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Glassy word problems: ultraslow relaxation, Hilbert space jamming, and computational complexity 玻璃文字问题:超慢速松弛、希尔伯特空间干扰和计算复杂性
Pub Date : 2023-12-07 DOI: arxiv-2312.04562
Shankar Balasubramanian, Sarang Gopalakrishnan, Alexey Khudorozhkov, Ethan Lake
We introduce a family of local models of dynamics based on ``word problems''from computer science and group theory, for which we can place rigorous lowerbounds on relaxation timescales. These models can be regarded either as randomcircuit or local Hamiltonian dynamics, and include many familiar examples ofconstrained dynamics as special cases. The configuration space of these modelssplits into dynamically disconnected sectors, and for initial states to relax,they must ``work out'' the other states in the sector to which they belong.When this problem has a high time complexity, relaxation is slow. In some ofthe cases we study, this problem also has high space complexity. When the spacecomplexity is larger than the system size, an unconventional type of jammingtransition can occur, whereby a system of a fixed size is not ergodic, but canbe made ergodic by appending a large reservoir of sites in a trivial productstate. This manifests itself in a new type of Hilbert space fragmentation thatwe call fragile fragmentation. We present explicit examples where slowrelaxation and jamming strongly modify the hydrodynamics of conserveddensities. In one example, density modulations of wavevector $q$ exhibit almostno relaxation until times $O(exp(1/q))$, at which point they abruptlycollapse. We also comment on extensions of our results to higher dimensions.
我们基于计算机科学和群论中的 "文字问题 "引入了一系列局部动力学模型,我们可以为这些模型设定严格的松弛时间尺度下限。这些模型既可视为随机电路动力学模型,也可视为局部哈密顿动力学模型,还包括许多我们熟悉的受约束动力学特例。这些模型的配置空间分裂成动态断开的扇区,初始态必须 "解决 "其所属扇区中的其他态才能松弛。在我们研究的某些情况下,这个问题的空间复杂度也很高。当空间复杂度大于系统大小时,就会出现一种非常规的干扰转换,即一个固定大小的系统不是遍历的,但可以通过在琐积状态中添加大量的位点库来使其成为遍历的。这表现为一种新型的希尔伯特空间碎片化,我们称之为脆弱碎片化。我们给出了一些明确的例子,在这些例子中,缓慢松弛和干扰强烈地改变了守恒性的流体力学。在其中一个例子中,波向量 $q$ 的密度调制在 $O(exp(1/q))$ 时间之前几乎没有松弛,而在此时它们会突然坍缩。我们还评论了我们的结果在更高维度上的扩展。
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引用次数: 0
Stability of buoyant-Couette flow in a vertical porous slot 垂直多孔槽中浮力-库埃特流动的稳定性
Pub Date : 2023-12-07 DOI: arxiv-2312.04270
B. M. Shankar, I. S. Shivakumara
The stability of two-dimensional buoyancy-driven convection in a verticalporous slot, wherein a plane Couette flow is additionally present, is studied.This complex fluid flow scenario is examined under the influence of Robin-typeboundary conditions, which are applied to perturbations in both velocity andtemperature. The inclusion of a time-derivative velocity term within the Darcymomentum equation notably introduces intricacies to the study. The stability ofthe basic natural convection flow is primarily governed by several keyparameters namely, the P'eclet number, the Prandtl-Darcy number, the Biotnumber and a non-negative parameter that dictates the nature of the verticalboundaries. Through numerical analysis, the stability eigenvalue problem issolved for a variety of combinations of boundary conditions. The outcomes ofthis analysis reveal the critical threshold values that signify the onset ofinstability. Furthermore, a detailed examination of the stability of the systemhas provided insights into both its commonalities and distinctions underdifferent conditions. It is observed that, except for the scenario featuringimpermeable-isothermal boundaries, the underlying base flow exhibitsinstability when subjected to various other configurations of perturbedvelocity and temperature boundary conditions. This underscores the notion thatthe presence of Couette flow alone does not suffice to induce instabilitywithin the system. The plots depicting neutral stability curves show eitherbi-modal or uni-modal characteristics, contingent upon specific parametervalues that influence the onset of instability.
