arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2006.04827cond-mat.dis-nncond-mat.mes-hall
收藏

数学正态Rosenzweig-Porter模型中的脆弱遍历相

Fragile ergodic phases in logarithmically-normal Rosenzweig-Porter model

I. M. Khaymovich, V. E. Kravtsov, B. L. Altshuler, L. B. Ioffe

摘要:

在本文中,我们提出了一个扩展的罗森茨威格-波特(RP)模型,LN-RP模型,其中的非对角矩阵元素有一个广泛的,对数正态分布。我们认为,该模型更适合于描述一个通用的多体局域化问题。与RP模型不同,在LN-RP模型中出现了一个脆弱的弱遍历相,其特征是基旋转对称性破缺,而完全遍历相也存在于该模型中,严格遵守热力学极限。因此,在LN-RP模型中,除了局部化和遍历性的过渡之外,还存在两个遍历性阶段之间的过渡(FWE过渡)。我们提出了新的非遍历相稳定性判据,给出了局域化和遍历相变点,并证明了LN-RP模型中的安德森局域化相变涉及本征函数支集的分形维数的跳跃.我们还建立了FWE相变的判据,并得到了该模型的完整相图。我们发现,截断对数正态尾缩小了弱遍历相位的区域,恢复了多重分形和完全遍历相位。

英文摘要:

In this paper we suggest an extension of the Rosenzweig-Porter (RP) model, the LN-RP model, in which the off-diagonal matrix elements have a wide, log-normal distribution. We argue that this model is more suitable to describe a generic many body localization problem. In contrast to RP model, in LN-RP model a fragile weakly ergodic phase appears that is characterized by broken basis-rotation symmetry which the fully-ergodic phase, also present in this model, strictly respects in the thermodynamic limit. Therefore, in addition to the localization and ergodic transitions in LN-RP model there exists also the transition between the two ergodic phases (FWE transition). We suggest new criteria of stability of the non-ergodic phases which give the points of localization and ergodic transitions and prove that the Anderson localization transition in LN-RP model involves a jump in the fractal dimension of the eigenfunction support set. We also formulate the criterion of FWE transition and obtain the full phase diagram of the model. We show that truncation of the log-normal tail shrinks the region of weakly-ergodic phase and restores the multifractal and the fully-ergodic phases.

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。

↑