title: Dynamical backaction of microwave fields on a nanomechanical oscillator.
abstract: We measure the response and thermal motion of a high-Q nanomechanical oscillator coupled to a superconducting microwave cavity in the resolved-sideband regime where the oscillator's resonance frequency exceeds the cavity's linewidth. The coupling between the microwave field and mechanical motion is strong enough for radiation pressure to overwhelm the intrinsic mechanical damping. This radiation-pressure damping cools the fundamental mechanical mode by a factor of 5 below the thermal equilibrium temperature in a dilution refrigerator to a phonon occupancy of 140 quanta.
authors.affiliation: JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, Colorado 80309, USA. john.teufel@colorado.edu
authors.forename: J D
authors.initials: JD
authors.lastname: Teufel
authors.forename: J W
authors.initials: JW
authors.lastname: Harlow
authors.forename: C A
authors.initials: CA
authors.lastname: Regal
authors.forename: K W
authors.initials: KW
authors.lastname: Lehnert