Non-Hermitian-induced higher-order topological phases in acoustic fractal lattices

Fuente: arXiv
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Auteurs principaux: Li, Shuanghuizhi, Wu, Bowei, Ma, Tingfeng, Zhang, Jiaqi, Lou, Chenbowen
Format: Preprint
Publié: 2026
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author Li, Shuanghuizhi
Wu, Bowei
Ma, Tingfeng
Zhang, Jiaqi
Lou, Chenbowen
author_facet Li, Shuanghuizhi
Wu, Bowei
Ma, Tingfeng
Zhang, Jiaqi
Lou, Chenbowen
contents Non-Hermitian systems enable continuous and smooth tuning of topological phases through externally controllable loss/gain parameters. Without altering the intrinsic lattice structure, merely fine-tuning the intensity or spatial distribution of the loss or gain can induce the emergence of higher-order topological states, and even achieve reversible switching of topological phases. However, in non-integer dimensions, topological states induced by non-Hermiticity remain unexplored, which hinders the continuous and smooth manipulation of systems with rich higher-order topological states. By introducing a loss contrast in a fractal lattice, this study proposes a non-Hermitian route to realize higher-order topological phases in acoustic fractal lattices. Based on the tight-binding approximation, calculating the Hamiltonian of the system yields the wave-function distribution of the zero-energy modes, revealing the formation mechanisms and conditions for the topological phase transitions induced by non-Hermiticity in acoustic fractal lattices. We numerically and experimentally realize non-Hermitian-induced topological edge and corner states in a fractal structure. Furthermore, theoretical and numerical results demonstrate that merely adjusting the loss contrast can alter the degree of energy localization. This work not only establishes an effective mechanism for manipulating higher-order topology in complex fractal geometries through non-Hermiticity but also provides a theoretical framework for exploring exotic topological states of matter in non-integer dimensions.
format Preprint
id arxiv_https___arxiv_org_abs_2603_09186
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Non-Hermitian-induced higher-order topological phases in acoustic fractal lattices
Li, Shuanghuizhi
Wu, Bowei
Ma, Tingfeng
Zhang, Jiaqi
Lou, Chenbowen
Applied Physics
Non-Hermitian systems enable continuous and smooth tuning of topological phases through externally controllable loss/gain parameters. Without altering the intrinsic lattice structure, merely fine-tuning the intensity or spatial distribution of the loss or gain can induce the emergence of higher-order topological states, and even achieve reversible switching of topological phases. However, in non-integer dimensions, topological states induced by non-Hermiticity remain unexplored, which hinders the continuous and smooth manipulation of systems with rich higher-order topological states. By introducing a loss contrast in a fractal lattice, this study proposes a non-Hermitian route to realize higher-order topological phases in acoustic fractal lattices. Based on the tight-binding approximation, calculating the Hamiltonian of the system yields the wave-function distribution of the zero-energy modes, revealing the formation mechanisms and conditions for the topological phase transitions induced by non-Hermiticity in acoustic fractal lattices. We numerically and experimentally realize non-Hermitian-induced topological edge and corner states in a fractal structure. Furthermore, theoretical and numerical results demonstrate that merely adjusting the loss contrast can alter the degree of energy localization. This work not only establishes an effective mechanism for manipulating higher-order topology in complex fractal geometries through non-Hermiticity but also provides a theoretical framework for exploring exotic topological states of matter in non-integer dimensions.
title Non-Hermitian-induced higher-order topological phases in acoustic fractal lattices
topic Applied Physics
url https://arxiv.org/abs/2603.09186