Cavity quantum electrodynamics of continuously monitored Bose-condensed atoms

TL;DR

This paper explores how continuous monitoring of light in a cavity QED system with Bose-condensed atoms can reveal and control collective atomic modes, enabling applications like sensitive phonon detection.

Contribution

It demonstrates the ability to engineer and measure collective modes in a Bose-Einstein condensate via cavity optomechanics with continuous light monitoring.

Findings

Symmetry breaking in individual measurement runs can be restored through ensemble averaging.

Cavity fields can be used to both drive and measure collective atomic modes.

The system can function as a sensitive phonon detector by counting scattered photons.

Abstract

We study cavity quantum electrodynamics of Bose-condensed atoms that are subjected to continuous monitoring of the light leaking out of the cavity. Due to a given detection record of each stochastic realization, individual runs spontaneously break the symmetry of the spatial profile of the atom cloud and this symmetry can be restored by considering ensemble averages over many realizations. We show that the cavity optomechanical excitations of the condensate can be engineered to target specific collective modes. This is achieved by exploiting the spatial structure and symmetries of the collective modes and light fields. The cavity fields can be utilized both for strong driving of the collective modes and for their measurement. In the weak excitation limit the condensate-cavity system may be employed as a sensitive phonon detector which operates by counting photons outside the cavity that have been selectively scattered by desired phonons.