摘要:
利用Von Neuuman量子约化熵理论研究了驻波激光场与囚禁在谐振势中的离子单量子共振相互作用系统中量子场熵的时间演化特性,通过数值计算详细讨论了Lamb-Dick参数、离子质心在驻波激光场中的位置以及囚禁离子初始状态对量子场熵演化特性的影响.结果表明:Lamb-Dick参数影响囚禁离子与驻波激光场之间量子纠缠的频率和幅度,其值越大离子与光场之间的平均纠缠程度越低;随着离子质心从驻波激光场的波节向波腹移动,二者之间量子纠缠的振荡频率逐渐变慢,纠缠强度逐渐减弱;随着囚禁离子处于激发态概率的减小,离子与光场之间的量子纠缠呈现先增强后减弱的变化趋势.这些特性对于纠缠态的制备以及利用囚禁离子进行量子通讯等信息处理过程有一定的参考价值.
Abstract:
The time evolution properties of the field quantum entropy in the system of a trapped ion interacting resonantly with a standing-wave laser field is studied by utilizing the Von Neumann reduced quantum entropy theory,and our attention focuses on the discussion of the influence of the Lamb-Dick parameter,the position of the ion in the standing-wave laser field and the initial state of the trapped ion on the evolution properties of the field quantum entropy.The results obtained from the numerical calculation indicate that:the value of the Lamb-Dick parameter effect the oscillation frequency and amplitude of the quantum entanglement between the trapped ion and the standing-wave laser field,the larger the Lamb-Dick parameter is,the weaker the average entanglement level between the ion and the field will be.When moving the tapped ion from the node of the standing-wave laser to the loop,the vibration frequency of the quantum entanglement between the field and the ion becomes slow gradually,and the entanglement degree gets weaker and weaker.With the decrease of the probability of the trapped ion being in the excited state,the quantum entanglement between the trapped ion and the stanging-wave laser field shows the tendency of increase first and then decrease.These properties have certain reference value for the preparation of entangled states and for the quantum communications with the thapped ion,and so on.
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