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2603.12006 2026-06-11 math.CO math.PR 版本更新

On the structure of the sandpile identity element on Sierpinski gasket graphs

关于Sierpinski垫片图上沙堆恒等元的结构

Robin Kaiser, Ecaterina Sava-Huss, Julia Überbacher

AI总结 研究Sierpinski垫片有限近似图的可交换沙堆群恒等元,证明其标度极限中的二阶项收敛到垫片上到最近角的路径距离。

Comments 14 pages, 11 figures

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AI中文摘要

我们考虑Sierpinski垫片有限近似图的可交换沙堆群的恒等元,并证明标度极限中的二阶项收敛到Sierpinski垫片上到最近角的路径距离。证明依赖于将沙堆群的恒等元分解为一个常数函数与近似图上图距离的拉普拉斯算子之和。

英文摘要

We consider the identity of the abelian sandpile group of finite approximation graphs of the Sierpinski gasket, and we show that the second-order term in the scaling limit converges to the path distance to the nearest corner on the Sierpinski gasket. The proof relies on a decomposition of the identity of the sandpile group into the sum of a constant function and the Laplacian of the graph distance on the approximating graphs.

2603.11817 2026-06-11 physics.optics physics.atom-ph physics.ins-det 版本更新

Temperature-insensitive tunable and stable Fabry-Perot cavity for atomic physics

用于原子物理的温度不敏感可调谐稳定法布里-珀罗腔

Joshua Ruelle, Martin Hauden, Francisco S. Ponciano-Ojeda, Marion Delehaye

AI总结 本文提出一种压电可调谐法布里-珀罗腔,在约5°C下热膨胀系数抵消,实现1秒积分时间4×10^{-13}的分数频率不稳定性,消除了原子-腔实验对外部稳定化的需求。

Comments Submission to SciPost - replaced with revised version

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AI中文摘要

光学法布里-珀罗腔是计量实验的关键工具,可实现极端的长度稳定性,同时对于某些原子物理实验,可调谐至原子跃迁以实现原子-光相互作用。然而,在单个腔中同时实现频率稳定性和可调谐性仍然是一个挑战,迫使利用原子-腔相互作用的计量实验依赖外部主动反馈系统来稳定腔长。在这里,我们描述了一种压电可调谐腔,在约$5^\circ\mathrm{C}$下热膨胀系数抵消,实现了1秒积分时间$4\times 10^{-13}$水平的分数频率不稳定性。这一进展消除了许多原子-腔实验对外部稳定化的需求,使得该设计非常适合用于超稳定超辐射激光器和其他腔量子电动力学实验等应用。

英文摘要

Optical Fabry-Perot cavities are crucial tools for metrology experiments, where they achieve extreme length stability, and for some atomic physics experiments, where tunability to atomic transitions enables atom-light interactions. However, achieving both frequency stability and tunability in a single cavity has remained a challenge, forcing metrology experiments exploiting atom-cavity interactions to rely on external active feedback systems to stabilize the length of the cavity. Here, we describe a piezoelectrically-tunable cavity with a cancellation of the coefficient of thermal expansion at around $5^\circ\mathrm{C}$, achieving fractional frequency instabilities at the $4\times 10^{-13}$ level for 1~s integration time. This advance eliminates the need for external stabilization in many atom-cavity experiments, making this design ideal for applications such as ultra-stable superradiant lasers and other cavity quantum electrodynamics experiments.

2603.11172 2026-06-11 nlin.SI cond-mat.stat-mech hep-th math-ph math.MP quant-ph 版本更新

Integrable Massless and Massive Fermions

可积无质量和有质量费米子

Zhao Zhang

AI总结 定义可积无质量费米子为同时满足Yang-Baxter方程和Shastry装饰YBE的R矩阵,并揭示两种产生有质量费米子的机制:破缺时间反演对称性和引入时间反演对称相互作用。

Comments 24 pages, 5 figures

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AI中文摘要

一维可积费米子可分为无质量和有质量区域,后者的$R$算符可由前者构造。这里,我通过$R$矩阵同时满足Yang-Baxter方程(YBE)和Shastry装饰YBE(DYBE)来定义可积无质量费米子。这一概念严格比Maassarani的“自由费米子代数”更一般,但比精确可解量子模型或对偶于量子自旋链的可积二维经典顶点模型中的自由费米子概念更具限制性。在此框架内,出现了两种打开能隙并产生有质量费米子的典型机制:(i)通过耦合到外场破缺时间反演对称性,以及(ii)引入时间反演对称相互作用。这些范式分别体现在纵向场中的XY链和Hubbard模型中,两者都具有非相对论的双变量$R$矩阵。识别了无质量和有质量费米子局域哈密顿量的可积条件,并提出了唯一确定其$R$矩阵的示意性程序。

英文摘要

One-dimensional integrable fermions can be classified into massless and massive regimes, and the $R$-operator for the latter can be constructed from that of the former. Here, I define integrable massless fermions by the simultaneous satisfaction of the Yang-Baxter equation (YBE) and Shastry's decorated YBE (DYBE) by the $R$-matrix. This notion is strictly more general than Maassarani's `free-fermion algebra', yet more restrictive than the notion of free fermions in exactly solvable quantum models or in integrable two-dimensional classical vertex models dual to quantum spin chains. Within this framework, there emerge two archetypal mechanisms for opening a spectral gap and generating massive fermions: (i) breaking time-reversal symmetry by coupling to external field, and (ii) introducing time-reversal symmetric interactions. These paradigms are realized, respectively, in the XY chain in a longitudinal field and in the Hubbard model, both of which possess non-relativistic, bivariate $R$-matrices. Integrability conditions on local Hamiltonians for both massless and massive fermions are identified, and schematic procedures for uniquely determining their $R$-matrices are proposed.

2502.01611 2026-06-11 quant-ph math-ph math.FA math.MP math.OA 版本更新

Additivity and chain rules for quantum entropies via multi-index Schatten norms

量子熵的可加性与链式法则:基于多指标Schatten范数

Omar Fawzi, Jan Kochanowski, Cambyse Rouzé, Thomas Van Himbeeck

AI总结 通过推广多指标Schatten范数,建立了量子信道优化夹层Rényi熵的通用可加性,并推导了Rényi条件熵的链式法则,用于分析时间自适应量子密码协议。

Comments 39 pages, 1 figure

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Journal ref
Commun. Math. Phys. 407, 75 (2026)
AI中文摘要

量子态的主要熵度量在张量积下是可加的。在量子信息处理任务的分析中,一组态的最小熵(例如信道的最小输出熵)通常起着关键作用。量子信息和密码学中的一个基本问题是,最小输出熵在信道的张量积下是否仍然可加。在这里,我们为量子信道的优化夹层Rényi熵建立了一个通用的可加性陈述。为此,我们将[Devetak, Junge, King, Ruskai, CMP 2006]的结果推广到多指标Schatten范数。作为一个应用,我们加强了[Van Himbeeck and Brown, 2025]的可加性陈述,从而允许分析时间自适应量子密码协议。此外,我们建立了Rényi条件熵的链式法则,类似于[Metger, Fawzi, Sutter, Renner, CMP 2024]中用于广义熵累积定理的法则。

英文摘要

The primary entropic measures for quantum states are additive under the tensor product. In the analysis of quantum information processing tasks, the minimum entropy of a set of states, e.g., the minimum output entropy of a channel, often plays a crucial role. A fundamental question in quantum information and cryptography is whether the minimum output entropy remains additive under the tensor product of channels. Here, we establish a general additivity statement for the optimized sandwiched Rényi entropy of quantum channels. For that, we generalize the results of [Devetak, Junge, King, Ruskai, CMP 2006] to multi-index Schatten norms. As an application, we strengthen the additivity statement of [Van Himbeeck and Brown, 2025] thus allowing the analysis of time-adaptive quantum cryptographic protocols. In addition, we establish chain rules for Rényi conditional entropies that are similar to the ones used for the generalized entropy accumulation theorem of [Metger, Fawzi, Sutter, Renner, CMP 2024].