研究了垂直多孔槽中二维浮力驱动对流的稳定性,其中还存在平面库埃特流。这种复杂的流体流动情况是在罗宾型边界条件的影响下进行研究的,罗宾型边界条件适用于速度和温度的扰动。在达西动量方程中加入时间衍生速度项,为研究带来了复杂性。基本自然对流的稳定性主要受几个关键参数的制约,即 P'eclet 数、普朗特-达西数、Biot 数和一个决定垂直边界性质的非负参数。通过数值分析,解决了各种边界条件组合下的稳定性特征值问题。分析结果揭示了标志着不稳定性开始的临界阈值。此外,通过对系统稳定性的详细研究,还深入了解了系统在不同条件下的共性和差异。研究发现,除了以不渗透等温边界为特征的情况外,底层基流在受到其他各种扰动速度和温度边界条件配置时都表现出不稳定性。这强调了一个概念,即仅仅存在库埃特流不足以引起系统的不稳定性。描述中性稳定性曲线的曲线图显示出双模态或单模态特征,这取决于影响不稳定性发生的特定参数值。
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引用次数: 0
Affine Symmetries for ABJM Partition Function and its Generalization ABJM 平分函数的仿射对称性及其泛化
Pub Date : 2023-12-07 DOI: arxiv-2312.04206
Sanefumi Moriyama, Tomoki Nosaka
Partially motivated by the fact that the grand partition function of the ABJMtheory or its generalization is expressed by a spectral operator enjoyingsymmetries of the Weyl group, it was found that the grand partition functionsatisfies the q-Painleve equation, which is constructed from the affine Weylgroup. In this paper we clarify the affine symmetries of the grand partitionfunction. With the affine symmetries, we find that the grand partition functionextends naturally outside the fundamental domain of duality cascades and oncethe Painleve equation holds in the fundamental domain, so does it outside.
部分原因是 ABJM 理论或其广义的大分区函数是由享有韦尔群对称性的谱算子表达的,研究发现大分区函数满足 q-Painleve 方程,而 q-Painleve 方程是由仿射韦尔群构造的。本文阐明了大分治函数的仿射对称性。有了仿射对称性,我们发现大分治函数可以自然地扩展到对偶级联的基域之外,而且在基域内的潘勒夫方程成立时,基域之外的潘勒夫方程也成立。
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引用次数: 0
Ergodic theorems for continuous-time quantum walks on crystal lattices and the torus 晶格和环上连续时间量子行走的遍历定理
Pub Date : 2023-12-07 DOI: arxiv-2312.04492
Anne Boutet de Monvel, Mostafa Sabri
We give several quantum dynamical analogs of the classical Kronecker-Weyltheorem, which says that the trajectory of free motion on the torus alongalmost every direction tends to equidistribute. As a quantum analog, we studythe quantum walk $exp(-i t Delta) psi$ starting from a localized initialstate $psi$. Then the flow will be ergodic if this evolved state becomesequidistributed as time goes on. We prove that this is indeed the case forevolutions on the flat torus, provided we start from a point mass, and we provediscrete analogs of this result for crystal lattices. On some periodic graphs,the mass spreads out non-uniformly, on others it stays localized. Finally, wegive examples of quantum evolutions on the sphere which do not equidistribute.
