Driving-induced multiple ${\cal PT}$-symmetry breaking transitions and reentrant localization transitions in non-Hermitian Floquet quasicrystals

TL;DR

This paper explores how periodic driving and non-Hermitian effects in one-dimensional quasicrystals lead to multiple PT-symmetry breaking and reentrant localization transitions, revealing complex spectral and transport phenomena.

Contribution

It uncovers multiple driving-induced PT-symmetry transitions and localization phenomena in non-Hermitian Floquet quasicrystals, demonstrating the richness of nonequilibrium phases.

Findings

Multiple PT-symmetry breaking and restoration transitions occur due to driving.

Reentrant localization transitions are observed in the system.

Spectral properties and wavepacket dynamics reveal complex localization behavior.

Abstract

The cooperation between time-periodic driving fields and non-Hermitian effects could endow systems with distinctive spectral and transport properties. In this work, we uncover an intriguing class of non-Hermitian Floquet matter in one-dimensional quasicrystals, which is characterized by the emergence of multiple driving-induced ${\cal PT}$-symmetry breaking/restoration, mobility edges, and reentrant localization transitions. These findings are demonstrated by investigating the spectra, level statistics, inverse participation ratios and wavepacket dynamics of a periodically quenched nonreciprocal Harper model. Our results not only unveil the richness of localization phenomena in driven non-Hermitian quasicrystals, but also highlight the advantage of Floquet approach in generating unique types of nonequilibrium phases in open systems.