Photon-Mediated Interaction between Two Distant Atoms

TL;DR

This paper investigates photon-mediated interactions between two distant atoms coupled via an optical element, revealing different dynamical regimes and coherence properties, with experimental validation of the theoretical model.

Contribution

It introduces a theoretical model describing two regimes of atom-atom interaction mediated by photons, supported by comparison with experimental data.

Findings

Identification of two distinct interaction regimes: bad resonator and dipole-dipole.

Observation that emitted light carries signatures of multiple scattering.

Experimental validation aligning with theoretical predictions.

Abstract

We study the photonic interactions between two distant atoms which are coupled by an optical element (a lens or an optical fiber) focussing part of their emitted radiation onto each other. Two regimes are distinguished depending on the ratio between the radiative lifetime of the atomic excited state and the propagation time of a photon between the two atoms. In the two regimes, well below saturation the dynamics exhibit either typical features of a bad resonator, where the atoms act as the mirrors, or typical characteristics of dipole-dipole interaction. We study the coherence properties of the emitted light and show that it carries signatures of the multiple scattering processes between the atoms. The model predictions are compared with the experimental results in J. Eschner {\it et al.}, Nature {\bf 413}, 495 (2001).