我们给出了经典的克朗内克尔-韦尔定理(Kronecker-Weyltheorem)的几个量子动力学类比,这个定理说的是环上自由运动的轨迹沿着几乎每个方向都趋于等分布。作为量子类比,我们研究了从局部初始状态 $psi$ 开始的量子行走 $exp(-i t Delta) psi$。如果这个演化状态随着时间的推移变得液态分布,那么这个流动就是遍历性的。我们证明,只要我们从一个点质量出发,平面环面上的旋转确实如此,我们还证明了这一结果在晶格上的离散类比。在某些周期图上,质量非均匀分布,而在另一些周期图上,质量则保持局部。最后,我们举例说明了球面上不等分布的量子演化。
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引用次数: 0
Para-spaces, their differential analysis and an application to Green's quantisation 准空间、其微分分析以及在格林量子化中的应用
Pub Date : 2023-12-07 DOI: arxiv-2312.04250
Ruibin Zhang
We introduce a class of non-commutative geometries, loosely referred to aspara-spaces, which are manifolds equipped with sheaves of non-commutativealgebras called para-algebras. A differential analysis on para-spaces isinvestigated, which is reminiscent of that on super manifolds and can bereadily applied to model physical problems, for example, by using para-spaceanalogues of differential equations. Two families of examples, the affinepara-spaces $mathbb{K}^{m|n}(p)$ and para-projective spaces$mathbb{KP}^{m|n}(p)$, with $mathbb{K}$ being $mathbb{R}$ and $mathbb{C}$,are treated in detail for all positive integers $p$. As an application of suchnon-commutative geometries, we interpret Green's theory of parafermions interms of para-spaces on a point. Other potential applications in quantum fieldtheory are also commented upon.
我们介绍了一类非交换几何,可宽泛地称为准空间,它们是配备有称为准代数的非交换代数的流形。我们对准空间的微分分析进行了研究,它让人想起超流形的微分分析,并且可以方便地应用于物理问题的建模,例如,通过使用微分方程的准空间模拟。对于所有正整数 $p$,我们详细讨论了两个系列的例子:affinepara-spaces $mathbb{K}^{m|n}(p)$ 和 para-projective spaces $mathbb{KP}^{m|n}(p)$ ,其中 $mathbb{K}$ 是 $mathbb{R}$ 和 $mathbb{C}$ 。作为这种非交换几何的一种应用,我们用点上的对位空间来解释格林的对位费米子理论。我们还评论了量子场论中的其他潜在应用。
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引用次数: 0
Zero-Class Poisson for Rare-Event Studies 零类泊松用于罕见事件研究
Pub Date : 2023-12-06 DOI: arxiv-2312.03894
Thomas M. Semkow
We developed a statistical theory of zero-count-detector (ZCD), which isdefined as a zero-class Poisson under conditions outlined in the paper. ZCD isoften encountered in the studies of rare events in physics, health physics, andmany other fields where counting of events occurs. We found no acceptablesolution to ZCD in classical statistics and affirmed the need for the Bayesianstatistics. Several uniform and reference priors were studied and we derivedBayesian posteriors, point estimates, and upper limits. It was showed that themaximum-entropy prior, containing the most information, resulted in thesmallest bias and the lowest risk, making it the most admissible and acceptableamong the priors studied. We also investigated application of zero-inflatedPoisson and Negative-binomial distributions to ZCD. It was showed usingBayesian marginalization that, under limited information, these distributionsreduce to the Poisson distribution.
