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2504.11224 2026-06-08 cond-mat.mtrl-sci physics.chem-ph quant-ph 版本更新

Accurate Machine Learning Interatomic Potentials for Polyacene Molecular Crystals: Application to Single Molecule Host-Guest Systems

多并苯分子晶体的精确机器学习原子间势:应用于单分子主客体系统

Burak Gurlek, Shubham Sharma, Paolo Lazzaroni, Angel Rubio, Mariana Rossi

AI总结 利用基于图神经网络的MACE架构和主动学习策略,开发了适用于萘、蒽、并四苯和并五苯等多并苯分子晶体的通用机器学习原子间势,准确捕捉振动动力学,并用于研究主客体系统中的振动耦合。

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Journal ref
npj Comput Mater 11, 318 (2025)
AI中文摘要

新兴的机器学习原子间势(MLIPs)为大规模精确材料模拟提供了有前景的解决方案,但针对分子晶体中振动动力学描述的严格测试仍然稀缺。在这里,我们利用基于图神经网络的MACE架构和主动学习策略,开发了一个通用的MLIP,以准确捕捉一系列基于多并苯的分子晶体(即萘、蒽、并四苯和并五苯)的振动动力学。通过仔细的误差传播,我们表明这些势能是准确的,并能够研究非谐振动特征、振动寿命和振动耦合。特别是,我们研究了基于这些分子晶体的大规模主客体系统,展示了基于分子动力学技术解释和量化主体与客体核运动之间振动耦合的能力。我们的结果为理解大规模复杂分子系统中的振动特征建立了一个框架,从而代表了在分子环境中工程化振动相互作用的重要一步。

英文摘要

Emerging machine learning interatomic potentials (MLIPs) offer a promising solution for large-scale accurate material simulations, but stringent tests related to the description of vibrational dynamics in molecular crystals remain scarce. Here, we develop a general MLIP by leveraging the graph neural network-based MACE architecture and active-learning strategies to accurately capture vibrational dynamics across a range of polyacene-based molecular crystals, namely naphthalene, anthracene, tetracene and pentacene. Through careful error propagation, we show that these potentials are accurate and enable the study of anharmonic vibrational features, vibrational lifetimes, and vibrational coupling. In particular, we investigate large-scale host-guest systems based on these molecular crystals, showing the capacity of molecular-dynamics-based techniques to explain and quantify vibrational coupling between host and guest nuclear motion. Our results establish a framework for understanding vibrational signatures in large-scale complex molecular systems and thus represent an important step for engineering vibrational interactions in molecular environments.

2504.04879 2026-06-08 math.PR 版本更新

Mixed memories in Hopfield networks

Hopfield网络中的混合记忆

Véronique Gayrard

AI总结 研究Hopfield网络中存储模式时产生的意外局部极小值问题,通过构造混合记忆来分析能量函数的局部极小值特性,并给出不同模型下M增长速率的条件。

Comments 3 figures

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AI中文摘要

我们考虑了一类具有激活函数F和状态空间{-1,1}^N的Hopfield关联记忆模型,其中每个立方体的顶点描述N个二元神经元的配置。M个随机选择的配置称为模式,通过设计能量函数使其成为局部极小值来存储。如果它们是局部极小值,则可通过减少能量的动力学过程检索。然而,存储模式到能量函数中也会产生意外的局部极小值,即虚假记忆。尽管自该主题最早的研究所知,但除了简单情况外,只有数值模拟和非严谨计算支持这一现象。我们的结果是双方面的。对于通用函数F,我们显式构造了一组称为混合记忆的配置,其性质旨在表征能量函数的局部极小值。对于三个著名模型,即经典、密集和现代Hopfield模型,分别对应二次、多项式和指数函数F,我们给出了M增长速率的条件,保证当N趋于无穷时,混合记忆成为检索动力学的固定点,从而成为能量的精确极小值。我们推测在该情况下,所有局部极小值都是混合记忆。

英文摘要

We consider the class of Hopfield models of associative memory with activation function $F$ and state space $\{-1,1\}^N$, where each vertex of the cube describes a configuration of $N$ binary neurons. $M$ randomly chosen configurations, called patterns, are stored using an energy function designed to make them local minima. If they are, which is known to depend on how $M$ scales with $N$, then they can be retrieved using a dynamics that decreases the energy. However, storing the patterns in the energy function also creates unintended local minima, and thus false memories. Although this has been known since the earliest work on the subject, it has only been supported by numerical simulations and non-rigorous calculations, except in elementary cases. Our results are twofold. For a generic function $F$, we explicitly construct a set of configurations, called mixed memories, whose properties are intended to characterise the local minima of the energy function. For three prominent models, namely the classical, the dense and the modern Hopfield models, obtained for quadratic, polynomial and exponential functions $F$ respectively, we give conditions on the growth rate of $M$ which guarantee that, as $N$ diverges, mixed memories are fixed points of the retrieval dynamics and thus exact minima of the energy. We conjecture that in this regime, all local minima are mixed memories.

2504.03844 2026-06-08 hep-lat astro-ph.CO cond-mat.stat-mech hep-ph hep-th 版本更新

Simple third order operator-splitting schemes for stochastic mechanics and field theory

用于随机力学和场论的简单三阶算子分裂方案

Andrey Shkerin, Sergey Sibiryakov

AI总结 本文提出一种构建具有最高3阶强收敛性的数值方案的方法,用于求解一类随机微分方程,包括 Langevin 类方程。通过两阶段构造,结合随机采样和算子分裂技术,适用于普通和偏随机微分方程,并通过机械示例和标量场模拟验证其有效性。

Comments 45 pages, 8 figures, v2: matches the published version

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Journal ref
Comp. Phys. Comm. 326, 2026, 110208
AI中文摘要

我们提出了一种构造具有最高3阶强收敛性的数值方案的方法,用于求解一类随机微分方程,包括Langevin型方程。构造过程分为两个阶段。第一阶段将随机方程近似为具有光滑系数的微分方程,随机采样于每个时间步。第二阶段使用传统算子分裂技术求解所得的规则方程。这种分离使方法灵活,允许自由结合最适合问题的数值技术。该方法适用于普通和偏随机微分方程。在后者情况下,自然产生伪谱算法。我们通过机械示例数值测试了几种由此方法获得的方案的强收敛性。应用到偏微分方程时,通过实时模拟一个具有四次自相互作用的标量场与热浴耦合的情况进行演示。模拟准确再现了该场的热力学性质,并用于研究负四次耦合情况下的热假真空衰变动力学。

英文摘要

We present a method for constructing numerical schemes with up to 3rd strong convergence order for solution of a class of stochastic differential equations, including equations of the Langevin type. The construction proceeds in two stages. In the first stage one approximates the stochastic equation by a differential equation with smooth coefficients randomly sampled at each time step. In the second stage the resulting regular equation is solved with the conventional operator-splitting techniques. This separation renders the approach flexible, allowing one to freely combine the numerical techniques most suitable to the problem at hand. The approach applies to ordinary and partial stochastic differential equations. In the latter case, it naturally gives rise to pseudo-spectral algorithms. We numerically test the strong convergence of several schemes obtained with this method in mechanical examples. Application to partial differential equations is illustrated by real-time simulations of a scalar field with quartic self-interaction coupled to a heat bath. The simulations accurately reproduce the thermodynamic properties of the field and are used to explore dynamics of thermal false vacuum decay in the case of negative quartic coupling.

