Relation between squeezing of vacuum fluctuations, quantum entanglement and sub-shot noise in Raman scattering

摘要

A completely quantum description of Raman process is used to investigate thenonclassical properties of the modes in the stimulated, spontaneous andpartially spontaneous Raman process. Both coherent scattering (where all theinitial modes are coherent) and chaotic scattering (where initial phonon modeis chaotic and all the other modes are coherent) are studied. Nonclassicalcharacter of Raman process is observed by means of intermodal entanglement,single mode and intermodal squeezing of vacuum fluctuations, sub-shot noise andwave variances. Joint photon-phonon number and integrated-intensitydistributions are then used to illustrate the observed nonclassicalities.Conditional and difference number distributions are also provided to illustratethe nonclassical character. The mutual relation between the obtainednonclassicalities and their variations dependent on phases, rescalled time andratio of coupling constants are also reported.