2603.10749 2026-06-11 cs.CR 版本更新

AttriGuard: Defeating Indirect Prompt Injection in LLM Agents via Causal Attribution of Tool Invocations

AttriGuard: 通过工具调用的因果归因击败LLM代理中的间接提示注入

Yu He, Haozhe Zhu, Yiming Li, Shuo Shao, Hongwei Yao, Zhihao Liu, Zhan Qin

AI总结 针对LLM代理易受间接提示注入攻击的问题,提出基于并行反事实测试的运行时防御AttriGuard,通过因果归因区分用户意图驱动与不可信观察驱动的工具调用,在多个基准上实现0%攻击成功率。

Comments Accepted by USENIX Security 2026

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AI中文摘要

LLM代理极易受到间接提示注入(IPI)的攻击,攻击者将恶意指令嵌入不可信的工具输出中以劫持执行。现有大多数防御将IPI视为输入级语义判别问题,通常无法泛化到未见过的载荷。我们提出了一种新的范式——动作级因果归因,通过询问为什么产生特定的工具调用来保护代理。核心目标是区分由用户意图支持的工具调用与由不可信观察因果驱动的工具调用。我们通过AttriGuard实例化该范式,这是一种基于并行反事实测试的运行时防御。对于每个提议的工具调用,AttriGuard通过在外部观察的控制衰减视图下重新执行代理来验证其必要性。技术上,AttriGuard结合了教师强制影子回放以防止归因混淆、层次化控制衰减以抑制多样化的控制通道同时保留任务相关信息,以及一个对LLM随机性鲁棒的模糊生存准则。在四个LLM和两个代理基准测试中,AttriGuard在静态攻击下实现了0%的攻击成功率,且效用损失可忽略,开销适中。重要的是,在基于自适应优化的攻击下,当领先的防御显著退化时,它仍然保持鲁棒性。

英文摘要

LLM agents are highly vulnerable to Indirect Prompt Injection (IPI), where adversaries embed malicious directives in untrusted tool outputs to hijack execution. Most existing defenses treat IPI as an input-level semantic discrimination problem, which often fails to generalize to unseen payloads. We propose a new paradigm, action-level causal attribution, which secures agents by asking why a particular tool call is produced. The central goal is to distinguish tool calls supported by the user's intent from those causally driven by untrusted observations. We instantiate this paradigm with AttriGuard, a runtime defense based on parallel counterfactual tests. For each proposed tool call, AttriGuard verifies its necessity by re-executing the agent under a control-attenuated view of external observations. Technically, AttriGuard combines teacher-forced shadow replay to prevent attribution confounding, hierarchical control attenuation to suppress diverse control channels while preserving task-relevant information, and a fuzzy survival criterion that is robust to LLM stochasticity. Across four LLMs and two agent benchmarks, AttriGuard achieves 0% ASR under static attacks with negligible utility loss and moderate overhead. Importantly, it remains resilient under adaptive optimization-based attacks in settings where leading defenses degrade significantly.

2603.09941 2026-06-11 math.DS 版本更新

A new approach to the Poincaré center problem

庞加莱中心问题的新方法

Isaac A. García, Jaume Giné

AI总结 提出用加权极坐标下的洛朗逆积分因子研究平面向量场族的中心问题,证明解析中心存在此类因子,并推导无零角速度曲线时庞加莱映射解析的条件,给出参数约束的理论程序。

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AI中文摘要

我们研究庞加莱在19世纪提出的经典(退化或非退化)中心问题,针对平面向量场族$\mathcal{X}$的单值奇点。我们证明每个解析中心在加权极坐标下都存在洛朗逆积分因子$V$。此外,我们证明当$\mathcal{X}$没有局部零角速度曲线时,庞加莱映射是解析的。基于这一结果,我们推导出一个理论程序,用于确定族中刻画无零角速度曲线中心的参数约束。还提供了对其他方法无效的非平凡族的应用。

英文摘要

We address the classical (degenerate or non-degenerate) center problem posed by Poincaré in the 19th century for monodromic singularities of analytic families of planar vector fields $\mathcal{X}$. We prove that every analytic center admits a Laurent inverse integrating factor $V$ in weighted polar coordinates. Moreover, we show that when $\mathcal{X}$ has no local curves of zero angular speed, the Poincaré map is analytic. Based on this result, we derive a theoretical procedure to determine parameter constraints within the family that characterize centers without curves of zero angular speed. Applications to nontrivial families that have resisted other methods are also provided.

2603.09824 2026-06-11 quant-ph physics.optics 版本更新

High-efficiency telecom conversion of heralded atomic biphoton wavepackets

宣布式原子双光子波包的高效电信转换

Ling-Chun Chen, Chang-Wei Lin, Jiun-Shiuan Shiu, Wei-Lin Chen, Yi-Che Wang, Yong-Fan Chen

AI总结 利用金刚石型原子系综实现宣布式原子双光子波包的高效电信频率转换,通过光谱匹配达到79.4%的转换效率并保持强时间关联和波形保真度。

Comments 5 pages, 4 figures, plus 2 pages of supplemental material

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AI中文摘要

我们展示了使用金刚石型原子系综对宣布式原子双光子波包的高效电信频率转换。通过将2.5 MHz的宣布光子光谱置于转换器响应的高效区域内,我们实现了79.4(2.6)%的转换效率,同时保持了强时间分辨关联和定义良好的时间波包。对于更宽的17.4 MHz输入带宽,转换效率降低至约55%,而时间波形基本保持不变。这种行为反映了转换器近乎平坦的中心响应,主要导致光谱边缘损耗而非时间模式失真。这些结果确定了光谱匹配是实现原子系统窄带量子光高效、低失真电信转换的有效途径。

英文摘要

We demonstrate high-efficiency telecom frequency conversion of heralded atomic biphoton wavepackets using a diamond-type atomic ensemble. By placing a 2.5 MHz heralded-photon spectrum within the high-efficiency region of the converter response, we achieve a conversion efficiency of 79.4(2.6)% while maintaining strong time-resolved correlations and well-defined temporal wavepackets. For a broader 17.4 MHz input bandwidth, the conversion efficiency is reduced to about 55%, whereas the temporal waveform remains largely preserved. This behavior reflects the nearly flat central response of the converter, which mainly causes spectral-edge loss rather than temporal-mode distortion. These results identify spectral matching as an effective route to efficient and low-distortion telecom conversion of narrowband quantum light from atomic systems.

2603.09818 2026-06-11 quant-ph physics.hist-ph 版本更新

An Introduction to the Foundations and Interpretations of Quantum Mechanics

量子力学基础与诠释导论

Theodore McKeever, Ahsan Nazir

AI总结 本文综述量子力学关键概念与诠释发展,从公设到测量、非定域性及经典涌现,分析哥本哈根、德布罗意-玻姆、多世界等诠释如何回应量子理论对物理实在本质的启示。

Comments 15 pages, 3 figures. Invited submission to Lectures from the 33rd Chris Engelbrecht Summer School, Stellenbosch 2025

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AI中文摘要

本文综述了量子力学中一系列关键的概念性和诠释性发展,从理论的基本公设追溯到当代关于测量、非定域性和经典性涌现的讨论。首先考察了希尔伯特空间的结构以及支配状态演化和测量的公设,审视了哥本哈根诠释的认识论立场及其现代重构。随后讨论了爱因斯坦-波多尔斯基-罗森论证、贝尔定理和哈代悖论,作为对定域性和实在性的探针,同时介绍了决定论但显式非定域的德布罗意-玻姆理论。分析了测量问题和语境性的含义,与客观坍缩模型相关联,这些模型引入了新的物理动力学来解释确定的结果。最后,探讨了退相干在抑制干涉和涌现经典行为中的作用,以及多世界和一致历史的诠释框架。本文旨在提供一个连贯的入门概述,说明几个最著名的诠释如何回应量子力学关于物理实在本质的核心问题。

英文摘要

This article surveys a selection of key conceptual and interpretational developments in quantum mechanics, tracing the theory from its foundational postulates to contemporary discussions of measurement, nonlocality, and the emergence of classicality. Beginning with the structure of Hilbert space and the postulates governing state evolution and measurement, the epistemic stance of the Copenhagen interpretation and its modern reformulations are examined. The Einstein-Podolsky-Rosen argument, Bell's theorem, and Hardy's paradox are then discussed as probes of locality and realism, alongside the deterministic but explicitly nonlocal de Broglie-Bohm theory. The measurement problem and the implications of contextuality are analyzed in relation to objective collapse models, which introduce new physical dynamics to account for definite outcomes. Finally, the role of decoherence in the suppression of interference and the emergence of classical behavior is explored, together with the interpretational frameworks of many-worlds and consistent histories. This material aims to provide a coherent introductory overview of how several of the most prominent interpretations address the central concern of what quantum mechanics tells us about the nature of physical reality.

