Theoretical Study Of Quantum State Transmission In Micro Cavity Coupled With Mechanical Oscillator

In recent years,quantum optomechanical system has become a new research field.The quantum characters and the applications in quantum information process turn out to be interesting focus.A typical optomechanical system is constituted by an optical resonator and a nano mechanical oscillator,which are coupled to each other through radiation pressure.On the one hand,the mechanical mode is driven by the optical cavity,on the other hand,the cavity twist,and further the cavity frequency,is influenced by mechanical displacement.It is well known,cavity QED system with high Q and large coherence plays an important role in quantum information process considering that cavity QED system can be applied for quantum information long-time storage,large-distance transmission and non-local processing,nano mechanical oscillator with high sensitivity and operability is widely applied in ultra precision detection.The nano mechanical displacement quantum detection and quantum information transmission can be remotely implemented by using a quantum optical cavity working with a mechanical oscillator.The preparation and the transmission character of hybrid interface constituted by different kinds of quantum bits such as phonons,photons,atoms,or Josephson Junctions.This thesis aims to discuss the characters of quantum state transfer implemented between distant optomechanical systems connected via optical fiber.In the thesis,a model of two distant optomehanical systems coupled to cavities connected via fiber is put forward.The advantages of the model,compared with the existing scheme,lie in that,firstly,unlike some other schemes that rely on photon transmission in free space or guided by isolator,two cavities intermediated by optical fiber strongly couple to each other ensures that two ends of the quantum system both act as the sender and receiver,secondly,large detuning condition is applied to adiabatically eliminate fiber mode and obtain the effective Hamiltonian of the distant cavity-cavity interaction intermediated by fiber.The efficiency of the quantum state transfer between distant oscillators is studied by solving Langevin equations under given parameters.It is shown that,in a certain operating time,without dissipation effect,100%efficiency of the quantum transfer is achieved.The dissipation effected caused by cavity leakage and oscillator damping can be reduced and the efficiency of quantum state transfer can be effectively increased.Under given experimental parameters,the minimum time required to complete the single quantum state transmission process is significantly reduced,compared with the existing model.