其他凝聚态物理

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[1] arXiv:2508.04765 (交叉列表自 physics.comp-ph) [中文pdf, pdf, html, 其他]

标题： O(1)时间内双曲镶嵌邻域 显示英文标题

标题： Hyperbolic tiling neighborhoods in O(1) time

Yanick Thurn, Manuel Schrauth, Johanna Erdmenger

评论： 12页，9图

主题： 计算物理 (physics.comp-ph) ; 其他凝聚态物理 (cond-mat.other) ; 高能物理 - 格点 (hep-lat)

双曲平面的镶嵌在许多数学、物理和计算机科学领域中具有重要意义。然而，它们的构建仍然是一个非平凡的任务。当前的方法主要使用基于树的递归算法，这些方法存在根本性的限制：它们不能直接生成表示单元邻接关系的邻域图，而这对许多应用来说却是必需的。我们引入了一种新方法，可以同时构建双曲镶嵌及其相关图结构，仅使用组合规则，而不需要显式的坐标表示。这使得能够生成任意大小的精确双曲图，其算法复杂度不依赖于晶格尺寸。我们提供了一个易于使用的实现，其性能显著优于现有方法，从而使这些几何结构上的超大规模数值模拟对科学界变得可行。 显示英文摘要

Tilings of the hyperbolic plane are of significant interest among many branches of mathematics, physics and computer science. Yet, their construction remains a non-trivial task. Current approaches primarily use tree-based recursive algorithms, which are fundamentally limited: they do not readily yield the neighborhood graph representing cell adjacencies, which is however required for many applications. We introduce a novel approach that allows to build hyperbolic tilings and their associated graph structure simultaneously, using only combinatoric rules without requiring an explicit coordinate representation. This allows to generate arbitrarily large, exact hyperbolic graphs, with an algorithmic complexity that does not depend on the lattice size. We provide an easy-to-use implementation which substantially outperforms existing methods, hence rendering ultra large-scale numerical simulations on these geometric structures accessible for the scientific community.

[2] arXiv:2508.05403 (交叉列表自 cond-mat.str-el) [中文pdf, pdf, html, 其他]

标题： 从Kramers-Wannier对偶性的量子多体疤痕 显示英文标题

标题： Quantum many-body scarring from Kramers-Wannier duality

Weslei B. Fontana, Fabrizio G. Oliviero, Yi-Ping Huang

评论： 6到7页，3到4图。欢迎提出意见

主题： 强关联电子 (cond-mat.str-el) ; 其他凝聚态物理 (cond-mat.other) ; 量子物理 (quant-ph)

克朗默斯-瓦尼尔对偶性是伊辛模型的标志性特性，最近由于其被重新解释为具有状态级作用的不可逆对称性而再次受到关注。 使用顺序量子电路（SQC），我们认为这种对偶性决定了非可积模型中量子多体疤痕（QMBS）态的稳定性，这取决于对偶是否保持疤痕的嵌入条件。 这一结论得到了一阶微扰理论与数值模拟之间显著一致的支持，尽管存在混沌谱，它们仍能捕捉到疤痕动力学。 我们的结果表明，不可逆对偶性既为新的QMBS提供了生成机制，也为它们的稳定性提供了诊断方法。 显示英文摘要

Kramers-Wannier duality, a hallmark of the Ising model, has recently gained renewed interest through its reinterpretation as a non-invertible symmetry with a state-level action. Using sequential quantum circuits (SQC), we argue that this duality governs the stability of quantum many-body scar (QMBS) states in a nonintegrable model, depending on whether the dual preserves the embedding conditions for scarring. This is supported by striking agreement between first-order perturbation theory and numerics, which capture scar dynamics despite chaotic spectra. Our results suggest that non-invertible dualities provide both a generative mechanism for new QMBS and a diagnostic for their stability.

