlo (DA-MCMC), designed to improve posterior simulation in quasi-Bayesian inference. Quasi-Bayesian methods, which do not require fully specifying a probabilistic model, are often computationally expensive owing to the need to evaluate the inverse and determinant of large covariance matrices. DA-MCMC addresses this challenge by employing a two-stage process: In the first stage, proposals are screened using an approximate posterior, whereas a final acceptance or rejection decision is made in the second stage based on the exact target posterior. This reduces the need for costly matrix computations, thereby improving efficiency without sacrificing accuracy. We demonstrate the effectiveness of DA-MCMC through applications to both synthetic and real data. The results demonstrate that, although DA-MCMC slightly reduces the effective sample size per iteration compared with the standard MCMC, it achieves substantial improvement in terms of effective sample size per second, approximately doubling the efficiency. This makes DA-MCMC particularly useful for cases where posterior simulation is computationally intensive. Thus, the DA-MCMC algorithm offers a significant advancement in computational efficiency for quasi-Bayesian inference, making it a valuable tool for robust Bayesian analysis.

2601.16977 2026-06-03 astro-ph.GA

ReveaLLAGN 1: JWST Emission-Line Spectra Reveal Low-Luminosity AGN with UV-Deficient SEDs and Warm Molecular Gas

ReveaLLAGN 1: JWST发射线光谱揭示具有紫外不足SED和温暖分子气体的低光度AGN

Kameron Goold, Anil Seth, Mallory Molina, David Ohlson, Nischal Acharya, Torsten Böker, Antoine Dumont, Michael Eracleous, Anja Feldmeier-Krause, Juan Antonio Fernández-Ontiveros, Elena Gallo, Andy D. Goulding, Kayhan Gültekin, Luis C. Ho, Nadine Neumayer, Richard M. Plotkin, Almudena Prieto, Jessie C. Runnoe, Shobita Satyapal, Glenn van de Ven, Jonelle L. Walsh, Feng Yuan, Nora Lützgendorf

AI总结 利用JWST/NIRSpec和MIRI的高空间分辨率,研究低光度活动星系核(LLAGN)的发射线,发现电离势线比以往暗一个数量级以上,并在log(L_bol/L_Edd) ~ -3.5处存在光谱能量分布紫外光子不足的转变,同时探测到旋转H2激发温度升高和硅酸盐发射。

Comments Accepted to The Astrophysical Journal, February 11, 2026. 25 pages, 10 figures

Journal ref The Astrophysical Journal, Volume 1000, Issue 2, id.281, 19 pp., April 2026

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AI中文摘要

我们展示了来自ReveaLLAGN项目的八颗低光度活动星系核(LLAGN)的近红外和中红外光谱,其黑洞质量和爱丁顿比率跨越近四个数量级,这些光谱由JWST/NIRSpec和MIRI获得,并包含了Cen A的相同档案数据。JWST的高空间分辨率清晰地将AGN发射与宿主星系污染分离,使得能够探测到比以往测量暗一个数量级以上的高电离势线。发射线诊断揭示在log($L_{bol}/L_{Edd}$) ~ -3.5处存在一个转变,此时光谱能量分布中的紫外光子变得日益不足。我们发现旋转H2激发温度比高光度AGN和恒星形成星系升高了约500 K,而H2(0-0)S(3)/PAH$_{11.3 μm}$比值与AGN种群中观测到的值一致。我们讨论了外流、喷流和X射线主导区域在塑造LLAGN周围星际介质中的可能作用。在大多数ReveaLLAGN目标中,探测到了局限于核区的~10 $μ$m硅酸盐发射。该数据集提供了首个基于JWST的LLAGN核区红外发射线的全面表征。

英文摘要

We present near- and mid-infrared spectra of eight Low-Luminosity Active Galactic Nuclei (LLAGN), spanning nearly four orders of magnitude in black hole mass and Eddington ratio, obtained with JWST/NIRSpec and MIRI as part of the ReveaLLAGN program along with identical archival data of Cen A. The high spatial resolution of JWST cleanly separates AGN emission from host-galaxy contamination, enabling detections of high-ionization potential lines more than an order of magnitude fainter than previously measured. Emission-line diagnostics reveal a transition at log($L_{bol}/L_{Edd}$) ~ -3.5, where the spectral energy distribution becomes increasingly deficient in ultraviolet photons. We find that rotational H$_2$ excitation temperatures are elevated (~500 K higher) compared to both higher-luminosity AGN and star-forming galaxies, while the H$_2$(0-0)S(3)/PAH$_{11.3 μm}$ ratios are consistent with those observed in the AGN population. We discuss the possible roles of outflows, jets, and X-ray dominated regions in shaping the interstellar medium surrounding LLAGN. Silicate emission at ~10 $μ$m, localized to the nuclear region, is detected in most ReveaLLAGN targets. This dataset offers the first comprehensive JWST-based characterization of infrared emission lines in the nuclear regions of LLAGN.

2602.09195 2026-06-03 hep-th

Boundary bound states and integrable Wilson loops in ABJM

ABJM中的边界束缚态与可积Wilson圈

Diego H. Correa, Maximiliano G. Ferro, Victor I. Giraldo-Rivera, Nicolas A. Ivanovich

AI总结 通过Yangian对称性确定具有SU(1|2)对称性的边界反射矩阵,发现ABJM理论中1/2 BPS Wilson圈插入的边界束缚态,并与边界束缚态自举结果比较。

Comments 29 pages, 3 figures. v2: minor clarifications, references added, published version

Journal ref J.Phys.A 59 (2026) 21, 215401

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AI中文摘要

我们推导了当反射过程保持$SU(1|2)$对称性时,具有自由度的边界上激发散射的可积反射矩阵。由于这种剩余对称性不足以完全确定反射矩阵,我们利用Yangian对称性的边界剩余部分,得到一族可积解。在ABJM理论中研究1/2 BPS Wilson圈插入时,发现了该设置的一个具体实现。边界自由度作为边界束缚态出现,源于反射矩阵 dressing 相中的极点。我们还将结果与边界束缚态自举程序得到的结果进行比较。ABJM Wilson圈的例子使我们能够对我们的结果进行微扰验证。

英文摘要

We derive an integrable reflection matrix for the scattering of excitations from a boundary with a degree of freedom when the reflection process preserves an $SU(1|2)$ symmetry. As this residual symmetry is not sufficient to fully determine the reflection matrix, we use the boundary remnant of the Yangian symmetry invariance and obtain a family of integrable solutions. A concrete realization of this setup is found when studying insertions in the 1/2 BPS Wilson loop in ABJM theory. The boundary degree of freedom appears as a boundary bound state due to poles in the dressing phase of the reflection matrix. We also compare our results with those obtained from the boundary bound state bootstrap procedure. The ABJM Wilson loop example enables us to perform perturbative verifications of our results.

