Versatile braiding of non-Hermitian topological edge states

作     者：Bofeng Zhu Qiang Wang You Wang Qi Jie Wang Y. D. Chong 

作者机构：Division of Physics and Applied Physics School of Physical and Mathematical Sciences  School of Physics School of Electrical and Electronic Engineering Centre for Disruptive Photonic Technologies 

出 版 物：《Physical Review B》 (Phys. Rev. B)

年 卷 期：2024年第110卷第13期

页      面：134317页

核心收录：

基　　金：National Research Foundation Singapore, NRF, (NRF-CRP23-2019-0007, NRF-CRP29-2022-0003, NRF-NRFI08-2022-0001, NRF-CRP23-2019-0005) National Research Foundation Singapore, NRF Agency for Science, Technology and Research, A*STAR, (R23I0IR041) Agency for Science, Technology and Research, A*STAR 

主　　题：Photonics Topological effects in photonic systems Topological phases of matter Microcavity & microdisk lasers Waveguide arrays Cavity resonators 

摘      要：Among the most intriguing features of non-Hermitian (NH) systems is the ability of complex energies to form braids under parametric variation. Several braiding behaviors, including link and knot formation, have been observed in experiments on synthetic NH systems, such as looped optical fibers. The exact conditions for these phenomena remain unsettled, but existing demonstrations have involved long-range nonreciprocal hoppings, which are hard to implement on many experimental platforms. Here, we present a route to realizing complex energy braids using one-dimensional NH Aubry-André-Harper lattices. Under purely local gain and loss modulation, the eigenstates exhibit a variety of braiding behaviors, including unknots, Hopf links, trefoil knots, Solomon links, and catenanes. We show how these are created by the interplay between non-Hermiticity and the lattice s bulk states and topological edge states. The transitions between different braids are marked by changes in the global Berry phase of the NH lattice.