Research On Dynamics Properties Of The System Of Two-Level Emitter Coupled To Nano-mechanical Oscillator

In recent years,with the continuous study of nano-mechanical oscillators,the size of mechanical oscillators has been able to achieve micron or even nano-scale.Nanomechanical oscillators have high vibration frequency and quality factor,minimal mass and low dissipation.They have important applications in high precision displacement measurement,force measurement,mass measurement and accurate quantum computation.In this paper,the coupling system of graphene mechanical oscillator and two-level emitter and the interaction system of diamond NV color center coupled mechanical oscillator and cavity field are studied.The basic knowledge of entropy compression,entanglement and variance compression of two-level emitter is introduced.The above two physical models and the mathematical derivation of the related models are also introduced.The main contents are as follows:Entropy squeezing properties,quantum entanglement,quantum state transfer and phonon field variance squeezing of two-level emitters in a two-level emitter-coupled graphene mechanical oscillator system are studied.The effects of coupling coefficient,coherence angle,detuning and coherence on the dynamic characteristics of the system are discussed.The dynamic characteristics of the system with dissipation are also discussed.The results show that the best entropy squeezed state of two-level emitter can be prepared by adjusting the coherence angle.Under certain conditions,the coherence transfer from the quantum state of two-level emitter to the quantum state of mechanical oscillator can be realized.By adjusting the coherence angle,the maximum entangled state can be obtained and the squeezed state of phonon field with long compression time and large compression amplitude can be obtained.Attenuation factor will reduce the exchange of information between two-level emitter and mechanical oscillator,thus affecting the preparation of maximum entropy compression,entanglement and variance compression.The dynamic characteristics of variance squeezing of phonon field in the interaction system of diamond NV color center coupled mechanical oscillator and cavity field are studied.The effects of coupling strength and initial state of diamond NV color center on variance squeezing of phonon field are analyzed.The results show that the squeezed state of phonon field with long compression time and large compression amplitude can be prepared.The physical reason is that the mechanical oscillator has the greatest coherence.By adjusting the initial state of NV color center and magnetic field gradient,the non-classical properties of mechanical oscillator variance compression can be controlled.This provides a way to control the variance compression of phonon field theoretically.