[3] arXiv:2508.05444 (交叉列表自 hep-th) [中文pdf, pdf, html, 其他]

标题： Krylov指数和最大量子混沌的功率谱：一种有效场论方法 显示英文标题

标题： Krylov exponents and power spectra for maximal quantum chaos: an EFT approach

Saskia Demulder, Maria Knysh, Andrew Rolph

评论： 41页，1图

主题： 高能物理 - 理论 (hep-th) ; 其他凝聚态物理 (cond-mat.other) ; 量子物理 (quant-ph)

我们通过Krylov复杂性和通用算符增长假说的视角来研究最大混沌的有效场论（EFT）。 我们检验了量子混沌的两种度量之间的关系：时间有序相关函数（OTOCs）和Krylov复杂性。 在EFT中，流体力学模式的平移对称性在OTOCs中强制最大李雅普诺夫指数，$\lambda_L = 2\pi T$，同时限制热力学两点自相关函数。 我们求解了自相关函数上的这些约束，并计算了几种示例的Lanczos系数和Krylov指数，发现两者分别为$\lambda_K = \lambda_L$和$\lambda_K = \lambda_L/2$。 这表明，在EFT中，仅靠平移对称性不足以强制最大Krylov指数，即使李雅普诺夫指数已经是最大的。 特别是，这一结果与猜想的界限$\lambda_L \leq \lambda_K \leq 2\pi T$存在矛盾。 最后，我们找到了自相关函数的解，其功率谱非常类似于全息系统中所谓的热力学乘积公式。 显示英文摘要

We examine the effective field theory (EFT) of maximal chaos through the lens of Krylov complexity and the Universal Operator Growth Hypothesis. We test the relationship between two measures of quantum chaos: out-of-time-ordered correlators (OTOCs) and Krylov complexity. In the EFT, a shift symmetry of the hydrodynamic modes enforces the maximal Lyapunov exponent in OTOCs, $\lambda_L = 2\pi T$, while simultaneously constraining thermal two-point autocorrelators. We solve these constraints on the autocorrelator, and calculate the Lanczos coefficients and Krylov exponents for several examples, finding both $\lambda_K = \lambda_L$ and $\lambda_K = \lambda_L/2$. This demonstrates that, within the EFT, the shift symmetry alone is insufficient to enforce maximal Krylov exponents even when the Lyapunov exponent is maximal. In particular, this result suggests a tension with the conjectured bound $\lambda_L \leq \lambda_K \leq 2\pi T$. Finally, we identify autocorrelator solutions whose power spectra closely resemble the so-called thermal product formula seen in holographic systems.

替换提交 (展示 1 之 1 条目 )

[4] arXiv:2501.09818 (替换) [中文pdf, pdf, html, 其他]

标题： CV-MDI-QKD概述 显示英文标题

标题： An Overview of CV-MDI-QKD

Alasdair I. Fletcher, Cillian Harney, Masoud Ghalaii, Panagiotis Papanastasiou, Alexandros Mountogiannakis, Gaetana Spedalieri, Adnan A. E. Hajomer, Tobias Gehring, Stefano Pirandola

评论： 简要综述论文

期刊参考： 代表。 进展。 物理。 88，084001（2025）

主题： 量子物理 (quant-ph) ; 其他凝聚态物理 (cond-mat.other) ; 应用物理 (physics.app-ph) ; 光学 (physics.optics)

随着量子密钥分发（QKD）作为一种应对量子计算机威胁的稳健防御手段逐渐兴起，研究人员已经取得了显著的进步。 一个关键的关注点是开发不仅简化硬件实现（如使用连续变量（CV）系统）的协议，而且消除了对可信节点的需要，如测量设备无关（MDI）方法所示。 本文深入探讨了这些方法在CV-MDI-QKD协议中的整合，提供了对其发展、主要特征以及理论和实验最新进展的深入分析。 显示英文摘要

As quantum key distribution (QKD) emerges as a robust defense against quantum computer threats, significant advancements have been realized by researchers. A pivotal focus has been the development of protocols that not only simplify hardware implementation like the use of continuous-variable (CV) systems, but also negate the necessity for trusted nodes, as seen with the measurement-device independent (MDI) approach. This paper delves into the integration of these methodologies in the CV-MDI-QKD protocol, offering an in-depth exploration of its evolution, primary characteristics, and the latest advancements in both theory and experiment.