arXivDaily arXiv每日学术速递 周一至周五更新
重置
全部学科分类 2084
2605.27198 2026-05-27 math-ph hep-th math.MP

Bounds on relative modular Hamiltonians in general QFT

一般QFT中相对模哈密顿量的界

Adriano Chialastri, Christoph Minz, Ko Sanders

AI总结 利用代数QFT的局域性,通过参考态的模哈密顿量估计两个态之间的相对模哈密顿量及其相对熵,并应用于相干态和自由标量场。

Comments 25 pages, 3 figures

详情
AI中文摘要

两个态之间的相对熵是量子信息论和量子场论中的一个关键概念。在量子场论中,其计算需要处理相对模哈密顿量,而后者通常难以显式计算。本文利用一般代数QFT的局域性,通过参考态$\hatω$的模哈密顿量来估计两个态$ω$和$\tildeω$之间的相对模哈密顿量,进而估计它们的相对熵,其中$\hatω$可能更易理解。对于合适的态对,我们可以从上方(或下方)用更大区域$V_3$(或更小区域$V_1$)上$\hatω$的模哈密顿量来估计区域$V_2$代数的相对模哈密顿量。适合我们方案的态对和区域选择与Sorkin悖论意义上的超光速信号传递有关。如果$ω=\hatω$,则存在一个幺正算符将$V_3$上的$ω$映射到$\tildeω$,且当我们的上界(或下界)适用时,该算符不允许从$V_3$的类空补集$V_3'$到$V_2$(或从$V_1$到$V_2'$)的超光速信号传递。为了研究我们估计的强度,我们考虑CCR系统的相干态,特别关注自由标量场。即使相对模哈密顿量无法精确计算,我们的估计也适用。对于足够规则的激发,我们通过压缩恢复精确结果。因此,我们的方法在相对模哈密顿量无法精确计算的情况下,为相对熵公式提供了独立证明。对于无质量场,我们还在双锥区域建立了类似结果。这些结果表明我们的估计不会丢失太多信息。

英文摘要

The relative entropy between two states is a key concept in quantum information theory and quantum field theory. In the setting of quantum field theory, its computation requires the handling of relative modular Hamiltonians, which are typically very difficult to compute explicitly. In this paper, we exploit locality properties of general algebraic QFTs to estimate relative modular Hamiltonians between two states, $ω$ and $\tildeω$, and hence also their relative entropy, in terms of the modular Hamiltonian of a reference state $\hatω$, which might be better understood. For suitable pairs of states we can estimate the relative modular Hamiltonian for the algebra of a region $V_2$ from above, resp. from below, in terms of the modular Hamiltonian of $\hatω$ on a larger region $V_3$, resp. a smaller region $V_1$. Pairs of states and choices of regions which are susceptible to our scheme are related to the presence of superluminal signalling in the sense of Sorkin's paradox. If $ω=\hatω$, then there exists a unitary that maps $ω$ to $\tildeω$ on $V_3$ and that does not allow superluminal signalling from the spacelike complement $V_3'$ to $V_2$, resp. from $V_1$ to $V_2'$, if our upper, resp. lower, bound applies. To investigate the strength of our estimates we consider coherent states for CCR systems, focussing particularly on free scalar fields. Our estimates apply even if the relative modular Hamiltonian cannot be computed exactly. For sufficiently regular excitations we recover an exact result by squeezing. Our method thus yields an independent proof for the relative entropy formula in cases where the relative modular Hamiltonian cannot be computed exactly. For massless fields we establish the analogous result also for double cone regions. These results indicate that our estimates do not lose too much information.

2605.27197 2026-05-27 math.QA math.RT

Representations of shifted twisted quantum affine algebras

平移扭曲量子仿射代数的表示

Fei-Fei Li, Jian-Rong Li, Yan-Feng Luo

AI总结 本文引入并研究平移扭曲量子仿射代数,通过平移Cartan-Drinfeld流给出其三角分解和分类,证明有理性和融合积,并分类有限维单模。

详情
AI中文摘要

本文引入并研究平移扭曲量子仿射代数,它们提供了平移量子仿射代数理论的扭曲对应。平移扭曲量子仿射代数 $\U_q^{\mu_+,\mu_-}(\hgs)$ 是通过根据余权对 $(\mu_+,\mu_-)$ 平移 Cartan-Drinfeld 流 $\phi_i^\pm(z)$ 从扭曲量子环代数的 Drinfeld 流表示中得到的。我们证明它允许三角分解,并且在同构意义下仅依赖于总平移 $\mu=\mu_+ + \mu_-$。对于每个平移 $\mu$,我们定义 $\U_q^\mu(\hgs) = \U_q^{0,\mu}(\hgs)$ 的表示范畴 $\mathcal O_\mu$,并证明 Cartan 流的有理性定理:在每个权空间上,两个流 $\phi_i^+(z)$ 和 $\phi_i^-(z)$ 是同一个有理算子值函数的展开,其次数由 $\alpha_i(\mu)$ 决定。作为推论,我们通过相应次数的有理 $\ell$-权对 $\mathcal O_\mu$ 的单对象进行分类。然后我们构造一个变形的 Drinfeld 余积,并用它定义范畴 $\mathcal O_\mu$ 的直和 $\mathcal{O}^{sh}$ 上的融合积。该融合积与 $q$-特征相容。我们还根据占优有理 $\ell$-权对 $\mathcal{O}^{sh}$ 中的有限维单模进行分类,其中 $A_{2n}^{(2)}$ 型单独处理。最后,我们构造限制表示,将扭曲量子仿射 Borel 代数的表示与平移扭曲量子仿射代数的表示联系起来,并建立平移扭曲量子仿射代数的有限维单表示的 $q$-特征公式,该公式用扭曲量子仿射 Borel 代数 $\U_q(\bs)$ 的相应单表示的 $q$-特征表示。

英文摘要

In this paper, we introduce and study shifted twisted quantum affine algebras which provide a twisted counterpart of the theory of shifted quantum affine algebras. The shifted twisted quantum affine algebra $\U_q^{μ_+,μ_-}(\hgs)$ is obtained from the Drinfeld current presentation of twisted quantum loop algebras by shifting the Cartan--Drinfeld currents $ϕ_i^\pm(z)$ according to a coweight pair $(μ_+,μ_-)$. We prove that it admits a triangular decomposition and that, up to isomorphism, they depend only on the total shift $μ=μ_+ + μ_-$. For each shift $μ$, we define a category $\mathcal O_μ$ of representations of $\U_q^μ(\hgs) = \U_q^{0,μ}(\hgs)$ and prove a rationality theorem for the Cartan currents: on every weight space, the two currents $ϕ_i^+(z)$ and $ϕ_i^-(z)$ are expansions of the same rational operator-valued function, whose degree is prescribed by $α_i(μ)$. As a consequence, we classify the simple objects of $\mathcal O_μ$ by rational $\ell$-weights of the corresponding degrees. We then construct a deformed Drinfeld coproduct and use it to define a fusion product on the direct sum $\mathcal{O}^{sh}$ of the categories $\mathcal O_μ$. This fusion product is compatible with $q$-characters. We also classify finite-dimensional simple modules in $\mathcal{O}^{sh}$ in terms of dominant rational $\ell$-weights, with a separate treatment of type $A_{2n}^{(2)}$. Finally, we construct restriction representations relating representations of twisted quantum affine Borel algebras to representations of shifted twisted quantum affine algebras, and establish a $q$-characters formula for simple finite-dimensional representations of shifted twisted quantum affine algebras in terms of the $q$-characters of the corresponding simple representations of the twisted quantum affine Borel algebra $\U_q(\bs)$.

2605.27196 2026-05-27 gr-qc astro-ph.CO

Hybrid Expansion Cosmology in f(T) Gravity: Late-Time Evolution and Observational Bounds

f(T)引力中的混合膨胀宇宙学:晚期演化与观测约束

Rajalakshmi Jena, Vishal M C, Sankarsan Tarai

AI总结 本研究在f(T)引力框架下,利用指数型f(T)函数形式,通过混合尺度因子建模宇宙从早期减速到当前加速膨胀的平滑过渡,并结合哈勃数据约束参数,验证了模型在精质区且渐近趋近ΛCDM。

Comments 16 pages, 8 figures

详情
AI中文摘要

本研究在teleparallel引力框架下,利用指数型f(T)函数形式,研究加速宇宙的宇宙学动力学。为了获得精确的宇宙学解,采用混合尺度因子来模拟宇宙从早期减速阶段到当前加速膨胀的平滑过渡。通过经典能量条件和宇宙学参数分析模型的物理一致性。利用31个哈勃数据点约束模型参数,我们发现得到的物质能量密度和压力演化与观测到的宇宙加速膨胀一致。诊断分析确认该模型保持在精质区,并渐近趋近ΛCDM情景。

英文摘要

This study investigates the cosmological dynamics of an accelerating universe within the framework of teleparallel gravity using an exponential f(T) functional form. To obtain exact cosmological solutions, a hybrid scale factor is employed to model the smooth transition from an early decelerated phase to the present accelerated expansion of the Universe. The physical consistency of the model is analyzed through classical energy conditions and cosmographic parameters. By constraining the model parameters using 31 Hubble data points, we find that the resulting matter-energy density and pressure evolution remain consistent with the observed cosmic acceleration. Diagnostic analysis confirms that the model remains within the quintessence regime and asymptotically approaches the ΛCDM scenario.

