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arXiv 2310.03412cond-mat.dis-nn
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非厄米系统中依赖于互易性与跳跃不对称性的局域化转变

Localization transition in non-Hermitian systems depending on reciprocity and hopping asymmetry

Daniil Kochergin, Vasilii Tiselko, Arsenii Onuchin

AI总结:

本文研究有向图非厄米系统中互易性与跳跃不对称性对安德森局域化的影响,揭示左、双正交和右局域态的出现规律、迁移率边及对角无序下的分形维数和局域化疤痕现象。

摘要:

我们研究了有向图上非厄米系统的单粒子安德森局域化问题。通过控制互易性和跳跃不对称性参数,对随机正则图以及多种无向标准随机图模型进行了修改。我们发现左、双正交和右局域态的出现同时依赖于这两个参数以及图的拓扑结构性质,例如节点度 $d$。对于有向随机图,双正交局域化在例外点附近的发生通过解析和数值方法得到了描述。数值结果展示了局域态在谱中心附近的聚集现象,以及左态和右态相应的迁移率边。我们还描述了导致局域化的结构特征,例如拓扑不变节点或汇与源。考虑对角无序时,我们观察到对于节点度 $d=4$ 的随机正则图,在 $W \sim 20$ 附近局域化对互易性的依赖消失。在较小对角无序下,平均双正交分形维数急剧降低。在 $W \sim 5$ 附近,谱内出现局域化疤痕,表现为左、右局域态聚集的垂直带状交替分布。

英文摘要:

We studied the single-particle Anderson localization problem for non-Hermitian systems on directed graphs. Random regular graph and various undirected standard random graph models were modified by controlling reciprocity and hopping asymmetry parameters. We found the emergence of left, biorthogonal and right localized states depending on both parameters and graph structure properties such as node degree $d$. For directed random graphs, the occurrence of biorthogonal localization near exceptional points is described analytically and numerically. The clustering of localized states near the center of the spectrum and the corresponding mobility edge for left and right states are shown numerically. Structural features responsible for localization, such as topologically invariant nodes or drains and sources, were also described. Considering the diagonal disorder, we observed the disappearance of localization dependence on reciprocity around $W \sim 20$ for a random regular graph $d=4$. With a small diagonal disorder, the average biorthogonal fractal dimension drastically reduces. Around $W \sim 5$ localization scars occur within the spectrum, alternating as vertical bands of clustering of left and right localized states.

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。

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