2013/04/30 by M. J. Woolley, A. A. Clerk · 1 citation
Physics and Astronomy · #quant-ph #cond-mat.mes-hall
paper · pdf · doi:10.1103/physreva.87.063846
published as Phys. Rev. A 87, 063846 (2013) · 28 pages, 7 figures
arxiv created 2013/06/04 · arxiv updated 2013/07/17
We study theoretically a three-mode optomechanical system where two mechanical oscillators are coupled to a single cavity mode. By using two-tone (i.e. amplitude-modulated) driving of the cavity, it is possible to couple the cavity to a single collective quadrature of the mechanical oscillators. In such a way, a back-action-evading measurement of the collective mechanical quadrature is possible. We discuss how this can allow one to measure both quadratures of a mechanical force beyond the full quantum limit, paying close attention to the role of dissipation and experimental imperfections. We also describe how this scheme allows one to generate steady-state mechanical entanglement; namely, one can conditionally prepare an entangled, two-mode squeezed mechanical state. This entanglement can be verified directly from the measurement record by applying a generalized version of Duan's inequality; we also discuss how feedback can be used to produce unconditional entanglement.