2603.09738 2026-06-11 cs.OS cs.DC 版本更新

Ensuring Data Freshness in Multi-Rate Task Chains Scheduling

确保多速率任务链调度中的数据新鲜度

José Luis Conradi Hoffmann, Antônio Augusto Fröhlich

AI总结 针对安全关键系统中数据新鲜度与确定性执行之间的权衡,提出基于任务的数据新鲜度约束调度框架,通过分解数据依赖图并设计偏移搜索算法同步多速率任务链,在不引入LET额外延迟的前提下保证端到端数据新鲜度。

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AI中文摘要

在安全关键自主系统中,数据新鲜度是一个基本的设计挑战。虽然逻辑执行时间(LET)范式保证了组合确定性,但通常以注入延迟为代价,可能降低高频控制回路上的数据年龄。此外,异构、多速率的任务依赖通常通过过采样来低效地保证。本文提出了一种扩展了数据新鲜度约束的基于任务的调度框架。与传统模型不同,调度决策由数据的生命周期驱动。我们引入了一种形式化方法,通过从执行器向后追踪最严格的数据新鲜度约束,将数据依赖图分解为主路径。基于这种分解,我们提出了一种偏移搜索算法,用于同步多速率、多依赖的任务链。该方法在不引入LET缓冲的人工延迟的情况下强制实现端到端数据新鲜度,这是数据新鲜度与执行确定性之间的权衡。我们正式证明,这种基于偏移的对齐在保证数据新鲜度的同时,保留了全局EDF的100%可调度性能力。

英文摘要

In safety-critical autonomous systems, data freshness presents a fundamental design challenge. While the Logical Execution Time (LET) paradigm ensures compositional determinism, it often does so at the cost of injected latency, possibly degrading the age of data on high-frequency control loops. Furthermore, heterogeneous, multi-rate, task dependencies is typically guaranteed inefficiently through oversampling. This paper proposes a Task-based scheduling framework extended with data freshness constraints. Unlike traditional models, scheduling decisions are driven by the lifespan of data. We introduce a formal methodology to decompose Data Dependency Graphs into dominant paths by tracing the strictest data freshness constraints backward from the actuators. Based on this decomposition, we propose an offset search algorithm that synchronizes multi-rate, multi-dependencies, task chains. This approach enforces end-to-end data freshness without the artificial latency of LET buffering, a trade-off between data freshness and execution determinism. We formally prove that this offset-based alignment preserves the 100% schedulability capacity of Global EDF while addressing data freshness guarantees.

2512.22169 2026-06-11 quant-ph cond-mat.stat-mech 版本更新

Wigner Cat Phases: A finely tunable system for exploring the transition to quantum chaos

维格纳猫相:一个精细可调的系统用于探索向量子混沌的转变

M. Süzen

AI总结 提出由冻结量子比特与完全热化混沌系统组成的量子力学设置,通过选择性保留状态实现子系统中的新型局域化,并发现从量子混沌到非热多体局域化(维格纳猫相)的转变。

Comments JMP formatted 9 pages 7 figures. Additional analyses: permutation operator, participation distributions and analytic moments ratio, enhanced notation and presentation. Data is released on Zenodo https://zenodo.org/records/18171032 with associated Python package released https://zenodo.org/records/17937440

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AI中文摘要

提出一个量子力学设置,由一个冻结量子比特与一个完全热化的N态混沌系统组成,具有量子控制的潜在相关性。观察组合系统的状态选择性保留状态,导致子系统中出现新型局域化。在调谐参数为1.0时(即无选择),系统表现出维格纳-戴森能级间距统计,指示量子混沌。随着调谐参数减小并在截止处发生选择,最近邻能级间距分布出现更重的尾部,这是谱混合被抑制和非热动力学出现的标志。在这些区域,本征密度发展出明显的“猫耳”结构,反映空间局域双峰本征态的形成。这些拓扑特征持续存在而不转变为泊松统计,表明从量子混沌到非热的新型多体局域化(MBL)区域的转变——称为维格纳猫相。所提出的混合随机矩阵系综为维持这种新型量子局域化设置提供了实用探针。我们严格的谱统计分析结果显示了“猫耳”如何根据选择或无序程度在谱密度中形成,并指出由于可能存在重尾维格纳-戴森分布,在检测完全可积极限时必须谨慎使用能隙比统计。

英文摘要

A quantum mechanical setting consisting of a frozen qubit composed with a fully thermalized chaotic system of N states is proposed, with potential relevance to quantum control. Observing the states of the composed system selectively retaining the states leads to the observation of novel localization in the subsystem. At a tuning parameter of 1.0, implying no selection, the system exhibits Wigner-Dyson level spacing statistics, indicative of quantum chaos. As the tuning parameter is reduced and selection occurs at a cutoff, the nearest-neighbor level spacing distribution develops heavier tails, a signature of suppressed spectral mixing and the emergence of non-thermal dynamics. In these regimes, the eigendensity develops a pronounced "cat-ears" structure, reflecting the formation of spatially localized bimodal eigenstates. These topological features persist without transitioning to Poisson statistics, indicating a transition from quantum chaos to a non-thermal, novel many-body localized (MBL) regime-referred to as Wigner Cat Phases. The proposed mixed random matrix ensemble offers a practical probe for sustaining this novel quantum localization setting. Results from our rigorous spectral statistics analysis show how "cat-ears" form in spectral densities based on the degree of selection or disorder and indicate that gap ratio statistics must be used with caution in detecting the full integrable limit due to the possibility of heavy-tailed Wigner-Dyson distributions.

2603.07081 2026-06-11 gr-qc hep-th math-ph math.MP 版本更新

Frozen Motion: Why Single Carrollian Scalars Cannot Propagate

冻结运动:为什么单个 Carroll 标量无法传播

Andrew James Bruce

AI总结 研究在 Carroll 平面上本征地定义的一类一阶标量场理论,发现扩展 Carroll 对称性(含超平移)迫使能量密度静态且动量密度为零,从而阻止场的在壳传播。

Comments 7 pages. Comments welcomed

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AI中文摘要

我们研究了一类一阶标量场理论,这些理论最小耦合到 Carroll 联络,并且是在 Carroll 平面上本征地定义的,即这些理论不是通过洛伦兹理论的极限来定义的。所构建的理论在扩展的 Carroll 变换下不变,其中包括超平移。对称性允许一大类拉格朗日量,仅要求时空坐标的独立性。然而,超平移(包括作为线性超平移的 boost)不变性迫使能量密度静态且动量密度为零——这阻止了场的在壳传播。因此,要得到传播的理论,必须超越最小耦合到几何的单场理论。

英文摘要

We investigate a class of first-order scalar field theories minimally coupled to a Carrollian connection that are defined intrinsically on the Carrollian plane, i.e., the theories are not defined via limits of Lorentzian theories. The theories built are invariant under the extended Carrollian transformations which include supertranslations. The symmetry allows for a large class of Lagrangians, independence of spacetime coordinates is all that is required. However, invariance under supertranslations (which include boosts as linear supertranslations) forces the energy density to be static and the momentum density to vanish -- this precludes on-shell propagation of fields. Thus, to have propagating theories, one must move beyond single field theories that are minimally coupled to the geometry.

2602.10456 2026-06-11 cs.GT econ.TH math.OC 版本更新

Informal and Privatized Transit: Incentives, Efficiency and Coordination

非正式与私有化公共交通:激励、效率与协调

Devansh Jalota, Matthew Tsao

AI总结 本文通过博弈论框架研究非正式公交系统中司机利润最大化行为导致的效率损失,并提出交叉补贴和票价优化两种机制来缓解低效。

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AI中文摘要

非正式和私有化的公交服务,如小巴和共享自动人力车,是大型城市日常出行的重要组成部分,在正规公共交通不足且其他选择难以负担的情况下提供经济实惠的通勤。这些系统的一个显著特征是它们的去中心化组织,司机根据乘客需求提供服务并赚取收入。虽然这种结构有助于填补关键的出行缺口,但当利润驱动的司机路线选择与系统范围的出行目标不一致时,也可能产生低效的服务模式。我们开发了一个可解析的博弈论框架,研究具有固定路线菜单的非正式和私有化公交系统中的激励问题,量化去中心化司机路线选择导致的效率损失,并设计激励机制以减轻这些低效。在此框架中,利润最大化的非正式运营商(司机)决定在何处提供服务,而成本最小化的通勤者(乘客)决定是否使用这些服务。我们建立了严格的价格无政府状态界限,表明去中心化、利润最大化的司机行为可能导致累计司机利润和乘客需求服务量的有界但显著的损失,并且这些损失可以通过有针对性的干预措施来缓解:预算平衡的交叉补贴(通过路线特定的通行费/补贴来塑造司机收益)和票价优化(通过中央监管的路线级票价改变乘客需求和司机利润)。最后,基于印度Nalasopara真实非正式公交系统的数值实验进一步验证了这些发现。

英文摘要

Informal and privatized transit services, such as minibuses and shared auto-rickshaws, are integral to daily travel in large urban metropolises, providing affordable commutes where formal public transport is inadequate and other options are unaffordable. A defining feature of these systems is their decentralized organization, with drivers providing service in response to rider demand and earning opportunities. While this structure helps fill critical mobility gaps, it can also generate inefficient service patterns when profit-driven driver route choices do not align with system-wide mobility goals. We develop an analytically tractable game-theoretic framework to study incentives underlying informal and privatized transit systems with a fixed menu of routes, quantify efficiency losses from decentralized driver route choice, and design incentive mechanisms to mitigate these inefficiencies. Here, profit-maximizing informal operators (drivers) decide where to provide service and cost-minimizing commuters (riders) decide whether to use these services. Within this framework, we establish tight price of anarchy bounds showing that decentralized, profit-maximizing driver behavior can lead to bounded yet substantial losses in cumulative driver profit and rider demand served and that these losses can be mitigated through targeted interventions: budget-balanced cross-subsidization, which uses route-specific tolls/subsidies to shape driver payoffs, and fare optimization, which changes rider demand and driver margins through centrally regulated route-level fares. Finally, numerical experiments based on a real-world informal transit system in Nalasopara, India, reinforce these findings.

