Non-Hermitian Floquet topological phases with arbitrarily many real-quasienergy edge states

TL;DR

This paper introduces a one-dimensional periodically driven non-Hermitian lattice model exhibiting rich Floquet topological phases with arbitrarily many real quasienergy edge states, characterized by integer winding numbers and detectable via spin texture imaging.

Contribution

It analytically derives the phase diagram, identifies non-Hermitian Floquet phases with unlimited winding numbers, and proposes a method to probe topological invariants through spin texture dynamics.

Findings

Discovery of non-Hermitian Floquet phases with unlimited winding numbers.

Existence of arbitrarily many real quasienergy edge states.

Proposal for experimental detection via spin texture imaging.

Abstract

Topological states of matter in non-Hermitian systems have attracted a lot of attention due to their intriguing dynamical and transport properties. In this study, we propose a periodically driven non-Hermitian lattice model in one-dimension, which features rich Floquet topological phases. The topological phase diagram of the model is derived analytically. Each of its non-Hermitian Floquet topological phases is characterized by a pair of integer winding numbers, counting the number of real 0- and \pi-quasienergy edge states at the boundaries of the lattice. Non-Hermiticity induced Floquet topological phases with unlimited winding numbers are found, which allow arbitrarily many real 0- and \pi-quasienergy edge states to appear in the complex quasienergy bulk gaps in a well-controlled manner. We further suggest to probe the topological winding numbers of the system by dynamically imaging the stroboscopic spin textures of its bulk states.