Rabi oscillation and fractional population via the bound states in the continuum in a giant atom waveguide QED setup

TL;DR

This paper investigates how bound states in the continuum influence the dynamics of giant atoms in a waveguide QED setup, revealing conditions for Rabi oscillations and fractional populations, and challenging traditional views on dissipation.

Contribution

It demonstrates how the number of BICs determines different dynamical behaviors in giant atom systems, providing new insights into controlling dissipation in open quantum systems.

Findings

Two BICs lead to Rabi oscillations.

Single BIC results in fractional population dynamics.

Bound states can suppress dissipation.

Abstract

We study the dynamics of two giant atoms interacting with a coupled resonator waveguide (CRW) beyond the Markovian approximation. The distinct atomic configurations determine the number of bound states in the continuum (BIC), leading to different dynamical behaviors. Our results show that when the system supports two BICs, Rabi oscillations dominate the dynamics, whereas fractional population dynamics emerge in the presence of a single BIC. The connection between these dynamics and the existence of BICs is further verified by analyzing the photonic distribution in the CRW during time evolution. These findings challenge the conventional notion that the environment always induces dissipation and decoherence. Instead, the bound states in the CRW-emitters coupled system can suppress complete dissipation of the emitters. This work offers an effective approach for controlling dissipative dynamics in open quantum systems.