Generation Of Hyperentangled Bell States Based On Whispering-gallery-mode Microresonators

Quantum informatics is a comprehensive subject with great development potential,which is born from the combination of quantum physics and information science.Quantum informatics,with its quantum mechanical properties,has solved many problems that cannot be solved by classical informatics.Therefore,it has attracted extensive attention,and people have made a lot of explorations in theory and experiment.In the field of quantum informatics,quantum entanglement plays a vital role in quantum key distribution,quantum teleportation,quantum computation and other quantum information processes(QIP).Therefore,the generation of quantum entanglement is indispensable for quantum informatics.At present,the generation of quantum entanglement is mainly based on linear optical systems,atom ensemble,ion trap and cavity quantum electrodynamics(cavity QED)systems.The cavity quantum electrodynamic system has been widely studied and used due to its excellent physical properties.Cavity quantum electrodynamic QED system is composed of optical microcavity and its coupled atoms,in which atoms act as the storage unit of quantum information.As a new type of artificial atom,the nitrogen-vacant center(NV center)has been proved to be a quantum bit in quantum information processes due to its strong stability and long-term coherence.Due to its high quality factor and small effective mode volume,the whispering-gallery-mode(WGM)resonator often acts as an ideal optical microcavity in theory and experiment.Therefore,the coupling system of NV center and the whispering-gallery-mode resonator is widely used in the field of quantum information.The following is the content and structure of this article.In this paper,the physical properties of NV center and whispering-gallery-mode resonator are first investigated,and the coupling system of NV center and whispering-gallery-mode resonator is studied.Secondly,the two-photon input/output coupling system is used to generate the two-photon Bell-state entanglement in the polarization mode.Thirdly,the coupling system of NV center and whispering-gallery-mode resonator is proposed,and the two-photon hyperentangled Bell-state in polarization mode and spatial mode is prepared.Finally,we use MATLAB for the simulation model design and in combination with loss factors,the degree of guarantee and efficiency of two-photon Bell-state entanglement prepared by the coupling system were obtained,so as to verify the feasibility of the scheme.