2605.27193 2026-05-27 cond-mat.str-el hep-th math-ph math.MP

Algebras of order parameters in one-dimensional spin systems

一维自旋系统中的序参量代数

Ameya Chavda, Clement Delcamp, Alex Turzillo, Minyoung You

AI总结 研究具有有限可逆或不可逆对称性的一维量子晶格模型中的序参量,通过张量网络方法证明弦序参量多重态在对称性范畴的Drinfel'd中心中组织成拉格朗日代数,并揭示其乘法规则在红外极限下扭曲扇区局域算符融合中的作用。

详情
AI中文摘要

我们研究具有有限可逆或不可逆对称性的一维量子晶格模型中的序参量。我们探究弦算符必须满足什么性质才能在给定的有能隙相中获得非零期望值。我们推导出弦序参量多重态在对称性范畴的Drinfel'd中心中组织成拉格朗日代数。特别地,我们强调乘法规则的作用,它控制着构成红外极限下弦算符的扭曲扇区局域算符的融合。我们的推导利用了张量网络方法对有能隙相进行分类,并将其重新表述为对称性范畴上的模范畴。在此框架内,有能隙相与自发对称性破缺的模式相关联,其中拓扑线的代数的Morita类在基态子空间中被保留。证明的关键是展示任何弦算符的期望值显式依赖于与拉格朗日代数相关的管代数模,该拉格朗日代数被实现为相应模范畴的全中心。最后,我们证明这些技术可以扩展到对称混合态的有能隙相。

英文摘要

We study order parameters in one-dimensional quantum lattice models with finite invertible or non-invertible symmetry. We investigate what properties a string operator must satisfy in order to acquire a non-vanishing expectation value in a given gapped phase. We deduce that multiplets of string order parameters organise into a Lagrangian algebra in the Drinfel'd centre of the symmetry category. In particular, we highlight the role of the multiplication rule as governing the fusion of the twisted sector local operators that constitute the string operator in the infrared limit. Our derivations exploit the tensor network approach to the classification of gapped phases and its reformulation in terms of module categories over the symmetry category. Within this framework, a gapped phase is associated with a pattern of spontaneous symmetry breaking wherein a Morita class of algebras of topological lines is preserved in the ground state subspace. The crux of the proof is to show that the expectation value of any string operator explicitly depends on the tube algebra module associated with the Lagrangian algebra, which is realised as the full centre of the corresponding module category. Finally, we demonstrate that these techniques extend to phases of symmetric mixed states.

2605.27192 2026-05-27 cs.LO cs.FL

Tree Automata Acceptance up to Measurable Defect

树自动机在可测量缺陷下的接受性

Anita Moyasari, Harsh Beohar, Charles Grellois, Clemens Kupke

AI总结 本文通过定义ε-接受博弈,将树自动机的接受性扩展到允许可测量缺陷预算,并证明树T被ε-接受当且仅当存在一棵传统意义上被接受的树T'且T'与T的双模拟距离不超过ε。

Comments 17 pages

详情
AI中文摘要

自动机接受性在多种感兴趣的情况下可以通过接受博弈以博弈论的方式捕获。验证者存在获胜策略则捕获了给定自动机在模型上存在获胜运行树。然而,这种接受性是刚性的,因为它不允许可测量的缺陷预算,这在软件验证中可能是一个挑战。在本文中,我们从如何将双模拟距离定义为双模拟性的扩展以定义ε-接受博弈中汲取灵感。我们的主要定理表明,一棵树T被ε-接受当且仅当存在一棵在传统(刚性)意义上被接受的树T',且T'与T的双模拟距离至多为ε。我们的工作还暗示了与测度论的紧密联系,我们通过适当的例子进行了初步探索。我们的框架定义在具有叶子和无限分支的二叉树上,并严格包含了将二叉节点视为概率选择且缺陷度量被拒绝分支集合的概率的情况。

英文摘要

Automata acceptance can, in several situations of interest, be captured game-theoretically via acceptance games. The existence of a winning strategy for Verifier then captures the existence of a winning run-tree of a given automaton over a model. However, such acceptance is rigid, in that it does not allow a measurable defect budget, which can be a challenge in software verification. In this paper, we draw inspiration from how bisimulation distance can be defined as an extension of bisimilarity to define epsilon-acceptance games. Our main theorem shows that a tree T is epsilon-accepted iff there is a tree T' that is accepted in the traditional (rigid) sense and the bisimulation distance of T' and T is at most epsilon. Our work also suggests a strong connection with measure theory, of which we give a preliminary exploration via appropriate examples. Our framework is defined over binary trees with leaves and infinite branches, and strictly contains the case in which binary nodes are seen as probabilistic choice and the defect measures the probability of the set of rejected branches.

2605.27191 2026-05-27 quant-ph eess.SP math.OC

Statistical and Algorithmic Foundations of Probing Quantum Systems with Compressive Measurements: A Review

压缩测量探测量子系统的统计与算法基础:综述

Zhen Qin, Michael B. Wakin, Zhihui Zhu

AI总结 本文综述了结构化量子态层析成像的统一视角,涵盖紧凑态表示、测量设计和计算算法,并探讨了样本复杂度、测量效率和可扩展恢复的理论基础。

详情
AI中文摘要

量子态层析成像(QST)是量子信息科学中的一项基本任务,旨在从测量数据中重建未知量子态。然而,希尔伯特空间维度随系统大小呈指数增长,使得一般量子态的全层析成像在统计和计算上变得不可行。这一挑战推动了结构化量子态层析成像的广泛研究,其中先验结构(如低秩性、张量网络表示、浅量子电路和神经量子态)可以显著减少有效自由度,并实现可扩展恢复。在本综述中,我们通过三个密切相关的主题为结构化量子态的QST提供了统一视角:紧凑态表示、测量设计和计算算法。在回顾结构化量子态的常见模型后,我们调查了测量框架的几何保持性质方面的现有工作,范围从信息完备的POVM到随机测量,及其对样本复杂度的影响。在算法方面,我们回顾了从经验测量中重建结构化量子态的优化方法。通过将QST与压缩感知、矩阵感知和结构化逆问题的更广泛原理联系起来,本综述强调了样本复杂度、测量效率和可扩展恢复背后的共同理论基础。

英文摘要

Quantum state tomography (QST) is a fundamental task in quantum information science that aims to reconstruct unknown quantum states from measurement data. However, the exponential growth of Hilbert-space dimension with system size makes full tomography of general quantum states statistically and computationally prohibitive. This challenge has motivated extensive research on structured quantum state tomography, where prior structure, such as low-rankness, tensor-network representations, shallow quantum circuits, and neural quantum states, can substantially reduce the effective degrees of freedom and enable scalable recovery. In this review, we provide a unified perspective on QST for structured quantum states through three closely related themes: compact state representations, measurement design, and computational algorithms. After reviewing common models for structured quantum states, we survey existing work on geometric preservation properties of measurement frameworks, ranging from informationally complete POVMs to randomized measurements, and their implications for sample complexity. On the algorithmic side, we review optimization methods for reconstructing structured quantum states from empirical measurements. By connecting QST with broader principles from compressive sensing, matrix sensing, and structured inverse problems, this survey highlights common theoretical foundations underlying sample complexity, measurement efficiency, and scalable recovery.

2605.27188 2026-05-27 math.AG

Vanishing of cohomology in infinitely ramified towers

无限分岔塔中上同调的消失

Bhargav Bhatt

AI总结 本文通过使用近旁周期的反常性(全局形式),给出了Esnault关于射影空间的“模拟”Frobenius覆盖塔中可构造层的上同调消失结果的新证明。

Comments Uploading this 2020 preprint for ease of reference; to appear in a Simons Symposium Proceedings

详情
AI中文摘要

我们给出了Esnault关于射影空间的“模拟”Frobenius覆盖塔中可构造层的上同调消失结果的新证明。关键思想是使用近旁周期的(全局形式的)反常性。

英文摘要

We give a new proof of vanishing result of Esnault for the cohomology of constructible sheaves in the tower of ``mock'' Frobenius covers of projective space. The key idea is to use (a global form of) the perversity of nearby cycles.

2605.27187 2026-05-27 cond-mat.mes-hall

Overcoming contact resistance at metal-2D semiconductor interfaces: atomically clean MoS2/Au ohmic junctions

克服金属-二维半导体界面的接触电阻:原子级清洁的MoS2/Au欧姆结

Rafal Dunal, Maxime Le Ster, Iaroslav Lutsyk, Michal Piskorski, Pawel Dabrowski, Pawel Krukowski, Witold Kozlowski, Aleksandra Nadolska, Wojciech Rys, Pawel J. Kowalczyk, Maciej Rogala

AI总结 通过超高真空下剥离的MoS2/Au结实验证明,本征界面是高度导电的欧姆接触,接触电阻高源于界面污染,并提出了力辅助层压恢复欧姆接触的方法。

详情
AI中文摘要

二维半导体(如单层MoS2)的应用受到高接触电阻的限制,这通常归因于金属接触处的界面势垒。此外,电导率对MoS2厚度的依赖性仍不确定,因为文献中报道了随层数增加而增加和减少的趋势。通过展示在超高真空和大气条件下在Au上剥离的单层和多层MoS2的电输运对比,我们实验证明,与文献中的主流观点相反,本征MoS2/Au结具有高导电性并表现出欧姆行为。我们的结果表明,界面污染是导致迄今为止报道的高接触电阻的原因,并影响电输运的厚度依赖性,解释了文献中观察到的差异。我们通过电输运模拟合理化了这些发现。最后,我们表明,在轻度污染的接触上施加局部力介导的层压可以恢复原始的欧姆接触,为纳米尺度图案化提供了一条途径。

英文摘要

The application of two-dimensional (2D) semiconductors, such as monolayer MoS2, is limited by the high contact resistance commonly attributed to interfacial barriers at metal contacts. Furthermore, the dependence of electrical conductivity on MoS2 thickness is still unsettled, as both increasing and decreasing trends with layer number have been reported. By showing the contrast between electrical transport of mono- and multilayer MoS2 exfoliated on Au under ultra-high vacuum (UHV) and ambient conditions, we experimentally prove that, contrary to the prevailing view in the literature, the intrinsic MoS2/Au junction is highly conductive and exhibits ohmic behaviour. Our results indicate that interfacial contamination is responsible for the high contact resistances reported to date and affects the thickness dependence of electrical transport, explaining the discrepancies observed in the literature. We rationalize those findings using electrical transport simulations. Lastly, we show that local force-mediated lamination on lightly contaminated contacts can recover pristine, ohmic contacts, offering a route towards nanoscale patterning.