2501.18693 2026-06-08 quant-ph 版本更新

Hierarchical Generation and Design of Tree-Codes for Resource-Efficient Loss-Tolerant Quantum Communications

分层生成与设计用于资源高效容错量子通信的树码

Francesco Cesa, Tommaso Feri, Angelo Bassi

AI总结 本文提出了一种高效的量子树码生成协议,通过自顶向下的快速编码解码减少信号损失,优化了树码结构并提升了容错性能,特别在量子中继协议中实现了更高的中继速率。

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AI中文摘要

我们开发了用于生成容错量子树码的协议;这些树码旨在保护信息免受量子比特损失的影响,并广泛应用于量子通信中。与之前的提案不同,我们的方法实现了自顶向下的快速编码和解码,从而减少了由于中继站中信号延迟和光子重排导致的损失。在硬件层面,我们展示了如何利用一个配备静态反馈机制的量子发射器实现这一目标,通过该机制可以并行地在反馈量子比特与多个发射量子比特之间构建纠缠门。此外,分析误差校正解码图中的典型模式,我们发现可以通过引入代码中的不对称性来优化树码结构,从而通过减少代码大小提升性能,这些优化基于对恢复过程内在适应性的模拟。我们通过数值分析证明,这些改进显著提升了损失校正性能。具体而言,在量子中继协议中,我们展示了我们的快速恢复方案(解码-编码)能够通过更小的每个代码光子数实现更高的中继速率。

英文摘要

We develop protocols for generating loss-tolerant quantum tree-codes; these are designed to safeguard information against qubit losses, with wide applications in quantum communications. Contrary to previous proposals, our method enables top-to-bottom fast encoding and decoding, thereby reducing losses due to the lagging and photon-reordering at the repeater stations. At the hardware level, we show how to achieve this with a single quantum emitter equipped with a static feedback mechanism, which we leverage to engineer entangling gates between a fed-back qubit and multiple emitted qubits in parallel. In addition, analyzing typical patterns within the error-correction decoding graphs, we find optimizations of the structure of tree-codes, which enable improved performance by also reducing the code size; these are based on the introduction of asymmetries in the code, which mimic the intrinsic adaptiveness of the recovery procedure. We show numerically that these improvements together significantly enhance the loss-correction performance. Specifically, focusing on quantum repeater protocols, we show that our fast recovery scheme (decoding-encoding) allows for improved repeater rates with smaller photon numbers per code.

2503.15609 2026-06-08 hep-ph 版本更新

Flavour and Electroweak Precision Constraints on a Simplified Dark Matter Model with a Light Spin-0 Mediator

轻自旋0中介子暗物质模型的味和电弱精确约束

Lipika Kolay, Soumitra Nandi

AI总结 本文研究了轻自旋0中介子暗物质模型的参数空间,结合味变化电荷和中性流过程及电弱精确观测,探讨其对B和K赝标量介子稀有和半轻子衰变的影响,并分析其对B介子不可见衰变数据的解释能力。

Comments Updated analysis with the inclusion of electric and magnetic dipole moment constraints

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AI中文摘要

本文研究了一种轻自旋0中介子暗物质模型的参数空间,结合味变化电荷和中性流过程及电弱精确观测,探讨其对B和K赝标量介子稀有和半轻子衰变的影响,并分析其对B介子不可见衰变数据的解释能力。

英文摘要

This work investigates the allowed parameter spaces of a simplified dark matter (DM) model characterized by a spin-0 mediator with masses in the low to intermediate range ($ < $ 10 GeV). We systematically divide the parameter space into various mass regions of the mediator and constrain the model parameters using a diverse set of observables, including flavour-changing charged and neutral current processes such as rare and semi-leptonic decays of pseudoscalar mesons (B and K), electroweak precision observables, alongside data from fixed-target experiments. Additionally, we explore the model's capability to explain recent Belle-II data on invisible B-meson decays. Our study includes a detailed examination of DM properties and the constraints from Big Bang nucleosynthesis. We present bounds on model parameters through individual and simultaneous analyses of the available inputs and highlight their implications for understanding DM phenomenology. Furthermore, we obtain bounds on the couplings of the possible gauge-invariant dimension-5 operators, leading to the possible interactions between the spin-0 mediator and the SM gauge bosons and fermions. This study comprehensively investigates the constraints and theoretical implications associated with low-mass spin-0 mediator DM models.

2502.08305 2026-06-08 math.NT 版本更新

On additive convolution sum of arithmetic functions and related questions

关于算术函数加法卷积和及相关问题

Bikram Misra, Biswajyoti Saha, Anubhav Sharma

AI总结 本文扩展Ingham的结果,推导出加法卷积和的渐近公式,并研究了具有绝对收敛拉马努金展开的算术函数的卷积和。

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AI中文摘要

Ingham研究了除数函数的两种卷积和,即移位卷积和$\sum_{n \le N} d(n) d(n+h)$和加法卷积和$\sum_{n < N} d(n) d(N-n)$,并推导出其渐近公式。本文扩展Ingham的经典结果,推导出对于某些整数$M \le N$,子和$\sum_{n < M} d(n) d(N-n)$的渐近公式,涉及对$M$适用范围的精心选择。我们还研究了卷积和$\sum_{n < M} f(n) g(N-n)$,其中$f$和$g$是具有绝对收敛拉马努金展开的算术函数,这导致了对拉马努金的已知预测。

英文摘要

Ingham studied two types of convolution sums of the divisor function, the shifted convolution sum $\sum_{n \le N} d(n) d(n+h)$ and the additive convolution sum $\sum_{n < N} d(n) d(N-n)$ for integers $N, h$ and derived their asymptotic formulas as $N \to \infty$. There have been numerous works extending Ingham's result on the shifted convolution sum, but only little has been done towards the additive convolution sum. In this article, we extend the classical result of Ingham to derive an asymptotic formula with an error term of the sub-sum $\sum_{n < M} d(n) d(N-n)$ for certain integers $M \le N$. This involves careful choice of an applicable range of $M$. We also study the convolution sum $\sum_{n < M} f(n) g(N-n)$ for certain arithmetic functions $f$ and $g$ with absolutely convergent Ramanujan expansions, which in turn leads us to a well-established prediction of Ramanujan.

2502.06360 2026-06-08 cond-mat.str-el 版本更新

Flat-Band Driven Kondo Breakdown and Reentrant Effects in Heavy-Fermion Moiré Superlattices

平面带驱动的Kondo破裂与重新进入效应在重费米莫尔达夫超晶格中

Fabian Eickhoff, Jian-Xin Zhu, Benedikt Fauseweh

AI总结 研究重费米莫尔达夫超晶格中电子相变,通过DMFT与NRG方法揭示新能标和莫尔带出现的Kondo破裂现象,并与Lieb-Mattis定理对比验证新能标必要性。

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AI中文摘要

莫尔超晶格(MSLs)在范德瓦耳斯(vdW)异质结构中展现出驱动新兴电子现象的能力,其中一些现象类似于通常仅在体强关联量子材料中观察到的现象。随着范德瓦耳斯f电子材料的发现,设计新型内在强关联MSLs已成为可能。本文研究了二维重费米MSL中电子相变,通过动态平均场理论(DMFT)与数值重整化群(NRG)方法,展示了新能标和莫尔带出现的Kondo破裂现象,并与Lieb-Mattis定理预测对比,验证了新能标在超大单元格情况下与传统单杂质极限一致的必要性。

英文摘要

Moiré superlattices (MSLs) in van der Waals (vdW) heterostructures have demonstrated their incredible power in driving emergent electronic phenomena, some of which are reminiscent of those usually only observed in bulk strongly correlated quantum materials. With the recent discovery of van der Waals $f$-electron materials, the design of novel MSLs of intrinsic strong correlation is now within the reach. Here we study the novel electron phases of two-dimensional heavy-fermion MSL with increasingly diluted f-electron local moments. By applying dynamical mean field theory (DMFT) with numerical renormalization group (NRG) as an impurity solver, we demonstrate the appearance of a new energy scale and a re-entrant Kondo breakdown in connection with the emergence of a flat band in the system. We further compare our numerical findings with predictions derived from the Lieb-Mattis theorem and show the necessity of the new energy scale to consistently reconcile the predictions with the conventional single-impurity limit for exceedingly large unit cells.

2412.00781 2026-06-08 math.AP 版本更新

Structure of the free interfaces near triple junction singularities in harmonic maps and optimal partition problems

谐映射与最优划分问题中三交点奇异性附近自由界面的结构

Roberto Ognibene, Bozhidar Velichkov

AI总结 研究谐映射到树的能量最小化问题,证明三交点附近自由界面的正则性,展示其由三个C^{1,α}光滑的(d-1)维流形组成,以120度角交汇。

Comments To appear in Arch. Ration. Mech. Anal

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AI中文摘要

我们考虑映射到树的能量最小化问题,并证明三交点附近自由界面的正则性。通过证明新的epiperimetric不等式,我们证明在频率3/2点附近,自由界面由三个C^{1,α}光滑的(d-1)维流形组成(由频率1点组成),具有共同的C^{1,α}正则边界(由频率3/2点组成),这些流形在边界处以120度角交汇。我们的结果也适用于狄利克雷特征值的最优划分问题。

英文摘要

We consider energy-minimizing harmonic maps into trees and we prove the regularity of the singular part of the free interface near triple junction points. Precisely, by proving a new epiperimetric inequality, we show that around any point of frequency $3/2$, the free interface is composed of three $C^{1,α}$-smooth $(d-1)$-dimensional manifolds (composed of points of frequency $1$) with common $C^{1,α}$-regular boundary (made of points of frequency $3/2$) that meet along this boundary at 120 degree angles. Our results also apply to spectral optimal partition problems for the Dirichlet eigenvalues.