2603.06518 2026-06-11 cond-mat.str-el cond-mat.mes-hall cond-mat.quant-gas 版本更新

Tomographic collective modes in a magnetic field

磁场中的层析集体模式

Jeff Maki, Johannes Hofmann

AI总结 研究二维费米液体在磁场中层析输运的转变,通过求解线性化玻尔兹曼方程发现奇偶模式弛豫率差异导致的集体模式在临界磁场下消失,并依赖朗道参数。

Comments 15 pages, 7 figures, 1 appendix

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Journal ref
Phys. Rev. B 113, 245122 (2026)
AI中文摘要

理论上已确定,低温下的二维费米液体在集体准粒子弛豫率中表现出奇偶效应,其中费米面的偶宇称变形比奇宇称变形衰减得更快。该效应的一个预测结果是出现一种新的层析输运机制,混合了流体动力学和碰撞输运。然而,在存在磁场的情况下,一旦回旋半径变得小于主导的奇宇称平均自由程,层析区域预计将演变为常规输运区域。在这项工作中,我们从集体模式的角度研究了这一转变,使用广义弛豫时间近似对奇宇称和偶宇称模式进行数值精确求解线性化玻尔兹曼方程。在没有磁场的情况下,横向电导率表现出两种扩散层析集体模式,我们发现,在临界磁场下,这两种层析模式之一消失。哪种层析模式持续存在取决于朗道参数,并在高场下逐渐被流体动力学模式主导。我们使用费米面变形的变分方法证实了我们的分析,该方法捕捉了变形的角结构和临界磁场强度。原则上,可以通过检查有限磁场中纵向和横向电流响应的阻尼来观察这里讨论的集体模式。

英文摘要

Two-dimensional Fermi liquids at low temperatures have been theoretically established to exhibit an odd-even effect in the collective quasiparticle relaxation rates where even-parity deformations of the Fermi surface decay at a much faster rate than odd-parity ones. A predicted consequence of this effect is a new tomographic transport regime that mixes hydrodynamic and collisionless transport. In the presence of a magnetic field, however, the tomographic regime is expected to evolve towards conventional transport regimes as soon as the cyclotron radius becomes smaller than the dominant odd-parity mean-free path. In this work, we examine this transition from the point of view of collective modes, using a numerically exact solution of the linearized Boltzmann equation within a generalized relaxation time approximation for the odd-parity and even-parity modes. In the absence of a magnetic field, the transverse conductivity exhibits two diffusive tomographic collective modes, and we find that at a critical magnetic field one of these two tomographic modes disappears. Which tomographic mode persists depends on the Landau parameters, and becomes increasingly dominated by hydrodynamic modes at high fields. We corroborate our analysis using a variational approach for the Fermi surface deformation that captures the angular structure of the deformation and the critical magnetic field strength. The collective modes discussed here can in principle be observed by examining the damping of longitudinal and transverse current responses in finite magnetic fields.

2603.05102 2026-06-11 physics.flu-dyn 版本更新

Lagrangian dispersion in experimental stratified turbulence

实验分层湍流中的拉格朗日弥散

Maelys Magnier, Costanza Rodda, Clément Savaro, Pierre Augier, Nathanael Machicoane, Thomas Valran, Samuel Viboud, Nicolas Mordant

AI总结 通过高浮力雷诺数和低弗劳德数的大规模实验,测量分层湍流中示踪粒子的拉格朗日弥散,发现垂直弥散受浮力尺度约束,速度谱呈1/f³衰减,小尺度呈现强非高斯统计。

Comments accepted for publication in Physical Review Letters

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AI中文摘要

本文呈现了分层湍流中示踪粒子弥散的拉格朗日测量结果,实验在大尺度下进行,实现了高浮力雷诺数和低弗劳德数——这是海洋条件的典型状态。分层对垂直粒子弥散有显著影响,观察到弥散被限制在浮力尺度 $w_{\mathrm{std}}/N$ 量级的距离内,其中 $w_{\mathrm{std}}$ 是垂直速度的标准差,$N$ 是布伦特-维萨拉频率。正如强非线性分层湍流中所预期的,拉格朗日速度的频率谱在高于 $N$ 的频率处变为各向同性。谱衰减遵循 $1/f^3$ 标度,这与均匀各向同性湍流中典型的 $1/f^2$ 行为形成对比。在内波对应的时间尺度上,速度增量的统计保持高斯分布,与弱非线性波湍流状态一致。然而,在更小尺度上,流动表现出强非高斯统计,表明存在由波破碎驱动的完全非线性湍流动力学。

英文摘要

Lagrangian measurements of tracer particle dispersion in stratified turbulence are presented from a large-scale experiment achieving both high buoyancy Reynolds numbers and low Froude numbers -- a regime characteristic of oceanic conditions. Stratification has a pronounced effect on the vertical particle dispersion, which is observed to be constrained to distances on the order of the buoyancy scale $w_{\mathrm{std}}/N$, where $w_{\mathrm{std}}$ is the standard deviation of the vertical velocity and $N$ is the Brunt-Väisälä frequency. As expected in strongly nonlinear, stratified turbulence, the frequency spectrum of the Lagrangian velocity becomes isotropic at frequencies higher than $N$. The spectral decay follows a $1/f^3$ scaling, which contrasts with the $1/f^2$ behavior typical of homogeneous isotropic turbulence. At time scales corresponding to internal waves, the statistics of velocity increments remain Gaussian, consistent with the weakly nonlinear regime of wave turbulence. At smaller scales, however, the flow exhibits strongly non-Gaussian statistics, indicative of fully nonlinear turbulent dynamics driven by wave breaking.

2510.19458 2026-06-11 math-ph gr-qc hep-th math.DG math.MP math.QA 版本更新

Foundations of Noncommutative Carrollian Geometry via Lie-Rinehart Pairs

非交换Carroll几何的基础:通过Lie-Rinehart对

Andrew James Bruce

AI总结 通过ρ-Lie-Rinehart对将Carroll李代数推广到几乎交换几何,建立非交换Carroll几何基础,并在扩展量子平面和非交换2-环面上构造实例。

Comments 17 pages. Improved exposition, typos corrected and references included

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Journal ref
J. Phys. A: Math. Theor. 59 085201 (2026)
AI中文摘要

Carroll流形为超相对论极限下的物理提供了内在几何框架。最近引入的Carroll李代数被推广到ρ-交换几何(也称为几乎交换几何)的设定中,其中底层代数交换至一个数值因子。通过ρ-Lie-Rinehart对,证明了Carroll几何的基本原理在几乎交换世界中具有类似表述。我们显式构建了两个玩具例子:为扩展量子平面和非交换2-环面装备Carroll结构。这开启了通过几乎交换几何对非交换Carroll几何的严格研究。

英文摘要

Carrollian manifolds offer an intrinsic geometric framework for the physics in the ultra-relativistic limit. The recently introduced Carrollian Lie algebroids are generalised to the setting of $ρ$-commutative geometry, (also known as almost commutative geometry), where the underlying algebras commute up to a numerical factor. Via $ρ$-Lie-Rinehart pairs, it is shown that the foundational tenets of Carrollian geometry have analogous statements in the almost commutative world. We explicitly build two toy examples: we equip the extended quantum plane and the noncommutative $2$-torus with Carrollian structures. This opens up the rigorous study of noncommutative Carrollian geometry via almost commutative geometry.

