Probing Floquet topological phases via non-Hermitian skin effect of reflected waves

Fuente: arXiv
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Autori principali: Ye, Fangqiao, Hu, Haiping
Natura: Preprint
Pubblicazione: 2026
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author Ye, Fangqiao
Hu, Haiping
author_facet Ye, Fangqiao
Hu, Haiping
contents Periodically driven systems host topological phases without static analogs, such as the anomalous Floquet phase characterized by trivial bulk bands yet robust boundary modes. In this work, we investigate the scattering problem of a Floquet Chern insulator and reveal the non-Hermitian skin effect (NHSE) of reflected waves. Using a discrete-time scattering formalism, we demonstrate how the non-Hermitian winding number of the reflection matrix is linked to the bulk Floquet invariant via boundary resonances. This reflected-wave NHSE relies on which quasienergy gap the incident wave resides in, leading to a gap-dependent Goos-Hänchen (GH) shift. We further show that the momentum-integrated GH shift quantitatively yields the Floquet topological invariant of the corresponding gap. Our work highlights a frequency-dependent NHSE of reflected waves in driven systems and provides a real-space scattering approach to identify non-equilibrium topology.
format Preprint
id arxiv_https___arxiv_org_abs_2605_13563
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Probing Floquet topological phases via non-Hermitian skin effect of reflected waves
Ye, Fangqiao
Hu, Haiping
Mesoscale and Nanoscale Physics
Quantum Gases
Quantum Physics
Periodically driven systems host topological phases without static analogs, such as the anomalous Floquet phase characterized by trivial bulk bands yet robust boundary modes. In this work, we investigate the scattering problem of a Floquet Chern insulator and reveal the non-Hermitian skin effect (NHSE) of reflected waves. Using a discrete-time scattering formalism, we demonstrate how the non-Hermitian winding number of the reflection matrix is linked to the bulk Floquet invariant via boundary resonances. This reflected-wave NHSE relies on which quasienergy gap the incident wave resides in, leading to a gap-dependent Goos-Hänchen (GH) shift. We further show that the momentum-integrated GH shift quantitatively yields the Floquet topological invariant of the corresponding gap. Our work highlights a frequency-dependent NHSE of reflected waves in driven systems and provides a real-space scattering approach to identify non-equilibrium topology.
title Probing Floquet topological phases via non-Hermitian skin effect of reflected waves
topic Mesoscale and Nanoscale Physics
Quantum Gases
Quantum Physics
url https://arxiv.org/abs/2605.13563