2501.15639 2026-06-08 math.OA cs.LO 版本更新

The continuous functional calculus in Lean

在Lean中连续函数演算

Anatole Dedecker, Jireh Loreaux

AI总结 本文介绍了在Lean中首次实现的连续函数演算形式化,阐述了其设计决策及对数学家的启示。

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AI中文摘要

连续函数演算可能是算子代数理论中最基本的构造,尤其是C*-代数。本文记录了我们在Lean中对连续函数演算的形式化,这是任何证明助手中的首次此类形式化。我们的实现已合并到Lean的数学库Mathlib中。我们为不熟悉该主题的人提供了简要的数学理论介绍,然后突出我们的形式化设计决策,这些决策对可操作性至关重要。我们的阐述面向一般数学家,通过揭示发现过程,提供了形式化世界的一瞥。

英文摘要

The continuous functional calculus is perhaps the most fundamental construction in the theory of operator algebras, especially $C^{*}$-algebras. Here we document our formalization of the continuous functional calculus in Lean, which constitutes the first such formalization in any proof assistant. Our implementation is already merged into Lean's mathematical library, Mathlib. We provide a brief introduction to the mathematical theory for those unfamiliar with the subject, and then highlight the design decisions in our formalization which proved to be important for usability. Our exposition is aimed at a general mathematical audience and provides a glimpse into the world of formalization by laying bare the discovery process.

2412.19946 2026-06-08 math.CT cs.PL math.LO 版本更新

Comparing semantic frameworks for dependently-sorted algebraic theories

比较依赖排序代数理论的语义框架

Benedikt Ahrens, Peter LeFanu Lumsdaine, Paige Randall North

AI总结 本文比较了依赖排序代数理论的不同语义框架,通过公理化范畴统一展示各类模型之间的关系,揭示其嵌套结构和核心贡献。

Comments 23 pages. Presented at APLAS 2024; arXiv version lightly revised and expanded. v2: Corrected statement of Prop. 46 (missing discreteness hypothesis); various minor cosmetic edits; numbering unchanged

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Journal ref
Programming Languages and Systems (Proc. APLAS 2024), Oleg Kiselyov (ed.), 2025, Springer Nature Singapore, pp. 3-22
AI中文摘要

具有种类间依赖的代数理论是马丁-洛夫类型论等系统的核心结构。其指称语义通常通过范畴论技术研究;许多不同的范畴结构已被引入以建模它们(上下文范畴、具有族的范畴、显示映射范畴等)。这些模型的比较散见于文献中,缺乏详尽的大图景分析。本文旨在提供清晰且全面的此类模型间关系概述。具体而言,我们以*公理化范畴*为统一语言,展示几乎所有已建立的模型嵌入为2-范畴的子2-范畴(通常为满)。

英文摘要

Algebraic theories with dependency between sorts form the structural core of Martin-Löf type theory and similar systems. Their denotational semantics are typically studied using categorical techniques; many different categorical structures have been introduced to model them (contextual categories, categories with families, display map categories, etc.) Comparisons of these models are scattered throughout the literature, and a detailed, big-picture analysis of their relationships has been lacking. We aim to provide a clear and comprehensive overview of the relationships between as many such models as possible. Specifically, we take *comprehension categories* as a unifying language and show how almost all established notions of model embed as sub-2-categories (usually full) of the 2-category of comprehension categories.

2411.16212 2026-06-08 cond-mat.soft 版本更新

Mesoscale simulation model for odd fluids

介观尺度奇流体模拟模型

Yuxing Jiao, Mingcheng Yang

AI总结 本文提出一种高效粗粒模拟方法,用于研究具有时间反演对称性破缺的奇流体,推导了其输运系数并验证了模型的准确性,为研究奇流体的异常输运现象提供了新途径。

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Journal ref
Phys. Rev. E, 113, 055102 (2026)
AI中文摘要

一种具有时间反演对称性破缺的流体将表现出奇输运系数,如奇粘性、热导率和扩散系数,这可能根本改变流体性质并显著影响浸没物体的结构和动力学。在此,我们开发了一种高效的粗粒模拟方法,以捕捉真实奇流体的所有本质特征。基于微观动力学理论,我们解析地推导了介观尺度奇流体的输运系数。此外,我们通过模拟和理论计算验证了我们的方法,以探索在各种外部驱动下奇流体的复杂输运现象。我们的工作因此为研究奇流体的异常输运现象以及大规模模拟奇复杂流体开辟了新途径。

英文摘要

A fluid, with broken time-reversal symmetry, would exhibit odd transport coefficients, such as odd viscosity, thermal conductivity and diffusion coefficient, which may fundamentally alter the fluid properties and significantly influence the structure and dynamics of immersed objects. Here, we develop an efficient coarse-grained simulation approach for the odd fluid, that captures all essential features of real odd fluids. Based on microscopic kinetic theory, we analytically derive the transport coefficients of the mesoscale odd fluid. Furthermore, we validate our approach by performing both simulations and theoretical calculations to explore the intricate transport phenomena of the odd fluid under various external drivings. Our work thus paves the way for studying anomalous transport in odd fluids and for large-scale simulations of odd complex fluids.

2411.03221 2026-06-08 math.GR math.DS 版本更新

Perfect kernel of generalized Baumslag-Solitar groups

广义巴尔萨-索尔特群的完美核

Sasha Bontemps

AI总结 本文研究广义巴尔萨-索尔特群的子群空间,提出一种扩展巴尔萨-索尔特群研究的整数指标,用于分解完美核并分析其拓扑性质。

Comments Some examples added in Section 2.3. Section 3 split into 2 Sections, and more detailed explanations added at the beginning of Section 3. Some typos corrected

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AI中文摘要

本文研究广义巴尔萨-索尔特群(GBS群)的子群空间,即作用于无反向的定向树上并具有无限循环顶点和边稳定子群的群。我们的结果扩展了[ CGLMS22 ]中对巴尔萨-索尔特群的研究。给定一个由巴斯-塞尔理论给出的GBS群G,我们为G的每个子群关联一个整数,这是[ CGLMS22 ]中定义的表型的推广。该量值在共轭下不变,允许我们将G的完美核分解为在共轭下不变且G高度拓扑传递作用的片段。为此,我们将G的子群图解释为

英文摘要

In this article, we study the space of subgroups of generalized Baumslag-Solitar groups (GBS groups), that is, groups acting cocompactly on an oriented tree without inversion and with infinite cyclic vertex and edge stabilizers. Our results generalize the study of Baumslag-Solitar groups in [CGLMS22]. Given a GBS group G defined by a graph of groups whose existence is given by Bass-Serre theory, we associate to any subgroup of G an integer, which is a generalization of the phenotype defined in [CGLMS22]. This quantity is invariant under conjugation and allows us to decompose the perfect kernel of G into pieces which are invariant under conjugation and on which G acts highly topologically transitively. To achieve this, we interpret graphs of subgroups of G as "blown up and shrunk" Schreier graphs of transitive actions of G. We also describe the topology of the pieces which appear in the decomposition.

2408.00201 2026-06-08 physics.ed-ph 版本更新

A New Visual Approach to Pendulum Period Determination

pendulum 周期确定的新视觉方法

Rodrigo Sánchez-Martínez, Esteban Heredia-Muñoz

AI总结 本文提出利用几何与代数方法推导单摆周期公式,替代传统微分方程方法,使学生更易理解。

Comments 8 pages, 7 figures

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AI中文摘要

单摆周期(T=2π√(l/g))是物理学生熟悉的公式,但传统推导需线性化运动方程并求解微分方程。本文提出基于几何、代数和物理直觉的新方法,将摆动路径视为无限多个微小倾斜平面的累积,通过几何推理求极限,无需微积分知识。

英文摘要

The period of oscillation of a simple pendulum ($T = 2π\sqrt{l/g}$) is a familiar formula to most first-year physics students. However, deriving this expression from first principles requires linearizing the equation of motion under the small-angle approximation and solving the resulting differential equation. From our point of view, this method may seem obscure to students in the early stages of learning calculus and lacking in physical insight. Therefore, we propose an alternative approach to the derivation of this formula that relies on geometry, algebra, and physical intuition. Our method follows the foundational idea of integral calculus, replacing the circular path of the pendulum with a successive collection of infinitesimal inclined planes and summing the travel times along each plane as the number of planes becomes very large. Remarkably, evaluating the limit of this sum relies solely on geometric reasoning, making the approach accessible to any student, even those not yet familiar with differential equations or integration techniques.

