Using Interference for High Fidelity Quantum State Transfer in Optomechanics

We revisit the problem of using a mechanical resonator to perform the transfer of a quantum state between two electromagnetic cavities (e.g., optical and microwave). We show that this system possesses an effective mechanically dark mode which is immune to mechanical dissipation; utilizing this feature allows highly efficient transfer of intracavity states, as well as of itinerant photon states. We provide simple analytic expressions for the fidelity for transferring both gaussian and non-gaussian states.