Lin Quan, Li Tianyu, Xiao Lei, Wang Kunkun, Yi Wei, Xue Peng
Beijing Computational Science Research Center, Beijing, 100084, China.
CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, 230026, China.
Nat Commun. 2022 Jun 9;13(1):3229. doi: 10.1038/s41467-022-30938-9.
Disorder and non-Hermiticity dramatically impact the topological and localization properties of a quantum system, giving rise to intriguing quantum states of matter. The rich interplay of disorder, non-Hermiticity, and topology is epitomized by the recently proposed non-Hermitian topological Anderson insulator that hosts a plethora of exotic phenomena. Here we experimentally simulate the non-Hermitian topological Anderson insulator using disordered photonic quantum walks, and characterize its localization and topological properties. In particular, we focus on the competition between Anderson localization induced by random disorder, and the non-Hermitian skin effect under which all eigenstates are squeezed toward the boundary. The two distinct localization mechanisms prompt a non-monotonous change in profile of the Lyapunov exponent, which we experimentally reveal through dynamic observables. We then probe the disorder-induced topological phase transitions, and demonstrate their biorthogonal criticality. Our experiment further advances the frontier of synthetic topology in open systems.
无序和非厄米性会极大地影响量子系统的拓扑和局域化特性，从而产生引人入胜的量子物态。无序、非厄米性和拓扑之间丰富的相互作用在最近提出的非厄米拓扑安德森绝缘体中得到了体现，该绝缘体展现出大量奇异现象。在此，我们利用无序光子量子行走对非厄米拓扑安德森绝缘体进行实验模拟，并表征其局域化和拓扑特性。特别地，我们关注由随机无序诱导的安德森局域化与非厄米趋肤效应之间的竞争，在非厄米趋肤效应下，所有本征态都被压缩到边界。这两种不同的局域化机制促使李雅普诺夫指数的分布发生非单调变化，我们通过动态可观测量从实验上揭示了这一点。然后，我们探究无序诱导的拓扑相变，并证明其双正交临界性。我们的实验进一步拓展了开放系统中合成拓扑的前沿领域。