2406.13826 2026-06-08 econ.EM stat.ME 版本更新

Testing identification in mediation and dynamic treatment models

中介和动态处理模型中的识别检验

Martin Huber, Kevin Kloiber, Lukas Laffers

AI总结 基于Huber和Kueck(2022)的检验,提出一种利用两组观测变量(协变量和疑似工具)来检验中介和动态处理模型中因果效应识别的方法,并应用于斯洛伐克劳动力市场数据。

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AI中文摘要

我们提出了一种检验中介和动态处理模型中因果效应识别的方法,该方法基于两组观测变量,即要控制的协变量和疑似工具,建立在Huber和Kueck(2022)针对单一处理模型的检验之上。我们考虑具有处理和中介变量顺序分配的模型,以评估直接处理效应(排除中介)、间接处理效应(通过中介)或处理和中介的联合效应。我们建立了在观测数据中识别这些效应的可检验条件。这些条件共同意味着(1)处理和中介在给定协变量下的外生性,以及(2)处理和中介的不同工具的有效性,即工具不直接影响结果(除了通过处理或中介)并且在给定协变量下是无混杂的。我们的框架扩展到当用选择指标替换中介以观察结果时的处理后样本选择或损耗问题,从而能够联合检验处理和损耗的选择性。我们提出了一种基于机器学习的检验,以数据驱动的方式控制协变量,并在模拟研究中分析其有限样本性能。此外,我们将我们的方法应用于斯洛伐克劳动力市场数据,发现对于动态处理评估中通常考虑的一系列培训项目,我们的可检验含义未被拒绝。

英文摘要

We propose a test for the identification of causal effects in mediation and dynamic treatment models that is based on two sets of observed variables, namely covariates to be controlled for and suspected instruments, building on the test by Huber and Kueck (2022) for single treatment models. We consider models with a sequential assignment of a treatment and a mediator to assess the direct treatment effect (net of the mediator), the indirect treatment effect (via the mediator), or the joint effect of both treatment and mediator. We establish testable conditions for identifying such effects in observational data. These conditions jointly imply (1) the exogeneity of the treatment and the mediator conditional on covariates and (2) the validity of distinct instruments for the treatment and the mediator, meaning that the instruments do not directly affect the outcome (other than through the treatment or mediator) and are unconfounded given the covariates. Our framework extends to post-treatment sample selection or attrition problems when replacing the mediator by a selection indicator for observing the outcome, enabling joint testing of the selectivity of treatment and attrition. We propose a machine learning-based test to control for covariates in a data-driven manner and analyze its finite sample performance in a simulation study. Additionally, we apply our method to Slovak labor market data and find that our testable implications are not rejected for a sequence of training programs typically considered in dynamic treatment evaluations.

2312.08788 2026-06-08 cond-mat.soft 版本更新

Oscillating edge current in polar active fluid

极性活性流体中振荡边缘电流

Hiroki Matsukiyo, Jun-ichi Fukuda

AI总结 研究极性活性流体在边界处的边缘电流行为,通过引入滑动边界条件,发现边缘电流方向随时间振荡,揭示了边界条件对集体动力学的重要性。

Comments 18 pages, 23 figures

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Journal ref
Phys. Rev. E, 109:054604, May 2024
AI中文摘要

致密细菌悬浮液表现出称为“细菌湍流”的湍流行为。 bulk 中未受约束的细菌湍流行为可通过 Toner-Tu-Swift-Hohenberg(TTSH)方程描述速度场。然而,细菌湍流与某些边界(如固体壁)接触时的边界条件处理仍不明确。尽管边缘电流(沿边界流动)在多个受限细菌悬浮液实验中已被证明重要,但基于 TTSH 方程的先前数值研究采用非滑动边界条件,似乎未能正确描述细菌接近边界的行为。在本研究中,我们对 TTSH 方程施加滑动边界条件以描述边界处的细菌运动。我们开发了一种实现滑动边界条件的方法。使用该方法,我们成功产生了边缘电流并发现其方向随时间振荡。振荡可归因于 TTSH 方程中的对流项。我们的工作表明,边界条件在活性系统的集体动力学中可能起重要作用。

英文摘要

Dense bacterial suspensions exhibit turbulent behaviour called ``bacterial turbulence''. The behavior of the bulk unconstrained bacterial turbulence is described well by the Toner-Tu-Swift-Hohenberg (TTSH) equation for the velocity field. However, it remains unclear how we should treat boundary conditions on bacterial turbulence in contact with some boundaries (e.g. solid walls). To be more specific, although the importance of the ``edge current'', the flow along the boundary, has been demonstrated in several experimental studies on confined bacterial suspensions, previous numerical studies based on the TTSH equation employ non-slip boundary conditions and do not seem to describe properly the behavior of bacteria near the boundaries. In this study, we impose a slip boundary condition on the TTSH equation to describe the bacterial motion at boundaries. We develop a method to implement the slip boundary condition. Using this method, we have successfully produced edge current and discovered that the direction of the edge current temporally oscillates. The oscillation can be attributable to the advection term in the TTSH equation. Our work demonstrates that boundary conditions could play an important role in the collective dynamics of active systems.

2403.16156 2026-06-08 math.OC 版本更新

Maximally Degenerate Floquet Structure and Possible Nonexistence of Optimal Control in a Pendulum Swing-Up Problem

极大退化Floquet结构与摆动上升问题中可能的最优控制不存在性

Noboru Sakamoto

AI总结 本文研究了通过关联的哈密顿系统分析摆体二次控制成本的无限时间最优控制问题,发现其强退化特性,通过李级数和切塔耶夫不稳定性定理证明平衡点非超双曲意义下弱不稳定,进而识别出形成不变圆柱的周期轨道族,其单列矩阵具有极大退化Floquet结构,暗示慢非指数动力学和长时过渡机制。

Comments Submitted for conference presentation on April 1st, 2026

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AI中文摘要

本文研究了通过关联的哈密顿系统分析摆体二次控制成本的无限时间最优控制问题。该问题强退化,因为在竖直平衡点处线性化具有纯虚特征值多重性,使标准线性分析不明确。利用李级数和切塔耶夫不稳定性定理,证明平衡点在非超双曲意义上弱不稳定。进一步识别出形成不变圆柱的一族周期轨道,其单列矩阵表现出由单个约当块构成的极大退化Floquet结构。此结构暗示慢非指数动力学,并提供长时过渡的机制,即使控制努力极小。尽管是为摆体推导的,此现象源于最优控制公式中的退化,可能更广泛存在,表明尽管可稳定化,最优控制可能不存在。

英文摘要

This paper studies an infinite-horizon optimal control problem for a pendulum with quadratic control cost via its associated Hamiltonian system. The problem is strongly degenerate, as the linearization at the upright equilibrium has purely imaginary eigenvalues with multiplicity, making standard linear analysis inconclusive. Using Lie series and Chetaev's instability theorem, we show that the equilibrium is weakly unstable in a non-hyperbolic sense. We further identify a family of periodic orbits forming an invariant cylinder, whose monodromy matrix exhibits a maximally degenerate Floquet structure consisting of a single Jordan block at the unit multiplier. This structure implies slow, non-exponential dynamics and provides a mechanism for long-time transitions with arbitrarily small control effort. Although derived for a pendulum, this phenomenon arises from degeneracy in the optimal control formulation and may occur more broadly, suggesting the possible nonexistence of optimal control despite stabilizability.

