Using dark modes for high-fidelity optomechanical quantum state transfer

In a recent publication (Wang and Clerk 2012 Phys. Rev. Lett. 108 153603), we demonstrated that one can use interference to significantly increase the fidelity of state transfer between two electromagnetic cavities coupled to a common mechanical resonator over a naive sequential-transfer scheme based on two swap operations. This involved making use of a delocalized electromagnetic mode which is decoupled from the mechanical resonator, a so-called ‘mechanically dark’ mode. Here, we demonstrate the existence of a new ‘hybrid’ state transfer scheme that incorporates the best elements of the dark-mode scheme (protection against mechanical dissipation) and the double-swap scheme (fast operation time). Importantly, this new scheme also does not require the mechanical resonator to be prepared initially in its ground state. We also provide additional details of the previously described interference-enhanced transfer schemes, and provide an enhanced discussion of how the interference physics here is intimately related to the optomechanical analogue of electromagnetically induced transparency. We also compare the various transfer schemes over a wide range of relevant experimental parameters, producing a ‘phase diagram’ showing the optimal transfer scheme for different points in parameter space.