Geometric origin of self-intersection points in non-Hermitian energy spectra

Fuente: arXiv
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Autores principales: Pi, Jinghui, Wang, Chenyang, Liu, Yong-Chun, Yan, Yangqian
Formato: Preprint
Publicado: 2025
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author Pi, Jinghui
Wang, Chenyang
Liu, Yong-Chun
Yan, Yangqian
author_facet Pi, Jinghui
Wang, Chenyang
Liu, Yong-Chun
Yan, Yangqian
contents Unlike Hermitian systems, non-Hermitian energy spectra under periodic boundary conditions can form closed loops in the complex energy plane, a phenomenon known as point gap topology. In this paper, we investigate the self-intersection points of such non-Hermitian energy spectra and reveal their geometric origins. We rigorously demonstrate that these self-intersection points result from the intersection of the auxiliary generalized Brillouin zone and the Brillouin zone in one-band systems, as confirmed by an extended Hatano-Nelson model. This finding is further generalized to multi-band systems, illustrated through a non-Hermitian Su-Schrieffer-Heeger model. Moreover, we address multiple self-intersection points and derive the geometric conditions for general n-fold self-intersection points. Our results enhance the fundamental understanding of generic non-Hermitian quantum systems and provide theoretical support for further experimental investigations of energy self-intersection points.
format Preprint
id arxiv_https___arxiv_org_abs_2502_04755
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Geometric origin of self-intersection points in non-Hermitian energy spectra
Pi, Jinghui
Wang, Chenyang
Liu, Yong-Chun
Yan, Yangqian
Quantum Physics
Quantum Gases
Optics
Unlike Hermitian systems, non-Hermitian energy spectra under periodic boundary conditions can form closed loops in the complex energy plane, a phenomenon known as point gap topology. In this paper, we investigate the self-intersection points of such non-Hermitian energy spectra and reveal their geometric origins. We rigorously demonstrate that these self-intersection points result from the intersection of the auxiliary generalized Brillouin zone and the Brillouin zone in one-band systems, as confirmed by an extended Hatano-Nelson model. This finding is further generalized to multi-band systems, illustrated through a non-Hermitian Su-Schrieffer-Heeger model. Moreover, we address multiple self-intersection points and derive the geometric conditions for general n-fold self-intersection points. Our results enhance the fundamental understanding of generic non-Hermitian quantum systems and provide theoretical support for further experimental investigations of energy self-intersection points.
title Geometric origin of self-intersection points in non-Hermitian energy spectra
topic Quantum Physics
Quantum Gases
Optics
url https://arxiv.org/abs/2502.04755