2304.05793 2026-06-08 astro-ph.GA astro-ph.CO hep-ph 版本更新

Confronting fuzzy dark matter with the rotation curves of nearby dwarf irregular galaxies

用近邻矮不规则星系的旋转曲线对抗模糊暗物质

Andrés Bañares-Hernández, Andrés Castillo, Jorge Martin Camalich, Giuliano Iorio

AI总结 本文通过高分辨率旋转曲线数据检验模糊暗物质模型的可行性,发现其在核心半径-质量关系和线性功率谱预测上存在显著矛盾。

Comments 22 pages, 9 figures, 3 tables (corrected typo in eq. 18)

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Journal ref
A&A 676, A63 (2023)
AI中文摘要

我们从现象学上检验了模糊暗物质(FDM)的可行性。我们通过将模型的预测,特别是暗物质晕中心溶iton核心的形成,与“LITTLE THINGS in 3D”目录中高分辨率旋转曲线的均匀且稳健样本进行对比。该目录包含孤立的、暗物质主导的矮不规则星系,为宇宙学研究提供了最佳的基准。我们使用基于马尔可夫链蒙特卡洛技术的统计框架,能够提取诸如轴子质量、溶iton核心质量、暗物质晕质量及其浓度参数等相关参数,除了对核心-晕关系的预测由模拟得出外,除了先验假设外,其余先验假设较为宽松。拟合结果用于对模型预测进行各种诊断。FDM对“LITTLE THINGS in 3D”目录中星系的旋转曲线提供了良好的拟合,从不同星系确定的轴子质量集中在$ m_a\approx2\times10^{-23}$ eV。然而,我们发现分析中存在两个主要问题。第一,数据遵循核心属性的缩放关系,与溶iton的预测不一致。这个问题在核心半径-质量关系中尤为突出,其显著性在面值上大于$ \gtrsim5σ$。第二个问题是与FDM对轴子质量预测的线性功率谱的强烈抑制有关。这可以通过我们样本中的星系计数非常保守地约束,导致再次超过$ 5σ$的张力。我们估计了分析中的物质效应,并讨论了它们是否能缓解模型与观测的张力。

英文摘要

We investigate phenomenologically the viability of fuzzy dark matter (FDM). We do this by confronting the predictions of the model, in particular, the formation of a solitonic core at the center of dark matter halos, with a homogeneous and robust sample of high-resolution rotation curves from the "LITTLE THINGS in 3D" catalog. This comprises a collection of isolated, dark matter dominated dwarf-irregular galaxies that provides an optimal benchmark for cosmological studies. We use a statistical framework based on Markov chain Monte Carlo techniques that allows us to extract relevant parameters such as the axion mass, the mass of the solitonic core, the mass of the dark matter halo and its concentration parameter with a rather loose set of priors except for the implementation of a core-halo relation that is predicted by simulations. The results of the fits are used to perform various diagnostics on the predictions of the model. FDM provides an excellent fit to the rotation curves of the "LITTLE THINGS in 3D" catalog, with axion masses determined from different galaxies clustering around $m_a\approx2\times10^{-23}$ eV. However, we find two major problems in our analysis. First, the data follow scaling relations of the properties of the core which are not consistent with the predictions of the soliton. This problem is particularly acute in the core radius - mass relation with a tension that, at face value, has a significance $\gtrsim5σ$. The second problem is related to the strong suppression of the linear power spectrum that is predicted by FDM for the axion mass preferred by the data. This can be constrained very conservatively by the galaxy counts in our sample, which leads to a tension exceeding again $5σ$. We estimate the effects of baryons in our analysis and discuss whether they could alleviate the tensions of the model with observations.

2312.15954 2026-06-08 cs.IT math.AC math.IT 版本更新

Structure and Construction of Two-Dimensional Minimal Linear Codes over the rings $\mathbb{Z}_{p^n}$ with Applications to Secret Sharing

二维环$\mathbb{Z}_{p^n}$上的最小线性码的结构与构造及其在秘密分享中的应用

Biplab Chatterjee, Sihem Mesnager, Ratnesh Kumar Mishra, Makhan Maji, Kalyan Hansda

AI总结 本文研究了环$\mathbb{Z}_{p^n}$上的二维最小线性码的结构与构造,提出了通过结构化的$2\times m$矩阵生成码族的方法,并证明了在生成矩阵包含所有本质列向量时码的最小性,同时探讨了其在秘密分享方案中的应用。

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AI中文摘要

最小线性码在编码理论和密码学中扮演重要角色,特别是在秘密分享方案的构造中。本文研究了有限环$\mathbb{Z}_{p^n}$上的二维最小线性码的结构与构造。我们提供了一种由结构化的$2\times m$矩阵生成的码族的显式构造,并证明当生成矩阵包含所有$p^n+p^{n-1}$种本质列向量时,这些码是最小的。进一步证明该条件是必要的:移除任何一种列类型会破坏码的最小性。作为结果,我们建立了二维最小线性码在$\mathbb{Z}_{p^n}$上的长度下界。本文还通过实例展示了构造方法并验证了理论结果。我们还表明,该构造不能简单地扩展到形式为$\mathbb{Z}_{p^n q^l}$的环。最后,我们将结果应用于基于$\mathbb{Z}_{p^n}$上最小线性码的秘密分享方案设计,并分析了相应的访问结构。本研究揭示了有限环上最小码与有限域上最小码之间的结构性差异,为密码学中的编码理论构造提供了新的视角。

英文摘要

Minimal linear codes play an important role in coding theory and cryptography, particularly in the construction of secret sharing schemes. In this paper, we investigate the structure and construction of two-dimensional minimal linear codes over the finite rings $\mathbb{Z}_{p^n}$. We provide an explicit construction of a family of two-dimensional linear codes generated by a structured $2\times m$ matrix over $\mathbb{Z}_{p^n}$ and prove that these codes are minimal whenever the generator matrix contains all $p^n+p^{n-1}$ essential types of column vectors. We further show that this condition is necessary: removing any of these column types destroys the resulting code's minimality. As a consequence, we establish a lower bound on the length of two-dimensional minimal linear codes over $\mathbb{Z}_{p^n}$. Several examples are presented to illustrate the construction and to verify the theoretical results. We also demonstrate that the proposed construction cannot be extended in a straightforward manner to rings of the form $\mathbb{Z}_{p^n q^l}$. Finally, we apply our results to the design of secret sharing schemes derived from minimal linear codes over $\mathbb{Z}_{p^n}$ and analyze the corresponding access structures. Our study highlights structural differences between minimal codes defined over finite rings and those over finite fields, revealing new perspectives for coding-theoretic constructions in cryptographic applications.

2312.05335 2026-06-08 quant-ph physics.app-ph 版本更新

Optical probing of phononic properties of a tin-vacancy color center in diamond

金刚石中锡空位色心的声子性质的光学探测

Cem Güney Torun, Joseph H. D. Munns, Franziska Marie Herrmann, Viviana Villafane, Kai Müller, Ulrich Kentsch, Shavkat Akhmadaliev, Anthony C. Withers, Andreas Thies, Wentao Zhang, Aleksei Tsarapkin, Katja Höflich, Tommaso Pregnolato, Gregor Pieplow, Tim Schröder

AI总结 通过光学方法研究金刚石中锡空位色心的相干特性,包括线宽展宽效应和基态轨道能级间的相干人口陷阱。利用谱分析确定声子耦合系数,并揭示轨道去极化时间尺度。

Comments 18 pages, 15 figures, 1 table

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Journal ref
Phys. Rev. Research 8, 023230, 2026
AI中文摘要

通过光学手段研究金刚石中锡空位色心(SnV)的相干特性,包括线宽展宽效应和基态轨道能级间的相干人口陷阱(CPT)。由于基态轨道的较大自旋-轨道分裂,基态间的热化速率在时域中难以直接测量。首先,通过温度依赖的线宽展宽测量确定声子耦合系数,这些测量在具有寿命限制线宽和原子特性的发射体上进行,使其具有代表性。其次,进行CPT型实验以独立分析4 K下的热退相干过程。将谱信息转换为共轭变量时间,提供皮秒分辨率,并揭示轨道去极化时间尺度约为30 ps。利用研究动态的影响估计受热效应限制的自旋退相干时间。

英文摘要

The coherence characteristics of a tin-vacancy color center (SnV) in diamond are investigated through optical means, including linewidth broadening effects and coherent population trapping (CPT) between the ground state orbital levels. Spectral analysis is required as due to the large spin-orbit splitting of the orbital ground states, thermalization between the ground states occurs at rates that are impractical to measure directly in the time domain. First, by implementing a temperature-dependent linewidth broadening measurement, including the challenging-to-measure D transition, phononic coupling coefficients are determined. These measurements are performed on an emitter with a lifetime-limited linewidth and atom-like properties, making the measurement representative for high-quality SnVs. Next, a CPT-type experiment is carried out to independently analyze thermal decoherence processes at 4 K. The spectral information is transformed into its conjugate variable time, providing picosecond resolution and revealing an orbital depolarization timescale of ${\sim30{\rm~ps}}$. Consequences of the investigated dynamics are then used to estimate spin dephasing times limited by thermal effects.

