Construction and Observation of Flexibly Controllable High-Dimensional Non-Hermitian Skin Effects

Qicheng Zhang; Yufei Leng; Liwei Xiong; Yuzeng Li; Kun Zhang; Liangjun Qi; Chunyin Qiu

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arXiv · 2406.02593

Construction and Observation of Flexibly Controllable High-Dimensional Non-Hermitian Skin Effects

Qicheng Zhang·Yufei Leng·Liwei Xiong·Yuzeng Li·Kun Zhang·Liangjun Qi·Chunyin Qiu

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Abstract

Non-Hermitian skin effect (NHSE) is one of the most fundamental phenomena in non-Hermitian physics. Although it is established that one-dimensional NHSE originates from the nontrivial spectral winding topology, the topological origin behind the higher-dimensional NHSE remains unclear so far. This poses a substantial challenge in constructing and manipulating high-dimensional NHSEs. Here, an intuitive bottom-to-top scheme to construct high-dimensional NHSEs is proposed, through assembling multiple independent one-dimensional NHSEs. Not only the elusive high-dimensional NHSEs can be effectively predicted from the well-defined one-dimensional spectral winding topologies, but also the high-dimensional generalized Brillouin zones can be directly synthesized from the one-dimensional counterparts. As examples, two two-dimensional nonreciprocal acoustic metamaterials are experimentally implemented to demonstrate highly controllable multi-polar NHSEs and hybrid skin-topological effects, where the sound fields can be frequency-selectively localized at any desired corners and boundaries. These results offer a practicable strategy for engineering high-dimensional NHSEs, which could boost advanced applications such as selective filters and directional amplifiers.

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Qicheng Zhang, Yufei Leng, Liwei Xiong, Yuzeng Li, Kun Zhang, Liangjun Qi, Chunyin Qiu. 2024-06-01. Construction and Observation of Flexibly Controllable High-Dimensional Non-Hermitian Skin Effects. https://arxiv.org/abs/2406.02593

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