混合态下运动原子与相干态光场相互作用的量子纠缠

利用负熵方法，研究了混合态运动原子与相干态光场相互作用系统的量子纠缠特性，讨论了原子初态、场模结构参数、相干场平均光子数、失谐量、跃迁光子数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，系统纠缠度在整个时域范围内出现了规则的周期振荡。原子初态趋于纯态时系统纠缠度较高。随着相干场平均光子数的增大，系统纠缠度的峰值逐渐变小，规则振荡的周期不变。随着跃迁光子数的增大，系统纠缠度的峰值逐渐变大，振荡变得越来越快。随着失谐量的增大，系统纠缠度的峰值逐渐变小。

Quantum Entanglement of the Coherent Field Interacting with the Moving Atom being in a Mixed State

Using the negative entropy method, the quantum entanglement character of the system of the coherent optical field interacting with the moving atom is studied. The influences of the atomic initial state, the field-mode structure parameter, the average photon number of the coherent field, the detuning, and the transition photon number on the entanglement character of the system are discussed. The result shows that the value of the entanglement degree of the system appears regular evolution and entanglement sudden death phenomenon (ESD) when the atomic motion is considered. When the atomic initial state tends to pure state, the entanglement degree of the system is larger relatively .With the increase of the average photon number of the coherent field, the value of the entanglement degree of the system becomes small, but the period for the regular evolution is almost unchanged .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 .