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Heralded single phonon preparation, storage and readout in cavity optomechanics

Christophe Galland

à 11h en salle C. Brot

"Progress in nanofabrication has recently enabled spectacular developments in the field of cavity optomechanics and its implementations on integrated photonic platforms. The past few years have seen the first demonstration of coherent coupling between photons and phonons as well as the optical preparation of mechanical oscillators close to their quantum ground states. An outstanding challenge remains the generation of phonon Fock (i.e. number) states, which would open a new era in quantum optomechanics - similar to the way in which photon number states have become the “work-horse” in quantum optics.

We analyze theoretically how to use the radiation pressure coupling between a mechanical oscillator and an optical cavity field to generate in a heralded way a single quantum of mechanical motion (a Fock state), and release on-demand the stored excitation as a single photon. Starting with the oscillator close to its ground state, a laser pumping the upper motional sideband leads to dynamical backaction amplification and to the creation of correlated photon-phonon pairs. The detection of one Stokes photon thus projects the macroscopic oscillator into a single-phonon Fock state. The non-classical nature of this mechanical state can be demonstrated by applying a readout laser on the lower sideband (i.e. optical cooling) to map the phononic state to a photonic mode, and by performing an autocorrelation measurement on the anti-Stokes photons.

We discuss the relevance of our proposal for the future of cavity optomechanics as an enabling quantum technology, in particular for future quantum communication networks based on single photon sources and quantum repeaters, using the DLCZ protocol to distribute entanglement.”

Ref. : http://arxiv.org/abs/1312.4303