Dynamical characterization of non-Hermitian Floquet topological phases in one-dimension

TL;DR

This paper introduces a method to dynamically identify non-Hermitian Floquet topological phases in one-dimensional systems by measuring spin textures, supported by a lattice model and numerical validation.

Contribution

It presents a systematic approach to characterize non-Hermitian Floquet topological phases via dynamical measurements of spin textures in chiral symmetric systems.

Findings

Topological invariants can be determined from winding angles of spin textures.

Numerical simulations confirm the theoretical predictions.

Comparison with mean chiral displacement validates the approach.

Abstract

Non-Hermitian topological phases in static and periodically driven systems have attracted great attention in recent years. Finding dynamical probes for these exotic phases would be of great importance in the detection and application of their topological properties. In this work, we propose a systematic approach to dynamically characterize non-Hermitian Floquet topological phases in one-dimension with chiral symmetry. We show that the topological invariants of a chiral symmetric Floquet system can be fully determined by measuring the winding angles of its time-averaged spin textures. We further purpose a piecewise quenched lattice model with rich non-Hermitian Floquet topological phases, in which our theoretical predictions are numerically demonstrated and compared with another approach utilizing the mean chiral displacement of a wavepacket.