2602.08985 2026-06-03 math.NT

An omega result for the least negative Hecke eigenvalue

最小负 Hecke 特征值的 Omega 结果

Youness Lamzouri

AI总结 本文证明存在许多大权重的全纯 Hecke 本征形式,其最小负 Hecke 特征值对应的整数至少为 (log k)^{1-o(1)},改进了 Kowalski 等人的结果,并推广到平方自由水平。

Comments 8 pages. The lower bound in Theorem 1.1 is improved by a factor of $\log\log k$ thanks to a suggestion by Sarvagya Jain. We also fixed a few typos and made some minor changes

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AI中文摘要

我们证明存在许多大权重 $k$ 的全纯 Hecke 本征形式 $f$(对于全模群),使得满足 $\lambda_f(n_f)<0$ 的最小正整数 $n_f$ 满足 $n_f \ge (\log k)^{1-o(1)}$。这被认为在指数上的 $o(1)$ 项意义下是最优的,并改进了 Kowalski、Lau、Soundararajan 和 Wu 的结果,他们证明了当限制在素数时,使得 $\lambda_f(p)<0$ 的最小素数 $p$ 可以大到 $(\log k)^{1/2+o(1)}$。我们还讨论了我们的结果到权重 $k$ 和平方自由水平 $N\geq 1$ 的原始全纯尖形式的推广。

英文摘要

We establish the existence of many holomorphic Hecke eigenforms $f$ of large weight $k$ for the full modular group, for which the least positive integer $n_f$ such that $λ_f(n_f)<0$ satisfies $n_f \ge (\log k)^{1-o(1)}.$ This is believed to be best possible up to the $o(1)$ term in the exponent, and improves on a result of Kowalski, Lau, Soundararajan and Wu, who showed that, when restricted to primes, the least prime $p$ such that $λ_f(p)<0$ can be as large as $(\log k)^{1/2+o(1)}$. We also discuss an extension of our result to primitive holomorphic cusp forms of weight $k$ and squarefree level $N\geq 1$.

2602.07631 2026-06-03 astro-ph.CO astro-ph.HE gr-qc

Gravitational Wave Informed Inference of 21-cm Global Signal Parameters

引力波启发的21厘米全局信号参数推断

Avinash Tiwari, Sajad A. Bhat, Tirthankar Roy Choudhury, Susmita Adhikari, Mukesh Kumar Singh, Shasvath J. Kapadia

AI总结 利用下一代引力波探测器观测到的双黑洞并合率作为高红移恒星形成率密度的示踪物,提出多信使框架以打破21厘米宇宙氢信号参数简并。

Journal ref Mon Not R Astron Soc (2026)

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AI中文摘要

理解第一代恒星和星系如何以及何时形成仍是现代宇宙学的核心挑战之一。这些结构出现在从黑暗时代到宇宙黎明的过渡期,尽管理论进展显著,但这一时期的观测仍缺乏约束。在这一时期,中性氢通过其21厘米超精细跃迁吸收了一部分宇宙微波背景光子,产生了21厘米吸收信号,其演化编码了早期宇宙的热历史和电离历史。然而,从该信号中提取潜在天体物理参数受到严重参数简并的限制,没有独立的观测探针就无法解决这些简并。下一代引力波探测器,如宇宙探索者(CE),将观测到极高红移的双黑洞(BBH)并合,因此将探测到其中一部分在红移范围~13-25内形成的双黑洞。这些BBH的并合率将取决于这些红移处的恒星形成率密度(SFRD),以及BBH形成效率和时间延迟分布。因此,这些BBH的并合率可以作为红移范围~13-25内SFRD的示踪物。在这封信中,我们建立了一个新颖的多信使框架,并提出了一个原理验证概念,即下一代引力波探测器对BBH并合的观测如何改进产生21厘米宇宙氢信号的参数推断,并帮助打破它们之间的简并。

英文摘要

Understanding how and when the first stars and galaxies formed remains one of the central challenges in modern cosmology. These structures emerged during the transition from the Dark Ages to the Cosmic Dawn, a period that remains observationally unconstrained despite strong theoretical progress. During this epoch, neutral hydrogen absorbed a fraction of cosmic microwave background photons through its 21-cm hyperfine transition, producing a 21-cm absorption signal whose evolution encodes the early Universe's thermal and ionization history. However, extracting the underlying astrophysical parameters from this signal is limited by severe parameter degeneracies, which cannot be resolved without independent observational probes. The next-generation gravitational wave (GW) detectors, such as Cosmic Explorer (CE), will observe binary black hole (BBH) mergers up to very large redshifts and hence will detect a fraction of them formed within the redshift range $\sim 13-25$. The merger rate of these BBHs will depend on the star formation rate density (SFRD) at these redshifts, together with the BBH formation efficiency and a time delay distribution. Therefore, the merger rate of these BBHs can work as a tracer of the SFRD in the redshift range $\sim 13-25$. In this Letter, we establish a novel multi-messenger framework and present a proof-of-principle concept of how the observations of BBH mergers form next-generation GW detectors can improve the inference of parameters generating the 21-cm cosmic hydrogen signal, and help break degeneracies between them.

2512.19824 2026-06-03 econ.EM

Regret in Treatment Choice when Welfare varies with an Uncertain Event: The Prediction-Threshold Problem

当福利随不确定事件变化时的治疗选择遗憾:预测-阈值问题

Jeff Dominitz, Charles F. Manski

AI总结 本文研究在福利随不确定二元事件变化时,使用插件概率预测和预设决策阈值进行二元治疗选择的最大遗憾,并分析其依赖因素。

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AI中文摘要

我们研究了在具有观测协变量x的人群中,当福利随不确定的二元事件变化时,二元治疗选择的最大遗憾(MR)。我们研究了使用事件的插件概率预测和预设决策阈值进行决策,我们称之为预测-阈值问题。在此设定下,对于协变量值为x的个体,如果二元结果y的条件概率P(y=1|x)超过特定的x特异性阈值,则最优治疗为B,否则为A。这种结构在医疗决策中很常见,也出现在非医疗情境中,如刑事司法。插件预测使用数据估计P(y|x),并假设该估计是准确的。然而,插件预测通常使用错误指定的预测模型和传统的x不变阈值进行。我们旨在为以这种方式进行治疗选择时的MR提供新的见解。我们结合代数和计算分析极限和样本MR,展示MR如何依赖于预测模型、状态空间以及用于选择治疗的阈值。

英文摘要

We study the maximum regret (MR) of binary treatment choice in a population with observed covariates x, when welfare varies with an uncertain binary event. We study decision making with plug-in probabilistic predictions of the event and pre-specified decision thresholds, which we term the prediction-threshold problem. In this setting, the optimal treatment for persons with covariate value x is B if the conditional probability P(y = 1|x) of a binary outcome y exceeds a particular x-specific threshold and is A otherwise. This structure is common in medical decision making and also arises in non-medical contexts such as criminal justice. Plug-in prediction uses data to estimate P(y|x) and acts as if the estimate is accurate. However, plug-in prediction is often performed with misspecified prediction models and conventional x-invariant thresholds. We aim to shed new light on MR when treatment choice is performed this way. We use a combination of algebraic and computational analysis of limit and sample MR, demonstrating how MR depends on the prediction model, the state space, and the thresholds used to choose treatments.

