Many-body Signatures of Collective Decay in Atomic Chains

TL;DR

This paper explores how finite interatomic distances affect collective decay and superradiance in atomic chains, revealing conditions for sustained superradiant bursts and correlated, directional photon emission.

Contribution

It provides a detailed analysis of the impact of interatomic separation on collective decay, highlighting the persistence of superradiance at small distances and the emergence of dephasing at larger separations.

Findings

Superradiant burst persists at small interatomic distances.

Dephasing suppresses superradiance at larger separations.

Emission remains correlated and directional, sensitive to interatomic spacing.

Abstract

Fully inverted atoms placed at exactly the same location synchronize as they deexcite, and light is emitted in a burst (known as "Dicke's superradiance"). We investigate the role of finite interatomic separation on correlated decay in mesoscopic chains, and provide an understanding in terms of collective jump operators. We show that the superradiant burst survives at small distances, despite Hamiltonian dipole-dipole interactions. However, for larger separations, competition between different jump operators leads to dephasing, suppressing superradiance. Collective effects are still significant for arrays with lattice constants of the order of a wavelength, and lead to a photon emission rate that decays nonexponentially in time. We calculate the two-photon correlation function and demonstrate that emission is correlated and directional, as well as sensitive to small changes in the interatomic distance. These features can be measured in current experimental setups, and are robust to realistic imperfections.