2603.02566 2026-06-11 stat.ME 版本更新

Modeling double bounded data based on correlated gamma random variables

基于相关伽马随机变量的双有界数据建模

Roberto Vila, Felipe Quintino, Marcelo Bourguignon

AI总结 针对单位区间上比率形式的有界数据,提出一种通过Copula连接相关伽马变量的新模型,克服传统独立假设的局限,允许正负相关,并通过模拟和真实经济数据验证其灵活性和有效性。

Comments 41 pages, 14 figures

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AI中文摘要

许多定义在单位区间上的有界数据自然以 $X/(X + Y)$ 的比率形式出现。在现有文献中,针对此类有界数据的主要统计模型通常基于随机变量 $X$ 和 $Y$ 独立的假设。然而,在实际应用中,由于共享的潜在机制或共同的变异来源,$X$ 和 $Y$ 往往存在相关性,因此这一假设常常不切实际。在本文中,我们克服了这些局限性,提出了一种模型,其中两个分量的边际分布通过Copula连接,从而得到更灵活、更真实的单位区间数据表示。特别地,在所提出的模型中,$X$ 和 $Y$ 是相依的伽马随机变量,其联合分布通过Morgenstern二元分布指定,允许分量之间存在正相关和负相关。我们严格研究了其数学性质和实践应用。所得分布呈现广泛的形状,适应不同程度的偏度,并且在某些参数配置下,具有更复杂的密度结构。进行了蒙特卡洛模拟研究,表明最大似然估计在多种参数选择场景下具有良好的性能。还讨论了高效基于似然计算的潜力和局限性。我们通过建模与经济相关的真实数据集,评估了新模型及其估计的有效性。

英文摘要

Many types of bounded data defined on the unit interval arise naturally as ratios of the form $X/(X + Y)$. In the existing literature, the main statistical models proposed for this type of bounded data typically based on the assumption that the random variables $X$ and $Y$ are independent. However, this assumption is often unrealistic in practical applications, where $X$ and $Y$ tend to be correlated due to shared underlying mechanisms or common sources of variability. In this paper, we overcome such limitations and propose a model in which the marginal distributions of the two components are linked by a copula, leading to a more flexible and realistic representation of unit-interval data. In particular, in the proposed model, $X$ and $Y$ are dependent gamma random variables whose joint distribution is specified via Morgenstern's bivariate distribution}, allowing for positive and negative correlations between the components. The mathematical properties and practical applications are rigorously investigated. The resulting distribution exhibits a wide range of shapes, accommodating different degrees of skewness and, for some parameter configurations, more complex density structures. A Monte Carlo simulation study is carried out that shows the good performance of the maximum likelihood estimator in several scenarios of parameter choices. The potential and limitations of efficient likelihood-based computations are also discussed. We evaluate the effectiveness of the new model and its estimates in modeling real-world datasets related to economics.

2603.01991 2026-06-11 hep-ex 版本更新

Search for massive, long-lived particles in events with displaced vertices and displaced muons in $pp$ collisions at $\sqrt{s}=13.6$ TeV with the ATLAS experiment

在ATLAS实验中搜索$\sqrt{s}=13.6$ TeV的$pp$碰撞中带有位移顶点和位移μ子的大质量长寿命粒子

ATLAS Collaboration

AI总结 利用ATLAS探测器2022-2024年采集的164 fb$^{-1}$数据,搜索包含至少一个位移顶点和至少一个位移μ子的事件,未发现显著超出背景的迹象,并对R宇称破坏超对称模型设置95%置信水平上限。

Comments 43 pages in total, author list starting page 26, 8 figures, 2 tables, Published by Phys. Lett. B. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/EXOT-2024-21/

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Journal ref
Phys. Lett. B 878 (2026) 140509
AI中文摘要

本文报道了一项针对大质量长寿命粒子的搜索,要求事件中至少有一个位移顶点和至少一个位移μ子。分析基于ATLAS探测器在大型强子对撞机上2022至2024年收集的质子-质子碰撞数据,质心能量为13.6 TeV,对应积分亮度164 fb$^{-1}$。该分析针对长寿命粒子在ATLAS内部探测器内衰变的场景,产生至少一个包含多条关联径迹的大质量位移顶点(DV),以及至少一个相对于主相互作用点具有大横向碰撞参数的μ子。μ子不必与DV关联。根据重建DV到相互作用点的横向距离定义了两个信号区域。背景贡献通过完全数据驱动的方法估计。未观察到显著超出预期背景的信号。在95%置信水平上设置了可见截面以及几个R宇称破坏超对称基准模型产生截面的上限。

英文摘要

A search is presented for massive long-lived particles in events featuring at least one displaced vertex and at least one displaced muon, using proton-proton collision data collected by the ATLAS detector at the Large Hadron Collider from 2022 to 2024 at a centre-of-mass energy of 13.6 TeV. The data sample corresponds to an integrated luminosity of 164 fb$^{-1}$. The analysis targets scenarios in which long-lived particles decay inside the ATLAS inner detector, resulting in a topology of at least one massive, displaced vertex (DV) with multiple associated tracks, and at least one muon with a large transverse impact parameter relative to the primary interaction point. The muon is not required to be associated with the DV. Two signal regions are defined by the transverse distance of the reconstructed DV from the interaction point. Background contributions are estimated by using fully data-driven techniques. No significant excess above the expected background is observed. Upper limits at 95% confidence level are set on the visible cross-section and on the production cross-sections of several benchmark models of $R$-parity-violating supersymmetry.

2603.01424 2026-06-11 math.RA math.AC math.RT 版本更新

Cotorsion pairs, thick subcategories, and finitely generated Gorenstein projective modules

Cotorsion对、厚子范畴与有限生成Gorenstein投射模

Souvik Dey, Jian Liu, Xue-Song Lu

AI总结 在Cohen-Macaulay环上的诺特代数上,证明有限生成Gorenstein投射模构成遗传cotorsion对的左半部分,并回答Takahashi的问题,刻画左弱Gorenstein性质。

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AI中文摘要

设$R$是Cohen-Macaulay环$S$上的诺特代数,$S$具有典范模$\omega$,并假设$R$在$S$上是极大Cohen-Macaulay的。我们证明有限生成Gorenstein投射$R$-模的范畴等于由$R$和${\mathrm Hom}_S(R,\omega)$生成的厚子范畴的左$\mathrm Ext$-正交类。作为应用,有限生成Gorenstein投射$R$-模形成遗传cotorsion对的左半部分。在Cohen-Macaulay局部环的情形,这给出了R. Takahashi一个问题的肯定回答。我们进一步刻画了$R$何时是左弱Gorenstein的。最后,我们证明一个Cohen-Macaulay局部环是Gorenstein的当且仅当有限生成Gorenstein投射模的右$\mathrm Ext$-正交类等于有限生成且具有有限投射维数的模的范畴。

英文摘要

Let $R$ be a noetherian algebra over a Cohen--Macaulay ring $S$ admitting a canonical module $ω$, and assume that $R$ is maximal Cohen--Macaulay over $S$. We prove that the category of finitely generated Gorenstein projective $R$-modules coincides with the left $\mathrm Ext$-orthogonal class of the thick subcategory generated by $R$ and ${\mathrm Hom}_S(R,ω)$. As an application, finitely generated Gorenstein projective $R$-modules form the left half of a hereditary cotorsion pair. In the case of Cohen--Macaulay local rings, this yields an affirmative answer to a question of R. Takahashi. We further characterize when $R$ is left weakly Gorenstein. Finally, we prove that a Cohen--Macaulay local ring is Gorenstein if and only if the right $\mathrm Ext$-orthogonal class of finitely generated Gorenstein projective modules coincides with the category of finitely generated modules of finite projective dimension.

2510.25843 2026-06-11 hep-th math-ph math.MP 版本更新

Semi-Classical Limit of Quantum Gravity on Corners

角落上量子引力的半经典极限

Ludovic Varrin

AI总结 研究量子角落对称群QCS的量子与经典系统,通过广义Perelomov相干态和Berezin量子化将量子可观测量与面积等经典几何可观测量关联,并应用于静态球对称带视界时空。

Comments 20 pages, V5: Published Version

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Journal ref
Phys. Rev. D 113, 126015, 2026
AI中文摘要

我们研究了与量子角落对称群 $\mathrm{QCS}=\widetilde{\mathrm{SL}}(2,\mathbb{R})\ltimes \mathrm{H}_3$ 相关的量子与经典系统,该群出现在量子引力背景中。我们利用广义Perelomov相干态和Berezin量子化框架,将量子可观测量(由表示论数据指定)与其经典对应物联系起来。这一过程将抽象的表示论输入与几何经典可观测量(如面积)联系起来。最后,我们将该形式应用于具有视界的静态球对称时空。

英文摘要

We study quantum and classical systems associated with the quantum corner symmetry group $\mathrm{QCS}=\widetilde{\mathrm{SL}}(2,\mathbb{R})\ltimes \mathrm{H}_3,$ which arises in the context of quantum gravity. We relate quantum observables -- specified by representation-theoretic data -- to their classical counterparts using generalized Perelomov coherent states and the framework of Berezin quantization. This procedure links abstract representation-theoretic input to geometric classical observables, such as area. We conclude by applying the formalism to static, spherically symmetric spacetimes admitting a horizon.

