Research On Quantum Properties Of Nitrogen-vacancy Center In Diamond Coupled To Nanomechanical Resonator And Cavity Field

As a basic content of quantum informatics,quantum entanglement plays an important role in quantum teleportation,quantum error correction,quantum key distribution and so on.Nitrogen-vacancy(NV)center in diamond can be utilized in solid-state quantum information processing and also exhibit initialization,readout,unitary manipulation,and long coherence times at room temperature.Nanoeletromechanical resonator(NAMR)can be used in high precision displacement measurement and have the advantages of high sensitivity,high quality factor,light weight and low dissipation.Therefore,a number of attentions have been drawn to the quantum entanglement of NV center coupled to NAMR.Based on the important application of quantum entanglement in quantum communication,this thesis mainly focuses on the quantum dynamics properties of the system consisting of NV center coupled to NAMR and superconducting coplanar waveguide(SCPW)cavity,and the entanglement properties of the system consisting of two NV centers in diamond coupled to two NAMRs and two SCPW cavities.The detailed contents are as follows:The entanglement properties in the NV center-cavity-NAMR system are investigated.The influences of the coupling strength,the detuning,and the dissipation on bipartite entanglement are discussed by negativity.In the condition of large detuning,quantum state transfer from the SCPW cavity to NAMR and the realization of intermediate coupling are discussed.With the help of SCPW cavity-assisted interactions,a maximally hybrid entangled state between the NV center and the NAMR can be prepared.Since there exists dissipation in the system,the SCPW-assisted interactions can enhance the ability of resisting entanglement disappearing.Meanwhile,a reliable high-fidelity quantum state transfer can be realized.A system consisting of the two independent NV center-cavity-NAMR subsystem is investigated.The effects of the initial entanglement degree of two SCPW cavities,the coupling strength between the NV center and NAMR,the coupling strength between the NV center and SCPW cavity on the bipartite entanglement are analyzed by concurrency.In theory,the proposal may provide a way to control and manipulate the hybrid entanglement.