  We propose a protocol for coherently transferring non-Gaussian quantum states
from optical field to a mechanical oscillator. The open quantum dynamics and
continuous-measurement process, which can not be treated by the
stochastic-master-equation formalism, are studied by a new path-integral-based
approach. We obtain an elegant relation between the quantum state of the
mechanical oscillator and that of the optical field, which is valid for general
linear quantum dynamics. We demonstrate the experimental feasibility of such
protocol by considering the cases of both large-scale gravitational-wave
detectors and small-scale cavity-assisted optomechanical devices.

Quantum Physics