Enhancement on quantum synchronization of directly coupled optomechanical oscillators via periodic modulations

We study a double-cavity optomechanical system with two movable mirrors acting as mechanical oscillators coupled via a common girder. The fluctuation parts of mechanical oscillations induced by vacuum noises exhibit a limited quantum synchronization owing to the Heisenberg uncertainty. Exerting periodic modulations on the driving lasers or mechanical oscillators, we find that it is viable to attain a 50% similar to 75% enhancement on this quantum synchronization with appropriate modulation frequencies and amplitudes. A direct comparison shows that the optimal modulations on driving lasers are more favorable than the optimal modulations on mechanical oscillators in that the former could result in a greater enhancement than the latter. Our findings should be instructive for further studies on multi-cavity optomechanical systems to pursue a promising platform for quantum information processing.