Research On Quantum Information Processing System Based On The Composite Hybrid Structure Of NV Centers In Diamonds

With the continuous development of society,the demand for information processing is increasing.The traditional information technology has met serious limitations in some ways.Quantum information science was born in the last century.It is a new interdisciplinary discipline involving quantum mechanics and information science.Quantum mechanics has an important impact on society.With the help of quantum theory,quantum information technology has incomparable advantages over classical information technology in some aspects of processing and transfering information,such as the theoretical unconditional secure transmission in quantum communication,and the parallelization of information in quantum computing,etc.The hardware to process information is essential for the research on quantum information.A suitable physical system is needed to realize quantum information processing experimentally.At present,the hopeful physical systems are ion traps,cavity quantum electrodynamics,nuclear magnetic resonance,superconducting Joseph junctions,quantum dots,and nitrogen vacancy(NV)in diamond systems and so on.The NV center electrons have the advantages of long spin coherence time and easy manipulation.The microtoroidal resonator(MTR)is an optical micro-cavity with high-quality factor and small mode volume.The solid-state optical cavity system composed by the NV center and MTR has been applied in many fields of quantum information processing.This article focuses on the following aspects:We designed an effective scheme for the synchronized preparation of quantum entangled states based on the coupling system of the nitrogen vacancy color center in diamond and the microtoroidal resonator.In our scheme,the two-particle entangled Bell state and three-particle entangled W state are discussed by utilizing the input-output process of the coupled system.The NV-MTR coupling system has the advantages of both solid-state qubits and optical microcavities,which makes our scheme not require high coupling strength and high-quality factor of the cavity,and have good experimental feasibility.Then,we propose a series of theoretical schemes of quantum logic gates in decoherence-free subspaces.Based on CNOT and Toffoli gates,we present the construction of non-local multi-qubit controlled logic gates,which can be used for the operations between different nodes in quantum networks.The scheme is robust because the decoherence-free subspace is immune to joint noise.The model we proposed in the scheme can also be used in other solid-state optical cavity systems,which has good scalability.The experimental requirements are further reduced in this system,as a result it has better performance within the range of the parameters that can be achieved currently.