2602.06667 2026-06-03 math.NT

Prime ideal divisors of parametric recurrence sequences

参数递归序列的素理想因子

Darsana N, Sudhansu Sekhar Rout

AI总结 本文研究单位根处参数线性递归序列的算术性质,给出了最大素理想因子和主理想生成元范数的有效下界,并证明了S-部分的有效上界。

Comments 16 pages

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AI中文摘要

我们证明了在单位根处参数线性递归序列$(U_n(ζ))_{n\geq 0}$的新算术结果。特别地,我们得到了$U_n(ζ)$生成的主理想的最大素理想因子和根范数的有效下界。我们进一步推导了$U_n(ζ)$的$S$-部分的有效上界,表明对于足够大的$n$,它严格小于其绝对范数的固定幂。

英文摘要

We prove new arithmetic results for parametric linear recurrence sequences specialized at roots of unity, denoted by $(U_n(ζ))_{n\geq 0}$. In particular, we obtain effective lower bounds for the largest prime ideal divisor and norm of the radical of the principal ideal generated by $U_n(ζ)$. We further derive an effective upper bound for the $S$-part of $U_n(ζ)$, showing that it is strictly smaller than a fixed power of its absolute norm for sufficiently large $n$.

2602.05575 2026-06-03 astro-ph.CO gr-qc

Forecast on $f(R)$ Gravity with HI 21cm Intensity Mapping Surveys

$f(R)$引力与HI 21厘米强度成图巡天的预测

Yanling Song, Yu Sang, Linfeng Xiao, Boyu Zhang, Bin Wang

AI总结 利用Fisher矩阵预测未来中性氢21厘米强度成图实验(BINGO和SKA1-MID)对$f(R)$引力中康普顿波长参数$B_0$的约束能力,发现结合CMB数据可显著提升约束精度。

Comments 13 pages, 5 figures, 2 tables

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AI中文摘要

修正引力理论为广义相对论提供了动机良好的扩展,并为宇宙晚期加速膨胀提供了可能的解释。其中,$f(R)$引力代表了一类最小且理论上吸引人的类别,其特征由康普顿波长参数$B_0$量化,该参数衡量与广义相对论的偏差。在这项工作中,我们探索了未来中性氢(HI)21厘米强度成图(IM)观测在低红移下约束$f(R)$引力的能力。我们使用即将到来的21厘米IM实验(包括BINGO和SKA1-MID(波段1和波段2)),单独以及与普朗克宇宙微波背景(CMB)先验结合,对$B_0$和标准宇宙学参数进行了Fisher矩阵预测。我们发现,即使是像BINGO这样的近期实验也能对$B_0$施加非平凡的限制,$σ(B_0)\simeq 2.27 imes 10^{-6}$,而SKA1-MID则提供了更严格的约束,其中SKA波段2在所考虑的配置中提供了最强的灵敏度,$σ(B_0)\simeq 6.37 imes 10^{-8}$。我们进一步证明,低红移21厘米IM数据与CMB观测的结合有效地打破了与背景宇宙学参数的简并,并导致对$B_0$约束的显著改善。这些结果凸显了未来HI强度成图巡天与CMB测量相结合,在宇宙学尺度上对广义相对论进行严格测试的潜力。

英文摘要

Modified gravity theories offer a well-motivated extension of General Relativity and provide a possible explanation for the late-time accelerated expansion of the Universe. Among them, $f(R)$ gravity represents a minimal and theoretically appealing class, characterized by the Compton wavelength parameter $B_0$, which quantifies deviations from General Relativity. In this work, we explore the capability of future neutral hydrogen (HI) 21 cm intensity mapping (IM) observations to constrain $f(R)$ gravity at low redshifts. We perform Fisher-matrix forecasts for $B_0$ and standard cosmological parameters using upcoming 21 cm IM experiments, including BINGO and SKA1-MID (Band 1 and Band 2), both individually and in combination with Planck cosmic microwave background (CMB) priors. We find that even near-term experiments such as BINGO are able to place nontrivial bounds on $B_0$, $σ(B_0)\simeq 2.27\times 10^{-6}$, while SKA1-MID yields substantially tighter constraints, with SKA Band 2 providing the strongest sensitivity among the considered configurations, $σ(B_0)\simeq 6.37\times 10^{-8}$. We further demonstrate that the combination of low-redshift 21 cm IM data with CMB observations efficiently breaks degeneracies with background cosmological parameters and leads to a significant improvement in the constraints on $B_0$. These results highlight the potential of future HI intensity mapping surveys, in combination with CMB measurements, to provide stringent tests of General Relativity on cosmological scales.

2602.02674 2026-06-03 physics.ins-det

A rapid low-background assay of $^{210}$Pb in archaeological lead

考古铅中$^{210}$Pb的快速低本底测量

M. Consonni, M. Clemenza, E. Di Stefano, N. Ferreiro Iachellini, F. Filippini, A. Gardini, G. Grosso, L. Pattavina, R. Della Pergola, S. Quitadamo, E. Sala, F. Saliu, A. Salvini, L. Trombetta

AI总结 本文提出一种使用商用低本底液体闪烁计数器结合化学制备与脉冲形状分析快速测量考古铅中$^{210}$Pb的方法,灵敏度达数百mBq/kg量级,一周内可完成测量。

Comments published version, accepted by EPJ-C

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AI中文摘要

在这项工作中,我们提出了一种快速高效的方法,用于测量金属考古铅中的$^{210}$Pb,该方法使用安装在米兰-比可卡大学(意大利)的商用低本底液体闪烁计数器Wallac Quantulus 1220。通过将优化的化学制备与脉冲形状分析(PSA)相结合,该技术在使用低于1克的样品质量时,在一周测量时间内达到了几百mBq/kg的灵敏度。该方法能够同时识别$^{210}$Pb和$^{210}$Bi的$β$衰变以及$^{210}$Po的$α$衰变,从而直接验证衰变链内的长期平衡。通过延长采集时间,约40天后检测限可低于100 mBq/kg。该方法为铅的放射性纯度筛选提供了一种快速、易用且可靠的工具,非常适用于下一代低本底和稀有事件物理实验的质量控制和研发活动。此外,该方法有潜力扩展到其他与低本底应用相关的材料。

英文摘要

In this work, we present a fast and highly efficient method for the measurement of $^{210}$Pb in metallic archaeological lead using the commercial low-background liquid scintillation counter Wallac Quantulus 1220 installed at the University of Milano-Bicocca (Italy). By combining an optimized chemical preparation with pulse-shape analysis (PSA), the technique achieves sensitivities at the level of a few $10^2$ mBq/kg within one week of measurement, using sample masses below 1 g. The method enables the simultaneous identification of the $β$ decays of $^{210}$Pb and $^{210}$Bi and the $α$ decay of $^{210}$Po, allowing a direct verification of secular equilibrium within the decay chain. With extended acquisition times, detection limits below 100 mBq/kg are reached after approximately 40 days. This approach provides a rapid, accessible, and reliable tool for the radiopurity screening of lead, and is well suited for quality control and R&D activities in next-generation low-background and rare-event physics experiments. Moreover, the method has the potential to be extended to other materials relevant for low-background applications.