2605.27184 2026-05-27 stat.ME stat.AP

Posterior Quantification of Borrowing from Multiple Historical Control Data in Bayesian Dynamic Borrowing Methods: A Scoping Review

贝叶斯动态借用方法中从多个历史对照数据借用的后验量化:一项范围综述

Tomohiro Ohigashi, Wataru Murasaki, Masahiko Gosho

AI总结 本文通过范围综述,聚焦贝叶斯动态借用方法中从多个历史对照借用的后验量化,区分了整体和源级别的借用度量,并通过案例展示了不同方法在借用总量和源特异性模式上的差异。

详情
AI中文摘要

贝叶斯动态借用方法将历史对照数据纳入当前临床试验分析,同时允许借用程度取决于历史数据与当前数据之间的兼容性。尽管已提出许多方法,但借用程度通常难以解释,尤其是当存在多个历史对照来源时。本范围综述聚焦于从多个历史对照借用的后验量化。我们讨论了基于有效历史样本量的整体借用摘要,以及源自幂先验、单位信息先验、多源可交换模型、狄利克雷过程混合模型和潜在偏倚模型的方法特异性源级别借用、信息贡献或兼容性摘要。我们将后验借用度量与描述先验信息分配或源特异性冲突的量区分开来。两个案例研究(一个二元终点,一个连续终点)表明,具有相似后验处理效应估计的方法可能在借用的整体数量和源特异性模式上有所不同。这些例子显示,较大的整体借用可能反映从兼容历史源的选择性借用,而非均匀地从所有源借用。我们建议在可能的情况下报告处理效应估计以及整体和源特异性借用摘要,以提高后验推断的透明度。

英文摘要

Bayesian dynamic borrowing methods incorporate historical control data into current clinical trial analyses while allowing the degree of borrowing to depend on the compatibility between historical and current data. Although many methods have been proposed, the degree of borrowing is often difficult to interpret, especially when multiple historical control sources are available. This scoping review focuses on posterior quantification of borrowing from multiple historical controls. We discuss overall borrowing summaries based on effective historical sample size, together with method-specific source-level summaries of borrowing, information contribution, or compatibility arising from power priors, unit information priors, multisource exchangeability models, Dirichlet process mixture models, and potential bias models. We distinguish posterior borrowing measures from quantities describing prior information allocation or source-specific conflict. Two case studies, one with a binary endpoint and one with a continuous endpoint, illustrate that methods with broadly similar posterior treatment effect estimates may differ in both the overall amount and source-specific pattern of borrowing. These examples show that large overall borrowing may reflect selective borrowing from compatible historical sources rather than uniform borrowing from all sources. We recommend reporting treatment effect estimates together with overall and source-specific borrowing summaries, when available, to improve transparency in posterior inference.

2605.27183 2026-05-27 math.CO cs.FL

$2$-word-$π$-representable Graphs

$2$-word-$\pi$-可表示图

Duncan Adamson, Amanita Dietz, Pamela Fleischmann, Annika Huch, Silas Cato Sacher

AI总结 本文提出$2$-word-$\pi$-可表示图的概念,证明所有图均可由此表示,并给出构造算法,同时探讨置换图与余图的相关性质。

详情
AI中文摘要

本文研究了$2$-word-$\pi$-可表示图的新概念:图的节点对应于两个单词的字母,如果两个单词中任意两个字母的投影相等,则节点之间存在边。与Kitaev和Pyatkin引入的仅使用一个单词进行表示相比,使用两个单词的好处是每个图都是$2$-word-$\pi$-可表示的。我们提出了一种算法,可以为任意图返回两个表示单词。此外,我们证明了每个置换图都可以由两个$1$-均匀单词表示,并给出了如何在表示单词上实现$2$-word-$\pi$-可表示图的图运算的构造,这进一步揭示了余图的表示。

英文摘要

This paper investigates the new notion of $2$-word-$π$-repre\-sentable graphs: the nodes of the graph correspond to the letters of the two words and there exists an edge between two nodes if the projections of any two letters of both words are equal. The benefit of not only using one word for a representation as introduced by Kitaev and Pyatkin is that every graph is $2$-word-$π$-representable. We present an algorithm that returns two representing words for any graph. Aside, we show that every permutation graph is representable by two $1$-uniform words and give constructions how graph operations on $2$-word-$π$-representable graphs can be realised on their representing words which give further insights into the representation of cographs.

2605.27182 2026-05-27 q-fin.PR q-fin.CP

Deep Least Squares Monte Carlo methods for the valuation of variable annuities with guarantees

深度最小二乘蒙特卡洛方法用于含保证条款的变额年金估值

Nicolas Langrené, Xiaolin Luo, Pavel V. Shevchenko, Ruiyi Zhang

AI总结 本文修改最小二乘蒙特卡洛算法,使其能直接用于含最优退保策略的变额年金定价,并比较多项式回归与神经网络回归在随机利率下的表现,发现深度LSMC在高维问题中更稳定鲁棒。

Comments 26 pages

详情
AI中文摘要

通常,含保证条款的变额年金定价可以通过求解相应的最优随机控制问题来完成,前提是假设合同退保策略是最优的。这通常作为动态规划问题使用确定性网格方法求解,但当状态变量超过几个时,计算变得不可行。在这种情况下,需要依赖模拟方法。过去几十年,最小二乘蒙特卡洛(LSMC)方法已成为量化金融中求解最优随机控制问题的流行模拟方法。原则上,最初为定价百慕大期权而开发的LSMC不能直接用于定价变额年金,除非进行简化假设,因为基础状态变量受控制决策影响。本文提出了LSMC算法的修改,使得一般变额年金的定价变得可行。在数值示例中,我们获得了在最优退保策略下具有保证最低提领利益的变额年金的定价,分别考虑了随机利率和非随机利率的情况,并在LSMC算法中使用多项式回归或神经网络回归。我们发现,经典的多项式LSMC可以给出非常精确的价格,但需要手动特征工程,并且当利率变为随机时,估计量的标准差大大增加。相比之下,神经网络LSMC给出的价格略欠精确,需要更多训练时间,但不需要手动特征工程,并且使利率随机化对其精度没有明显影响,表明深度LSMC在高维定价问题中具有更稳定和鲁棒的定价性能。

英文摘要

In general, the pricing of variable annuities with guarantees can be done by solving the corresponding optimal stochastic control problem if the contract withdrawal strategy is assumed to be optimal. This is typically solved as a dynamic programming problem using deterministic grid methods, which become computationally infeasible for more than a few state variables. In such situations, one needs to rely on simulation methods. The least-squares Monte Carlo (LSMC) method has become a popular simulation method for solving optimal stochastic control problems in quantitative finance over the last decades. In principle, the LSMC, originally developed for pricing Bermudan options, cannot be used directly for pricing variable annuities without simplifying assumptions because the underlying state variables are affected by the control decisions. This paper presents modifications of the LSMC algorithm that makes the pricing of general variable annuities feasible. For numerical illustrations, the pricing of variable annuities with guaranteed minimum withdrawal benefit under optimal withdrawal strategies is obtained with and without stochastic interest rates, using either polynomial regression or neural network regression in the LSMC algorithm. We found that the classical polynomial LSMC can give very accurate prices, at the cost of manual feature engineering, and with a standard deviation of the estimator that increases greatly when interest rates are made stochastic. By contrast, neural network LSMC gives slightly less accurate prices, requires more training time, but does not require manual feature engineering, and making interest rates stochastic makes no visible difference to its accuracy, suggesting a more stable and robust pricing performance of deep LSMC for higher-dimensional pricing problems.

2605.27181 2026-05-27 cond-mat.mes-hall cond-mat.str-el

Microwave-driven Floquet-Fano interference in a ring-chord quantum dot structure for enhanced spin-caloritronic performance

微波驱动的Floquet-Fano干涉在环弦量子点结构中增强自旋热电子性能

Parbati Senapati, Kalpataru Pradhan

AI总结 研究微波驱动下环弦几何四量子点纳米结构中的Floquet-Fano干涉,通过非平衡格林函数和Floquet理论,实现ZT≈12和自旋热电优值Z_sT≈18的高性能。

Comments 17 pages, 12 figures

详情
AI中文摘要

我们研究了与铁磁引线耦合的四量子点纳米结构(具有环和环弦几何)中的光子辅助热电输运。重点关注微波诱导的Floquet边带与几何驱动的Fano干涉之间的相互作用,我们采用非平衡格林函数形式结合Floquet理论和线性响应区域内电子-电子相互作用的自洽Hartree处理。连接引线耦合点的纵向量子点间弦的引入引入了一个离散的干涉路径,与环介导的连续态竞争,产生显著的Fano共振。微波辐照通过光子吸收和发射过程动态重塑这些共振,实现对电导、热电功率和电子热导的可调控制。定量上,在中间温度$T=0.3\Gamma_0$(其中$\Gamma_0$表示点-引线耦合强度)下,微波驱动的环弦几何表现出优异的热电优值ZT $\approx$ 12和最佳的效率-功率权衡,达到卡诺效率的近$62\%$,输出功率为$6.24~\mathrm{fW}$。关键的是,来自引线的自旋极化注入和点内塞曼分裂的结合在此Floquet-Fano干涉中诱导出稳健的自旋依赖性。这种协同相互作用导致增强的自旋塞贝克响应和最大自旋热电优值接近$Z_sT \approx 18$。我们的研究结果确立了微波驱动的Fano干涉工程作为调节多量子点器件中自旋热电子行为的有效策略。

英文摘要

We investigate photon-assisted thermoelectric transport in four--quantum-dot nanostructures featuring ring and ring--chord geometries coupled to ferromagnetic leads. Focusing on the interplay between microwave-induced Floquet sidebands and geometry-driven Fano interference, we employ the nonequilibrium Green's function formalism combined with Floquet theory and a self-consistent Hartree treatment of electron-electron interactions within the linear response regime. The inclusion of a longitudinal interdot chord bridging the lead-coupled dots introduces a discrete interference pathway that competes with the continuum of ring-mediated states, giving rise to pronounced Fano resonances. Microwave irradiation dynamically reshapes these resonances through photon absorption and emission processes, enabling tunable control of electrical conductance, thermopower, and electronic thermal conductance. Quantitatively, at an intermediate temperature of $T=0.3Γ_0$ (where $Γ_0$ denotes the dot-lead coupling strength), the microwave-driven ring-chord geometry exhibits an exceptional thermoelectric figure of merit of ZT $\approx$ 12 and an optimal efficiency--power trade-off, reaching nearly $62\%$ of the Carnot efficiency with an output power of $6.24~\mathrm{fW}$. Crucially, the combination of spin-polarized injection from the leads and Zeeman splitting within the dots induces a robust spin-dependence within this Floquet--Fano interference. This cooperative interplay results in an enhanced spin Seebeck response and a maximum spin thermoelectric figure of merit of nearly $Z_sT \approx 18$. Our findings establish microwave-driven engineering of Fano interference as an effective strategy for modulating spin-caloritronic behavior in multi-quantum-dot devices.

