Heralded Single-Phonon Preparation, Storage, and Readout in Cavity Optomechanics

TLDR

The study demonstrates a heralded method to generate a single‑phonon Fock state via radiation‑pressure coupling between a mechanical oscillator and an optical cavity. Starting from the oscillator near its ground state, a laser tuned to the upper motional sideband creates correlated photon‑phonon pairs through optomechanical parametric down‑conversion; detecting a single Stokes photon projects the oscillator into a single‑phonon Fock state, and a readout laser on the lower sideband maps this state to a photonic mode for autocorrelation measurement. Our approach proves the relevance of cavity optomechanics as an enabling quantum technology.

Abstract

We show how to use the radiation pressure optomechanical 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). Starting with the oscillator close to its ground state, a laser pumping the upper motional sideband produces correlated photon-phonon pairs via optomechanical parametric down-conversion. Subsequent detection of a single scattered Stokes photon projects the macroscopic oscillator into a single-phonon Fock state. The nonclassical nature of this mechanical state can be demonstrated by applying a readout laser on the lower sideband to map the phononic state to a photonic mode and performing an autocorrelation measurement. Our approach proves the relevance of cavity optomechanics as an enabling quantum technology.