Optomechanical strong coupling between a single cavity photon and a single atom

TL;DR

This paper proposes a new approach to achieve optomechanical strong coupling with single atoms in cavity QED systems by coupling atomic motion to a narrow cavity-dressed resonance, enabling observable quantum effects.

Contribution

It introduces a novel method to realize optomechanical strong coupling in systems where traditional approaches are unfeasible, using atomic motion coupled to a narrow resonance.

Findings

Highly entangled scattering properties of single photons with atomic motion.

Per-photon motional heating exceeds single-photon recoil energy.

Mechanically-induced oscillations in the second-order correlation function.

Abstract

Single atoms coupled to a cavity offer unique opportunities as quantum optomechanical devices because of their small mass and strong interaction with light. A particular regime of interest in optomechanics is that of "single-photon strong coupling," where motional displacements on the order of the zero-point uncertainty are sufficient to shift the cavity resonance frequency by more than its linewidth. In many cavity QED platforms, however, this is unfeasible due to the large cavity linewidth. Here, we propose an alternative route in such systems, which instead relies on the coupling of atomic motion to the much narrower cavity-dressed atomic resonance frequency. We discuss and optimize the conditions in which the scattering properties of single photons from the atom-cavity system become highly entangled with the atomic motional wave function. We also analyze the prominent observable features of this optomechanical strong coupling, which include a per-photon motional heating that is significantly larger than the single-photon recoil energy, as well as mechanically-induced oscillations in time of the second-order correlation function of the emitted light. This physics should be realizable in current experimental setups, such as trapped atoms coupled to photonic crystal cavities, and more broadly opens the door to realizing qualitatively different phenomena beyond what has been observed in optomechanical systems thus far.