耦合系数的线性变化对量子纠缠的调控

考虑原子－光场耦合系数随时间变化的双Jaynes－Cummings模型组成的系统，研究两原子初始处于最大纠缠态时，耦合系数的线性调制对原子纠缠的影响。结果表明：初始纠缠保持时间的长短与耦合系数的线性调制密切相关。无论是单光子过程还是双光子过程，较耦合系数为常数的情形而言，耦合系数线性调制下的初始纠缠消失的时间被大大延迟，延迟时间的长短与耦合系数线性调制的参数选择密切相关，并且在双光子过程中延迟的时间更长。

Controlling quantum entanglement by linear change of the atom-field couplings

.Considering a double Jaynes-Cummings model with the time-dependent atom-field couplings, we have studied the effects of the linear modulation of the atom-field couplings on entanglement between two atoms when the two atoms are initially in an entangled state. The results show that the entanglement is very sensitive to the linear modulation of the atom-field coupling. Both for one-photon processes and for two-photon processes, the disappearance of the initial entanglement is delayed due to the linear modulation as compared to the double standard Jaynes-Cummings model. The delayed time is longer for two-photon processes than that for one-photon processes, and long or short depending on the value of the parameters in the modulation function.