利用负熵方法,研究了混合态下运动二能级原子与二项式光场相互作用多光子跃迁过 程系统中的量子纠缠特性,讨论了原子初态、场模结构参数、光场最大光子数、二项式系数、 跃迁光子数、失谐量等物理参量对系统纠缠度的影响。结果表明:考虑原子运动时,系统出现了 规则的周期振荡,并且有退纠缠现象产生。随着场模结构参数的增大,振荡周期缩短,振幅减小。 系统的纠缠值与原子初始混合程度有关,原子初态趋于纯态时系统纠缠度较高。随着二项式光场 最大光子数的增大,系统纠缠度的峰值逐渐变小,系统规则振荡的周期不发生改变。二项式光场 趋于中间态时纠缠值较小。随着跃迁光子数的增大,系统纠缠度的峰值逐渐变大,振荡周期缩短, 并且振荡变得越来越快。考虑失谐时,系统出现了不规则的纠缠,系统纠缠度的最大值随着失谐量的增大而减小。

Using negative entropy method, the quantum entanglement characteristics of the system of binomial optical field interacting with moving atom were studied. The influences of the atomic initial state, field-mode structure parameter, maximum photon number of binomial field, coefficient of binomial field, transition photon number and detuning were discussed. The results show that the value of entanglement degree of the system appears regular evolution and entanglement sudden death (ESD) phenomenon when atomic motion was considered. The increasing of the field-mode structure parameter shortens the period of the entanglement and results in a slight decreasing of amplitude. The atomic initial state affects the entanglement degree of the system. When the atomic initial state tends to pure state, the entanglement degree of the system is larger relatively. With increase of the maximum photon number of binomial field, the value of the entanglement degree of system becomes small, but the period for regular evolution is almost unchanged. When the field is in the middle states, the entanglement degree is smaller relatively. With the increase of the transition photon number, the value of the entanglement degree of the system becomes larger, the period of the oscillation becomes shorter, meanwhile the oscillation of the system becomes faster and faster. With the detuning increasing, the entanglement becomes small.