我们提出了零计数探测器(ZCD)的统计理论,它在本文概述的条件下被定义为零类泊松。在物理学、健康物理学以及其他许多需要对事件进行计数的领域中,对罕见事件的研究经常会遇到 ZCD。我们发现在经典统计学中没有可接受的解决 ZCD 的方法,因此肯定了贝叶斯统计的必要性。我们研究了几种均匀先验和参考先验,并得出了贝叶斯后验、点估计和上限。结果表明,包含最多信息的最大熵先验导致了最小偏差和最低风险,使其成为所研究先验中最可接受和可接受度最高的先验。我们还研究了零膨胀泊松分布和负二叉分布在 ZCD 中的应用。使用贝叶斯边际化方法表明,在信息有限的情况下,这些分布会还原为泊松分布。
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引用次数: 0
On the Obtaining Solutions of Nonlinear Differential Equations by Means of the Solutions of Simpler Linear or Nonlinear Differential Equations 论通过较简单线性或非线性微分方程的解来获取非线性微分方程的解
Pub Date : 2023-12-06 DOI: arxiv-2312.03621
Nikolay K. Vitanov
In this article, we follow an idea that is opposite to the idea of Hopf andCole: we use transformations in order to transform simpler linear or nonlineardifferential equations (with known solutions) to more complicated nonlineardifferential equations. In such a way, we can obtain numerous exact solutionsof nonlinear differential equations. We apply this methodology to the classicalparabolic differential equation (the wave equation), to the classicalhyperbolic differential equation (the heat equation), and to the classicalelliptic differential equation (Laplace equation). In addition, we use themethodology to obtain exact solutions of nonlinear ordinary differentialequations by means of the solutions of linear differential equations and bymeans of the solutions of the nonlinear differential equations of Bernoulli andRiccati. Finally, we demonstrate the capacity of the methodology to lead toexact solutions of nonlinear partial differential equations on the basis ofknown solutions of other nonlinear partial differential equations. As anexample of this, we use the Korteweg--de Vries equation and its solutions.Traveling wave solutions of nonlinear differential equations are of specialinterest in this article. We demonstrate the existence of the followingphenomena described by some of the obtained solutions: (i) occurrence of thesolitary wave--solitary antiwave from the solution, which is zero at theinitial moment (analogy of an occurrence of particle and antiparticle from thevacuum); (ii) splitting of a nonlinear solitary wave into two solitary waves(analogy of splitting of a particle into two particles); (iii) soliton behaviorof some of the obtained waves; (iv) existence of solitons which move with thesame velocity despite the different shape and amplitude of the solitons.
在本文中,我们遵循一种与霍普夫和科尔相反的思想:我们利用变换来将较简单的线性或非线性微分方程(已知解)变换为较复杂的非线性微分方程。通过这种方法,我们可以得到许多非线性微分方程的精确解。我们将这一方法应用于经典抛物微分方程(波方程)、经典双曲微分方程(热方程)和经典椭圆微分方程(拉普拉斯方程)。此外,我们还通过线性微分方程的解以及伯努利和里卡提非线性微分方程的解,利用这些方法获得非线性常微分方程的精确解。最后,我们展示了该方法在其他非线性偏微分方程已知解的基础上得出非线性偏微分方程精确解的能力。本文特别关注非线性微分方程的行波解。我们证明了所得到的一些解所描述的以下现象的存在:(i) 解中出现孤波-孤反波,在初始时刻为零(类似于真空中出现的粒子和反粒子);(ii) 非线性孤波分裂为两个孤波(类似于一个粒子分裂为两个粒子);(iii) 部分所得波的孤子行为;(iv) 尽管孤子的形状和振幅不同,但存在以相同速度运动的孤子。
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引用次数: 0
Temporal coupled-mode theory in nonlinear resonant photonics: From basic principles to contemporary systems with 2D materials, dispersion, loss, and gain 非线性谐振光子学中的时间耦合模式理论:从基本原理到二维材料、色散、损耗和增益的现代系统
Pub Date : 2023-12-06 DOI: arxiv-2312.03539
Thomas Christopoulos, Odysseas Tsilipakos, Emmanouil E. Kriezis
Temporal coupled-mode theory (CMT) is an acclaimed and widely usedtheoretical framework for modeling the continuous wave (CW) response andtemporal dynamics of any integrated or free-space photonic resonant structure.It was initially employed to understand how energy is coupled into and out of acavity and how it is exchanged between different resonant modes. In the 30years that followed its establishment, CMT has been expanded to describe abroad range of nonlinear interactions as well (self- and cross-phasemodulation, saturable absorption, frequency generation, gain, etc.). In thistutorial, we thoroughly present the basic principles and the evolution of CMTthroughout the years, showcasing its immense capabilities for the analysis anddesign of linear and nonlinear resonant photonic systems. Importantly, we focuson examples of modern, open nanophotonic resonators incorporating contemporarybulk or sheet (2D) materials that may be lossy and dispersive. For eachlinear/nonlinear effect under study we follow a meticulous, step-by-stepapproach, starting from an accurate model of the physical phenomenon andproceeding to its introduction in the CMT framework all the way to theefficient solution of the resulting system of equations. Our work highlightsthe merits of CMT as an efficient, accurate, and versatile theoretical tool. Weenvision that it can serve both as an introductory reference for any reader, aswell as a comprehensive handbook on how to incorporate a broad range of linearand nonlinear effects in the CMT framework.