2605.27179 2026-05-27 cond-mat.supr-con quant-ph

Impact of Stoichiometry of MoSi Thin Films for Enhanced Sensitivity of Superconducting Nanowire Single-Photon Detectors

MoSi薄膜化学计量比对超导纳米线单光子探测器灵敏度增强的影响

Stefanie Grotowski, Damjan Pecijareski, Hadrien Le Petit Delacour, Lucio Zugliani, Fabian Wietschorke, Christian Schmid, Stefan Strohauer, Matthias Althammer, Rudolf Gross, Kai Müller, Jonathan Finley

AI总结 研究MoSi薄膜化学计量比对超导纳米线单光子探测器性能的影响,发现临界温度、薄层电阻与厚度的普适标度行为,并确定Mo0.53Si0.47薄膜在5.4 nm厚度下具有最高灵敏度。

详情
AI中文摘要

我们报道了超导MoSi薄膜的化学计量比对超导纳米线单光子探测器(SNSPDs)性能的影响。具体地,我们研究了薄膜参数临界温度Tc、薄层电阻Rs和超导体厚度d之间的关系,并观察到普适标度行为。为了评估由不同化学计量比薄膜制成的SNSPD的性能,我们在探测器被波长为780 nm至1550 nm的光照射时测量了偏压相关的计数率曲线。不同纳米线宽度的探测器性能随光子能量的变化揭示了探测电流与光子能量之间的线性关系。此外,我们通过测量SNSPD的回流电流确定了超导薄膜与衬底之间的界面热边界电导β,并发现β随Mo浓度的增加而增加。在所有比较的器件中,Mo0.53Si0.47薄膜(厚度5.4 nm,低Tc为4.1 K,高Rs为397 Ω/sq)实现了最高灵敏度。

英文摘要

We report on the impact of the stoichiometry of superconducting MoSi thin films on the performance of superconducting nanowire single-photon detectors (SNSPDs). Specifically, we investigate the relation between the film parameters critical temperature Tc , sheet resistance Rs and superconductor thickness d and observe a universal scaling behavior. To benchmark the performance of SNSPDs fabricated from films having different stoichiometry, we measure the bias dependent count rate curves, while the detector is illuminated with wavelengths between 780 nm and 1550 nm. The detector performance as a function photon energy for different nanowire widths reveals a linear relation between the detection current and the photon energy. Furthermore, we determine the interfacial thermal boundary conductance $β$ between the superconducting thin film and the substrate, by measuring the return current of the SNSPD and find an increase of $β$ with increasing Mo concentration. The highest sensitivity amongst all compared devices is achieved for Mo$_{0.53}$Si$_{0.47}$, with low Tc (4.1 K) and high Rs (397$Ω$/sq) at a film thickness of 5.4 nm.

2605.27177 2026-05-27 astro-ph.GA physics.chem-ph

Digging into the Massive Protostar S255IR NIRS3: A Study of Nitrogen-Bearing Molecules and Their Prebiotic Chemistry

深入探索大质量原恒星S255IR NIRS3:含氮分子及其前生物化学研究

Arijit Manna, Sabyasachi Pal, Tapas Baug, Ariful Hoque, Sandip Dutta, Sekhar Sinha, Sushanta Kumar Mondal

AI总结 利用ALMA波段4观测,识别了S255IR NIRS3中多种含氮分子的转动发射线,通过LTE谱线建模导出柱密度和激发温度,并讨论了其形成路径。

Comments Published in The Astronomical Journal (AJ)

详情
Journal ref
AJ, Volume 368, Page 171, 2026
AI中文摘要

复杂含氮分子的研究对于探测恒星形成区域的物理和化学演化至关重要。本文利用ALMA波段4观测,在大质量原恒星S255IR NIRS3中识别了多种复杂含氮物种的转动发射线,如甲基氰(CH$_{3}$CN)、乙基氰(C$_{2}$H$_{5}$CN)、乙烯基氰(C$_{2}$H$_{3}$CN)、氰胺(NH$_{2}$CN)和甲酰胺(NH$_{2}$CHO)。此外,还检测到了氰基乙炔(HC$_{3}$N,$ν_{7}$ = 2)的振动激发跃迁。通过LTE谱线建模导出了这些分子的柱密度和激发温度,激发温度范围为175$-$220 K。高激发温度(175$-$220 K)表明所识别的含氮分子来源于源内温暖的内区($T \geq 100$ K)。进一步估算了相对于H$_{2}$、CH$_{3}$OH和CH$_{3}$CN的丰度分数。丰度的皮尔逊相关热图显示,氰化物家族中的三种分子(如CH$_{3}$CN、C$_{2}$H$_{3}$CN和C$_{2}$H$_{5}$CN)之间存在强正相关($r > 0.7$),表明这些含氮分子可能存在化学联系。与三相升温化学模型的比较表明,观测到的CH$_{3}$CN、C$_{2}$H$_{5}$CN、C$_{2}$H$_{3}$CN、NH$_{2}$CN、NH$_{2}$CHO和HC$_{3}$N($ν_{7}$ = 2)相对于H$_{2}$的丰度与模型预测在因子1.04、0.67、1.28、0.76、0.72和0.96内一致。最后,我们讨论了在S255IR NIRS3的气-粒化学背景下所识别含氮分子的潜在形成路径。

英文摘要

The study of complex nitrogen (N)-bearing molecules is essential for probing the physical and chemical evolution of star-forming regions. In this paper, we present the identification of rotational emission lines from several complex N-bearing species such as methyl cyanide (CH$_{3}$CN), ethyl cyanide (C$_{2}$H$_{5}$CN), vinyl cyanide (C$_{2}$H$_{3}$CN), cyanamide (NH$_{2}$CN), and formamide (NH$_{2}$CHO) toward the high-mass protostar S255IR NIRS3 using ALMA band 4 observations. In addition, the vibrationally excited transitions of cyanoacetylene (HC$_{3}$N, $ν_{7}$ = 2) were detected. The column densities and excitation temperatures of these molecules were derived through LTE spectral modelling, yielding excitation temperatures in the range of 175$-$220 K. The high excitation temperatures (175$-$220 K) indicate that the identified N-bearing molecules arise from the warm inner regions ($T \geq 100$ K) of the source. The fractional abundances were further estimated relative to H$_{2}$, CH$_{3}$OH, and CH$_{3}$CN. A Pearson correlation heat map of the abundances reveals a strong positive correlation ($r > 0.7$) among three molecules in the cyanide family, such as CH$_{3}$CN, C$_{2}$H$_{3}$CN, and C$_{2}$H$_{5}$CN, suggesting that these N-bearing molecules may be chemically linked. Comparison with three-phase warm-up chemical models shows that the observed abundances of CH$_{3}$CN, C$_{2}$H$_{5}$CN, C$_{2}$H$_{3}$CN, NH$_{2}$CN, NH$_{2}$CHO, and HC$_{3}$N ($ν_{7}$ = 2) relative to H$_{2}$ are consistent with model predictions within factors of 1.04, 0.67, 1.28, 0.76, 0.72, and 0.96, respectively. Finally, we discuss the potential formation pathways of the identified N-bearing molecules in the context of gas-grain chemistry within S255IR NIRS3.

2605.27175 2026-05-27 math.OC math.AP math.FA

Polyak-Lojasiewicz Inequality for Quadratically Regularized Optimal Transport

二次正则化最优传输的Polyak-Lojasiewicz不等式

Alberto González-Sanz, Marcel Nutz, Andrés Riveros Valdevenito

AI总结 针对二次正则化最优传输对偶问题,在温和假设下证明了局部误差界和Polyak-Lojasiewicz不等式,并推导出梯度上升等算法的线性收敛速率。

Comments To appear in 'SIAM Journal on Optimization'

详情
AI中文摘要

二次正则化最优传输(QOT)是熵正则化的一种替代方案,它产生稀疏耦合,并避免由于指数缩放导致的数值不稳定性。从优化角度看,对偶QOT目标是凹的,但具有一个正部函数,这阻止了强凹性并降低了优化器的光滑性。因此,算法的线性收敛的标准论证不适用。在本文中,我们仍然为QOT对偶建立了一个定量曲率性质。在涵盖连续和半离散传输问题的温和假设下,我们证明了一个局部误差界和一个Polyak-Lojasiewicz(PL)不等式,其显式常数仅依赖于问题原始数据。这些结果是通过泛函分析技术获得的,利用了在最优解附近,正部函数的自变量在最优耦合支撑的内部为正。作为应用,我们在对偶问题上推导了梯度上升、坐标上升和坐标梯度上升算法的线性收敛,并给出了显式收缩率。

英文摘要

Quadratically regularized optimal transport (QOT) is an alternative to entropic regularization that yields sparse couplings and avoids numerical instabilities due to exponential scaling. From an optimization viewpoint, the dual QOT objective is concave but features a positive part function which prevents strong concavity and reduces smoothness of optimizers. Consequently, standard arguments for linear convergence of algorithms do not apply. In this paper, we nevertheless establish a quantitative curvature property for the QOT dual. Under mild assumptions covering both continuous and semi-discrete transport problems, we prove a local error bound and a Polyak-Lojasiewicz (PL) inequality, with explicit constants depending only on the problem primitives. These results are obtained by functional-analytic techniques exploiting that near the optimum, the argument of the positive part function is positive on the interior of the support of the optimal coupling. As applications, we derive linear convergence of the gradient ascent, coordinate ascent, and coordinate gradient ascent algorithms on the dual problem, with explicit contraction rates.

