Reconfigurable Defect States in Non-Hermitian Topolectrical Chains with Gain and Loss

Fuente: arXiv
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Autores principales: Rafi-Ul-Islam, S. M., Siu, Zhuo Bin, Razo, Md Saddam Hossain, Jalil, Mansoor B. A.
Formato: Preprint
Publicado: 2025
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author Rafi-Ul-Islam, S. M.
Siu, Zhuo Bin
Razo, Md Saddam Hossain
Jalil, Mansoor B. A.
author_facet Rafi-Ul-Islam, S. M.
Siu, Zhuo Bin
Razo, Md Saddam Hossain
Jalil, Mansoor B. A.
contents We investigate the interplay between the non-Hermitian skin effect (NHSE), parity-time (PT) symmetry, and topological defect states in a finite non-Hermitian Su-Schrieffer-Heeger (SSH) chain. In the conventional NHSE regime, non-reciprocal hopping leads to an asymmetric localization of all eigenstates at one edge of the system, including the bulk and topological edge states. However, the introduction of staggered gain and loss restores the symmetric localization of topological edge states while preserving the bulk NHSE. We further examine the response of defect states in this system, demonstrating that their spatial localization is dynamically controlled by the combined effects of NHSE and PT symmetry. Specifically, we identify three distinct regimes in which the defect states localize at the defect site, shift to the system's edges, or become completely delocalized. These findings extend beyond previous works that primarily explored the activation and suppression of defect states through gain-loss engineering. To validate our theoretical predictions, we propose an experimental realization using a topolectrical circuit, where non-Hermitian parameters are implemented via impedance converter-based non-reciprocal elements. Circuit simulations confirm the emergence and tunability of defect states through voltage and admittance measurements, providing a feasible platform for experimental studies of non-Hermitian defect engineering. Our results establish a route for designing reconfigurable non-Hermitian systems with controllable topological defect states, with potential applications in robust signal processing and sensing.
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id arxiv_https___arxiv_org_abs_2505_20791
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Reconfigurable Defect States in Non-Hermitian Topolectrical Chains with Gain and Loss
Rafi-Ul-Islam, S. M.
Siu, Zhuo Bin
Razo, Md Saddam Hossain
Jalil, Mansoor B. A.
Mesoscale and Nanoscale Physics
Other Condensed Matter
We investigate the interplay between the non-Hermitian skin effect (NHSE), parity-time (PT) symmetry, and topological defect states in a finite non-Hermitian Su-Schrieffer-Heeger (SSH) chain. In the conventional NHSE regime, non-reciprocal hopping leads to an asymmetric localization of all eigenstates at one edge of the system, including the bulk and topological edge states. However, the introduction of staggered gain and loss restores the symmetric localization of topological edge states while preserving the bulk NHSE. We further examine the response of defect states in this system, demonstrating that their spatial localization is dynamically controlled by the combined effects of NHSE and PT symmetry. Specifically, we identify three distinct regimes in which the defect states localize at the defect site, shift to the system's edges, or become completely delocalized. These findings extend beyond previous works that primarily explored the activation and suppression of defect states through gain-loss engineering. To validate our theoretical predictions, we propose an experimental realization using a topolectrical circuit, where non-Hermitian parameters are implemented via impedance converter-based non-reciprocal elements. Circuit simulations confirm the emergence and tunability of defect states through voltage and admittance measurements, providing a feasible platform for experimental studies of non-Hermitian defect engineering. Our results establish a route for designing reconfigurable non-Hermitian systems with controllable topological defect states, with potential applications in robust signal processing and sensing.
title Reconfigurable Defect States in Non-Hermitian Topolectrical Chains with Gain and Loss
topic Mesoscale and Nanoscale Physics
Other Condensed Matter
url https://arxiv.org/abs/2505.20791