2511.08714 2026-06-03 physics.plasm-ph

Collisional stopping power of ions in warm dense matter

离子在温稠密物质中的碰撞阻止本领

Lucas Babati, Shane Rightley, Nathaniel Shaffer, Scott Baalrud

AI总结 基于等离子体动理论,结合费米简并效应和平均原子模型中的强库仑关联,发展了离子在温稠密物质中碰撞阻止本领的模型,并验证了其准确性。

Comments 14 pages, 6 figures

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AI中文摘要

我们开发并探索了一个描述离子在温稠密物质中与自由电子发生碰撞阻止的模型。该模型基于等离子体动理论,但针对温稠密物质状态进行了修正。具体而言,它使用玻尔兹曼-乌林-乌伦贝克动方程来纳入电子费米简并效应。截面通过量子散射计算得到,散射过程由平均原子模型导出的平均力势描述,该模型包含了强库仑关联效应。该模型的预测结果与时间依赖密度泛函理论计算在固体密度附近、温度几个电子伏特的氘中的结果相比,具有相当的精度,而计算成本却低得多。此外,该模型捕捉了等离子体从经典极限到简并极限的转变,包括固态理论的定性行为。

英文摘要

A model for the collisional stopping of ions on free electrons in warm dense matter is developed and explored. It is based on plasma kinetic theory, but with modifications to address the warm dense matter regime. Specifically, it uses the Boltzmann-Uehling-Uhlenbeck kinetic equation to incorporate effects of Fermi degeneracy of electrons. The cross section is computed from quantum scattering of electrons and ions occuring via the potential of mean force derived from an average atom model, which incorporates effects of strong Coulomb correlations. Predictions from this model show comparable accuracy to results from time-dependent density functional theory calculations for deuterium near solid density and a temperature of several electronvolts, at a fraction of the computational cost. Further, the model captures the transition of a plasma from the classical limit to the degenerate limit, including qualitative behaviors of solid state theory.

2602.04497 2026-06-03 astro-ph.CO

A model-independent measurement of the Hubble constant from gravitational-wave standard sirens and electromagnetic observations

基于引力波标准警报器和电磁观测的哈勃常数模型无关测量

Gaurav N. Gadbail, Kazuharu Bamba

AI总结 采用高斯过程这一完全模型无关方法,结合GWTC3引力波标准警报器数据和电磁观测,测量得到与SH0ES结果高度一致的哈勃常数,张力小于2σ。

Comments 11 pages, 3 figures

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AI中文摘要

哈勃张力是现代宇宙学中最重大的挑战之一。因此,开发估计哈勃常数的新方法至关重要,在这项工作中,我们采用高斯过程,一种完全模型无关且仅依赖于观测数据的方法。为了确定哈勃常数,我们不仅使用电磁观测,还包括来自GWTC3的引力波标准警报器数据。我们对哈勃常数的测量与SH0ES结果高度一致,张力小于$2σ$,表明没有统计上显著的差异。这种方法量化了引力波数据对哈勃常数确定的影响,检验了其与电磁测量的一致性,并探讨了其在解决哈勃张力问题中的潜在作用。

英文摘要

The Hubble tension is one of the most significant challenges in modern cosmology. Developing new approaches to estimate the Hubble constant is therefore crucial, and in this work, we employ a Gaussian process, a fully model-independent method that relies solely on observational data. To determine the Hubble constant, we use not only electromagnetic observations but also include gravitational-wave standard siren data from GWTC3. Our measurements of the Hubble constant are strongly consistent with the SH0ES result, with tensions less than $2σ$, indicating no statistically significant discrepancy. This approach quantifies the impact of gravitational-wave data on the determination of the Hubble constant, examines its consistency with electromagnetic measurements, and explores its potential role in addressing the Hubble tension.

2602.04065 2026-06-03 physics.plasm-ph astro-ph.HE

Eigenmodes in an ultra-relativistic ultra-magnetized pair QED-plasma

超相对论超磁化对QED等离子体中的本征模

Ryan T. Low, Mikhail V. Medvedev

AI总结 研究超强磁场和相对论温度对超相对论电子-正电子等离子体(电荷中性及非中性)中正常等离子体模式的联合修正,发现等离子体频率截止降低导致相对论和场致透明,以及电磁波折射率的温度无关修正。

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AI中文摘要

超相对论量子电动力学(QED)等离子体,其特征是磁场强度接近甚至超过大约$B_{Q} \approx 4 imes 10^{13}$高斯的施温格场,对于激光等离子体实验以及中子星和磁星的 astrophysical 观测具有重要意义。在本研究中,我们探讨了超强磁场和等离子体相对论温度对超相对论电子-正电子等离子体(电荷中性和非中性)中正常等离子体模式的联合修正。我们的分析表明,最显著的修正是等离子体频率截止的降低,导致相对论和场致透明。此外,我们观察到电磁波折射率的温度无关修正,这与冷QED等离子体中观察到的行为一致。

英文摘要

Ultra-relativistic quantum-electrodynamic (QED) plasmas, characterized by magnetic field strengths approaching and even exceeding the Schwinger field of approximately $B_{Q} \approx 4 \times 10^{13}$ gauss, hold significant interest for laser-plasma experiments and astrophysical observations of neutron stars and magnetars. In this study, we investigate the joint modification of normal plasma modes in ultra-relativistic electron-positron plasmas, both charge neutral and non-neutral, by the super-strong magnetic field and plasma relativistic temperature. Our analysis shows that the most substantial modification concerns the reduction of the plasma frequency cutoff, resulting in relativistic and field-induced transparency. Additionally, we observe a temperature-independent modification of the index of refraction of electromagnetic waves, which coincides with the behavior observed in a cold QED plasma.