2605.27173 2026-05-27 math.CO

Sufficient conditions for fractional $k$-factor-critical graphs with minimum degree to be $k$-factor-critical

最小度分数 $k$-因子临界图成为 $k$-因子临界的充分条件

Jiaxu Zhong, Yong Lu

AI总结 研究在最小度条件下,具有分数 $k$-因子临界性的图成为 $k$-因子临界的充分条件,通过边数下界和谱半径条件推广了已有结果。

详情
AI中文摘要

一个图 $G$ 称为 $k$-因子临界的,如果删除任意 $k$ 个顶点后,剩余子图仍有一个完美匹配。Fan 和 Lin [Adv. in Appl. Math. 174 (2026) 103019] 提出了一个关于最小度图成为 $k$-因子临界的邻接谱条件。一个图 $G$ 称为分数 $k$-因子临界的,如果删除任意 $k$ 个顶点后,剩余子图仍有一个分数完美匹配。显然,图的分数 $k$-因子临界性是图成为 $k$-因子临界的一个必要条件。Jia, Fan 和 Liu [Discrete Appl. Math. 386 (2026) 255-263] 提出了一个关于谱半径的紧的充分条件,使得具有分数 $k$-因子临界性的图成为 $k$-因子临界。一个自然的问题是:我们能否通过引入图的最小度参数来推导类似的充分条件? 我们首先建立了一个边数的下界,以确保一个具有分数 $k$-因子临界性的 $(k+1)$-连通图是 $k$-因子临界的,其中 $k$ 是正整数且 $k\geq1$。此外,我们给出了一个关于谱半径的充分条件,使得具有分数 $k$-因子临界性的 $(k+1)$-连通图成为 $k$-因子临界。我们的结果将 Jia, Fan 和 Liu 的结果推广到了 $(k+1)$-连通图。此外,与 Fan 和 Lin 以及 Jia 等人的结果相比,我们的谱条件适用于更广泛的连通图族。

英文摘要

A graph $G$ is called $k$-factor-critical if after deleting any $k$ vertices the remaining subgraph still has a perfect matching. Fan and Lin [Adv. in Appl. Math. 174 (2026) 103019] posed an adjacency spectral condition for a graph with minimum degree to be $k$-factor-critical. A graph $G$ is fractional $k$-factor-critical if after deleting any $k$ vertices the remaining subgraph still has a fractional perfect matching. Clearly, the fractional $k$-factor-criticality of a graph is a necessary property for a graph to be $k$-factor-critical. Jia, Fan and Liu [Discrete Appl. Math. 386 (2026) 255-263] proposed a tight sufficient condition in terms of the spectral radius for a graph with fractional $k$-factor-criticality to be $k$-factor-critical. A natural question arises: can we derive analogous sufficient conditions by incorporating the minimum degree parameter of graphs? We first establish a lower bound on the size to ensure that a $(k+1)$-connected graph with fractional $k$-factor-criticality is $k$-factor-critical, where $k$ is a positive integer with $k\geq1$. Moreover, we provide a sufficient condition in terms of the spectral radius for a $(k+1)$-connected graph with fractional $k$-factor-criticality to be $k$-factor-critical. Our results generalize the result of Jia, Fan and Liu to $(k+1)$-connected graphs. Furthermore, our spectral conditions apply to a broader family of connected graphs compared with the results of Fan and Lin, as well as Jia et al.

2605.27172 2026-05-27 math.ST math.PR stat.TH

Convergence Rates of Ordering, Testing and Estimation Procedures for Graphons With Fast Boundary Decay Rates

具有快速边界衰减率的图收敛排序、检验和估计的收敛速度

Jeannette Janssen, Na Lin, Aaron Smith

AI总结 针对潜在空间为[0,1]的潜在位置随机图模型,研究了顶点排序、图估计和模型检验三个问题,证明了排序估计在某些图族上可达到快于1/√n的收敛速度,并提出了计算高效的图估计算法。

Comments 47 pages, 2 figures

详情
AI中文摘要

在潜在位置随机图模型(LPM)中,潜在顶点位置$U_{1},\ldots,U_{n}$从潜在空间$\Omega$上的某个分布中采样,然后观测图$G = ([n],E)$的边以依赖于未观测潜在位置的概率$\mathbb{P}[(i,j) \in E ]=w(U_i,U_j)$进行采样。LPM在网络统计分析中无处不在,提供了具有良好经验性能、强理论保证和可处理算法的模型。特殊情况$\Omega= [0,1]$很重要,因为它对应于具有时间或偏好结构的图。本文研究了潜在空间为$[0,1]$的LPM相关的三个问题:根据潜在位置对顶点进行 extit{排序}, extit{估计}生成图$w$,以及 extit{检验}观测图$G$是否可能来自状态空间为$[0,1]$的LPM。关于排序问题的结果大大推广了Janssen/Smith (2022)的两个观察:(i) 对于 extit{某些}图族,排序的最佳估计收敛速度远快于通常的统计速率$\frac{1}{\sqrt{n}}$,并且(ii) 即使对于相同的图族,潜在位置的最佳估计仍然以通常的$\frac{1}{\sqrt{n}}$速率发生。作为主要结果,我们开发了一种计算高效的图估计算法,并证明其具有与Gao等人(2015)的非显式最优算法相同的收敛速度。我们还推导并分析了一个检验程序。

英文摘要

In latent-position random graph models (LPMs), latent vertex positions $U_{1},\ldots,U_{n}$ are sampled from some distribution on a latent space $Ω$, then edges of an observed graph $G = ([n],E)$ are sampled with some probability $\mathbb{P}[(i,j) \in E ]=w(U_i,U_j)$ that depends on the unobserved latent positions. LPMs are ubiquitous in the statistical analysis of networks, offering models that have good empirical performance, strong theoretical guarantees, and tractable algorithms. The special case $Ω= [0,1]$ is important, as it corresponds to graphs with temporal or preference-based structure. In this paper, we study three problems related to LPMs with latent space $[0,1]$: \textit{ordering} the vertices according to the latent positions, \textit{estimating} the generating graphon $w$, and \textit{testing} whether an observed graph $G$ could have come from an LPM with state space $[0,1]$. Our results on the ordering problem greatly generalize two observations of Janssen/Smith (2022): (i) for \textit{some} families of graphons, the best estimate of the ordering converges much faster than the usual statistical rate of $\frac{1}{\sqrt{n}}$, and (ii) this occurs even though, for the same families of graphons, the best estimate of the latent positions still occurs at the usual $\frac{1}{\sqrt{n}}$ rate. As a main consequence, we develop a computationally-efficient graphon-estimation algorithm and show that it has the same convergence rate as the non-explicit optimal algorithm of Gao et al (2015). We also derive and analyze a testing procedure.

2605.27171 2026-05-27 cs.CY cs.DB

Faults and Pitfalls in Implementing the Right to be Forgotten

实施被遗忘权的缺陷与陷阱

Chen Sun, Nikolas Guggenberger, Supreeth Shastri

AI总结 本文从计算角度识别支持被遗忘权(RTBF)的不确定性和风险,提出两阶段方法弥合法律与计算之间的固有二分法,通过将RTBF能力引入Elasticsearch展示其可避免80%的GDPR违规,并发现六种长期存在的反模式。

详情
Journal ref
Communications of the ACM 69(6), 2026
AI中文摘要

被遗忘权(RTBF)是最古老且最突出的合法数据权利之一。尽管其法律意图直截了当(例如,GDPR仅用417个词描述),但计算社区发现其在实践中实施具有挑战性。例如,在GDPR实施的头五年内,监管机构发布了205次RTBF违规,即平均每9天发生一次RTBF失败。在这项工作中,我们从计算角度识别了支持RTBF的不确定性和风险。然后,为了缓解这些挑战,我们提出了一种两阶段方法,弥合法律与计算之间的内在二分法。我们通过展示该方法如何完全避免GDPR第6年发生的80%的RTBF违规,证明了其有效性。我们还发现了六种长期存在的计算和数据管理实践,这些实践已成为RTBF的反模式。最后,为了将我们的研究落地,我们将RTBF能力引入Elasticsearch,一个流行的开源搜索引擎。

英文摘要

Right to be Forgotten (RTBF) in one of the oldest and prominent of the legal data rights. While its legal intention is straight forward (for example, the GDPR describes it in just 417 words), the computing community has found it challenging to implement this in practice. For example, regulators have issued 205 RTBF violations in the first five years of GDPR i.e., an RTBF failure once every 9 days, on average. In this work, we identify the uncertainties and risks in supporting RTBF from a computing perspective. Then, to mitigate these challenges, we propose a two-phase approach that bridges an intrinsic dichotomy between law and computing. We demonstrate the effectiveness of our technique by showing how it could have fully avoided 80% of RTBF violations that occurred in the year-6 of GDPR. We also discover six long-standing practices of computing and data management that have become anti-patterns for RTBF. Finally, to ground our research, we introduce RTBF capability into Elasticsearch, a popular open-source search engine.

