Strongly coupled giant-atom waveguide quantum electrodynamics

TL;DR

This paper explores the non-Markovian dynamics of giant atoms in waveguide QED, revealing how bound states influence their stability and oscillations, which aids in designing decoherence-resistant quantum interconnects.

Contribution

It extends the understanding of giant atom waveguide QED beyond Markovian approximations by analyzing the role of bound states in non-Markovian dynamics.

Findings

Bound states lead to stable excited-state probabilities.

Presence of bound states causes lossless Rabi oscillations.

Energy spectrum determines dynamical behaviors of giant atoms.

Abstract

Describing systems of superconducting atoms coupled to a continuum of photonic modes at multiple separated locations in a waveguide, waveguide quantum electrodynamics (QED) with giant atoms has emerged as a promising platform for realizing quantum interconnect. Such systems have been reported to exhibit rich phenomena that differ from those of natural atoms. Going beyond the widely used Born-Markov and Wigner-Weisskopf approximations, we investigate the non-Markovian dynamics of one and two giant atoms interacting with a waveguide formed by an array of coupled resonators. We discover that the diverse dynamical behaviors of the giant atoms are intrinsically determined by the energy spectrum of the composite system consisting of the giant atoms and the photonic modes in the waveguide. As long as one and more bound states are present in the energy spectrum, their excited-state probabilities, respectively, tend to stable finite values and lossless Rabi-like oscillations with frequencies proportional to the differences of the bound-state eigenenergies. Our result provides an insightful guideline for suppressing the decoherence of giant atoms and facilitates the development of quantum interconnect devices using giant-atom waveguide QED.