Non-Markovian Collective Emission of Giant emitters in the Zeno Regime

TL;DR

This paper investigates the unique collective emission dynamics of giant artificial atoms in the Zeno regime, revealing smooth buildup of emission rates, directional superradiance, and prolonged subradiant oscillations, with implications for waveguide QED experiments.

Contribution

It introduces a comprehensive theoretical framework for understanding non-Markovian collective emission of giant atoms, highlighting differences from traditional models and predicting novel phenomena.

Findings

Giant atoms exhibit a smooth transition from zero to Markovian decay rates.

Directional superradiance is observed in collective emission.

Prolonged oscillations in subradiant photons indicate energy exchange between atoms and field.

Abstract

We explore the collective Zeno dynamics of giant artificial atoms that are coupled, via multiple coupling points, to a common photonic or acoustic reservoir. In this regime, the establishment of atomic cooperativity and the revivification of exponential decay, are highly intertwined, which is utterly beyond the non-Markovian regime with only retarded backaction. We reveal that giant atoms build up their collective emission smoothly from the decay rate of zero to that predicted by Markovian approximation, and show great disparity between different waveguide QED setups. As a comparison, the step-like growth of instantaneous decay rates in the retardation-only picture has also been shown. All of these theoretical pictures predict the same collective behavior in the long time limit. From a phenomenological standpoint, we observe that the atomic superradiance exhabits significant directional property. In addition, the subradiant photons feature prolonged oscillation in the early stage of collective radiance, where the energy is exchanged remarkably between giant emitters and the field. Our results might be probed in state-of-art waveguide QED experiments, and fundamentally broaden the fields of collective emission in systems with giant atoms.