报告题目 ：Some progress of the Anderson localization problems in disordered non-Hermitian systems

报告人：汪晨 （副教授） 天津大学 

报告时间：2024 年 6 月 28 日（周五）14:00-15:00

报告地点：北洋园校区49教410室（线上：腾讯会议 838-9499-4192）

报告摘要：

      Disorder-induced quantum phase transitions from delocalized to localized states, known as Anderson localization transitions, are a fundamental problem in condensed matter physics. As a long-term investigation issue, the localization problem has attracted enormous research interest, and one of the milestones in this field is the one-parameter scaling theory that predicts the criticality of such transitions. Anderson localization transitions cannot happen in disordered one-dimensional systems within the conventional one-parameter scaling theory scheme. More recent research has shown that this picture needs to be completed since Anderson localization transitions emerge in one dimension if the disordered systems are non-Hermitian.

    This talk contributes to some recent progress in investigating Anderson localization transitions and related topics in disordered non-Hermitian systems. First, we show that extended states can exist in dirty non-Hermitian two-dimensional electron gases, whose level statistics follow the Poisson distribution rather than the Wigner-Dyson statistics [1]. Second, the criticality of Anderson localization transitions near the exceptional point in some specific symmetric systems found a new superuniversality [2]. Finally, we propose a new one-parameter scaling function and prove its validity in a large class of non-Hermitian reciprocal and non-reciprocal systems [3].

报告人简介：

     Dr. Chen WANG received his Ph.D. degree from Hong Kong University of Science and Technology in 2016 and joined the department of science of Tianjin University in 2019. His research interests include quantum phase transitions induced by disorders, topological phases, spintronics, and quantum chaos. Recently, he has focused on exploring novel phenomena in non-Hermitian systems.

参考文献：

[1] C. Wang and X. R. Wang, Level statistics of extended states in random non-Hermitian Hamiltonians, Phys. Rev. B 101, 165114 (2020).

[2] C. Wang and X. R. Wang, Anderson localization transitions in disordered non-Hermitian systems with exceptional points, Phys. Rev. B 107, 024202 (2023).

[3] C. Wang, Wenxue He, X. R. Wang, and Hechen Ren, Unified one-parameter scaling function for Anderson localization transitions in non-reciprocal non-Hermitian systems, arXiv:2406.01984v1.