arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1908.11388cond-mat.dis-nncond-mat.stat-mechquant-ph
收藏

随机正则图上Anderson模型的次扩散

Sub-diffusion in the Anderson model on random regular graph

Giuseppe De Tomasi, Soumya Bera, Antonello Scardicchio, Ivan M. Khaymovich

摘要:

研究了随机正则图(RRG)上Anderson模型中初始定域波包的有限时间动力学。考虑到一个粒子的全概率分布$Π(x,t)$是在一定的距离$x$从初始状态在时间$t$,我们给出的证据表明,$Π(x,t)$传播亚扩散在一个范围内的无序强度,宽于一个假定的非遍历相。我们提供了一个详细的分析$Π(x,t)$在时空$(x,t)$域的传播,确定四个不同的制度。$(x,t)$中的这些区域由波前$X_{\text{front}}(t)$的位置确定,波前$X_{\text{front}}(t)$以指数$β< 1$亚扩散地移动到最远的位置$X_{\text{front}}(t) \sim t^β$。我们支持我们的数值计算结果的自洽半经典图片的波包传播有关的指数$β$与松弛率的返回概率$Π(0,t) \sim e^{-Γt^β}$。重要的是,RRG上的Anderson模型可以被认为是一般相互作用系统在Fock空间上的多体局域化跃迁(MBL)的代理。在最后的讨论中,我们概述了我们的研究结果MBL的可能影响。

英文摘要:

We study the finite-time dynamics of an initially localized wave-packet in the Anderson model on the random regular graph (RRG). Considering the full probability distribution $Π(x,t)$ of a particle to be at some distance $x$ from the initial state at time $t$, we give evidence that $Π(x,t)$ spreads sub-diffusively over a range of disorder strengths, wider than a putative non-ergodic phase. We provide a detailed analysis of the propagation of $Π(x,t)$ in space-time $(x,t)$ domain, identifying four different regimes. These regimes in $(x,t)$ are determined by the position of a wave-front $X_{\text{front}}(t)$, which moves sub-diffusively to the most distant sites $X_{\text{front}}(t) \sim t^β$ with an exponent $β< 1$. We support our numerical results by a self-consistent semiclassical picture of wavepacket propagation relating the exponent $β$ with the relaxation rate of the return probability $Π(0,t) \sim e^{-Γt^β}$. Importantly, the Anderson model on the RRG can be considered as proxy of the many-body localization transition (MBL) on the Fock space of a generic interacting system. In the final discussion, we outline possible implications of our findings for MBL.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