Measuring non-Hermitian topological invariants directly from quench dynamics

While non-Hermitian (NH) topological phases and phenomena have been observed across various quantum systems, directly measuring NH topological invariants remains a significant challenge. In this study, we present a generic and unified framework for the direct measurement of various NH topological in...

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Main Authors: Xiao-Dong Lin, Long Zhang
Format: Article
Language:English
Published: American Physical Society 2025-03-01
Series:Physical Review Research
Online Access:http://doi.org/10.1103/PhysRevResearch.7.L012060
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author Xiao-Dong Lin
Long Zhang
author_facet Xiao-Dong Lin
Long Zhang
author_sort Xiao-Dong Lin
collection DOAJ
description While non-Hermitian (NH) topological phases and phenomena have been observed across various quantum systems, directly measuring NH topological invariants remains a significant challenge. In this study, we present a generic and unified framework for the direct measurement of various NH topological invariants in odd-dimensional systems through quench dynamics. We demonstrate that in one-dimensional (1D) NH systems with sublattice symmetry, the line-gap winding number and point-gap braiding degree can be extracted from the winding patterns of a dynamically constructed field based on postquench spin textures. Specifically, line-gap topology is characterized by integer-valued winding, whereas point-gap complex-band braiding is revealed by half-integer or integer winding with abrupt jumps. We also extend our approach to higher-dimensional winding numbers and non-Bloch topological invariants under open-boundary conditions. Additionally, we propose a practical cold-atom setup to realize and detect 1D NH topological phases, showing that our dynamical measurement scheme is feasible in current experimental settings. This work paves the way for the direct measurement of NH topological invariants in quantum systems.
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spelling doaj-art-19e2e9bc2de3426daaa35efe72a754e72025-08-20T02:58:34ZengAmerican Physical SocietyPhysical Review Research2643-15642025-03-0171L01206010.1103/PhysRevResearch.7.L012060Measuring non-Hermitian topological invariants directly from quench dynamicsXiao-Dong LinLong ZhangWhile non-Hermitian (NH) topological phases and phenomena have been observed across various quantum systems, directly measuring NH topological invariants remains a significant challenge. In this study, we present a generic and unified framework for the direct measurement of various NH topological invariants in odd-dimensional systems through quench dynamics. We demonstrate that in one-dimensional (1D) NH systems with sublattice symmetry, the line-gap winding number and point-gap braiding degree can be extracted from the winding patterns of a dynamically constructed field based on postquench spin textures. Specifically, line-gap topology is characterized by integer-valued winding, whereas point-gap complex-band braiding is revealed by half-integer or integer winding with abrupt jumps. We also extend our approach to higher-dimensional winding numbers and non-Bloch topological invariants under open-boundary conditions. Additionally, we propose a practical cold-atom setup to realize and detect 1D NH topological phases, showing that our dynamical measurement scheme is feasible in current experimental settings. This work paves the way for the direct measurement of NH topological invariants in quantum systems.http://doi.org/10.1103/PhysRevResearch.7.L012060
spellingShingle Xiao-Dong Lin
Long Zhang
Measuring non-Hermitian topological invariants directly from quench dynamics
Physical Review Research
title Measuring non-Hermitian topological invariants directly from quench dynamics
title_full Measuring non-Hermitian topological invariants directly from quench dynamics
title_fullStr Measuring non-Hermitian topological invariants directly from quench dynamics
title_full_unstemmed Measuring non-Hermitian topological invariants directly from quench dynamics
title_short Measuring non-Hermitian topological invariants directly from quench dynamics
title_sort measuring non hermitian topological invariants directly from quench dynamics
url http://doi.org/10.1103/PhysRevResearch.7.L012060
work_keys_str_mv AT xiaodonglin measuringnonhermitiantopologicalinvariantsdirectlyfromquenchdynamics
AT longzhang measuringnonhermitiantopologicalinvariantsdirectlyfromquenchdynamics