Extended imaginary gauge transformation in a general nonreciprocal lattice

Fuente: arXiv
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Main Authors: Qi, Yunyao, Pi, Jinghui, Wu, Yuquan, Lin, Heng, Zheng, Chao, Long, Gui-Lu
Format: Preprint
Published: 2024
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author Qi, Yunyao
Pi, Jinghui
Wu, Yuquan
Lin, Heng
Zheng, Chao
Long, Gui-Lu
author_facet Qi, Yunyao
Pi, Jinghui
Wu, Yuquan
Lin, Heng
Zheng, Chao
Long, Gui-Lu
contents Imaginary gauge transformation (IGT) provides a clear understanding of the non-Hermitian skin effect by transforming the non-Hermitian Hamiltonians with real spectra into Hermitian ones. In this paper, we extend this approach to the complex spectrum regime in a general nonreciprocal lattice model. We unveil the validity of IGT hinges on a class of pseudo-Hermitian symmetry. The generalized Brillouin zone of Hamiltonians respect such pseudo-Hermiticity is demonstrated to be a circle, which enables easy access to the continuum bands, localization length of skin modes, and relevant topological numbers. Furthermore, we investigate the applicability of IGT and the underlying pseudo-Hermiticity beyond nearest-neighbor hopping, offering a graphical interpretation. Our theoretical framework is applied to establish bulk-boundary correspondence in the nonreciprocal trimer Su-Schrieffer-Heeger model and to analyze the localization behaviors of skin modes in the two-dimensional Hatano-Nelson model.
format Preprint
id arxiv_https___arxiv_org_abs_2401_12785
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Extended imaginary gauge transformation in a general nonreciprocal lattice
Qi, Yunyao
Pi, Jinghui
Wu, Yuquan
Lin, Heng
Zheng, Chao
Long, Gui-Lu
Quantum Physics
Mesoscale and Nanoscale Physics
Imaginary gauge transformation (IGT) provides a clear understanding of the non-Hermitian skin effect by transforming the non-Hermitian Hamiltonians with real spectra into Hermitian ones. In this paper, we extend this approach to the complex spectrum regime in a general nonreciprocal lattice model. We unveil the validity of IGT hinges on a class of pseudo-Hermitian symmetry. The generalized Brillouin zone of Hamiltonians respect such pseudo-Hermiticity is demonstrated to be a circle, which enables easy access to the continuum bands, localization length of skin modes, and relevant topological numbers. Furthermore, we investigate the applicability of IGT and the underlying pseudo-Hermiticity beyond nearest-neighbor hopping, offering a graphical interpretation. Our theoretical framework is applied to establish bulk-boundary correspondence in the nonreciprocal trimer Su-Schrieffer-Heeger model and to analyze the localization behaviors of skin modes in the two-dimensional Hatano-Nelson model.
title Extended imaginary gauge transformation in a general nonreciprocal lattice
topic Quantum Physics
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2401.12785