Optimization Research Of Quantum Cooling Based On Cavity Optomechanical Coupling System

The cavity optomechanics system which couples the light field and the mechanical vibrator by the laser radiation pressure is used to quantum control the macro mechanical vibrator and is fundamental to quantum theory and applied technology.The mechanical vibrator tends to be excited by the external thermal environment due to its low frequency,which hinders further research on quantum phenomena.Therefore,it is significant to optimize the cooling of mechanical vibrator.The research in this paper mainly includes two parts,which respectively use two different cavity optomechanics systems to optimize the cooling of the mechanical vibrator under the weak coupling and the resolvable sideband condition.In the first part,we study the cooling and optimization of the mechanical oscillator based on F-P cavity optomechanics system.First of all,we describe the dynamic evolution of the system by the equation of quantum Langevin and the equation of input noise relation which are derived from system’s Hamiltonian.And then the average fluctuation theory and the Fourier transform formula are used to linearize the equetions of system and transform them into the frequency domain.In the second part,we study the cooling and optimization of the mechanical oscillator based on film cavity optomechanics system.First,we deduce the transmittance and the resonance frequency of the optical cavity by the transmission matrix theory and then deduce the system’s linearized quantum Langevin equation,which is subsequently transformed into the covariance matrix of its dimensionless equations by using the dimensionless operators.Consequently,the evolution of the system can be expressed by Lyapunov equation.Finally,we study the optimal parameter conditions for cooling based on the cavity reciprocal and the non-reciprocal film inserted in and the phonon number of the steady state of the mechanical vibrator.In summary,this article uses two cavity optomechanical coupling systems to study the cooling of the mechanical oscillator and the optimal parameter conditions.The numerical calculation method is used to analyze the influence of various parameters of the system on the cooling of the mechanical vibrator and to optimize the parameter conditions of the cooling under the weak coupling and unresolved sideband condition.It provides a new idea for the ground state cooling of mechanical oscillators,and is helpful for further research on the quantization operation of macroscopic objects.