耦合非厄米趋肤效应与异常点
近日，吉林大学张旭霖团队实现了耦合非厄米趋肤效应与异常点。相关论文发表在2025年9月23日出版的《光：科学与应用》杂志上。
非厄米系统表现出两个独特的特征：异常点（EPs）和非厄米趋肤效应（NHSE）。EP来自于多个能级的相互作用，特征值谱的简并表现为特征值谱，而NHSE则与特征函数的局域化特征有关。由于其不同的起源和后果，这两个标志之间的相互作用引起了相当大的兴趣。
研究组提出了耦合NHSE的概念，即两个具有独立NHSE的非厄米系统耦合在一起。他们发现，通过引入具有特殊对称性的非厄米损失，可以出现多对EPs，极大地压缩了特征值谱，加速了耦合NHSE的击穿。相比之下，在没有EPs的系统中，耦合NHSE的衰减明显减轻。从这个意义上说，EP可以作为调整NHSE和控制非厄米动力学的自由度。该概念是在具有人工规范场的光子晶格中实验实现的，这将架起这两个重要概念的桥梁，并为同时与它们相关的非厄米应用开辟了道路。
附：英文原文
Title: Coupled non-Hermitian skin effect with exceptional points
Author: Wang, Guo-Huai, Tao, Ran, Tian, Zhen-Nan, Chen, Qi-Dai, Zhang, Xu-Lin
Issue&Volume: 2025-09-23
Abstract: Non-Hermitian systems exhibit two unique hallmarks: exceptional points (EPs) and non-Hermitian skin effect (NHSE). The EP arises from the interplay of multiple energy levels, marked by degeneracy in eigenvalue spectra, while the NHSE is associated with the localization feature of eigenfunctions. Due to their different origins and consequences, the interplay between the two hallmarks has drawn considerable interest. Here, we propose the concept of coupled NHSE, i.e., two non-Hermitian systems with independent NHSE are coupled together. We find that by introducing non-Hermitian losses with special symmetry, multiple pairs of EPs can appear, greatly compressing the eigenvalue spectrum and accelerating the breakdown of the coupled NHSE. In contrast, the attenuation of coupled NHSE is significantly alleviated in systems without EPs. In this sense, the EP can act as a degree of freedom to tune the NHSE and govern the non-Hermitian dynamics. The proposed concept is experimentally realized in photonic lattices with artificial gauge fields, which will bridge these two significant concepts and open avenues for non-Hermitian applications simultaneously associated with them.
DOI: 10.1038/s41377-025-02006-6