2602.02827 2026-06-03 cs.IR

Col-Bandit: Query-Time Top-$K$ Estimation for Late-Interaction Retrieval

Col-Bandit:面向延迟交互检索的查询时Top-$K$估计

Roi Pony, Adi Raz Goldfarb, Oshri Naparstek, Idan Friedman, Udi Barzelay, Eli Schwartz

AI总结 提出Col-Bandit方法,通过批量揭示矩阵条目并维护置信区间,在查询时高效估计多向量延迟交互检索中的Top-$K$结果,大幅减少计算量且保持高保真度。

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AI中文摘要

多向量延迟交互检索器(如ColBERT)实现了最先进的质量,但其查询时成本主要来自对每个候选文档穷举计算词级MaxSim交互。N个候选与T个查询词的MaxSim得分构成N×T矩阵,其行和为延迟交互得分,而识别top-$K$通常不需要所有条目。我们提出Col-Bandit,一种穷举MaxSim top-$K$的查询时估计方法:它批量揭示矩阵条目,维护每个候选得分的有限总体Bernstein-Serfling置信区间,并永久丢弃上界低于第K大下界的文档,仅计算分离top-$K$所需的单元格。一个松弛旋钮$α_{\mathrm{ef}}\in(0,1]$调节计算-保真度权衡。我们部署$α_{\mathrm{ef}}{=}0.2$,而$α_{\mathrm{ef}}{=}1$在简化半径下提供$δ$-PAC保证。在BEIR和REAL-MM-RAG上,Col-Bandit在每个语料库上对穷举top-$5$保持$\geq 90\%$的保真度,同时将MaxSim FLOPs减少高达${\sim}8\times$,在x86和ARM上实现高达${\sim}13\times$的单线程CPU加速。作为即插即用的重排序层,它无需重新训练或更改索引。

英文摘要

Multi-vector late-interaction retrievers such as ColBERT achieve state-of-the-art quality, but their query-time cost is dominated by exhaustively computing token-level MaxSim interactions for every candidate document. The MaxSim scores of $N$ candidates against $T$ query tokens form an $N\times T$ matrix whose row-sums are the late-interaction scores, and identifying the top-$K$ rarely requires every entry. We introduce Col-Bandit, a query-time estimator of the exhaustive-MaxSim top-$K$: it reveals matrix entries in batches, maintains a finite-population Bernstein-Serfling confidence interval on each candidate's score, and permanently drops any document whose upper bound falls below the $K$-th largest lower bound, computing only the cells needed to separate the top-$K$. A single relaxation knob $α_{\mathrm{ef}}\in(0,1]$ tunes the compute-fidelity trade-off. We deploy $α_{\mathrm{ef}}{=}0.2$, while $α_{\mathrm{ef}}{=}1$ admits a $δ$-PAC guarantee under a simplified radius. On BEIR and REAL-MM-RAG, Col-Bandit preserves $\geq 90\%$ fidelity to the exhaustive top-$5$ on every corpus while cutting MaxSim FLOPs by up to ${\sim}8\times$, for up to ${\sim}13\times$ single-thread CPU speedups across x86 and ARM. A drop-in reranking layer, it needs no retraining or index changes.

1205.1980 2026-06-03 math.NA cs.NA

A posteriori estimates for errors of functionals on finite volume approximations to solutions of elliptic boundary value problems

椭圆边值问题有限体积近似解泛函误差的后验估计

Lutz Angermann

AI总结 本文扩展了后验误差估计方法(如对偶加权残差法)到节点中心有限体积离散格式,针对二阶椭圆边值问题(包括迎风离散),估计建模误差和离散误差相对于用户定义输出泛函的影响。

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AI中文摘要

本文描述了后验误差估计的最新方法(如对偶加权残差法)向节点中心有限体积离散格式的扩展,用于二阶椭圆边值问题,包括迎风离散。展示了如何针对用户定义的输出泛函估计不同来源的误差,特别是建模误差和离散误差。

英文摘要

This article describes the extension of recent methods for a posteriori error estimation such as dual-weighted residual methods to node-centered finite volume discretizations of second order elliptic boundary value problems including upwind discretizations. It is shown how different sources of errors, in particular modeling errors and discretization errors, can be estimated with respect to a user-defined output functional.

1102.3100 2026-06-03 math.NA cs.NA

Interpolation, projection and hierarchical bases in discontinuous Galerkin methods

间断Galerkin方法中的插值、投影与层次基

Lutz Angermann, Christian Henke

AI总结 本文研究Sobolev-Slobodecki空间中张量积型分片多项式逼近的插值与投影技术、基于层次基的求积规则与投影算子的误差估计以及逆不等式,主要应用于离散守恒律。

Journal ref Numer. Math. Theor. Meth. Appl., 8 (2015), pp. 425-450

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AI中文摘要

本文给出了Sobolev-Slobodecki空间中通过多种插值与投影技术得到的张量积型分片多项式逼近的结果,基于层次基的求积规则和投影算子的误差估计,以及逆不等式。主要关注离散守恒律的应用。

英文摘要

The paper presents results on piecewise polynomial approximations of tensor product type in Sobolev-Slobodecki spaces by various interpolation and projection techniques, on error estimates for quadrature rules and projection operators based on hierarchical bases, and on inverse inequalities. The main focus is directed to applications to discrete conservation laws.

1011.2750 2026-06-03 math.NA cs.NA

$L^\infty(L^\infty)$-boundedness of DG($p$)-solutions for nonlinear conservation laws with boundary conditions

$L^\infty(L^\infty)$-有界性:带边界条件的非线性守恒律的DG($p$)-解

Lutz Angermann, Christian Henke

AI总结 针对一般标量守恒律,基于$p\geq 0$次多项式的激波捕捉流线扩散DG方法,证明了其解在$L^\infty(L^\infty)$范数下的有界性,适用于多维空间及初边值条件。

Journal ref IMA Journal of Numerical Analysis, Volume 34, Issue 4, October 2014, pp. 1598-1624

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AI中文摘要

我们证明了基于$p\geq 0$次多项式的高阶激波捕捉流线扩散DG方法对于一般标量守恒律的$L^\infty(L^\infty)$-有界性。该估计适用于多个空间维度以及带有初始条件和边界条件的守恒律。

英文摘要

We prove the $L^\infty(L^\infty)$-boundedness of a higher-order shock-capturing streamline-diffusion DG-method based on polynomials of degree $p\geq 0$ for general scalar conservation laws. The estimate is given for the case of several space dimensions and for conservation laws with initial and boundary conditions.

