Floquet-surface bound states in the continuum in a resonantly driven 1D tilted defect-free lattice

TL;DR

This paper investigates Floquet-surface bound states in a resonantly driven 1D lattice, revealing their stability, analytical conditions for existence, and proposing experimental detection methods, thus advancing understanding of bound states in driven quantum systems.

Contribution

It demonstrates the existence and stability of Floquet-surface BICs in a wide parameter range and provides analytical conditions and experimental detection strategies.

Findings

Floquet-surface BICs are stable against structural perturbations.

Analytical explanation of Floquet-surface bound states via effective Tamm-type defects.

Proposal to detect transition points using quantum walk.

Abstract

We study the Floquet-surface bound states embedded in the continuum (BICs) and bound states out the continuum (BOCs)in a resonantly driven 1D tilted defect-free lattice. In contrast to fragile single-particle BICs assisted by specially tailored potentials, we find that Floquet-surface BICs, stable against structural perturbations, can exist in a wide range of parameter space. By using a multiple-time-scale asymptotic analysis in the high-frequency limit, the appearance of Floquet-surface bound states can be analytically explained by effective Tamm-type defects at boundaries induced by the resonance between the periodic driving and tilt. The phase boundary of existing Floquet-surface states is also analytically given. Based on the repulsion effect of surface states, we propose to detect transition points and measure the number of Floquet-surface bound states by quantum walk. Our work opens a new door to experimental realization of BICs in quantum system.