2605.27170 2026-05-27 astro-ph.HE

Regular black hole solutions and the quark chemical potential at the QCD phase transition

正则黑洞解与QCD相变时的夸克化学势

G. Lambiase, A. Ovgun, V. Vertogradov

AI总结 本文通过耦合两种有效状态方程到球对称几何,研究有限夸克化学势下的QCD物质能否在引力坍缩中动态支持正则黑洞内部,发现化学势本身无法提供自正则化黑洞核心。

Comments 21 pages, 9 figures

详情
AI中文摘要

受文献[1,2]启发,我们研究了有限夸克化学势下,量子色动力学(QCD)启发的物质在引力坍缩过程中能否动态支持正则黑洞内部。为此,我们将两种有效状态方程——即有限温度和化学势下的三味手征夸克模型以及具有动态胶子质量的冷QGP平均场模型——耦合到球对称的先进Eddington–Finkelstein几何中。物质源被视为有效各向异性流体。我们并未先验地假设正则质量分布,而是从局部守恒定律确定径向温度依赖性,并从爱因斯坦方程重建质量函数。在手征模型中,守恒方程允许精确的Lambert函数解,但物理系数选择了近中心奇异分支。在冷QGP模型中,精确的隐式温度-半径关系导致温度在中心附近发散,使得热力学源项和重建的质量函数与正则中心条件不相容。因此,我们发现在本文采用的有效框架内,有限夸克化学势重塑了坍缩相的热力学,但本身并未提供自正则化的黑洞核心。任何正则化完成必须引入额外的内部真空相或超越本文考虑的两种QCD启发状态方程的进一步微观物理学。

英文摘要

Motivated by Refs.[1, 2], we investigate whether quantum chromodynamics (QCD)-inspired matter at finite quark chemical potential can dynamically support \emph{regular} black-hole interiors during gravitational collapse. To this end, we couple two effective equations of state, namely a three-flavor chiral quark model at finite temperature and chemical potential and a cold-QGP mean-field model with a dynamical gluon mass, to a spherically symmetric advanced Eddington--Finkelstein geometry. The matter source is treated as an effective anisotropic fluid. Rather than assuming a regular mass profile a priori, we determine the radial temperature dependence from the local conservation law and reconstruct the mass function from the Einstein equations. In the chiral model, the conservation equation admits an exact Lambert-function solution, but the physical coefficients select a singular near-center branch. In the cold-QGP model, the exact implicit temperature-radius relation drives the temperature to diverge near the center, causing the thermodynamic source terms and the reconstructed mass function to become incompatible with the regular-center condition. We therefore find that, within the effective framework adopted here, finite quark chemical potential reshapes the thermodynamics of the collapse phase but does not by itself provide a self-regularizing black-hole core. Any regular completion must invoke an additional inner vacuum-like phase or further microphysics beyond the two QCD-inspired equations of state considered in this work.

2605.27166 2026-05-27 cond-mat.str-el quant-ph

Quantum criticality and factorization in a constrained Rydberg spin chain

约束里德伯自旋链中的量子临界性与因子化

Yuan Jiang, Wen-Long You, Liangsheng Li, Maoxin Liu

AI总结 通过精确对角化、密度矩阵重正化群和变分均匀矩阵乘积态计算,研究了一维约束量子自旋链的零温相图,揭示了反铁磁序的两种破坏机制以及有序相内精确的基态因子化线。

Comments 12 pages, 7 figures

详情
Journal ref
Phys. Rev. A 113, 053322 (2026)
AI中文摘要

我们研究了在相干驱动的里德伯原子阵列中,具有竞争性局域拉比驱动和偶极-偶极交换相互作用的一维约束量子自旋链的零温相图。投影到阻塞约束的希尔伯特空间得到一个有效模型,其中局域和非局域量子涨落在同等条件下竞争。结合精确对角化、密度矩阵重正化群和变分均匀矩阵乘积态计算,我们建立了一个完整的相图,包括Luttinger液体、反铁磁有序相和极化顺磁体。我们识别了两种不同的反铁磁序破坏机制:强驱动下的常规Ising转变和弱驱动下连续量子熔化进入Luttinger液体,后者通过基于纠缠的诊断和有限纠缠标度进行表征。此外,我们发现了有序相内嵌入的一条精确基态因子化线,为可编程里德伯量子模拟器的实验提供了一个解析可处理的零纠缠参考点。

英文摘要

We investigate the zero-temperature phase diagram of a one-dimensional constrained quantum spin chain realized in coherently driven Rydberg-atom arrays with competing local Rabi driving and dipole-dipole exchange interactions. Projecting onto the blockade-constrained Hilbert space yields an effective model in which local and nonlocal quantum fluctuations compete on equal footing. Combining exact diagonalization, the density-matrix renormalization group, and variational uniform matrix-product-state calculations, we establish a complete phase diagram comprising a Luttinger liquid, an antiferromagnetic ordered phase, and a polarized paramagnet. We identify two distinct mechanisms for the destruction of antiferromagnetic order: a conventional Ising transition at strong driving and a continuous quantum melting into the Luttinger liquid at weak driving, characterized using entanglement-based diagnostics and finite-entanglement scaling. In addition, we uncover an exact ground-state factorization line embedded within the ordered phase, providing an analytically tractable zero-entanglement reference point for experiments with programmable Rydberg quantum simulators.

2605.27165 2026-05-27 math.FA math.CA

Weighted Riesz--Kolmogorov criterion and multilinear extrapolation of compactness on variable Lebesgue spaces

加权Riesz-Kolmogorov准则与变指数Lebesgue空间上紧性的多线性外推

Spyridon Kakaroumpas, Stefanos Lappas

AI总结 本文通过建立加权Riesz-Kolmogorov定理,在变指数Lebesgue空间上实现了多线性紧算子的外推,并得到了交换子、分数次积分和Fourier乘子的新加权紧性估计。

Comments 48 pages

详情
AI中文摘要

本文研究了加权变指数Lebesgue空间中的新型加权Riesz-Kolmogorov定理以及多线性紧算子的外推。我们通过Riesz-Kolmogorov定理建立了后一个结果,该定理在变指数Lebesgue空间中给出了多线性紧算子的加权插值定理。在证明过程中,我们还证明了混合范数变指数Lebesgue空间中的加权插值定理。利用我们的外推结果,我们得到了加权变指数Lebesgue空间上多线性$ω$-Calderón-Zygmund算子、多线性分数次积分和多线性Fourier乘子的交换子的新的加权紧性估计。我们的工作推广了近期的一些结果,包括但不限于Cao、Olivo和Yabuta在经典加权Lebesgue空间上的多线性算子情形,以及作者之前在双线性算子和变指数Lebesgue空间中的结果。

英文摘要

This paper addresses a novel weighted Riesz--Kolmogorov theorem and the extrapolation of multilinear compact operators in the context of weighted variable Lebesgue spaces. We establish the latter result via our Riesz--Kolmogorov theorem which yields a weighted interpolation theorem for multilinear compact operators in the variable Lebesgue setting. In proving this, we also show a weighted interpolation theorem in mixed-norm variable Lebesgue spaces. By means of our extrapolation result, we obtain new weighted compactness estimates for the commutators of multilinear $ω$-Calderón--Zygmund operators, multilinear fractional integrals and multilinear Fourier multipliers on weighted variable Lebesgue spaces. Our work generalizes several recent ones, including but not limited to those of Cao, Olivo and Yabuta in the setting of multilinear operators acting on the classical weighted Lebesgue spaces as well as the previous result by the authors in the setting of bilinear operators and variable Lebesgue spaces.

2605.27162 2026-05-27 cond-mat.mtrl-sci

Rapid estimation of synthesizability windows of inorganic materials from first principles

基于第一性原理的无机材料合成窗口快速估计

Finja Tadge, Javier Sanz Rodrigo, Andrea Crovetto

AI总结 提出一种高通量生成相优势图的方法,通过拟合元素相参考能量和机器学习原子间势,快速估计无机材料在温度与气体分压下的合成条件,大幅降低计算成本。

详情
AI中文摘要

即使在热力学平衡假设下,快速预测材料的合成条件仍然具有挑战性。仅基于凸稳定壳的方法忽略了有限温度效应,而基于声子的相图计算计算量巨大。在此,我们展示了作为温度和气体反应物分压函数的相优势图的高通量生成,有助于弥合计算预测与实验合成之间的差距。我们采用将元素相参考能量拟合到零温度总能的方法以改进生成焓的计算,并结合机器学习原子间势来快速确定振动熵和热容。由此产生的优势图可以被实验人员直观理解,并用于将稳定壳之上的能量转化为合成条件。我们为选定的氧化物、氮化物、硫化物和磷化物体系,以及48个更复杂的三元金属磷硫化物体系生成了优势图。计算得到的优势图通常与实验合成文献吻合良好,且与依赖基于DFT声子计算的传统方法相比,计算成本大幅降低。我们识别出几种在明确定义的热力学窗口内被预测为稳定的化合物,尽管它们在零温度稳定壳图像中表现为亚稳态。该方法可应用于快速估计任何无机材料的合成条件。

英文摘要

Fast prediction of the synthesizability conditions of materials remains challenging, even assuming synthesis under thermodynamic equilibrium. Approaches solely based on convex stability hulls neglect finite-temperature effects, while phonon-based phase diagram calculations are computationally demanding. Here, we demonstrate high-throughput generation of phase predominance diagrams as a function of temperature and partial pressures of gaseous reactants, helping bridge the gap between computational predictions and experimental synthesis. We employ fitting of elemental phase reference energies to zero-temperature total energies for improved calculation of formation enthalpies, along with machine-learned interatomic potentials for rapid determination of vibrational entropy and heat capacity. The resulting predominance diagrams can be intuitively understood by experimentalists and can be used to translate energies above stability hulls into synthesis conditions. Predominance diagrams are generated for selected oxide, nitride, sulfide, and phosphide systems, as well as for 48 more complex ternary metal phosphosulfide systems. The calculated predominance diagrams generally show good agreement with the experimental synthesis literature, with a drastic reduction in computational cost compared to a conventional approach relying on DFT-based phonon calculations. We identify several compounds predicted to be stable under well-defined thermodynamic windows, even though they appear as metastable in a zero-temperature stability hull picture. The method can be applied to rapidly estimate synthesis conditions for any inorganic material.