2602.22964 2026-06-11 eess.SP 版本更新

A guided residual search for nonlinear state-space identification

非线性状态空间辨识的引导残差搜索

Merijn Floren, Jan Swevers

AI总结 针对非线性状态空间模型参数辨识的非凸优化问题,提出引导残差搜索与多步优化结合的方法,提升收敛可靠性与效率。

Comments Code is available at: https://github.com/merijnfloren/guided-residual-search ; published paper in IEEE Xplore: https://ieeexplore.ieee.org/document/11556202

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AI中文摘要

从输入-输出数据中辨识非线性状态空间模型的参数通常需要求解高度非凸的优化问题,这容易导致收敛缓慢和次优局部解。本文通过将整体优化问题分解为一系列易处理的子问题,提高了估计过程的可靠性和效率。从线性基线模型开始,首先使用引导残差搜索(GRS)估计非线性残差动态,然后通过多步优化进行细化。在两个基准上的实验表明,该方法与最先进的黑箱方法相比具有竞争性能,并且比朴素初始化具有更好的收敛性。

英文摘要

Identifying the parameters of nonlinear state-space models from input-output data typically requires solving a highly non-convex optimization problem, which is prone to slow convergence and suboptimal local solutions. This work improves the reliability and efficiency of the estimation process by decomposing the overall optimization problem into a sequence of tractable subproblems. Starting from a linear baseline model, nonlinear residual dynamics are first estimated using a guided residual search (GRS) and subsequently refined through multiple-shooting optimization. Experiments on two benchmarks show competitive performance with state-of-the-art black-box methods and improved convergence over naive initialization.

2602.22860 2026-06-11 astro-ph.GA 版本更新

A FUV-optical approach for studying hierarchical star formation in nearby galaxies with UVIT

利用UVIT研究近邻星系中层级恒星形成的FUV-光学方法

Sanal Ananthu, Gairola Shashank, Smitha Subramanian, Rao C. Jayanth, Shyam H. Menon, Chayan Mondal, Sreedevi Muraleedharan

AI总结 提出结合UVIT远紫外与DECaLS g波段数据的方法,通过FUV-g颜色替代FUV-NUV颜色作为年龄指标,在NGC 5457和NGC 1313中表征年轻星团并研究层级恒星形成。

Comments Published in ApJ in May 2026; 22 pages, 10 figures. Link : https://iopscience.iop.org/article/10.3847/1538-4357/ae5bb9

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Journal ref
ApJ, 1002, 220 (2026)
AI中文摘要

年轻恒星形成团块(SFCs)在紫外(UV)波段强烈辐射,使得紫外成像成为探测它们的理想手段。搭载于AstroSat上的紫外成像望远镜(UVIT)具有1.5角秒的分辨率,能够在近邻星系中表征数十秒差距尺度上最近形成(长达300 Myr)的SFCs。不同年龄SFCs的空间分布可以提供对恒星形成层级的洞察。本研究提出了一种半新颖的方法,通过结合UVIT的FUV数据与暗能量相机遗留巡天(DECaLS)的g波段数据,表征两个近邻旋涡星系NGC 5457和NGC 1313中的SFCs。我们在NGC 5457上测试并优化了该方法,表明在适当的背景扣除后,SFCs的FUV-g颜色可以作为与广泛使用的FUV-NUV颜色同样可靠的年龄指标。接着,我们利用两点相关函数(TPCF)参数化了NGC 5457中的恒星形成层级,发现基于FUV-NUV和FUV-g年龄推导的层级参数之间具有良好的一致性。利用基于FUV-g的SFC年龄,我们还首次约束了NGC 1313的整体层级参数。我们开发基于FUV-g的方法的动机在于,UVIT的NUV通道不可用,而存在大量近邻星系的UVIT FUV-only观测档案。这项工作展示了我们的方法在利用FUV和光学观测约束SFC年龄以及研究近邻星系中层级恒星形成方面的潜力。

英文摘要

Young star-forming clumps (SFCs) emit strongly in the ultraviolet (UV), making UV imaging ideal for detecting them. The Ultraviolet Imaging Telescope (UVIT) onboard AstroSat, with 1.5arcsec resolution, has enabled the characterization of recently formed (up to 300 Myr) SFCs on tens of parsec scales in nearby galaxies. The spatial distribution of SFCs with different ages can provide insights into the hierarchy of star formation. This study presents a semi-novel approach to characterize SFCs in two nearby spiral galaxies, NGC 5457 and NGC 1313, by combining UVIT FUV data with g-band data from the Dark Energy Camera Legacy Survey (DECaLS). We tested and optimized our method on NGC 5457 and showed that after proper background subtraction, the FUV-g color of SFCs can serve as an equally reliable age indicator as the widely-used FUV-NUV color. Next, we parametrized the star formation hierarchy in NGC 5457 using the two-point correlation function (TPCF) and found good agreement between the hierarchy parameters derived using FUV-NUV and FUV-g based ages. Using our FUV-g based SFC ages, we also constrained the global hierarchy parameter of NGC 1313 for the first time. The development of our FUV-g based method is motivated by the fact that the NUV channel of the UVIT is not operational, and there is a wealth of archival UVIT FUV-only observations of nearby galaxies. This work demonstrates the potential of our method in constraining the SFC ages and investigating hierarchical star formation in nearby galaxies using FUV and optical observations.

2602.22005 2026-06-11 cond-mat.str-el cond-mat.mtrl-sci 版本更新

Crystallography-driven molecularization of a two-dimensional spin-$3/2$ magnet

晶体学驱动的二维自旋$3/2$磁体的分子化

Hari Borutta, Tobias Müller, Ronny Thomale, Harald O. Jeschke, Yasir Iqbal

AI总结 通过晶体学不等价性将磁性自由度分子化,解释二维自旋$3/2$材料Na$_2$Mn$_3$O$_7$中无磁有序但存在两个热力学交叉标度的反常行为。

Comments 19 pages, 6 figures, 1 table, and Supplementary Material

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Journal ref
Rep. Prog. Phys. 89, 068003 (2026)
AI中文摘要

大自旋二维磁体通常预期在主导交换作用变得显著时发展出常规长程序。层状自旋$3/2$枫叶型化合物Na$_2$Mn$_3$O$_7$违背了这一预期:尽管存在可观的反铁磁相互作用且无明显无序,它不显示磁有序,而是呈现两个分离良好的热力学交叉标度。我们证明这种行为源于晶体学驱动的磁性自由度分子化。低对称性结构将Mn子晶格划分为不等价的交换路径,产生显著的层级,几乎孤立出反铁磁六边形。因此,磁关联分两个阶段发展:首先在单个六边形内以主导交换作用设定的标度发展,只有在更低温度下,受挫的六边形间耦合才试图在整个晶格上建立相干性。虽然孤立六边形再现了两步热力学结构,但实验相关的温度标度只有在六边形嵌入受挫二维网络后才出现。最终的量子基态是磁无序的,其特征是强六边形内关联和快速衰减的六边形间关联。这些结果将晶体学不等价性识别为一种材料层面的机制,用于稳定大自旋二维磁体中的分子化和量子无序态。

英文摘要

Large-spin two-dimensional magnets are generally expected to develop conventional long-range order once the dominant exchange scale becomes appreciable. The layered spin-$3/2$ maple-leaf compound Na$_2$Mn$_3$O$_7$ defies this expectation: despite sizable antiferromagnetic interactions and no evident disorder, it exhibits no magnetic ordering and displays two well-separated thermodynamic crossover scales. We show that this behavior originates from a crystallography-driven molecularization of the magnetic degrees of freedom. The low-symmetry structure partitions the Mn sublattice into inequivalent exchange pathways, generating a pronounced hierarchy that nearly isolates antiferromagnetic hexagons. Magnetic correlations therefore develop in two stages: first within individual hexagons at a scale set by the dominant exchange, and only at much lower temperatures do frustrated inter-hexagon couplings attempt to establish coherence across the lattice. While isolated hexagons reproduce the two-step thermodynamic structure, the experimentally relevant temperature scales emerge only once the hexagons are embedded in the frustrated two-dimensional network. The resulting quantum ground state is magnetically disordered, characterized by strong intra-hexagon correlations and rapidly decaying inter-hexagon correlations. These results identify crystallographic inequivalence as a materials-level mechanism for stabilizing molecularized and quantum-disordered states even in large-spin two-dimensional magnets.

