Coexistence of topological Anderson insulator and multifractal critical phase in a non-Hermitian quasicrystal

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Hauptverfasser: Zeng, Qi-Bo, Lü, Rong
Format: Preprint
Veröffentlicht: 2026
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author Zeng, Qi-Bo
Lü, Rong
author_facet Zeng, Qi-Bo
Lü, Rong
contents The interplay of topology, disorder, and non-Hermiticity gives rise to phenomena beyond the conventional classification of quantum phases. We propose a one-dimensional non-Hermitian Su-Schrieffer-Heeger model with quasiperiodically modulated nonreciprocal intracell hopping. We show that quasiperiodic modulation can substantially enhance the topological regime and, remarkably, induce a non-Hermitian topological Anderson insulator (TAI) phase. Beyond the topological transition, increasing nonreciprocity drives a cascade of localization transitions in which all bulk eigenstates evolve from extended to multifractal critical and ultimately to localized states. Strikingly, the extended-to-critical transition coincides exactly with a real-complex spectral transition. We establish complete phase diagrams and derive exact analytical boundaries for both topological and localization transitions, uncovering an unanticipated coexistence of TAI and multifractal critical phases. Finally, we propose a feasible implementation in topolectrical circuits. Our results reveal a new paradigm for studying the cooperative effects of topology, quasiperiodicity, and non-Hermiticity.
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id arxiv_https___arxiv_org_abs_2602_14026
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Coexistence of topological Anderson insulator and multifractal critical phase in a non-Hermitian quasicrystal
Zeng, Qi-Bo
Lü, Rong
Disordered Systems and Neural Networks
The interplay of topology, disorder, and non-Hermiticity gives rise to phenomena beyond the conventional classification of quantum phases. We propose a one-dimensional non-Hermitian Su-Schrieffer-Heeger model with quasiperiodically modulated nonreciprocal intracell hopping. We show that quasiperiodic modulation can substantially enhance the topological regime and, remarkably, induce a non-Hermitian topological Anderson insulator (TAI) phase. Beyond the topological transition, increasing nonreciprocity drives a cascade of localization transitions in which all bulk eigenstates evolve from extended to multifractal critical and ultimately to localized states. Strikingly, the extended-to-critical transition coincides exactly with a real-complex spectral transition. We establish complete phase diagrams and derive exact analytical boundaries for both topological and localization transitions, uncovering an unanticipated coexistence of TAI and multifractal critical phases. Finally, we propose a feasible implementation in topolectrical circuits. Our results reveal a new paradigm for studying the cooperative effects of topology, quasiperiodicity, and non-Hermiticity.
title Coexistence of topological Anderson insulator and multifractal critical phase in a non-Hermitian quasicrystal
topic Disordered Systems and Neural Networks
url https://arxiv.org/abs/2602.14026