Controlling the entanglement of mechanical oscillators in composite optomechanical system

A controllable entanglement scheme of two mechanical oscillators is proposed in a composite optomechanical system.In the case of strong driving and high dissipation,the dynamics of the movable mirror of the optomechanical cavity is characterized by an effective frequency in the long-time evolution of the system.Considering the classical nonlinear effects in an optomechanical system,we investigate the relationship between the effective frequency of the movable mirror and the adjustable parameters of the cavity.It shows that the effective frequency of the movable mirror can be adjusted ranging fromωm（the resonance frequency of the coupling oscillator） to-ωm.Under the condition of experimental realization,we can generate and control steady-state entanglement between two oscillators by adjusting the effective frequency of the movable mirror and reducing the effective dissipation by selecting the parameter of the cavity driving laser appropriately.Our scheme provides a promising platform to control the steady-state behavior of solid-state qubits using classical manipulation,which is significant for quantum information processing and fundamental research.

Double-passage mechanical cooling in a coupled optomechanical system

We consider a three-mode optomechanical system where two cavity modes are coupled to a common mechanical oscillator. We focus on the resolved sideband limit and illustrate the relation between the significant parameters of the system and the instantaneous-state mean phonon number of the oscillator cooled to the ground state, particularly at the early stage of the evolution. It is worth noting that the optical coupling sets up a correlation between the two cavity modes,which has significant effect on the cooling process. Using numerical solutions, we find that the inter-cavity coupling will decrease the cooling effect when both cavities have the same effective optomechanical coupling. However, when the effective optomechanical couplings are different, the cooling effect will be strongly improved by selecting appropriate range of inter-cavity coupling.

Optomechanical state transfer between two distant membranes in the presence of non-Markovian environments

The quantum state transfer between two membranes in coupled cavities is studied when the system is surrounded by non-Markovian environments. An analytical approach for describing non-Markovian memory effects that impact on the state transfer between distant membranes is presented. We show that quantum state transfer can be implemented with high efficiency by utilizing the experimental spectral density, and the performance of state transfer in non-Markovian environments is much better than that in Markovian environments, especially when the tunneling strength between the two cavities is not very large.