论文标题
在一个定期淬火的两腿阶梯中
Non-Hermitian Floquet phases with even-integer topological invariants in a periodically quenched two-leg ladder
论文作者
论文摘要
周期性驱动的非热系统可能具有具有独特拓扑，动力学和运输特性的异国情调的非平衡阶段。在这项工作中，我们引入了一个具有实验性可实现的两腿阶梯模型，该模型既有时间周期性淬灭和非弱者效应，又属于扩展的CII对称类别。由于驱动与非循环性之间的相互作用，该系统中出现了丰富的非热浮光拓扑阶段，它们的特征是一对均匀的直觉拓扑不变性$（w_ {0}，w_π），w_π）在开放的边界条件下，这些不变性进一步预测了围绕系统边缘的零和$π$ - Quasienergy模式的数量。我们最终构建了平均手性位移的广义版本，该版本可以用作CII对称类别中非荷米特浮标阶段拓扑不变的动态探针。因此，我们的工作介绍了一种新型的非热浮标拓扑问题，并进一步揭示了驱动开放系统中拓扑和动态的丰富性。
Periodically driven non-Hermitian systems could possess exotic nonequilibrium phases with unique topological, dynamical and transport properties. In this work, we introduce an experimentally realizable two-leg ladder model subjecting to both time-periodic quenches and non-Hermitian effects, which belongs to an extended CII symmetry class. Due to the interplay between drivings and nonreciprocity, rich non-Hermitian Floquet topological phases emerge in the system, with each of them been characterized by a pair of even-integer topological invariants $(w_{0},w_π)\in2\mathbb{Z}\times2\mathbb{Z}$. Under the open boundary condition, these invariants further predict the number of zero- and $π$-quasienergy modes localized around the edges of the system. We finally construct a generalized version of the mean chiral displacement, which could be employed as a dynamical probe to the topological invariants of non-Hermitian Floquet phases in the CII symmetry class. Our work thus introduces a new type of non-Hermitian Floquet topological matter, and further reveals the richness of topology and dynamics in driven open systems.