2602.02073 2026-06-03 hep-th cond-mat.mes-hall math-ph math.MP nlin.SI quant-ph

The soliton nature of the super-Klein tunneling effect

超克莱因隧穿效应的孤子本质

Francisco Correa, Luis Inzunza, Olaf Lechtenfeld

AI总结 本文通过建立Davey-Stewartson II可积系统与超克莱因隧穿效应Dirac哈密顿量之间的联系,利用Darboux变换构造孤子解,揭示了超克莱因隧穿效应的孤子本质。

Comments 24 pages, 12 Figures

Journal ref Phys. Rev. D 113, 105027 (2026)

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AI中文摘要

我们在$(2{+}1)$维Davey-Stewartson II (DS II)可积系统与表现出超克莱因隧穿(SKT)效应的准精确可解平面相互作用Dirac哈密顿量之间建立了关系。Dirac相互作用由DS II系统的呼吸子解的实部和虚部构造而成。在此框架下,当能量调谐到与孤子的常数背景匹配时,SKT效应出现,同时得到的Dirac哈密顿量支持嵌入连续谱中的束缚态。通过施加SKT边界条件,我们利用Darboux变换构造了一个一般的三参数DS II呼吸子解族,该族可映射到Dirac哈密顿量。在初始孤子时间,相应的Dirac系统形成具有非平凡静电势的无质量两参数Hermitian模型族。随着孤子时间的演化,系统变为$\mathcal{PT}$-对称并发展出非平凡的虚质量项。最后,当孤子时间取为虚数时,构造产生缺乏时间反演对称性的Hermitian Dirac系统。在所有情况下,我们识别出准对称变换的出现,这些变换保持SKT态子空间,但不与完整哈密顿量对易。

英文摘要

We establish a relationship between the Davey--Stewartson II (DS II) integrable system in $(2{+}1)$ dimensions and quasi-exactly solvable planar interacting Dirac Hamiltonians that exhibit the super-Klein tunneling (SKT) effect. The Dirac interactions are constructed from the real and imaginary parts of breather solutions of the DS II system. In this framework, the SKT effect arises when the energy is tuned to match the constant background of the soliton, while the resulting Dirac Hamiltonians simultaneously support bound states embedded in the continuum. By imposing the SKT boundary conditions, we employ Darboux transformations to construct a general three-parameter family of DS II breather solutions that can be mapped to Dirac Hamiltonians. At the initial soliton time, the corresponding Dirac systems form a massless two-parameter family of Hermitian models with nontrivial electrostatic potentials. As the soliton time evolves, the systems become $\mathcal{PT}$-symmetric and develop a nontrivial imaginary mass term. Finally, when the soliton time is taken to be imaginary, the construction yields Hermitian Dirac systems that lack time-reversal symmetry. In all cases, we identify the emergence of quasi-symmetry transformations that preserve the SKT subspace of states while not commuting with the full Hamiltonian.

2602.01108 2026-06-03 astro-ph.CO

Skewness in the Hellings-Downs curve

Hellings-Downs 曲线的偏度

Ryosuke Fujimoto, Keitaro Takahashi

AI总结 本文推导了 Hellings-Downs 相关的三阶中心矩(偏度),发现其在大量源极限下非零,并由新的几何三点函数控制,表明高阶矩可提供源离散性的额外信息。

Comments 15 pages, 8 figures. Accepted for publication in Physical Review D

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AI中文摘要

最近的脉冲星计时阵列数据集为纳赫兹引力波背景提供了令人信服的证据,但稳健的探测需要表征来自有限离散源群体的 Hellings-Downs (HD) 相关的统计涨落。基于 Allen (2023) 的方差计算,我们推导了单个非偏振点源以及混淆噪声区域中多个干涉点源集合的 HD 相关的三阶中心矩(偏度)。为了隔离背景的内在非高斯性,我们通过引入三点平均相关函数将脉冲星平均形式推广到三阶,从而定义了宇宙偏度。我们发现偏度在大源数极限下保持非零,并由一个新的几何三点函数控制。这些结果表明,纳入高阶矩可以为标准高斯分析之外的源离散性提供额外信息。

英文摘要

Recent Pulsar Timing Array datasets provide compelling evidence for a nano-Hertz gravitational-wave background, but robust detection requires characterizing statistical fluctuations of the Hellings-Downs (HD) correlation expected from a finite population of discrete sources. Building on the variance calculation of Allen (2023), we derive the third central moment (skewness) of the HD correlation for a single unpolarized point source and an ensemble of many interfering point sources in the confusion-noise regime. To isolate the intrinsic non-Gaussianity of the background, we extend the pulsar-averaging formalism to third order by introducing a three-point averaged correlation function, which allows us to define the cosmic skewness. We find that the skewness remains non-zero in the large-source-number limit and is controlled by a new geometric three-point function. These results suggest that incorporating higher-order moments could provide additional information on source discreteness beyond standard Gaussian analyses.

2602.00529 2026-06-03 nucl-th

General Radial-Composition Correlations in Two-Component Many-Body Systems

双组分多体系统中的通用径向组成关联

Y. Lei

AI总结 研究双组分多体系统中均方根半径差与组成不对称性之间的线性关联,通过短程吸引中心力、低能谐振子近似、维里定理和泡利原理/硬芯势揭示其普遍机制。

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AI中文摘要

双组分多体系统中均方根半径差与组成不对称性之间的线性关联是一个稳健的特征,在核实验、多种核结构模型、双金属团簇的分子动力学模拟以及自相互作用暗物质的星系建模中均有观察到。我们确定短程吸引中心力是其出现的关键因素,这一机制由低能谐振子近似下的坐标变换、维里定理以及多费米子系统/经典多体系统中的泡利原理/硬芯势支撑。

英文摘要

The linear correlation between RMS radius difference and composition asymmetry in two-component many-body systems is a robust feature observed across nuclear experiments, diverse nuclear structural models, molecular dynamic simulations for bimetallic clusters, and galactic modeling with self-interacting dark matter. We identify the short-range attractive central force as the key ingredient for its emergence, a mechanism underpinned by the coordinate transformation under low-energy harmonic-oscillator approximation, the virial theorem, and Pauli principle/hard core potential, in many-fermion system/classic many-body system.

2601.22424 2026-06-03 cs.CY

Toward Third-Party Assurance of AI Systems: Design Requirements, Prototype, and Early Testing

面向人工智能系统的第三方保障:设计需求、原型与早期测试

Rachel M. Kim, Blaine Kuehnert, Alice Lai, Kenneth Holstein, Hoda Heidari, Rayid Ghani

AI总结 提出一个第三方AI保障框架,包括责任分配矩阵、访谈协议、成熟度矩阵和保障报告模板,并通过两个用例和专家访谈验证其有效性。

Comments Published at ACM FAccT 2026. 61 pages, 1 figure

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AI中文摘要

随着人工智能(AI)系统的普及,对系统、透明且可操作的评估流程的需求日益增长。尽管存在许多支持AI评估的资源,但它们存在若干局限性。很少有资源同时涵盖AI系统设计、开发和部署的过程及其产生的结果。此外,很少有资源是端到端且可操作的,提供可操作的指导,或展示其在实践中的可用性或有效性。在本文中,我们介绍了一个第三方AI保障框架,以解决这些差距。我们专注于第三方保障,以防止利益冲突并确保流程的可信度和问责性。我们首先从几个关键维度区分保障与审计。然后,遵循设计原则,我们反思现有资源的不足,以确定AI保障的一组设计需求。接着,我们构建了一个保障流程的原型,包括:(1)责任分配矩阵,用于确定每个利益相关者在AI生命周期各阶段的不同参与程度;(2)针对AI系统每个利益相关者的访谈协议;(3)成熟度矩阵,用于评估AI系统对最佳实践的遵循程度;(4)借鉴商业会计中更成熟的保障实践的保障报告模板。我们通过将框架应用于两个不同的AI用例——大型私营企业下游处理的商业文档标记工具和公共机构的住房资源分配工具——并进行六次专家验证访谈,对AI保障框架进行了早期验证。我们的发现提供了早期证据,表明我们的AI保障框架是健全且全面的,在不同组织背景下可用,并且能够有效识别AI系统的特定问题。

