Pseudo-Hermitian Topology of Multiband Non-Hermitian Systems

• URL: http://arxiv.org/abs/2405.17749v1
• Date: Tue, 28 May 2024 02:04:09 GMT
• Title: Pseudo-Hermitian Topology of Multiband Non-Hermitian Systems
• Authors: Jung-Wan Ryu, Jae-Ho Han, Chang-Hwan Yi, Hee Chul Park, Moon Jip Park,
• Abstract summary: Non-Hermitian multibands can be topologically non-trivial without exceptional points in two-dimensional space. Our work builds on the fundamental and comprehensive understanding of non-Hermitian multiband systems.
• Score: 1.188383832081829
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: The complex eigenenergies and non-orthogonal eigenstates of non-Hermitian systems exhibit unique topological phenomena that cannot appear in Hermitian systems. Representative examples are the non-Hermitian skin effect and exceptional points. In a two-dimensional parameter space, topological classifications of non-separable bands in multiband non-Hermitian systems can be established by invoking a permutation group, where the product of the permutation represents state exchange due to exceptional points in the space. We unveil in this work the role of pseudo-Hermitian lines in non-Hermitian topology for multiple bands. Contrary to current understanding, the non-separability of non-Hermitian multibands can be topologically non-trivial without exceptional points in two-dimensional space. Our work builds on the fundamental and comprehensive understanding of non-Hermitian multiband systems and also offers versatile applications and realizations of non-Hermitian systems without the need to consider exceptional points.

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