近日，华南理工大学的杨中民&刘涛及其研究团队取得一项新进展。经过不懈努力，他们揭示周期驱动耗散超冷原子中的非厄米集肤效应。相关研究成果已于2024年6月25日在国际知名学术期刊《物理评论A》上发表。

在这项研究中，研究人员提出了在交错原子损失条件下，通过周期性驱动超冷原子在一维光学晶格中实现非厄米皮肤效应（NHSE）的方法。他们深入研究了高频近似下的有效Floquet哈密顿量，从而揭示了周期驱动诱导NHSE的内在机制。研究结果显示，鲁棒的NHSE可以通过调整驱动相位来调控，这一特性体现在动态局域化现象上。

尤为引人注目的是，研究人员发现，当两个具有不同驱动相位的耦合链被周期性驱动时，会诱导出临界NHSE，并伴随着尺寸相关的拓扑隙内模式的出现。这项研究提供了一种可行的方法来观察超冷原子系统中非厄米统计量和多体统计量的相互作用所导致的NHSE，并探索相应的独特物理现象。

据悉，非厄米集肤效应(NHSE)是非厄米物理界中最引人注目的性质之一，其特征是体能带本征态坍缩为系统的局域边界模。与NHSE相关的独特物理现象引起了极大的兴趣，然而，它们的实验实现通常需要非互易跳跃，这在超冷原子系统中面临着很大的挑战。

附：英文原文

Title: Non-Hermitian skin effect in periodically driven dissipative ultracold atoms

Author: Zhao-Fan Cai, Tao Liu, Zhongmin Yang

Issue&Volume: 2024/06/25

Abstract: The non-Hermitian skin effect (NHSE), characterized by the collapse of bulk-band eigenstates into the localized boundary modes of the systems, is one of most striking properties in the field of non-Hermitian physics. Unique physical phenomena related to the NHSE have attracted a great deal of interest; however, their experimental realization usually requires nonreciprocal hopping, which faces a great challenge in ultracold-atom systems. In this work we propose the realization of the NHSE in a one-dimensional optical lattice by periodically driven ultracold atoms in the presence of staggered atomic loss. By studying the effective Floquet Hamiltonian in the high-frequency approximation, we reveal the underlying mechanism for the periodic-driving-induced NHSE. We find that the robust NHSE can be tuned by the driving phase, which is manifested by the dynamical localization. Most remarkably, we uncover the periodic-driving-induced critical skin effect for two coupled chains with different driving phases, accompanied by the appearance of size-dependent topological in-gap modes. Our study provides a feasible way to observe the NHSE and explore the corresponding unique physical phenomena due to the interplay of non-Hermiticity and many-body statistics in ultracold-atom systems.

DOI: 10.1103/PhysRevA.109.063329

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.109.063329