英文摘要

As Artificial Intelligence (AI) systems proliferate, the need for systematic, transparent, and actionable processes for evaluating them is growing. While many resources exist to support AI evaluation, they have several limitations. Few address both the process of designing, developing, and deploying an AI system and the outcomes it produces. Furthermore, few are end-to-end and operational, give actionable guidance, or present evidence of usability or effectiveness in practice. In this paper, we introduce a third-party AI assurance framework that addresses these gaps. We focus on third-party assurance to prevent conflict of interest and ensure credibility and accountability of the process. We begin by distinguishing assurance from audits in several key dimensions. Then, following design principles, we reflect on the shortcomings of existing resources to identify a set of design requirements for AI assurance. We then construct a prototype of an assurance process that consists of (1) a responsibility assignment matrix to determine the different levels of involvement each stakeholder has at each stage of the AI lifecycle, (2) an interview protocol for each stakeholder of an AI system, (3) a maturity matrix to assess AI systems' adherence to best practices, and (4) a template for an assurance report that draws from more mature assurance practices in business accounting. We conduct early validation of our AI assurance framework by applying the framework to two distinct AI use cases -- a business document tagging tool for downstream processing in a large private firm, and a housing resource allocation tool in a public agency -- and conducting six expert validation interviews. Our findings show early evidence that our AI assurance framework is sound and comprehensive, usable across different organizational contexts, and effective at identifying bespoke issues with AI systems.

2601.21300 2026-06-03 eess.SY cs.SY

Distributed Circumnavigation Using Bearing Based Control with Limited Target Information

基于方位控制且目标信息有限的分布式环绕航行

Kushal Pratap Singh, Manvi Bengani, Darshit Mittal, Twinkle Tripathy

AI总结 针对具有单轮运动学的异构多智能体系统,提出一种仅利用部分智能体(领导者)已知目标位置的分布式制导律,通过控制角速度实现所有智能体对静止目标的环绕,并利用Zubov定理保证全局渐近稳定性。

Comments 6 pages, 17 figures

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AI中文摘要

本文研究了由具有单轮运动学的$\textbf{n}$个自主智能体组成的异构群体对静止目标的环绕问题。假设智能体具有恒定线速度,我们仅控制角速度。考虑到智能体有限的感知能力,只有一部分智能体(称为领导者)知道目标位置,其余智能体(称为跟随者)不知道。我们提出了一种分布式制导律,驱使所有智能体达到期望目标;通过Zubov定理保证了全局渐近稳定性(GAS)。通过数值仿真和硬件实验验证了该方法的有效性。

英文摘要

In this paper, we address the problem of circumnavigation of a stationary target by a heterogeneous group comprising of $\textbf{n}$ autonomous agents, having unicycle kinematics. The agents are assumed to have constant linear speeds, we control only the angular speeds. Assuming limited sensing capabilities of the agents, only a subset of agents, termed as \textit{leaders}, know the target location. The rest, termed as \textit{followers}, do not. We propose a distributed guidance law which drives all the agents towards the desired objective; global asymptotic stability (GAS) is ensured by using Zubov's theorem. The efficacy of the approach is demonstrated through both numerical simulations and hardware experiments.

2411.19864 2026-06-03 math.HO math.NT

An Elementary Proof of a Remarkable Relation Between the Squircle and Lemniscate

一个关于方圆与双纽线之间显著关系的基础证明

Zbigniew Fiedorowicz, Muthu Veerappan Ramalingam

AI总结 本文通过基本积分运算,给出了方圆(四次费马曲线 $x^4+y^4=1$)的扇形面积与双纽线 $(x^2+y^2)^2=x^2-y^2$ 的弧长之间关系的基础证明,并提供了几何解释。

Comments 14 pages, 3 figures

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AI中文摘要

众所周知,四次费马曲线 $x^4+y^4=1$(即方圆)的面积与双纽线 $(x^2+y^2)^2=x^2-y^2$ 的弧长之间存在某种神秘的关系。这一事实的标准证明利用了椭圆积分与伽马函数之间的关系。在本文中,我们将这一结果推广,将方圆的扇形面积与双纽线的弧段长度联系起来。我们给出了这种关系的几何解释,以及一个仅使用基本积分运算的基础证明。我们还讨论了这种关系的另一种形式,这隐含在 Siegel 的一个计算中。

英文摘要

It is well known that there is a somewhat mysterious relation between the area of the quartic Fermat curve $x^4+y^4=1$, aka squircle, and the arc length of the lemniscate $(x^2+y^2)^2=x^2-y^2$. The standardproof of this fact uses relations between elliptic integrals and the gamma function. In this article we generalize this result to relate areas of sectors of the squircle to arc lengths of segments of the lemniscate. We provide a geometric interpretation of this relation and an elementary proof of the relation, which only uses basic integral calculus. We also discuss an alternate version of this kind of relation, which is implicit in a calculation of Siegel.

2601.19458 2026-06-03 cond-mat.str-el cond-mat.supr-con

Coupled Majorana modes in a dual vortex of the Kitaev honeycomb model

Kitaev蜂窝模型双涡旋中的耦合马约拉纳模式

Surajit Basak, Jean-Noël Fuchs

AI总结 本文研究Kitaev蜂窝模型中双涡旋束缚的有限能量费米子模式,该模式等价于两个耦合的马约拉纳零模,并通过连续近似和数值微扰理论计算了其波函数和耦合强度。

Comments 17 pages, 9 figures

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AI中文摘要

Kitaev模型在马约拉纳费米子跳跃于蜂窝晶格并与静态$\mathbb{Z}_2$规范场耦合的意义上是精确可解的,从而在六边形格点中可能存在$\pi$-涡旋。在充满涡旋的扇区中,且存在强度为$κ$的时间反演破缺三自旋项时,能谱有能隙,基态具有偶陈数。一个孤立的无涡旋格点充当“双涡旋”,并在体带隙中束缚一个有限能量$ε$的费米子模式。该模式等价于位于同一双涡旋上的两个耦合的马约拉纳零模。在连续近似下,我们解析计算了小$κ$和大$κ$两种极限下的马约拉纳波函数及其耦合$ε$。解析方法通过直接在晶格上的数值微扰理论得到验证,后者与有限尺寸系统的全数值结果高度一致。我们将结果与偶陈数拓扑超导体中孤立涡旋束缚态进行了对比。

英文摘要

The Kitaev model is exactly solvable in terms of Majorana fermions hopping on a honeycomb lattice and coupled to a static $\mathbb{Z}_2$ gauge field, giving the possibility of $π$-vortices in hexagonal plaquettes. In the vortex-full sector and in the presence of a time-reversal-breaking three-spin term of strength $κ$, the energy spectrum is gapped and the ground state possesses an even Chern number. An isolated vortex-free plaquette acts as a ``dual vortex'' and binds a fermionic mode at finite energy $ε$ in the bulk gap. This mode is equivalent to two coupled Majorana zero modes located on the same dual vortex. In a continuum approximation, we analytically compute the Majorana wavefunctions and their coupling $ε$ in the two limits of small or large $κ$. The analytical approach is confirmed by numerical perturbation theory directly on the lattice. The latter is in excellent agreement with the full numerics on a finite-size system. We contrast our results with states bound to an isolated vortex in a topological superconductor with even Chern number.