时间耦合模式理论(CMT)是一种广受赞誉和广泛应用的理论框架,用于对任何集成或自由空间光子谐振结构的连续波(CW)响应和时间动态进行建模。在其问世后的 30 年中,CMT 的应用范围不断扩大,也可用于描述各种非线性相互作用(自相位和跨相位调制、可饱和吸收、频率产生、增益等)。在本教程中,我们将全面介绍 CMT 的基本原理和多年来的发展历程,展示其在分析和设计线性和非线性谐振光子系统方面的巨大能力。重要的是,我们将重点放在现代开放式纳米光子谐振器的例子上,这些谐振器采用了当代的块状或片状(2D)材料,可能具有损耗和色散特性。对于所研究的每一种线性/非线性效应,我们都采用细致入微、循序渐进的方法,从建立物理现象的精确模型开始,到将其引入 CMT 框架,再到有效求解所产生的方程组。我们的工作凸显了 CMT 作为一种高效、精确和多功能理论工具的优点。我们希望这本书既可以作为任何读者的入门参考书,也可以作为一本全面的手册,介绍如何将广泛的线性和非线性效应纳入 CMT 框架。
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引用次数: 0
Vertex algebras from divisors on Calabi-Yau threefolds 来自 Calabi-Yau 三折上除数的顶点代数
Pub Date : 2023-12-06 DOI: arxiv-2312.03648
Dylan Butson
We construct vertex algebras $mathbb{V}(Y,S)$ from divisors $S$ on toricCalabi-Yau threefolds $Y$, satisfying conjectures of Gaiotto-Rapcak andFeigin-Gukov, as the kernel of screening operators on lattice vertex algebrasdetermined by the GKM graph of $Y$ and a filtration on $mathcal{O}_S$. Weprove that there are representations of $mathbb{V}(Y,S)$ on the homologygroups of various moduli spaces of coherent sheaves on $Y$ supported on $S$constructed in a companion paper with Rapcak, defined by certain Heckemodifications of these sheaves along points and curve classes in the divisor$S$. This generalizes the common mathematical formulation of a conjecture ofAlday-Gaiotto-Tachikawa, the special case in which $Y=mathbb{C}^3$ and$S=r[mathbb{C}^2]$, to toric threefolds and divisors as proposed byGaiotto-Rapcak. We outline an approach to the general conjecture and prove manyspecial cases and partial results using tools developed in the companion paper,following the proof of the original conjecture by Schiffmann-Vasserot and itsgeneralization to divisors in $mathbb{C}^3$ by Rapcak-Soibelman-Yang-Zhao. The vertex algebras $mathbb{V}(Y,S)$ conjecturally include $W$-superalgebras$ W_{f_0,f_1}^kappa(mathfrak{gl}_{m|n})$ and genus zero class $mathcal{S}$chiral algebras $mathbb{V}^{mathcal{S}}_{text{Gl}_m;f_1,...,f_k}$, each forgeneral nilpotents $f_i$. By definition, this implies the existence of a familyof compatible free field realizations of these vertex algebras, relevant totheir parabolic induction and inverse quantum Hamiltonian reduction. We provethese conjectures in the examples of lowest non-trivial rank for each case, andoutline the proof in general for some cases.