2602.21769 2026-06-11 hep-th nucl-th 版本更新

A Consistent Holographic Analysis of Anomaly-induced Charge Transport in the D3/D7 Model

D3/D7模型中反常诱导电荷输运的一致全息分析

Shin Nakamura, Kensei Tanaka

AI总结 提出一种在D3/D7模型中正确包含手征反常贡献的方案,通过允许D7膜在紧致额外方向旋转并开启Wess-Zumino项,计算了磁阻,发现有限轴化学势实现且负磁阻被反常增强。

Comments v1: 19 pages, 2 figures, v2: 20 pages, 2 figures, reference added, accepted version for publication in JHEP

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Journal ref
J. High Energ. Phys. 2026, 89 (2026)
AI中文摘要

我们提出了一种方案,以正确地将手征反常的贡献纳入D3/D7模型中,用于计算手征输运现象。为了确保D7膜适当地包裹S^5并开启Wess-Zumino项,我们允许D7膜在紧致额外方向上旋转,并据此进行分析。为了证明该计算过程有效,我们专门计算了D3/D7模型中的磁阻。我们发现,实现了有限的轴化学势,并且负磁阻被反常贡献增强。

英文摘要

We propose a scheme to correctly incorporate the contribution of the chiral anomaly in the D3/D7 model to calculate chiral transport phenomena. To ensure the D7-brane wraps S^5 appropriately and the Wess-Zumino term is switched on, we allow the D7-brane to rotate in the compactified extra directions and perform the analysis accordingly. To demonstrate that this calculation procedure works well, we specifically compute the magnetoresistance in the D3/D7 model. We find that a finite axial chemical potential is realized and the negative magnetoresistance is enhanced by the anomaly contribution.

2602.21705 2026-06-11 hep-lat cond-mat.str-el nucl-th 版本更新

Phase diagram of the single-flavor Gross--Neveu--Wilson model from the Grassmann corner transfer matrix renormalization group

单味Gross-Neveu-Wilson模型的相图:基于Grassmann角转移矩阵重正化群

Jian-Gang Kong, Shinichiro Akiyama, Tao Shi, Z. Y. Xie

AI总结 利用Grassmann角转移矩阵重正化群研究单味Gross-Neveu模型相结构,通过赝标量凝聚序参量和中心电荷c识别相边界普适类,发现Aoki相与拓扑绝缘相被c=1/2和c=1的临界线分隔,且Aoki相在强耦合区不持续。

Comments 26 pages, 20 figures

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Journal ref
Phys. Rev. D 113, 114504(2026)
AI中文摘要

我们利用Grassmann角转移矩阵重正化群(CTMRG)研究了带有Wilson费米子的单味Gross-Neveu模型的相结构。路径积分被表述为二维Grassmann张量网络,并通过Grassmann CTMRG算法近似收缩。我们通过改变费米子质量和四费米子耦合来研究相图,使用赝标量凝聚作为$\mathbb{Z}_{2}$宇称对称性破缺相的序参量。通过纠缠熵的标度分析得到的中心电荷$c$,识别了相边界的普适类。此外,我们从收敛的CTMRG环境中提取了与纠缠谱相关的量,从而能够区分拓扑绝缘体相和平凡相。得到的相结构表明,Aoki相与其他相由$c=1/2$的临界线分隔,而$c=1$的临界线分隔了拓扑绝缘相和平凡相。我们的数值结果还表明,对于单味理论,Aoki相在强耦合区域不持续。

英文摘要

We investigate the phase structure of the single-flavor Gross--Neveu model with Wilson fermions using the Grassmann corner transfer matrix renormalization group (CTMRG). The path integral is formulated as a two-dimensional Grassmann tensor network and approximately contracted by the Grassmann CTMRG algorithm. We investigate the phase diagram by varying the fermion mass and the four-fermion coupling, using the pseudoscalar condensate as an order parameter for the $\mathbb{Z}_{2}$ parity symmetry breaking phase. The universality classes of the phase boundaries are identified through the central charge $c$ obtained via scaling analysis of the entanglement entropy. Furthermore, we extract the quantity related to the entanglement spectrum from the converged CTMRG environments, allowing us to distinguish the topological insulator phase and the trivial phase. The resulting phase structure suggests that the Aoki phase is separated from the other phases by critical lines characterized by $c=1/2$, while the critical lines with $c=1$ separate the topological insulating and trivial phases. Our numerical results also indicate that the Aoki phase does not persist in the strong-coupling regime for the single-flavor theory.

2405.10200 2026-06-11 cond-mat.supr-con 版本更新

Dynamics of Topological Defects in Type-II Superconductors under Gradients of Temperature/Spin Density

第二类超导体中温度/自旋密度梯度下的拓扑缺陷动力学

Takuma Kanakubo, Hiroto Adachi, Masanori Ichioka, Yusuke Kato

AI总结 通过时变金兹堡-朗道方程与热/自旋扩散方程耦合模型,研究温度或自旋积累不均匀驱动的畴壁和涡旋运动,发现它们向抑制序参量的区域移动,并基于动量平衡分析驱动力。

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AI中文摘要

我们从理论上研究了由温度或自旋积累的不均匀性驱动的第二类超导体中畴壁和涡旋的运动。该模型由时变金兹堡-朗道方程和热或自旋扩散方程组成,其输运系数(如热导率和自旋电导率以及自旋弛豫时间)依赖于序参量,并在超导态和正常态的值之间插值。数值和解析计算表明,畴壁向温度较高或自旋积累较大的区域移动,这些区域中序参量被抑制。我们还推导了涡旋速度的解析表达式,并通过数值模拟证实了预测的涡旋运动方向。这些拓扑缺陷的动力学可以理解为减少凝聚能损失的过程。我们还基于动量平衡关系分析了驱动力、粘滞力、热力和自旋积累梯度引起的力。

英文摘要

We theoretically investigate the motion of a domain wall and a vortex in type-II superconductors driven by inhomogeneities of temperature or spin accumulation. The model consists of the time-dependent Ginzburg-Landau equation and the thermal or spin diffusion equation, whose transport coefficients, such as the thermal and spin conductivities and the spin relaxation time, depend on the order parameter and interpolate between their values in the superconducting and normal states. Numerical and analytical calculations indicate that the domain wall moves toward the higher-temperature region or the region with larger spin accumulation, where the order parameter is suppressed. We also derive analytical expressions for the vortex velocity and confirm the predicted direction of vortex motion by numerical simulations. The dynamics of these topological defects can be understood as processes that reduce the loss of condensation energy. We also analyze the driving force, viscous force, thermal force, and force due to the spin accumulation gradient on the basis of momentum balance relations.

2602.20266 2026-06-11 math.PR math.ST q-bio.PE stat.TH 版本更新

Multiple Poisson-Dirichlet diffusions on generalized Kingman simplices

广义Kingman单纯形上的多重Poisson-Dirichlet扩散

Cristina Costantini, Matteo Ruggiero

AI总结 构造了有限标记广义Kingman单纯形上的无穷维扩散过程,通过分块斜积分解和极限过程,得到了多重Poisson-Dirichlet平稳分布。

Comments Revised version; dedicated to the memory of T.G. Kurtz

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AI中文摘要

我们在带有有限个标记的广义Kingman单纯形上构造了一类新的无穷维扩散过程。该模型描述了由有限个$H$标记标记的无穷多种类型的相对频率的时间演化,但在每个标记内类型是无标记的。我们首先建立了有限类型Wright-Fisher扩散的分块斜积表示,扩展了Dirichlet律的聚合-重归一化自相似性质。该分解将控制演化中的随机标记质量的$H$维Wright-Fisher扩散与$H$个Wright-Fisher扩散(每个在其自己的随机时钟上运行)分开,后者描述了每个标记内相对频率的演化。在对标记内频率进行降序排序后,我们确定了当每个标记的类型数趋于无穷大时的分布极限,并在适当定义域上推导出其无穷小生成元的显式形式。极限扩散以多重Poisson-Dirichlet分布作为平稳分布;当所有类型共享相同标记时,它恢复为无穷多中性等位基因扩散,而当有两个标记时,它产生Thoma单纯形上的扩散。

英文摘要

We construct a new class of infinite-dimensional diffusions with values in a generalized Kingman simplex with finitely many marks. The model describes the temporal evolution of the relative frequencies of infinitely many types that are labeled by a finite number $H$ of marks, but unlabeled within each mark. We first establish a blockwise skew-product representation for a finite-type Wright-Fisher diffusion, extending the aggregation-renormalization self-similarity property of Dirichlet laws. The decomposition separates an $H$-dimensional Wright-Fisher diffusion governing the evolving random mark masses, from $H$ Wright-Fisher diffusions, each run on its own random clock, which describe the evolution of the relative frequencies within each mark. After ranking the within-mark frequencies in decreasing order, we identify the distributional limit as the number of types per mark tends to infinity and we derive an explicit form of its infinitesimal generator on a suitable domain. The limiting diffusion admits the multiple Poisson-Dirichlet distribution as a stationary distribution; it recovers the infinitely-many-neutral-alleles diffusion when all types share the same mark and yields a diffusion on the Thoma simplex when there are two marks.

