Entanglement generation in 3-mode optomechanical systems (Prof. Dr. Yingdan Wang)

We find that large steady-state entanglement can be achieved in a 3-mode optomechanical system by effectively laser cooling a delocalized Bogoliubov mode. This approach allows one to surpass the bound on the maximum stationary intracavity entanglement possible with a coherent 2-mode interaction. In particular, we find that optimizing the relative ratio of optomechanical couplings, rather than simply increasing their magnitudes, is essential for achieving strong entanglement. We also provide analytic insight into the generation of stationary itinerant photon entanglement in such system. We identify the parameter regime of maximal entanglement, and show that strong entanglement is possible even for weak many-photon optomechanical couplings. We also show that strong tripartite entanglement can be generated between the photonic and phononic output fields.