2311.11925 2026-06-08 physics.soc-ph cs.ET quant-ph 版本更新

Quantum Computing Standards & Accounting Information Systems

量子计算标准与会计信息系统

Maksym Lazirko

AI总结 本文探讨量子计算对会计信息系统安全性的威胁,分析量子标准作为治理机制的作用,揭示美国与欧盟在标准制定上的差异及潜在风险。

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AI中文摘要

近年来,量子技术的进步威胁了会计信息系统(AIS)的加密基础,亟需转向量子安全标准。本文研究量子标准为何属于会计领域,将其视为确保数据完整性、可审计性和合法性的关键制度治理机制。通过新制度理论,分析强制性、规范性和模仿性压力如何推动各国采纳这些标准。通过对主要标准制定机构的结构化文件分析,研究发现美国与欧盟/欧洲方法存在显著差异:美国标准强调市场驱动创新和务实合法性,而欧盟和欧洲标准则优先考虑监管协调和社会隐私目标。研究发现,尽管这些标准目前是自愿的,但其不一致的实施会带来脱节和碎片化的保证实践风险,挑战全球AIS安全控制的可比性。

英文摘要

Recent advancements in quantum technology threaten the cryptographic foundations of Accounting Information Systems (AIS), necessitating a transition to quantum-safe standards. This paper investigates why quantum standards fall within the purview of accounting by framing them as essential institutional governance mechanisms that ensure the integrity, auditability, and legitimacy of data. Utilizing neo-institutional theory, the study analyzes how coercive, normative, and mimetic pressures drive the adoption of these standards across jurisdictions. Through a structured documentary analysis of major standard-setting bodies, the research identifies significant divergence between U.S. and EU/European approaches: U.S. standards emphasize market-driven innovation and pragmatic legitimacy, while EU and Pan-European standards prioritize regulatory harmonization and societal privacy objectives. The findings suggest that while these standards are currently voluntary, their inconsistent implementation creates risks of decoupling and fragmented assurance practices, challenging the global comparability of AIS security controls.

2202.05907 2026-06-08 cs.DS 版本更新

Fast and perfect sampling of subgraphs and polymer systems

快速且完美的子图和聚合系统采样

Antonio Blanca, Sarah Cannon, Will Perkins

AI总结 本文提出了一种高效算法,用于根带度图的加权连通诱导子图采样,在亚临界条件下实现完美采样,并应用于聚合模型和非根图let,解决了两种不同问题,改进了自旋系统的采样方法。

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AI中文摘要

我们为根带度图的加权连通诱导子图(或图let)提供了一种高效的完美采样算法。该算法利用顶点渗透过程和精心设计的拒绝过滤器,并在渗透亚临界条件下工作。我们证明该条件最优,即当条件不满足时,无限图的(近似)采样在有限期望时间内不可能,有限图的采样则不可行。我们将该采样算法作为子程序,为有限图中的聚合模型和加权非根图let提供近线性时间的完美采样算法,解决两种广泛研究但差异很大的问题。该新的聚合模型完美采样算法为低温度下扩张图和不平衡二分图上的自旋系统提供了改进的采样算法,以及其他应用。

英文摘要

We give an efficient perfect sampling algorithm for weighted, connected induced subgraphs (or graphlets) of rooted, bounded degree graphs. Our algorithm utilizes a vertex-percolation process with a carefully chosen rejection filter and works under a percolation subcriticality condition. We show that this condition is optimal in the sense that the task of (approximately) sampling weighted rooted graphlets becomes impossible in finite expected time for infinite graphs and intractable for finite graphs when the condition does not hold. We apply our sampling algorithm as a subroutine to give near linear-time perfect sampling algorithms for polymer models and weighted non-rooted graphlets in finite graphs, two widely studied yet very different problems. This new perfect sampling algorithm for polymer models gives improved sampling algorithms for spin systems at low temperatures on expander graphs and unbalanced bipartite graphs, among other applications.

2207.13752 2026-06-08 math.CO cs.DM 版本更新

Almost covering all the layers of hypercube with multiplicities

用多重性覆盖超立方体的几乎所有层

Arijit Ghosh, Chandrima Kayal, Soumi Nandi

AI总结 研究通过多项式覆盖超立方体不同层的多重性,证明了多项式次数下限并构造了覆盖方案,同时推翻了关于对称子集的猜想。

Comments 16 pages, substantial changes from previous version, title and abstract changed to better reflect the content of the paper

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AI中文摘要

给定超立方体Q^n={0,1}^n和k∈{0,…,n},k层Q^n_k是坐标中恰好有k个1的点集。对于固定的t∈N和k∈{0,…,n},设P∈R[x₁,…,xₙ]为多项式,其在Q^n\Q^n_k处有至少t重零点,在Q^n_k处有恰好t−1重零点。本文证明deg(P)≥max{k,n−k}+2t−2。匹配该下界,我们构造了超平面族H₁,…,Hₘ,其中m=max{k,n−k}+2t−2,使得Q^n_k中的每个点被覆盖恰好t−1次,其他点被覆盖至少t次。当k=0,t=1时,恢复了Alon和Füredi的结果。利用该超平面族推翻了Venkitesh关于对称子集的猜想。我们还研究了一个新的受限和集问题变体。

英文摘要

Given a hypercube $\mathcal{Q}^{n} := \{0,1\}^{n}$ in $\mathbb{R}^{n}$ and $k \in \{0, \dots, n\}$, the $k$-th layer $\mathcal{Q}^{n}_{k}$ of $\mathcal{Q}^{n}$ denotes the set of all points in $\mathcal{Q}^{n}$ whose coordinates contain exactly $k$ many ones. For a fixed $t \in \mathbb{N}$ and $k \in \{0, \dots, n\}$, let $P \in \mathbb{R}\left[x_{1}, \dots, x_{n}\right]$ be a polynomial that has zeroes of multiplicity at least $t$ at all points of $\mathcal{Q}^{n} \setminus \mathcal{Q}^{n}_{k}$, and $P$ has zeros of multiplicity exactly $t-1$ at all points of $\mathcal{Q}^{n}_{k}$. In this short note, we show that $$deg(P) \geq \max\left\{ k, n-k\right\}+2t-2.$$Matching the above lower bound we give an explicit construction of a family of hyperplanes $H_{1}, \dots, H_{m}$ in $\mathbb{R}^{n}$, where $m = \max\left\{ k, n-k\right\}+2t-2$, such that every point of $\mathcal{Q}^{n}_{k}$ will be covered exactly $t-1$ times, and every other point of $\mathcal{Q}^{n}$ will be covered at least $t$ times. Note that putting $k = 0$ and $t=1$, we recover the much celebrated covering result of Alon and Füredi (European Journal of Combinatorics, 1993). Using the above family of hyperplanes we disprove a conjecture of Venkitesh (The Electronic Journal of Combinatorics, 2022) on exactly covering symmetric subsets of hypercube $\mathcal{Q}^{n}$ with hyperplanes. To prove the above results we have introduced a new measure of complexity of a subset of the hypercube called index complexity which we believe will be of independent interest. We also study a new interesting variant of the restricted sumset problem motivated by the ideas behind the proof of the above result.

2108.05695 2026-06-08 physics.hist-ph math-ph math.MP nlin.SI 版本更新

Obituary: Aristophanes Dimakis

讣告:阿里斯托费尼斯·迪马基斯

Folkert Müller-Hoissen

AI总结 本文回顾了理论物理学家和数学家阿里斯托费尼斯·迪马基斯的生平、职业和科学成就,强调其对物理学和数学的贡献。

Comments 13 pages, 4 figures, second version: birth date corrected

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AI中文摘要

理论物理学家和数学家阿里斯托费尼斯·迪马基斯于2021年7月8日在希腊雅典去世,享年68岁。本文简要回顾了他的生平、职业生涯和科学成就。

英文摘要

The theoretical physicist and mathematician Aristophanes Dimakis passed away on July 8, 2021, at the age of 68, in Athens, Greece. We briefly review his life, career and scientific achievements.

