Study On Quantum Entanglement In The Optomechanical System Of Rotating Cavity

Cavity optomechanics is an important frontier field in the world,which has great academic significance and application value in basic physics research,quantum information and high-precision measurement.Traditional cavity optomechanics realizes the interaction between the optical field and the mechanical vibrator by means of the radiation pressure of the optical field to the mechanical vibrator in the optical resonant cavity.While the rotational cavity optomechanics developed recently,in which the spiral phase plates as cavity mirrors and the vortex light as cavity modes,resorts to the exchange of the angular momenta between vortex light and rotating mirror to realize the interaction between them.And it provides a platform to study the cavity cooling,rotation induced transparency and quantum entanglement of the rotational cavity optomechanical system.In this paper we study a rotational cavity optomechanical system with both rotating mirrors(rotors)and focus on the quantum entanglement of both rotors established by the exchange of angular momenta between the rotors and the common Laguerre-Gaussian(L-G)cavity mode.The paper mainly consists of two parts.In the first part,we give a brief review about the optical cavity optomechanics and discuss several related cavity optomechanical systems and their applications including several achievements about the quantum entanglement.In addition,we talk about the basic theory about the quantum entanglement in cavity optomechanical systems.The second part is the principal part of this paper which contains my main research results about quantum entanglement for two rotational cavity mirrors in a rotational cavity optomechanical system.The quantum entanglement is established by exchanging angular momenta between the cavity mirrors with a common L-G cavity mode.By using numerical simulation,we study the relation of quantum entanglement with the various factors of the system and find several interesting results.Firstly,when the angular frequencies of two rotating mirrors are not close,the entanglementcan be effectively generated,indicating that the selection of the angular frequencies of two rotating mirrors in the system will determine the amount of the exchanged orbital angular momentum and thus affect the magnitude of entanglement.Secondly,by adjusting the cavity detuning,the range of large quantum entanglement is determined.We find that the maximum entanglement can be enhanced by reducing the mass of the rotating mirrors.Thirdly,the influence of the temperature on the entanglement is studied,and a competitive relationship between the temperature and the mass of the rotating mirrors to the robustness of the entanglement is found.Finally,we study the dependence of quantum entanglement on the orbital angular momentum of L-G light and find that there is a threshold for the orbital angular momentum,below which quantum entanglement cannot be generated.We also find the orbital angular momentum threshold is influenced by the coupling strength and the temperature.This work is of great significance to the study of continuous variable quantum entanglement,and is expected to be applied to quantum information and high-precision measurement.