我们从环状卡拉比-约三围 $Y$ 上的分维 $S$ 构造了顶点代数 $mathbb{V}(Y,S)$,满足盖奥托-拉普卡克(Gaiotto-Rapcak)和费金-古可夫(Feigin-Gukov)的猜想,作为由 $Y$ 的 GKM 图和 $mathcal{O}_S$ 上的滤波决定的晶格顶点代数上的筛选算子的内核。我们证明,在与拉普卡克合作的一篇论文中构建的$S$上支持$Y$的相干卷的各种模空间的同调群上,存在着$mathbb{V}(Y,S)$的表征,这些表征是由这些卷沿分部$S$中的点和曲线类的某些赫克修正定义的。这就把阿尔代-盖奥托-立川猜想的常见数学表述,即$Y=mathbb{C}^3$和$S=r[mathbb{C}^2]$的特殊情况,推广到了盖奥托-拉普卡克提出的环状三褶和除数。我们概述了实现一般猜想的方法,并使用同伴论文中开发的工具证明了许多特殊情况和部分结果,这是继 Schiffmann-Vasserot 对原始猜想的证明,以及 Rapcak-Soibelman-Yang-Zhao 对 $mathbb{C}^3$ 中的除数的概括之后的又一次证明。顶点代数 $mathbb{V}(Y,S)$ 猜想包括 $W$-superalgebras$ W_{f_0,f_1}^kappa(mathfrak{gl}_{m|n})$ 和零属类 $mathcal{S}$chiral 代数 $mathbb{V}^{mathcal{S}}_{text{Gl}_m;f_1,...,f_k}$ 。...,f_k}$,每一个都包含零potents $f_i$。根据定义,这意味着存在这些顶点代数的兼容自由场实化族,这与它们的抛物线归纳和逆量子哈密顿还原有关。我们在每种情况下的最低非琐秩的例子中证明了这些猜想,并概述了某些情况下的一般证明。
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引用次数: 0
The three limits of the hydrostatic approximation 流体静力学近似的三个极限
Pub Date : 2023-12-06 DOI: arxiv-2312.03418
Ken Furukawa, Yoshikazu Giga, Matthias Hieber, Amru Hussein, Takahito Kashiwabara, Marc Wrona
The primitive equations are derived from the $3D$-Navier-Stokes equations bythe hydrostatic approximation. Formally, assuming an $varepsilon$-thin domainand anisotropic viscosities with vertical viscosity$nu_z=mathcal{O}(varepsilon^gamma)$ where $gamma=2$, one obtains theprimitive equations with full viscosity as $varepsilonto 0$. Here, we taketwo more limit equations into consideration: For $gamma<2$ the$2D$-Navier-Stokes equations are obtained. For $gamma>2$ the primitiveequations with only horizontal viscosity $-Delta_H$ as $varepsilonto 0$.Thus, there are three possible limits of the hydrostatic approximationdepending on the assumption on the vertical viscosity. The latter convergencehas been proven recently by Li, Titi, and Yuan using energy estimates. Here, weconsider more generally $nu_z=varepsilon^2 delta$ and show how maximalregularity methods and quadratic inequalities can be an efficient approach tothe same end for $varepsilon,deltato 0$. The flexibility of our methods isalso illustrated by the convergence for $deltato infty$ and $varepsilonto0$ to the $2D$-Navier-Stokes equations.
原始方程是通过流体静力学近似从 3D$ 纳维尔-斯托克斯方程导出的。形式上,假设有一个 $varepsilon$ 薄的域和各向异性的粘度,垂直粘度为$nu_z=mathcal{O}(varepsilon^gamma)$(其中$gamma=2$),那么当 $varepsilon 到 0$ 时,我们就得到了具有全粘度的原始方程。在这里,我们还要考虑两个极限方程:对于 $gamma2$ ,当 $varepsilonto 0$ 时,原始方程只有水平粘度 $-Delta_H$。因此,静力学近似有三种可能的极限,取决于对垂直粘度的假设。最近,Li、Titi 和 Yuan 利用能量估计证明了后一种收敛性。在这里,我们更广泛地考虑了 $nu_z=varepsilon^2 delta$,并展示了最大正则方法和二次不等式是如何有效地实现 $varepsilon,deltato 0$ 的。我们方法的灵活性还体现在$deltato infty$和$varepsilonto0$对2D$-Navier-Stokes方程的收敛性上。
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引用次数: 0
期刊
arXiv - PHYS - Mathematical Physics
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