2111.14981 2026-06-08 math.NT 版本更新

Almost Sure Bounds for Discrepancies of Linear Forms on the Circle

圆上线性形式偏差的几乎必然界

Hao Wu

AI总结 研究圆上线性形式序列的偏差,证明对于几乎全部向量,偏差主次阶为(log N)^d,改进了Beck关于多维Kronecker序列的定理。

Comments Rewrite to improve readability, with several mistakes and typos fixed

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AI中文摘要

作为无理旋转的推广和高维Kronecker序列的对偶情况,我们研究圆上线性形式序列的偏差。给定无理数α₁,…,α_d,考虑N^d个点{ k₁α₁+…+k_dα_d mod 1 : 1≤k_j≤N }。我们证明,对于几乎全部向量(α₁,…,α_d)∈R^d,这些点相对于[0,1)内区间的最大偏差具有最优主次阶(log N)^d,至多乘以log log N的幂。该结果在线性形式设定下,提供了Beck关于多维Kronecker序列(Ann. of Math., 1994)的几乎精确对偶类比。证明结合了傅里叶分析、度量乘法丢番图估计和一个将某些格点计数误差还原到Beck偏差定理的对偶论证。

英文摘要

As a generalization of irrational rotations and a dual case of higher-dimensional Kronecker sequences, we study the discrepancy of sequences of linear forms on the circle. Given irrationals $α_1,\dots,α_d$, consider the set of $N^d$ points $\{k_1α_1+\cdots+k_dα_d \mod 1 : 1\le k_j\le N\}$. We prove that for a full-measure set of vectors $(α_1,\dots,α_d)\in\mathbb{R}^d$, the maximal discrepancy of these points relative to intervals in $[0,1)$ has the optimal principal order $(\log N)^d$, up to powers of $\log\log N$. This result provides a nearly sharp dual analogue, in the setting of linear forms, to Beck's celebrated theorem on multidimensional Kronecker sequences (Ann. of Math., 1994). The proof combines Fourier analysis, metric multiplicative Diophantine estimates, and a duality argument which reduces certain lattice-counting errors to Beck's discrepancy theorem.

1906.11685 2026-06-08 math.QA math.GR 版本更新

Finite-dimensional pointed Hopf algebras over finite simple groups of Lie type VI. Suzuki and Ree groups

有限维指针Hopf代数 over 有限简单李型VI. Suzuki和Ree群

Giovanna Carnovale, Mauro Costantini

AI总结 研究Suzuki和Ree群共轭类的rack结构,确定kthulhu类,并利用阿贝尔rack技术证明仅有的有限维复指针Hopf代数是群代数。

Comments D. Craven has detected one missing maximal subgroup in the list in [20], when q=8. This version takes into account the missing subgroup in Lemma 4.9. The main result and all intermediate results remain unchanged

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Journal ref
The post-print version is published in Journal of Pure and Applied Algebra, Volume 225, Issue 4, April 2021, 106568
AI中文摘要

我们分析了Suzuki和Ree群共轭类的rack结构,并确定哪些类是kthulhu类。结合这一结果与阿贝尔rack技术,我们证明仅有的有限维复指针Hopf代数 over 有限简单李型VI. Suzuki和Ree群是它们的群代数。

英文摘要

We analyse the rack structure of conjugacy classes in simple Suzuki and Ree groups and determine which classes are kthulhu. Combining this results with abelian rack techniques, we show that the only finite-dimensional complex pointed Hopf algebras over the simple Suzuki and Ree groups are their group algebras.

2606.06450 2026-06-08 cond-mat.mes-hall cond-mat.str-el

1/3 Fractional and Gapless Integer Quantum Anomalous Hall States in Rhombohedral Graphene

菱方石墨烯中的1/3分数量子反常霍尔效应和无能隙整数量子反常霍尔态

Jackson P. Butler, Tonghang Han, Andrew DiFabbio, Zach Hadjri, Emily Aitken, Kenji Watanabe, Takashi Taniguchi, Long Ju, Raymond C. Ashoori

AI总结 通过量子电容和输运测量,在菱方五层石墨烯/六方氮化硼莫尔超晶格中观察到1/3填充的FQAH态,并发现从分数量子反常霍尔态到平庸电荷密度波态的拓扑相变,以及整数量子反常霍尔态到无能隙高可压缩态的转变。

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AI中文摘要

分数量子反常霍尔效应发生在扭曲双层MoTe$_2$和与六方氮化硼对齐的菱方$n$层石墨烯(R$n$G/hBN)的莫尔超晶格中,这是一种由相互关联的电子关联和拓扑结构驱动的新型量子相。尽管已经识别出Jain序列中的几个分数量子反常霍尔态,但在这两种系统中都缺失了1/3态——传统分数量子霍尔系统中最稳健和最基本的状态。确定其是否存在将对理解FQAH机制产生重大影响,特别是在理论上仍存在争议的R$n$G/hBN系统中。在这里,我们通过量子电容和输运测量的结合,报告了在R$5$G/hBN莫尔超晶格器件中,在莫尔填充因子$ν= 1/3$处的FQAH效应。通过调节位移场,我们观察到了从1/3分数量子反常霍尔绝缘体到平庸电荷密度波态的拓扑相变。包含1/3态后,R$5$G/hBN中的FQAH态现在表现出令人惊讶的关于半填充的粒子-空穴对称性,与最低朗道能级中FQH态的行为非常相似。此外,我们在每个莫尔晶胞一个电子的填充$ν=1$以及$ν\lesssim 1$处进行了压缩率和输运测量,之前的输运测量显示扩展量子反常霍尔效应。虽然我们的输运测量显示整数量子反常霍尔态和EQAH区域之间没有变化,但压缩率测量揭示了从有能隙的IQAH态到无能隙且高度可压缩的EQAH态的明显转变。我们对丰富相图的直接热力学表征为零磁场下任意子编织和非阿贝尔准粒子的工程化铺平了道路。

英文摘要

The fractional quantum anomalous Hall (FQAH) effect occurs in moiré superlattices in both twisted bilayer MoTe$_2$ and rhombohedral $n$-layer graphene aligned to hexagonal boron nitride (R$n$G/hBN) as a novel quantum phase driven by intertwined electron correlation and topology. Although several fractional states in the Jain sequence have been identified, the $1/3$ state, the most robust and fundamental state in conventional fractional quantum Hall (FQH) systems, was missing in either FQAH system. Determining whether it exists would have a major impact on understanding the mechanism of FQAH, especially in the theoretically still-debated R$n$G/hBN system. Here we report the FQAH effect at moiré filling factor $ν= 1/3$ in R$5$G/hBN moiré superlattice devices, through a combination of quantum capacitance and transport measurements. By tuning the displacement field, we observed a topological phase transition from a $1/3$ fractional Chern insulator (FCI) to a trivial charge density wave state. With the inclusion of the $1/3$ state, the FQAH states in R$5$G/hBN now exhibit a surprising level of particle-hole symmetry about half-filling, closely resembling the behavior of FQH states in the lowest Landau level. Additionally, we perform compressibility and transport measurements at a filling of one electron per moiré unit cell, $ν=1$, and also for $ν\lesssim 1$, where previous transport measurements displayed the extended quantum anomalous Hall (EQAH) effect. While our transport measurements show no change between the integer quantum anomalous Hall state (IQAH) and the EQAH region, compressibility measurements reveal a distinct transition from a gapped IQAH state to a gapless and highly compressible EQAH state. Our direct thermodynamic characterization of the rich phase diagram paves the way to engineering of anyon braiding and non-Abelian quasiparticles at zero magnetic field.

2606.06068 2026-06-08 math.NT math.CO

An Elementary Analysis of the Prime Partition Function

素数划分函数的基本分析

Asaf Cohen Antonir, Asaf Shapira

AI总结 本文通过初等方法证明了素数划分函数pp(n)的对数渐近于2π√(n/(3 log n)),并展示了该方法可推广到相关问题的渐近估计。

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AI中文摘要

令 $pp (n)$ 表示将 $n$ 写成素数之和的方式数。在本文中,我们证明 $$ \log pp (n) \sim 2\pi\sqrt{\frac{n}{3\log n}}\;. $$ 虽然已有更精确的估计,但它们依赖于高度复杂且冗长的证明。与此形成鲜明对比的是,我们的方法使用了一个简短的初等配方,并且可以轻松调整以对几个相关的、被广泛研究的问题给出类似的渐近估计。

英文摘要

Let $pp (n)$ denote the number of ways to write $n$ as a sum of primes. In this paper, we show that $$ \log pp (n) \sim 2π\sqrt{\frac{n}{3\log n}}\;. $$ While sharper estimates are already known, they rely on highly involved and lengthy proofs. In sharp contrast, our approach uses a short, elementary recipe that easily adapts to yield similar asymptotic estimates for several related, extensively studied problems.

