Floquet Bosonic Kitaev Chain

TL;DR

This paper introduces periodically driven bosonic Kitaev chains that exhibit rich non-Hermitian Floquet topological phenomena, including skin effects and multiple topological modes, with robustness to certain perturbations.

Contribution

It proposes a new class of Hermitian, periodically driven bosonic chains hosting non-Hermitian topological phases, and analyzes their robustness and tunability under perturbations.

Findings

Coexistence of skin effect, zero modes, and π modes in one model.

Robustness of topological edge modes against perturbations.

Differential sensitivity of skin effect to disorder and onsite frequency.

Abstract

We propose a class of periodically driven (Hermitian) modified bosonic Kitaev chains that effectively hosts rich nonHermitian Floquet topological phenomena. Two particular models are investigated in details as case studies. The first of these represents a minimal topologically nontrivial model in which nonHermitian skin effect, topological zero modes, and topological $\pi$ modes coexist. The other displays a more sophisticated model that supports multiple topological zero modes and topological $\pi$ modes in a tunable manner. By subjecting both models to perturbations such as a finite onsite bosonic frequency and spatial disorder, these features exhibit distinct responses. In particular, while generally all topological edge modes are robust against such perturbations, the nonHermitian skin effect is easily suppressed and revived by, respectively, the onsite bosonic frequency and spatial disorder in the first model, but it could be insensitive to both perturbations in the second model. Our studies thus demonstrate the prospect of a periodically driven bosonic Kitaev chain as a starting point in exploring various nonHermitian Floquet topological phases through the lens of a Hermitian system.