Circuit QED with a Giant Atom Coupling to Left-handed Superlattice Metamaterials

TL;DR

This paper investigates the quantum dynamics of a giant atom coupled to left-handed superlattice metamaterials, revealing unique interference, non-Markovian effects, and Rabi oscillations due to the asymmetric band structure.

Contribution

It is the first study to analyze giant atom interactions with left-handed superlattice metamaterials, highlighting unconventional quantum optical phenomena and bound state formation.

Findings

Periodic enhancement and suppression of spontaneous emission due to interference.

Asymmetric decay rates between upper and lower bands caused by group velocity differences.

Observation of Rabi oscillations between two coupled emitters.

Abstract

Giant atoms, where the dipole approximation ceases to be valid, allow us to observe unconventional quantum optical phenomena arising from interference and time-delay effects. Most previous studies consider giant atoms coupling to conventional materials with right-handed dispersion. In this study, we first investigate the quantum dynamics of a giant atom interacting with left-handed superlattice metamaterials. Different from those right-handed counterparts, the left-handed superlattices exhibit an asymmetric band gap generated by anomalous dispersive bands and Bragg scattering bands. First, by assuming that the giant atom is in resonance with the continuous dispersive energy band, spontaneous emission will undergo periodic enhancement or suppression due to the interference effect. At the resonant position, there is a significant discrepancy in the spontaneous decay rates between the upper and lower bands, which arises from the differences in group velocity. Second, we explore the non-Markovian dynamics of the giant atom by considering the frequency of the emitter outside the energy band, where bound states will be induced by the interference between two coupling points. By employing both analytical and numerical methods, we demonstrate that the steady atomic population will be periodically modulated, driven by variations in the size of the giant atom. The presence of asymmetric band edges leads to diverse interference dynamics. Finally, we consider the case of two identical emitters coupling to the waveguide and find that the energy within the two emitters undergoes exchange through the mechanism Rabi oscillations.