Multiple topological transitions and spectral singularities in non-Hermitian Floquet systems

Fuente: arXiv
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Auteurs principaux: Zhu, Weiwei, Zhou, Longwen, Li, Linhu, Gong, Jiangbin
Format: Preprint
Publié: 2024
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author Zhu, Weiwei
Zhou, Longwen
Li, Linhu
Gong, Jiangbin
author_facet Zhu, Weiwei
Zhou, Longwen
Li, Linhu
Gong, Jiangbin
contents The interplay between Floquet driving and non-Hermitian gain/loss could give rise to intriguing phenomena including topological funneling of light, edge-state delocalization, anomalous topological transitions and Floquet non-Hermitian skin effects. In this work, we uncover two unique phenomena in Floquet systems caused by gain and loss. First, multiple topological transitions from anomalous Floquet second-order topological insulators to anomalous Floquet first-order topological insulators and then to normal insulators can be induced by gain and loss. Interestingly, the resulting anomalous Floquet insulators further carry hybrid skin-topological boundary modes, which could either be fully localized or localized to different edges at different time slices and traversing along all edges in a single driving period. The topological phase transitions are also shown to be detectable through studies of transmission properties in the setting of coupled ring resonators. Second, gain and loss are found to induce singularities in the Floquet spectral, around which anomalous transmissions at flat quasienergy bands are predicted. These discoveries not only enhanced our understanding of topological matter and phase transitions in driven non-Hermitian systems, but also promoted their experimental realizations in optical and acoustic settings.
format Preprint
id arxiv_https___arxiv_org_abs_2407_02806
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Multiple topological transitions and spectral singularities in non-Hermitian Floquet systems
Zhu, Weiwei
Zhou, Longwen
Li, Linhu
Gong, Jiangbin
Applied Physics
Mesoscale and Nanoscale Physics
Optics
The interplay between Floquet driving and non-Hermitian gain/loss could give rise to intriguing phenomena including topological funneling of light, edge-state delocalization, anomalous topological transitions and Floquet non-Hermitian skin effects. In this work, we uncover two unique phenomena in Floquet systems caused by gain and loss. First, multiple topological transitions from anomalous Floquet second-order topological insulators to anomalous Floquet first-order topological insulators and then to normal insulators can be induced by gain and loss. Interestingly, the resulting anomalous Floquet insulators further carry hybrid skin-topological boundary modes, which could either be fully localized or localized to different edges at different time slices and traversing along all edges in a single driving period. The topological phase transitions are also shown to be detectable through studies of transmission properties in the setting of coupled ring resonators. Second, gain and loss are found to induce singularities in the Floquet spectral, around which anomalous transmissions at flat quasienergy bands are predicted. These discoveries not only enhanced our understanding of topological matter and phase transitions in driven non-Hermitian systems, but also promoted their experimental realizations in optical and acoustic settings.
title Multiple topological transitions and spectral singularities in non-Hermitian Floquet systems
topic Applied Physics
Mesoscale and Nanoscale Physics
Optics
url https://arxiv.org/abs/2407.02806