2605.27160 2026-05-27 astro-ph.SR

The pollution from massive AGB stars favoured by strong hot bottom burning

强热底燃烧青睐的大质量AGB星污染

Paolo Ventura, Francesca D'Antona

AI总结 研究中等质量恒星在AGB阶段强热底燃烧(HBB)对星际物质污染的作用,总结其在质子俘获元素演化、球状星团多星族形成及早期星系高N/O热气体起源中的成就与问题。

Comments 19 pages, 2 figures

详情
AI中文摘要

中等质量恒星(约4-8倍太阳质量)通过渐近巨星分支(AGB)阶段演化到白矮星:包括稳态氢壳燃烧和氦热脉冲、星风质量损失及行星状星云抛射。几乎全部损失的质量(初始质量减去剩余白矮星质量)都经历了强烈的“热底燃烧”(HBB),因为普通对流到达氢燃烧壳层的外缘。过去25年,这一阶段一直是三个主要研究课题的重点:1)这些恒星中质子俘获元素的化学演化及其因AGB模型描述不确定性导致的内在不确定性;2)AGB在球状星团多星族形成中的作用;3)AGB在一些早期星系(尤其是那些拥有大质量黑洞的星系)中高N/O热气体成分的可能作用。我们在此总结了这些研究领域的一些主要成就和问题。

英文摘要

Stars of intermediate mass (~4-8Msun) evolve to the stage of white dwarfs through the asymptotic giant branch (AGB) stage: stationary hydrogen shell burning and helium thermal pulses, wind mass loss and planetary nebula ejection. Almost the totality of the mass lost (the initial mass minus the remnant white dwarf mass) is heavily processed `hot bottom burning' (HBB), as plain convection reaches the outer edge of the H-burning shell. This phase has been subject of intense investigations in the latest 25 years, in connection to three main research subjects: 1) the chemical evolution of proton-capture elements cycled in these stars, and their intrinsic uncertainties due to the uncertainty in the description of the AGB models; 2) the role of AGBs in the formation of multiple populations in globular clusters; 3) the possible AGB role in the composition of hot gas with high N/O in some primordial galaxies, particularly in those hosting a massive black holes. We here summarize some main achievements and problems in these research fields.

2605.27159 2026-05-27 physics.chem-ph

Dyck language and fermionic second quantization: II. Applications

Dyck语言与费米子二次量子化:II. 应用

Jérémy Morere, Thibaud Etienne

AI总结 本文通过将Dyck语言与费米子二次量子化中的期望值计算相联系,推导出无需显式应用Wick定理的零值条件,并扩展为图解框架,实现了对全收缩项符号的可视化确定。

详情
AI中文摘要

在这项工作中,我们建立了补充Dyck语言与相对于物理真空和单行列式态的二次量子化算子链的有符号期望值之间的直接联系。受Dyck语言在语言框架分析中提供Catalan数出现的例子的启发,我们表明这些数字在计数消除由Dyck语言应用于费米子二次量子化所检测到的消失贡献后剩余的项时是核心。通过将产生和湮灭算子(或算子对)翻译成括号字母表,我们推导出期望值为零的简单且直观的充分条件,这不需要显式应用Wick定理。这里针对物理真空或相对于单行列式态进行了处理。我们还将这种翻译扩展到一个图解框架,该框架允许可视化确定全收缩项的符号,重现Wick定理的结果。该方法已扩展到包括至少一个激发或去激发算子的费米子二次量子化算子对(嵌套)对易子的情况。我们的结果已在一个软件MobiDyck中实现,其源代码可在网上免费获取。本文详细介绍了受我们关于Dyck语言的工作启发的算法方法。最后,将我们的图解方法与Goldstone图进行了比较,并以此结束本文。

英文摘要

In this work, we establish a direct connection between supplemented Dyck language and the signed expectation value of chains of second quantization operators relatively to the physical vacuum and relatively to a one-determinant state. Inspired by the fact that Dyck language provides an example of the emergence of the Catalan numbers in linguistic framework analysis, we show that these numbers are central when numbering the terms remaining when eliminating vanishing contributions detected by our application of Dyck language to fermionic second quantization. From the translation of creation and annihilation operator - or of pairs of operators - into a bracket alphabet, we derive simple and intuitive sufficient conditions for the nullity of expectation values that does not require an explicit application of Wick's theorem. This is done here with respect to the physical vacuum or relatively to a one-determinant state. We also extend this translation into a diagrammatic framework that allows a visual determination of the signature of fully contracted terms, reproducing the results of Wick's theorem. This approach has been extended to the case of (nested) commutators of pairs of fermionic second quantization including at least one excitation or deexcitation operator. Our results have been implemented in a software, MobiDyck, whose source code is freely available on the web. The algorithmic approach inspired by our work on Dyck language is detailed in this paper. Finally, a comparison of our diagrammatic approach with Goldstone diagrams is provided and closes the article.

2605.27153 2026-05-27 cs.CY

Building an Atlas of Social Experiments to Link Studies, Reconcile Conflicts, and Bridge Gaps

构建社会实验图谱:连接研究、调和冲突、弥合空白

Jiawei Zhang, Honglin Bao, Pengda Wang, Alex Yan, Xiao Liu, James A. Evans

AI总结 提出ExAtlas框架,通过将实验档案转化为结构化图谱,自动链接一致研究、调和冲突结果并建议桥接实验,以促进社会科学知识的累积。

详情
AI中文摘要

社会和行为科学每年进行数千次实验,然而它们的发现很少积累成一张关于已知、冲突和缺失内容的连贯图谱。我们引入ExAtlas,一个将实验档案转化为图谱的框架:一种结构化地图,其中研究相互连接、冲突或留下可弥合的空白。给定一个目标研究,ExAtlas搜索在处理和结果空间上局部接近的先前研究,并询问它们的观测效应是否可以组合以预测目标效应。这产生三种情况。如果组合成功且与观测结果一致,ExAtlas将目标与一致的先前证据连接。如果组合成功但不一致,ExAtlas调和冲突并提出可能解释该冲突的候选调节变量或更高层次理论。如果组合失败,ExAtlas提出桥接实验以填补空白。我们提供了在处理效应曲面局部光滑条件下组合的误差界。在经认证为局部支持的保留目标上,ExAtlas在98.6%的情况下恢复了效应方向。人类评估进一步表明,其提出的桥接实验是合理的且表现出连通性,其冲突解释对理论生成有用。这些结果表明,社会实验档案包含比当前实践提取的更多潜在结构——并且使这种结构明确化可以指导未来的理论和实验。

英文摘要

Social and behavioral science runs thousands of experiments each year, yet their findings rarely accumulate into a coherent map of what is known, what conflicts, and what remains missing. We introduce ExAtlas, a framework for turning an archive of experiments into an atlas: a structured map in which studies link, conflict, or leave bridgeable gaps. Given a target study, ExAtlas searches for prior studies that are locally close in treatment and outcome space and asks whether their observed effects can be composed to predict the target effect. This yields three cases. If the composition succeeds and agrees with the observed result, ExAtlas links the target to consistent prior evidence. If composition succeeds but disagrees, ExAtlas reconciles the conflict and proposes candidate moderators or higher-level theories that could explain it. If composition fails, ExAtlas proposes bridge experiments to close the gap. We provide an error bound for composition under local smoothness of the treatment-effect surface. On held-out targets certified as locally supported, ExAtlas recovers effect direction in 98.6% of cases. Human evaluations further suggest that its proposed bridge experiments are plausible and exhibit connectedness, and that its conflict explanations are useful for theory generation. These results suggest that the archive of social experiments contains more latent structure than current practice extracts -- and that making this structure explicit can guide both future theory and future experimentation.

2605.27152 2026-05-27 math.AG

Blowups, Gale duality, and moduli spaces

Blowups, Gale duality, and moduli spaces

Carolina Araujo, Ana-Maria Castravet, Inder Kaur, Diletta Martinelli

AI总结 本文通过Gale对偶将一般位置n+4个点的射影空间Pn的爆破与曲面上秩2向量丛的Gieseker模空间联系起来,并研究极化变化导致的模空间变化,从而部分描述X的双有理几何。

Comments 32 pages

详情
AI中文摘要

本文的目标是描述在非常一般位置的n+4个点上爆破Pn的双有理几何。为此,我们遵循Mukai的思想,探索Gale对偶的一个特例,即射影空间Pn和P2中n+4个点构型之间的对应关系。我们首先证明,在n+4个一般点上爆破Pn得到的X同构于曲面S上的秩2向量丛的某个Gieseker模空间,其中S是通过在n+4个Gale对偶点上爆破P2得到的。然后,我们研究当极化L在S上变化时这些模空间的变化,并将这种变化转化为Eff(X)的部分Mori chamber分解,从而在一定程度上描述X的双有理几何。

英文摘要

The goal of this paper is to describe the birational geometry of the blowup of $\mathbb{P}^n$ at $n+4$ points in very general position. To achieve this, we follow an idea of Mukai and explore a special instance of Gale duality, namely, a correspondence between configurations of $n+4$ points in the projective spaces $\mathbb{P}^n$ and $\mathbb{P}^2$. We first prove that the blowup $X$ of $\mathbb{P}^n$ at $n+4$ general points is isomorphic to a certain Gieseker moduli space of rank $2$ vector bundles on the surface $S$ obtained by blowing up $\mathbb{P}^2$ at the $n+4$ Gale dual points. We then study the variation of these moduli spaces as we vary the polarization $L$ on $S$, and translate this variation into a partial Mori chamber decomposition of $\overline{Eff}(X)$, describing to some extent the birational geometry of $X$.

