ABSTRACT: I will describe measurements in which we detect the individual sideband photons produced by an optomechanical device consisting of a nanogram of superfluid helium confined in a cavity. We use the photon-counting data to probe the phonon-phonon correlations (up to fourth order) in a single acoustic mode of the superfluid. The data is consistent with the acoustic mode being in a thermal state with mean phonon number ~ 1. We also use sideband-photon counting to show that the acoustic mode can be driven to a coherent amplitude corresponding to tens of thousands of phonons without harming the state's purity. I will discuss applying these results to testing models of discrete spacetime, and to distributing entanglement over kilometer-scale optical fiber networks.

BIO: Prof. Jack Harris received his undergraduate and graduate degrees from Cornell and UCSB, and was a postdoctoral researcher at the MIT/Harvard Center for Ultracold atoms. In 2004, he joined the faculty of the physics department at Yale University, where his research has focused on experimental optomechanics. Along the way, he spent one summer at SLAC as an undergraduate researcher working with the accelerator physics group.

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