原子-光场耦合的线性调制对原子纠缠的影响

研究由两个相同的二能级原子和一个单模量子化腔场组成的系统中，两原子初始处于纠缠态时，原子与光场的耦合系数随时间线性变化对纠缠的影响。结果表明：初始纠缠的保持时间与耦合系数的线性调制密切相关。较耦合系数为常数的情形而言，当耦合系数的变化比较平缓时，耦合系数线性调制下的初始纠缠消失的时间被大大延迟；当耦合系数的变化很急促时，两原子的初始纠缠将很快消失。

Effect of linear modulation of the atom-field couplings on atom entanglement

Considering a model containing two two-level atoms and a single-mode cavity, we have studied the effects of the time-dependent atom-field couplings on entanglement between the two atoms when the two atoms are initially in an entangled state. The results show that, the time of initial entanglement preservation is very sensitive to the linear modulation of the atom-field couplings. Compared to the case of the constant coupling model, when the atom-field couplings change smoothly, the disappearance of the initial entanglement is delayed due to the linear modulation. However, the disappearance of the initial entanglement can be hastened for the sudden jump in the coupling.