title: Cavity optomechanics with a Bose-Einstein condensate.
abstract: Cavity optomechanics studies the coupling between a mechanical oscillator and the electromagnetic field in a cavity. We report on a cavity optomechanical system in which a collective density excitation of a Bose-Einstein condensate serves as the mechanical oscillator coupled to the cavity field. A few photons inside the ultrahigh-finesse cavity trigger strongly driven back-action dynamics, in quantitative agreement with a cavity optomechanical model. We approach the strong coupling regime of cavity optomechanics, where a single excitation of the mechanical oscillator substantially influences the cavity field. The results open up new directions for investigating mechanical oscillators in the quantum regime and the border between classical and quantum physics.
authors.affiliation: Institute for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland.
authors.forename: Ferdinand
authors.initials: F
authors.lastname: Brennecke
authors.forename: Stephan
authors.initials: S
authors.lastname: Ritter
authors.forename: Tobias
authors.initials: T
authors.lastname: Donner
authors.forename: Tilman
authors.initials: T
authors.lastname: Esslinger