title: Optomechanical cavity cooling of an atomic ensemble.
abstract: We demonstrate cavity sideband cooling of a single collective motional mode of an atomic ensemble down to a mean phonon occupation number ⟨n⟩(min⁡)=2.0(-0.3)(+0.9). Both ⟨n⟩(min) and the observed cooling rate are in good agreement with an optomechanical model. The cooling rate constant is proportional to the total photon scattering rate by the ensemble, demonstrating the cooperative character of the light-emission-induced cooling process. We deduce fundamental limits to cavity cooling either the collective mode or, sympathetically, the single-atom degrees of freedom.
authors: Department of Physics, MIT-Harvard Center for Ultracold Atoms, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors: Monika H
authors: MH
authors: Schleier-Smith
authors: Ian D
authors: ID
authors: Leroux
authors: Hao
authors: H
authors: Zhang
authors: Mackenzie A
authors: MA
authors: Van Camp
authors: Vladan
authors: V
authors: Vuletić