Southwest Quantum Information and Technology

Twelfth Annual Meeting, February 18-21, 2010
Santa Fe, New Mexico

Full Program | Thursday | Friday | Saturday | Sunday

SESSION 4: Nanomechanical Resonators
Session Chair:
3:30-4:15	Keith Schwab, Caltech
	Preparation and Detection of an RF Mechanical Resonator Near the Ground State of Motion
	Abstract. The tools and techniques to prepare mechanical structures in fundamental quantum states are being rapidly developed, using both optical and electrical techniques. To prepare the quantum ground state, we are preforming experiments with a mechanical resonator parametrically coupled to a electrical resonator. The mechanical resonator is a very low dissipation (Q>1M), 6 MHz, nanomechanical structure; the electrical resonator is a lithographic, low dissipation (Q=20,000), superconducting niobium, 7.5 GHz resonator. We pump this structure with carefully prepared microwave photons and demonstrate cooling of the mechanical structure of quantum occupation =3.8. The deep quantum limit, <<1, appears within reach with a modified device.
4:15-4:45	Tobias Donner, JILA, National Institute of Standards and Technology and the University of Colorado, Boulder
	Nanomechanical motion measured with an imprecision below the standard quantum limit
	Abstract. Observing quantum behavior of mechanical motion is challenging because it is difficult both to prepare pure quantum states of motion and to detect those states with high enough precision. We present displacement measurements of a nanomechanical oscillator with an imprecision below that at the standard quantum limit [1]. To achieve this, we couple the motion of the oscillator to the microwave field in a high-Q superconducting resonant circuit. The oscillator's displacement imprints a phase modulation on the microwave signal. We attain the low imprecision by reading out the modulation with a Josephson Parametric Amplifier, realizing a microwave interferometer that operates near the shot-noise limit. The apparent motion of the mechanical oscillator due the interferometer's noise is now substantially less than its zero-point motion, making future detection of quantum states feasible. In addition, the phase sensitivity of the demonstrated interferometer is 30 times higher than previous microwave interferometers, providing a critical piece of technology for many experiments investigating quantum information encoded in microwave fields. [1] J. D. Teufel, T. Donner, M. A. Castellanos-Beltran, J. W. Harlow, K. W. Lehnert, Nature Nanotechnology, doi:10.1038/nnano.2009.343, (2009).