Non-Hermitian dynamics and non-Bloch band theory

by Ms Wen-Tan Xue (Institute for Advanced Study, Tsinghua University)

Wednesday 30 Mar 2022, 10:00 → 11:00 Asia/Shanghai

ONLINE

Abstract

I will talk about two of our recent progresses in non-Hermitian physics. 1. Based on non-Bloch band theory, we obtain simple Green’s function formulas of general 1D non-Hermitian bands. Furthermore, in the large-size limit, these formulas dramatically reduce to finding the roots of a simple algebraic equation. As an application, our formulation provides the desirable formulas for the defining quantities, the gain and directionality, of directional amplification.   2. We unveil an unexpected non-Hermitian phenomenon, dubbed edge burst, in non-Hermitian quantum dynamics. Specifically, in a class of non-Hermitian quantum walk in periodic lattices with open boundary condition, an exceptionally large portion of loss occurs at the system boundary. The physical origin of this edge burst is found to be an interplay between two unique non-Hermitian phenomena: non-Hermitian skin effect and imaginary gap closing. Furthermore, we establish a universal bulk-edge scaling relation underlying the non-Hermitian edge burst. Our predictions are experimentally accessible in various non-Hermitian systems including quantum-optical and cold-atom platforms.

[1] Wen-Tan Xue, Yu-Min Hu, Fei Song, and Zhong Wang, Phys. Rev. Lett. 128, 120401 (2022)

[2] Wen-Tan Xue, Ming-Rui Li, Yu-Min Hu, Fei Song, and Zhong Wang, Phys. Rev. B. 103, L241408 (2021).

Biography

Wen-Tan Xue is currently a PhD student of Prof. Zhong Wang’s group in Institute for Advanced Study, Tsinghua University. Her current research focuses are non-Hermitian physics and topological phases of matter. She received her Bachelor degree of physics at Xiamen University in 2017.

Division

Condensed Matter

Other information

Vedio link: https://vshare.sjtu.edu.cn/open/a61e6fd381a8f5a0cd1944973b30052e