线性共振力作用下振幅衰减模型中激发相干态的退相干

Decoherence of excited coherent state in amplitude damping model under the action of linear resonance force

采用热纠缠态表象求解密度算符主方程的方法,结合有序算符积分技术,求解了线性共振力作用下振幅衰减模型中密度算符主方程,导出了主方程解的算符无限和表示。利用密度算符无限和表示,导出了激发相干态在振幅衰减模型中的演化规律。利用数值计算方法,描绘了Wigner函数的演化曲线,以及负部体积随耗散时间的演化曲线。通过对Wigner函数和负部体积随耗散时间的演化曲线分析,讨论了耗散和线性共振力对Wigener函数的影响。研究结果表明,随耗散时间的延长,激发相干态的Wigener函数的负性减弱,负部体积减小;线性共振力作用,对Wigener函数的负性没有影响。

The amplitude damping model master equations of density operators under action of linear resonance force can be solved by virtue of thermo entangled state representation and the technique of integration within an ordered product of operators.We obtain the infinitive operator-sum representation of density operators with this model.Further,the evolution of excited coherent state in this model is discussed.The Wigner function evolution formula of excited coherent state is given.By numerical calculation,we plot the Wigner function.The effects of decoherence on nonclassical properties of the state are discussed.Numerical results show that the negativity area size and the depth of negativity of Wigner function decrease and until vanish with dissipation time increases.In addition,we calculate the evolution of negative volume of Wigner function with dissipation time.We find that the negative volume of Wigner function decreases with dissipation time increases.The nonclassical properties of the state are weakened and disappear with dissipation time increases.