Study Of The Entanglement In A Hybrid Optomechanical System

Optomechanical cavity is a high-finesses system.The classical optomechanical system consisting of a resonant cavity,and one of the mirror is movable.When driven by an external laser field,the momentum carried by the light can transferred in the system by the radiation pressure,and leads to the vibration of the movable mirror in the steady-state,the length of the cavity is changed and caused the feed-back control.Owing to the particular trait and precise structure,optomechanical system is used in some scientific areas,such as gravitational wave detection,atomic cooling and etc.And it also provided a solution to generate quantum entanglement at macroscopic scale,for this years,many researchers propose lots of scheme for it,great progress has been made by improving the structure of the system in order to improve the degree of entanglement and the stability of the system.However,the simlation results shows that most of the existing system have a defect that the degree of entanglement is not very obvious and the critical temperature is minimal,which is not conductive to the preparation in the experiment.Designing an entangled system with strong stability has become an important issue.In this paper,a hybrid optomechanical system is proposed and the entanglement state which effected by the coupling strength in the system are analyzed.And this nolinear system contains the couplings between cavity and atomic ensemble,and the coupling between two cavities.By the Lyapunov equation and the logarithmic negativity,the effects of different coupling strength on the entanglement is studied,The time evolution of the entanglement and the critical temperature under various parameters situation is analyzed.The contents of this paper include the following:A hybrid optomechanical system is proposed,and the theoretical model is constructed by using the theoretical formula.Under different parameters condition,the stability of the operators are studied and the time evolution of the logarithmic negativity is simulated,find the initial condition have no effect on the steadt-state entanglement.The effects of the two cavities with different structure on the system are investigated.The resistance of entanglement to the temperature by injects two atomic ensembles in two cavities are studied respectively.Find that the atomic ensembles causes the entanglement transfer to the itself and increase the capacity of entangled photons in the cavity,the two atomic ensembles have oppose function to the system.The generation,transfer and dissipation of entanglement in the system under the coupling strength between two cavities are investigated respectively.The appropriate parameters range is obtained and the effect of this coupling is studied.By the change of the steady state and the effective detuning in the system versus coupling strength,the function of the two types of coupling are analyzed.According to the parameters the resistance of entanglement to temperature in the system is simulated and the maximum critical temperature in the hybrid system is obtained,which is 190 K,much higher than most existing systems,which is more conducive to the realization of the experiment.