2606.05366 2026-06-08 cs.DS cs.CC

Exponential Quantum Space Advantage for Approximating Max-$k$SAT in the Streaming Setting

流式设置中近似Max-$k$SAT的指数级量子空间优势

Haoyu Wang, Guangxu Yang

AI总结 本文提出了一种单次量子流算法,使用polylog(n)空间在Max-kSAT问题上达到0.7172近似比,相比经典算法需要Ω(√n)空间,展示了指数级量子空间优势。

Comments 57 pages

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AI中文摘要

在本文中,我们给出了一种用于Max-$k$SAT的单次量子流算法,该算法使用$\operatorname{polylog}(n)$空间,并在具有$n$变量的实例上实现了$0.7172$近似。相比之下,Chou、Golovnev和Velusamy(FOCS 2020)的先前工作表明,对于Max-$k$SAT,任何经典流算法要实现优于$\sqrt{2}/2 \approx 0.7071$的近似比都需要$Ω(\sqrt{n})$空间。因此,它在流式设置中为Max-$k$SAT带来了指数级的量子空间优势。 我们进一步给出了一种用于Max-2OR的单次量子流算法,该算法使用$\operatorname{polylog}(n)$空间,并在具有$n$变量的实例上实现了$0.7425$近似。结合已知结果,这为所有布尔Max-2CSP的量子空间优势提供了完整分类。

英文摘要

In this paper, we give a one-pass quantum streaming algorithm for Max-$k$SAT that uses $\operatorname{polylog}(n)$ space and achieves a $0.7172$-approximation on instances with $n$ variables. In contrast, prior work by Chou, Golovnev, and Velusamy (FOCS 2020) implies that achieving an approximation ratio better than $\sqrt{2}/2 \approx 0.7071$ for Max-$k$SAT requires $Ω(\sqrt{n})$ space for any classical streaming algorithm. Therefore, it yields an exponential quantum space advantage for Max-$k$SAT in the streaming setting. We further give a one-pass quantum streaming algorithm for Max-2OR that uses $\operatorname{polylog}(n)$ space and achieves a $0.7425$-approximation on instances with $n$ variables. Combining with the known results, it gives a complete classification of quantum space advantages for all Boolean Max-2CSPs.

2606.05273 2026-06-08 cs.CY cs.CR

Online Safety Regulation Increases Privacy Risk: Evidence from the UK Online Safety Act

在线安全监管增加隐私风险:来自英国《在线安全法》的证据

Dhyey Mehta, Eldar Jalilzade, Maksim Kalameyets, Rebecca Owens, Marc Juarez, Stergios Aidinlis, Lei Shi, Tuğrulcan Elmas

AI总结 通过分析Reddit讨论和VPN服务隐私政策,研究英国《在线安全法》分阶段实施对用户隐私行为的影响,发现监管里程碑显著增加了VPN相关讨论和搜索,表明在线安全监管可能产生次要隐私成本。

Comments 14 pages, 9 figures. Submitted to PoPETs 2027

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AI中文摘要

世界各国政府越来越多地对数字平台进行监管,以减少在线伤害,特别是影响儿童的伤害。然而,访问限制可能会改变用户行为并引入新的隐私和安全风险。英国《在线安全法》(OSA)于2023年10月通过,体现了这一趋势:它将年龄保证和安全要求扩展到社交媒体、搜索和色情服务,并分阶段推出。Ofcom的非法内容执法职责于2025年3月生效,成人内容强制性年龄验证于2025年7月生效。这种分阶段推出使得能够实时观察对监管的行为反应。为此,我们分析了Reddit上VPN和英国政治社区的讨论,并对69个独特VPN服务进行了隐私政策风险分析。我们发现,这三个里程碑中的每一个都导致Reddit上VPN相关讨论的显著逐步增加:在英国用户中,明确涉及监管或隐私背景下VPN使用的帖子和评论分别增加了+100%、+217%和+415%。英国政治社区显示出更大的效应,英国用户中与OSA相关的政治讨论分别增加了+213%、+545%和+464%。在年龄验证截止日期,英国Google上VPN搜索兴趣增加了+89%。用户主要将这种反应归因于隐私、监视以及对年龄验证中介的不信任,而非简单的访问寻求。低、中、高风险VPN的需求均有所增加,但比例分布基本保持稳定。这些发现表明,在线安全监管即使没有不成比例地将注意力转向高风险提供商,也可能产生次要隐私成本。

英文摘要

Governments worldwide are increasingly regulating digital platforms to reduce online harms, particularly those affecting children. However, access restrictions can alter user behaviour and introduce new privacy and security risks. The UK Online Safety Act (OSA), passed in October 2023, illustrates this trend: it extends age-assurance and safety requirements to social media, search, and pornography services, and rolled out in phases. Ofcom's illegal content enforcement duties came into force in March 2025, and mandatory age verification for adult content took effect in July 2025. This phased rollout enables real-time observation of behavioural responses to regulation. To address this, we analyse Reddit discourse across VPN and UK Politics communities and conduct a privacy-policy risk analysis of 69 unique VPN services. We find that each of these three milestones produced significant stepwise increases in VPN-related discussion on Reddit: among UK-based users, posts and comments explicitly about VPN use in a regulatory or privacy context rose by +100%, +217%, and +415% respectively. UK Politics communities showed even larger effects, with OSA-related political discourse rising by +213%, +545%, and +464%, respectively, among UK-based users. UK VPN search interest on Google rose by +89% at the age-verification deadline. Users primarily framed this response around privacy, surveillance, and distrust of age-verification intermediaries rather than simple access-seeking. Demand increased across low, medium, and high-risk VPNs, but the proportional distribution remained broadly stable. These findings suggest that online safety regulation can create secondary privacy costs even when it does not disproportionately shift attention toward higher-risk providers.

2606.02672 2026-06-08 cs.AR cs.ET

Heterogeneous Mapping for Analog In-Memory Computing Accelerators: A Unified Workflow

模拟内存计算加速器的异构映射:统一工作流

Corey Lammie

AI总结 本文提出一个统一的四阶段工作流,用于将DNN工作负载分区到模拟内存计算加速器中的模拟和数字资源上,并通过GPT-2案例展示了投影级映射和选择性数字执行的重要性。

Comments Accepted by IEEE Computer Architecture Letters

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Journal ref
IEEE Computer Architecture Letters 2026
AI中文摘要

模拟内存计算(AIMC)加速器直接在内存阵列中执行矩阵-向量乘法,减少数据移动并提高DNN推理效率。其有限的有效精度促使了结合模拟计算瓦片和数字处理单元的异构架构。本文根据映射粒度、优化策略和模型支持,对现有的将DNN工作负载分区到这些资源上的方法进行了分类,并将其提炼为一个统一的四阶段工作流。为了在现有方法尚未涉及的模型类别上演示该工作流,我们将其前两个阶段应用于GPT-2,生成了首个针对解码器-only Transformer的AIMC特定精度敏感性剖面。敏感性由49个投影中的4个主导,其中第一个解码器块的注意力输出主导了一个数量级。这表明投影级映射和早期块及输出投影的选择性数字执行对于在AIMC硬件上可靠部署解码器Transformer至关重要。

英文摘要

Analog In-Memory Computing (AIMC) accelerators execute matrix-vector multiplications directly within memory arrays, reducing data movement and improving DNN inference efficiency. Their limited effective precision motivates heterogeneous architectures that combine analog compute tiles with digital processing units. This letter classifies existing methods for partitioning DNN workloads across these resources by mapping granularity, optimization strategy, and model support, and distills them into a unified four-stage workflow. To demonstrate the workflow on a model class not yet addressed by existing methods, we apply its first two stages to GPT-2, producing the first AIMC-specific precision sensitivity profile for a decoder-only transformer. Sensitivity is dominated by 4 of 49 projections, with the first decoder block's attention output dominating by an order of magnitude. This suggests that projection-level mapping and selective digital execution of early-block and output-facing projections are important for reliable decoder-transformer deployment on AIMC hardware.