2602.19230 2026-06-11 math.CO 版本更新

Towards the Erdős matching conjecture for 4-uniform hypergraphs: stability and applications

关于4一致超图的Erdős匹配猜想:稳定性及其应用

Peter Frankl, Hongliang Lu, Jie Ma, Yuze Wu

AI总结 本文证明了对于n≥5s且n足够大时,4一致超图的Erdős匹配猜想成立,主要技术贡献是一个独立的稳定性结果,并应用于解决5和6一致超图中匹配的最小d度阈值猜想。

Comments 19 pages,

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AI中文摘要

Erdős的一个著名猜想断言:对于$k\ge 3$,在$n$个顶点的$k$一致超图中,如果没有$s+1$条两两不相交的边,则最大边数为$\max\{\binom{n}{k}-\binom{n-s}{k},\binom{sk+k-1}{k}\}$。这个问题一直是极值组合学的核心问题,文献中取得了实质性进展,包括第一作者对$k=3$情况的完整解决。在本文中,我们朝着$4$一致情况取得进展,证明了对于$n\ge 5s$且$n$足够大时猜想成立,从而迈出了类似于$3$一致情况的第一步。主要技术贡献是一个具有独立意义的稳定性结果。我们进一步应用这一稳定性,以加强的形式解决了关于$5$和$6$一致超图中匹配的最小$d$度阈值的两个新猜想实例。

英文摘要

A famous conjecture of Erdős asserts that for $k\ge 3$, the maximum number of edges in an $n$-vertex $k$-uniform hypergraph without $s+1$ pairwise disjoint edges is $\max\{\binom{n}{k}-\binom{n-s}{k},\binom{sk+k-1}{k}\}$. This problem has been central in extremal combinatorics, with substantial progress in the literature, including a complete solution for $k=3$ due to the first author. In this paper, we make progress towards the $4$-uniform case, proving the conjecture for $n\ge 5s$ and sufficiently large $n$, thereby taking a first step analogous to the $3$-uniform case. The main technical contribution is a stability result of independent interest. We further apply this stability to resolve two new instances of conjectures on the minimum $d$-degree threshold for matchings in $5$- and $6$-uniform hypergraphs, in a strengthened form.

2602.18785 2026-06-11 cond-mat.soft 版本更新

Phase fluctuations in a confined fluid

受限流体中的相位涨落

Frédéric Caupin, Alberto Zaragoza, Miguel A. Gonzalez, Chantal Valeriani

AI总结 研究封闭系统中气泡相对于均匀液相的稳定性,分析亚稳态气泡的寿命及相翻转现象,并通过Lennard-Jones流体模拟验证。

Comments 11 pages, 17 figures, 2 tables. Some misprints were corrected, and a more accurate method for detecting bubbles was implemented in the simulations

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AI中文摘要

流体相平衡取决于施加在系统上的外部约束。在体积固定的封闭系统中,根据平均密度,气泡相对于均匀液相可能是稳定的、亚稳态的或不稳定的。在气泡亚稳态的情况下,我们研究其寿命,即观察到气泡坍缩所需的平均等待时间,以及均匀液相的相应寿命。对于最小的系统,我们预测当流体在有无气泡的状态之间振荡时,可能观察到相翻转。我们提供了Lennard-Jones流体模拟中相翻转的一个例子。

英文摘要

Fluid phase equilibrium depends on the external constraints imposed on a system. In a closed system with fixed volume, depending on the average density, a vapor bubble may be stable, metastable, or unstable, with respect to the homogeneous liquid phase. In the case where the bubble is metastable, we study its lifetime, i.e. the average waiting time needed to observe bubble collapse, and the corresponding lifetime of the homogeneous liquid. For the smallest systems, we predict the possibility to observe phase flipping, when the fluid oscillates between states with and without bubble. We provide an example of phase flipping in a simulation of a Lennard-Jones fluid.

2602.14380 2026-06-11 math.KT math.AT 版本更新

Syntomic cohomology of truncated Brown--Peterson spectra

截断Brown–Peterson谱的合成上同调

Gabriel Angelini-Knoll

AI总结 计算了所有截断Brown–Peterson谱BP⟨n⟩的E1 MU-代数形式的MU基合成上同调,解决了其代数K-理论的Lichtenbaum–Quillen、望远镜和红移问题,并首次显式计算了高度3的E1-环的代数K-理论。

Comments 30 pages, 2 figure, comments welcome! V3: Improved exposition and strengthened results

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AI中文摘要

我们计算了所有截断Brown–Peterson谱BP⟨n⟩的E1 MU-代数形式的基于MU的合成上同调,模(p,v1,⋯,vn)。作为定性结论,我们解决了所有BP⟨n⟩的E1 MU-代数形式的代数K-理论的Lichtenbaum–Quillen、望远镜和红移问题。这推广了Hahn和Wilson的工作。我们还显式计算了所有素数p≥5时任意BP⟨2⟩的E1 MU-代数形式的代数K-理论,推广了作者、Ausoni、Culver、Höning和Rognes先前的工作。此外,我们给出了所有素数p≥7时任意BP⟨3⟩的E1 MU-代数形式的模(p,v1,v2,v3)代数K-理论的新计算,这是高度3的E1-环的代数K-理论的首次显式计算。

英文摘要

We compute the $\mathrm{MU}$-based syntomic cohomologies, mod $(p,v_1,\cdots,v_n)$, of all $\mathbb{E}_1$ $\mathrm{MU}$-algebra forms of the truncated Brown--Peterson spectrum $\mathrm{BP}\langle n\rangle$. As qualitative consequences, we resolve the Lichtenbaum--Quillen, telescope, and redshift questions for the algebraic K-theories of all $\mathbb{E}_{1}$ $\mathrm{MU}$-algebra forms of $\mathrm{BP} \langle n\rangle$. This extends work of the Hahn and Wilson. We also explicitly compute the algebraic K-theory of arbitrary $\mathbb{E}_{1}$ $\mathrm{MU}$-algebra forms of $\mathrm{BP}\langle 2\rangle$ at all primes $p\ge 5$ extending previous work of the author, Ausoni, Culver, Höning, and Rognes.A dditionally, we present a new computation of mod $(p, v_1, v_2, v_3)$ algebraic K-theory of arbitrary $\mathbb{E}_1$ $\mathrm{MU}$-algebra forms of $\mathrm{BP}\langle 3\rangle$ at all primes $p\ge 7$, the first explicit computation of algebraic K-theory of an $\mathbb{E}_1$-ring of height $3$.

2511.07333 2026-06-11 math.LO 版本更新

Abstract independence relations in neostability theory

新稳定性理论中的抽象独立关系

Alberto Miguel-Gómez

AI总结 本文在Adler框架下发展抽象独立关系间的“见证”概念,统一新稳定性理论中的Kim引理变体,证明见证与对称性等价,并推导出链局部特征、弱独立定理等结果,最后证明NSOP₁与BTP之间的二分法。

Comments 52 pages; expands and improves results from the previous version. Comments are welcome

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AI中文摘要

我们发展了一个框架,采用Adler的风格,用于解释“见证”概念——该概念在新稳定性理论的不同领域中(通常作为Kim引理的变体)以抽象独立关系之间的二元关系出现。这涉及将Mutchnik对Kim-独立和Conant-独立的相对化扩展到任意独立关系。在开发这一框架后,我们展示了来自简单性、$\ ext{NTP}_2$、$\ ext{NSOP}_1$及更远领域的几个结果如何作为抽象独立关系的一般定理的实例。特别地,我们证明了见证与对称性之间的等价性,以及从这一概念到链局部特征和弱独立定理的蕴含关系,并恢复了一些部分逆命题。最后,我们利用这一框架证明了$\ ext{NSOP}_1$与Kruckman和Ramsey的$\ ext{BTP}$之间的一个二分法,该二分法适用于文献中大多数已知的$\ ext{NSOP}_4$例子。

英文摘要

We develop a framework, in the style of Adler, for interpreting the notion of "witnessing" that has appeared (usually as a variant of Kim's Lemma) in different areas of neostability theory as a binary relation between abstract independence relations. This involves extending the relativisations of Kim-independence and Conant-independence due to Mutchnik to arbitrary independence relations. After developing this framework, we show that several results from simplicity, $\text{NTP}_2$, $\text{NSOP}_1$, and beyond follow as instances of general theorems for abstract independence relations. In particular, we prove the equivalence between witnessing and symmetry and the implications from this notion to chain local character and the weak independence theorem, and recover some partial converses. Finally, we use this framework to prove a dichotomy between $\text{NSOP}_1$ and Kruckman and Ramsey's $\text{BTP}$ that applies to most known $\text{NSOP}_4$ examples in the literature.