Generation and Stabilization of Bound States in the Continuum in Dissipative Floquet Optical Lattices

TL;DR

This paper introduces a novel mechanism for creating and stabilizing bound states in the continuum within dissipative Floquet lattices, highlighting their robustness and potential for experimental realization in quantum systems.

Contribution

It reveals a new dark Floquet state mechanism for stable BICs, enhanced by dissipation and high-frequency driving, with implications for dissipative quantum system control.

Findings

Stable BICs arise from dark Floquet states with zero quasi-energy.

Increasing driving frequency or dissipation strength enhances BIC stability.

Dissipation can extend BIC existence and enable wave packet reflection.

Abstract

This paper investigates the generation and stabilization of bound states in the continuum (BICs) in a one-dimensional dissipative Floquet lattice. We find a different mechanism for the generation of stable BICs in the open one-dimensional lattice system, which stems from a peculiar dark Floquet state, a state with zero quasi-energy and negligible population on the lossy sites. Our results reveal that the evolutionary stability of BICs resulting from the dark Floquet state can be significantly enhanced, as evidenced by their very low decay rate, by increasing the driving frequency or, counterintuitively, increasing the dissipation strength. We further demonstrate that stable dark Floquet BICs can robustly persist even in nonlinear regimes. The existence of these stable dark Floquet BICs can be attributed to the role of higher-order correction terms in the effective Floquet Hamiltonian derived via the high-frequency expansion (HFE) method. Furthermore, we demonstrate that incorporating non-Hermitian dissipation can extend the parameter regime for the existence of BICs, and the dissipation-induced BICs can lead to complete reflection of wave packets. Our findings provide theoretical support for the experimental realization of stable BICs in dissipative quantum systems.