Technical advances in the fabrication of micro- and nano-structures has recently led to, among other things, the laser cooling of mechanical resonators down to their ground-state of mechanical motion [1,2]. Current experiments seek to utilize "cold" mechanical transducers for a variety of applications, ranging from precision force measurements to noise-free and efficient quantum translation of microwave and optical signals [3,4,5]. In this talk I will discuss our efforts at Caltech to employ phonon counting techniques to measure, prepare, and entangle the mechanical state of nanoscale optomechanical resonators.
 J. D. Teufel, T. Donner, Dale Li, J. W. Harlow, M. S. Allman, K. Cicak, A. J. Sirois, J. D. Whittaker, K. W. Lehnert & R. W. Simmonds, "Sideband cooling of micromechanical motion to the quantum ground state," Nature, v475, pg. 359–363, July 11, 2011.
 Jasper Chan, T. P. Mayer Alegre, Amir H. Safavi-Naeini, Jeff T. Hill, Alex Krause, Simon Gröblacher, Markus Aspelmeyer & Oskar Painter, "Laser cooling of a nanomechanical oscillator into its quantum ground state," Nature, v478, pg. 89–92, October 6, 2011.
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 T. Bagci, A. Simonsen, S. Schmid, L. G. Villanueva, J. Zeuthen, E.and Appel, J. M. Taylor, A. Srensen, K. Usami, S. A., and E. S. Polzik, Nature 507, 81 (2014).
 R. W. Andrews, R. W. Peterson, T. P. Purdy, K. Cicak, R. W. Simmonds, C. A. Regal, and K. W. Lehnert, Nat. Phys. 10, 321 (2014).