2601.06815 2026-06-03 astro-ph.GA astro-ph.CO

Joint Optical-HI mock catalogues and prospects for upcoming HI surveys

联合光学-HI模拟星表及对即将开展的HI巡天的展望

Sauraj Bharti, J. S. Bagla

AI总结 本文提出一种为即将开展的SKA前导巡天(MIGHTEE-HI、LADUMA和WALLABY)创建光学-HI联合模拟星表的新方法,并展示其在预测巡天结果、研究HI质量函数及星系演化中的应用。

Comments 16 pages, 11 figures, 4 tables. Accepted for publication in the MNRAS

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AI中文摘要

原子氢(HI)通过冷气体为恒星形成提供燃料,从而调节恒星形成过程,它是重子循环中的关键阶段。红移的21厘米谱线发射是研究遥远星系星际介质(ISM)和星系周介质(CGM)中HI的重要示踪物,并使得研究星系演化成为可能。由于21厘米发射线本质上很弱,目前对HI的直接探测仅限于红移$z \leq 0.4$。正在进行的和即将开展的大型射电巡天旨在探测红移$z \gtrsim 1$的星系的21厘米发射。我们提出了一种为即将开展的SKA前导巡天(MIGHTEE-HI、LADUMA和WALLABY)创建光学-HI联合模拟星表的新方法。将光学性质与HI相结合,使得这些模拟星表成为预测巡天结果的强大工具,并为探索这些巡天预期的HI科学(例如条件HI质量函数和光学-HI标度关系)提供了基准。作为案例研究,我们展示了联合星表在预测低于直接探测阈值的星系平均HI质量堆叠探测预期结果方面的应用。我们表明,将堆叠观测仅与直接探测数量相结合,就对HI质量函数施加了很强的约束。我们还表明,可以针对星系颜色-星等图的不同部分分别进行此操作,从而实现对星系演化的精细研究。这可用于为完全确定HI质量函数设置先验。

英文摘要

Atomic hydrogen (HI) regulates star formation as cold gas fuels star formation. It represents a key phase in the baryon cycle. Redshifted $21$ cm line emission serves as a key tracer for investigating HI in the interstellar medium (ISM) and circumgalactic medium (CGM) in distant galaxies, and enables the study of galaxy evolution. Direct detections of HI are currently limited to $z \leq 0.4$ due to the inherently weak $21$ cm emission line. Ongoing and upcoming large radio surveys aim to detect $21$ cm emission from galaxies up to $z \gtrsim 1$. We present a novel approach for creating optical-HI joint mock catalogues for upcoming SKA precursor surveys: MIGHTEE-HI, LADUMA and WALLABY. Incorporation of optical properties along with HI makes these mock catalogues a powerful tool for making predictions for surveys and provides a benchmark for exploring the HI science (e.g., conditional HIMF and optical-to-HI scaling relations) expected from these surveys. As a case study, we show the use of the joint catalogues for predicting the expected outcome of stacking detection for average HI mass in galaxies that are below the threshold for direct detection. We show that combining stacking observations with only the number of direct detections puts a strong constraint on the HI mass function. We also show that this can be done separately for parts of the color-magnitude diagram for galaxies, enabling a fine grained study of galaxy evolution. This may be used to set priors for the full determination of the HI mass function.

2601.18916 2026-06-03 gr-qc astro-ph.HE astro-ph.IM

Reconsidering the consistent use of precessing, higher order multipole models for gravitational wave analyses

重新考虑引力波分析中进动高阶多极模型的一致使用

Charlie Hoy

AI总结 针对引力波分析中进动高阶多极模型计算成本高的问题,提出选择准则以在保证无偏估计的前提下使用廉价模型,可将贝叶斯推断成本降低20%-78%。

Comments 15 pages, 9 figures, 4 appendices

Journal ref Mon Not R Astron Soc (2026)

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AI中文摘要

引力波观测数量的增长使得对黑洞潜在种群施加约束成为可能;当前估计表明,黑洞自旋较小,双星更可能具有可比的成分质量。由于广义相对论效应(如自旋诱导的轨道进动和高阶多极矩)更可能在不对称双星系统中被观测到,直接测量仍然不太可能。尽管如此,我们仍通过使用最精确且计算成本最高的模型进行贝叶斯推断来持续探测这些效应。随着引力波探测数量的增加,一致使用这些模型进行分析可能很快变得不可行。在本文中,我们提供了一个选择准则,该准则确定何时可以使用精度较低且计算成本较低的模型,而不会对宇宙中黑洞的种群特性产生有偏估计。我们表明,当使用我们的选择准则时,对于模拟的“最坏情况”场景种群,可以获得黑洞质量和自旋分布的相当估计,同时将种群贝叶斯推断的总成本降低约20%。我们预计,对于天体物理动机的种群,总成本可降低高达78%,因为具有可观测自旋进动和高阶多极功率的事件较少。

英文摘要

The growing number of gravitational-wave (GW) observations allows for constraints to be placed on the underlying population of black holes; current estimates show that black hole spins are small, with binaries more likely to have comparable component masses. Since general relativistic effects, such as spin-induced orbital precession and higher order multipole moments, are more likely to be observed for asymmetric binary systems, a direct measurement remains unlikely. Nevertheless, we continue to consistently probe these effects by performing Bayesian inference with our most accurate and computationally expensive models. As the number of GW detections increases, it may soon become infeasible to consistently use these models for analyses. In this paper, we provide a selection criterion that determines when less accurate and computationally cheaper models can be used without giving biased estimates for the population properties of black holes in the Universe. We show that when using our selection criterion, comparable estimates can be obtained for the underlying mass and spin distribution of black holes for a simulated "worst-case" scenario population, while reducing the overall cost of performing Bayesian inference on our population by $\sim 20\%$. We anticipate a reduction of up to $78\%$ in the overall cost for an astrophysically motivated population, since there are fewer events with observable spin-precession and higher order multipole power.