频率变化场多光子J-C模型中的量子态保真度  

Fidelity of quantum states in the multiphoton Jaynes-Cummings model with a time-varying frequency field

作　　者：卢道明[1] 

机构地区：[1]武夷学院电子工程系,福建武夷山354300

出　　处：《光学技术》2010年第2期264-268,共5页Optical Technique

基　　金：基金项目：福建省自然科学基金（2D08J0217）资助项目

摘　　要：利用多光子J-C模型,考虑场频率随时间以正弦函数形式作小量变化,在旋波近似下,研究了二能级原子通过多光子跃迁与单模辐射场相互作用时的量子态保真度的演化。利用数值计算方法给出了量子态保真度随时间的演化曲线。研究结果表明：场频率随时间正弦函数形式的变化对系统和光场的量子态保真度的演化影响很小,但对原子的量子态保真度的演化具有显著的影响;原子的量子态保真度的演化受场频率变化的调制,场频率振荡的幅值u越大,调制作用越强,在场频率振荡的幅值u大于一定值后,量子态保真度将按场频率周期性的变化规律作周期性振荡;原子初始状态的分布对原子量子态保真度的演化也具有明显的影响。Using the multiphoton Jaynes-Cummings model,the dynamical properties of the fidelity of quantum states in the system that consists of a two-level atom interacting with a single-mode field via multiphoton transition are studied.The frequency of the field varying with time in the form of sine is considered.The results obtained by numerical calculations show that the time-evolution behavior of the fidelities of field and system is not influenced by the frequency variation of field,but the time-evolution behavior of the fidelity of atom is modulated by the frequency variation of field.The larger the amplitude of the field frequency variance u is,the stronger modulation interaction of the field frequency variance is.When the amplitude u is larger than a fixed value,the time-evolution behavior of the fidelity of atom will display quasiperiodic oscillation behavior.Its oscillation period is in agreement with the period of frequency varying.The initial state of atom influences the time-evolution behavior of the fidelity of atom.

关 键 词：二能级原子 多光子J-C模型 频率变化场 量子态保真度 

分 类 号：O431.2[机械工程—光学工程]