2605.27150 2026-05-27 math.SP math.DS

The butterflies' effects

蝴蝶效应

Siegfried Beckus

AI总结 研究非周期序中薛定谔算子的谱性质,通过加权Delone集探讨动力学与谱的相互作用,并分析参数依赖族形成的谱蝴蝶结构。

Comments Habilitation thesis

详情
AI中文摘要

本文研究非周期序背景下薛定谔算子的谱性质,利用加权Delone集探索底层动力学与谱性质之间的相互作用。我们研究了在周期与非周期区域之间插值的参数依赖族,其谱形成所谓的谱蝴蝶。这些蝴蝶反映了谱的分形和自相似结构。我们回顾了现有结果,介绍了额外的例子,并在文献中的工作之间建立了新的联系。该框架在很大程度上是维度无关的,并扩展到非阿贝尔群和更一般的设置。

英文摘要

This work studies spectral properties of Schrödinger operators in the context of aperiodic order, using weighted Delone sets to explore the interplay between the underlying dynamics and spectral properties. We study parameter-dependent families interpolating between periodic and aperiodic regimes, whose spectra form so-called spectral butterflies. These reflect fractal and self-similar structures of the spectra. We review existing results, introduce additional examples, and establish new connections between works in the literature. The framework is largely dimension-independent and extends to non-Abelian groups and more general settings.

2605.27149 2026-05-27 astro-ph.GA

Nearby galaxies in the LOFAR Two-metre Sky Survey IV. A fundamental plane of the radio-SFR relation

LOFAR两米巡天中的近邻星系IV. 射电-恒星形成率关系的基本平面

V. Heesen, H. W. Edler, M. Brüggen, M. Stein, D. J. Bomans, R. Paladino, K. T. Chyży, K. Małek, M. A. Lara-López, F. S. Tabatabaei

AI总结 利用LOFAR 144 MHz和1.4 GHz数据,研究近邻星系的射电-恒星形成率关系,发现射电光度、恒星形成率和射电谱指数构成一个基本平面,从而建立统一的射电-SFR关系。

Comments 10 pages plus 8 pages appendix. Accepted to Astronomy and Astrophysics. Interactive version of Figure 3 can be downloaded here: https://doi.org/10.5281/zenodo.20395673

详情
AI中文摘要

射电连续谱辐射有潜力成为不受消光影响的恒星形成示踪剂。然而,射电连续谱光度与恒星形成率之间的关系(射电-SFR关系)受到宇宙线输运、自由-自由吸收和宇宙线电子能量损失等多种效应的影响。我们旨在校准从矮星系到旋涡星系、覆盖近五个数量级SFR范围的近邻星系样本中的射电-SFR关系。我们同时包含了整体(单个星系)和局部(千秒差距尺度)的测量。我们利用低频阵列(LOFAR)在$144\\\,\\rm MHz$观测测量射电连续谱光度,并利用辅助的$1.4\\\,\\rm GHz$数据测量射电谱指数。选取70个近邻(距离$d < 30\\\,\\rm Mpc$)星系,其中15个用于局部测量,并拥有丰富的辅助数据,我们使用总红外、中红外、H$α$和远紫外作为互补的SFR示踪剂,对射电-SFR关系进行了研究。约三分之一的样本是至少中等恒星形成的侧向星系,其余星系则被选为代表广泛形态类型和SFR值的样本。我们首次证明,射电光度($L_{144}$)、恒星形成率(SFR)和射电谱指数($α$)在[$\\log(L_{144})$, $\\log(\rm SFR)$, $α$]空间中定义了一个“基本平面”。这使得我们能够定义一个统一的射电-SFR关系,当使用射电谱指数作为第二参数时,该关系同时适用于整体和局部数据。一个适用于整体和局部数据的统一射电-SFR关系可以作为包含宇宙线和磁场效应的星系模拟的试金石。它也加强了将射电-SFR关系用作不受消光影响的恒星形成示踪剂的理由。

英文摘要

Radio continuum emission has the potential to be an extinction-free tracer of star formation. However, the relation between radio continuum luminosity and star formation rate, the radio-SFR relation, is affected by various effects such as cosmic-ray transport, free-free absorption, and cosmic-ray electron energy losses. We aim to calibrate the radio-SFR relation in a sample of nearby galaxies ranging from dwarf to spiral galaxies covering nearly five orders of magnitude in SFR range. We include, both, global (individual galaxies) and local (kiloparsec sized) measurements. We measured radio continuum luminosities at $144\,\rm MHz$ using observations with the LOw Frequency ARray (LOFAR) and measure radio spectral indices using ancillary $1.4\,\rm GHz$ data. Selecting 70 nearby (distance $d < 30\,\rm Mpc$) galaxies, 15 of which were used for local measurements, with rich ancillary data we present a study of the radio-SFR relation using total infrared, mid-infrared, H$α$, and far-ultraviolet as complementary SFR tracers. About one third of our sample are at least moderately star-forming edge-on galaxies with the remaining ones chosen to be a representative sample of a wide range of morphological types and SFR values. For the first time, we show that the radio luminosity ($L_{144}$), the star-formation rate (SFR), and the radio spectral index ($α$) define a 'fundamental plane' in the [$\log(L_{144})$, $\log(\rm SFR)$, $α$] space. This allows us to define a unified radio-SFR relation that works both for global and local data when using the radio spectral index as a second parameter. A unified radio-SFR relation for, both, global and local data may serve as a litmus test for galaxy simulations that include the effect of cosmic rays and magnetic fields. It also strengthens the case for using the radio-SFR relation as an extinction-free tracer of star formation.

2605.27147 2026-05-27 cs.DS cs.PF

Virtual-Memory Powersort

虚拟内存Powersort

Finn Moltmann, Tamio-Vesa Nakajima, Sebastian Wild

AI总结 提出一种自适应归并排序的改进版本——虚拟内存Powersort,通过内部缓冲技术将内存消耗从n/2个对象降至O(√(n log n))个对象,同时保持与原始Powersort几乎相同的移动和比较次数,实验表明在多数场景下可实现几乎原地稳定排序且开销可忽略。

详情
AI中文摘要

我们给出了一种更节省空间的自适应归并排序实现:虚拟内存Powersort。利用内部缓冲技术,我们显著降低了算法的内存消耗;具体而言,对于排序n个对象,所需的缓冲区空间从n/2个对象减少到O(√(n log n))个对象。虽然这种空间效率在概念上可以通过已知的就地归并算法轻松实现(甚至可降至O(1)),但将这些算法作为标准归并算法的直接替代会导致显著的性能下降。相比之下,虚拟内存Powersort使用的移动和比较次数与之前的Powersort实现相同,仅增加O(n)项。我们报告了一项实证运行时间研究,将我们的实现与其他Powersort变体以及最先进的稳定排序方法进行比较,证明在多数场景下,几乎原地稳定排序可以以可忽略的开销实现。

英文摘要

We give a more space-efficient implementation of adaptive mergesort: Virtual-Memory Powersort. Using internal buffering techniques, we significantly reduce the memory consumption of the algorithm; specifically, for sorting $n$ objects the required buffer area is reduced from space for $n/2$ objects to $O(\sqrt{n \log n})$ objects. While this space-efficiency can be achieved (indeed reduced to $O(1)$) conceptually very easily with known inplace merging algorithms, using these as a drop-in replacement for the standard merge algorithm incurs a substantial slow-down. Virtual-Memory Powersort, by contrast, uses the same number of moves and comparisons as previous Powersort implementations up to an additive $O(n)$ term. We report on an empirical running-time study comparing our implementation against other Powersort variants and state-of-the-art stable sorting methods, demonstrating that almost in-place stable sorting can be achieved with negligible overhead in many scenarios.

2605.27145 2026-05-27 cond-mat.stat-mech

Subdiffusion equation with Cattaneo effect

具有Cattaneo效应的次扩散方程

Tadeusz Kosztołowicz, Aldona Dutkiewicz, Katarzyna D. Lewandowska

AI总结 本文通过引入Mittag-Leffler函数控制的时间延迟概率分布,提出了Cattaneo型次扩散方程,讨论了该方程的解及其在部分吸收边界条件下的应用,并提出了实验识别Cattaneo效应的方法。

Comments 14 pages, 11 figures

详情
AI中文摘要

普通的次扩散方程,其分数时间导数最多为一阶,描述了扩散分子传播速度无限的过程。为了避免这种非物理性质,人们提出了不同形式的Cattaneo次扩散方程。我们将Cattaneo效应定义为普通次扩散通量被随机时间延迟激活。通过将此效应纳入通量方程,我们得到了Cattaneo型次扩散方程(CTSE)。我们考虑一个次扩散过程,其中Cattaneo效应由Mittag-Leffler函数控制的时间延迟概率分布产生。此时,CTSE与普通次扩散方程的区别在于一个分数时间导数项,其阶数可以独立于次扩散指数。讨论了Cattaneo效应对CTSE解的影响。我们表明,由CTSE描述的过程在整个时间域内都是次扩散,尽管在短时间极限下扩散粒子的均方位移的时间演化是超扩散的典型特征。次扩散方程中通量激活的延迟也应导致边界条件中的通量延迟。作为例子,我们研究了具有部分吸收壁的系统中带有Cattaneo效应的次扩散,其中假设了Robin边界条件。我们还提出了一种在次扩散系统中实验识别Cattaneo效应的方法。

英文摘要

The ordinary subdiffusion equation, with a fractional time derivative of at most first order, describes a process in which the propagation velocity of diffusing molecules is unlimited. To avoid this non-physical property different forms of the Cattaneo subdiffusion equation have been proposed. We define the Cattaneo effect as a delay of the ordinary subdiffusion flux activation by a random time. By incorporating this effect into the flux equation we get a Cattaneo--type subdiffusion equation (CTSE). We consider a subdiffusion process in which the Cattaneo effect is generated by the time-delay probability distribution controlled by the Mittag-Leffler function. Then, CTSE differs from the ordinary subdiffusion equation by a term with a fractional time derivative, whose order can be independent of the subdiffusion exponent. The influence of the Cattaneo effect on the solutions to the CTSE is discussed. We show that the process described by CTSE is subdiffusion in the entire time domain even though the temporal evolution of the mean square displacement of diffusing particle in the short-time limit is typical for superdiffusion. The delay in the flux activation in the subdiffusion equation should also cause a flux delay in a boundary condition. As an example, we study subdiffusion with the Cattaneo effect in a system with a partially absorbing wall at which the Robin boundary condition is assumed. We also propose a method for experimentally identifying the Cattaneo effect in a subdiffusive system.