When and why non-Hermitian eigenvalues miss eigenstates in topological physics

Fuente: arXiv
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Main Authors: Jezequel, Lucien, Herviou, Loïc, Bardarson, Jens
Format: Preprint
Published: 2026
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author Jezequel, Lucien
Herviou, Loïc
Bardarson, Jens
author_facet Jezequel, Lucien
Herviou, Loïc
Bardarson, Jens
contents Non-Hermitian systems exhibit a fundamental spectral dichotomy absent in Hermitian physics: the eigenvalue spectrum and the eigenstate spectrum can deviate significantly in the thermodynamic limit. We explain how non-Hermitian Hamiltonians can support eigenstates completely undetected by eigenvalues, with the unidirectional Hatano-Nelson model serving as both a minimal realization and universal paradigm for this phenomenon. Through exact analytical solutions, we show that this model contains not only hidden modes but multiple macroscopic hidden exceptional points that appear more generally in all systems with a non-trivial bulk winding. Our framework explains how the apparent bulk-edge correspondence failures in models like the non-Hermitian SSH chain instead reflect the systematic inability of the eigenvalue spectrum to detect certain eigenstates in systems with a skin-effect. These results establish the limitation of the eigenvalue spectrum and suggest how the eigenstate approach can lead to improved characterization of non-Hermitian topology.
format Preprint
id arxiv_https___arxiv_org_abs_2601_05234
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle When and why non-Hermitian eigenvalues miss eigenstates in topological physics
Jezequel, Lucien
Herviou, Loïc
Bardarson, Jens
Mesoscale and Nanoscale Physics
Quantum Physics
Non-Hermitian systems exhibit a fundamental spectral dichotomy absent in Hermitian physics: the eigenvalue spectrum and the eigenstate spectrum can deviate significantly in the thermodynamic limit. We explain how non-Hermitian Hamiltonians can support eigenstates completely undetected by eigenvalues, with the unidirectional Hatano-Nelson model serving as both a minimal realization and universal paradigm for this phenomenon. Through exact analytical solutions, we show that this model contains not only hidden modes but multiple macroscopic hidden exceptional points that appear more generally in all systems with a non-trivial bulk winding. Our framework explains how the apparent bulk-edge correspondence failures in models like the non-Hermitian SSH chain instead reflect the systematic inability of the eigenvalue spectrum to detect certain eigenstates in systems with a skin-effect. These results establish the limitation of the eigenvalue spectrum and suggest how the eigenstate approach can lead to improved characterization of non-Hermitian topology.
title When and why non-Hermitian eigenvalues miss eigenstates in topological physics
topic Mesoscale and Nanoscale Physics
Quantum Physics
url https://arxiv.org/abs/2601.05234