推广的Jaynes-Cummings模型中原子纠缠的时间演化和热纠缠态

利用共生纠缠度研究了一个推广Jaynes Cummings模型中两原子纠缠的时间演化和有限温度下系统热纠缠态. 结果表明，腔场中两原子展现出周期性的纠缠演化过程，演化周期随原子偶极 偶极相互作用强度的增大而减小；在有限温度下，系统的共生纠缠度随温度的升高而降低，当趋近临界温度时，系统纠缠现象消失，这一临界温度值与原子偶极-偶极相互作用强度成正比. 对于典型的实验数据，临界温度约在10-5K数量级. 此外，在这种Jaynes Cummings模型中存在量子相位转变. 关键词： Jaynes Cummings模型 原子纠缠态 热纠缠态 共生纠缠度 偶极 偶极相互作用

Time evolution of two-atom entanglement and thermal entanglement in a generalized Jaynes-Cummings model

In this paper, we investigate two-atom entanglement in time evolution and the thermal entanglement in a generalized Jaynes-Cummings model by means of concurrence. The result shows that the two-atom entangled state appears with periodicity, which decreases with increasing dipole-dipole coupling between the two atoms. In a finite temperature, the concurrence decreases with increasing temperature, and the thermal entanglement vanishes in this Jaynes-Cummings model when the system temperature reaches the critical temperature, which is proportional to the dipole-dipole coupling strength of the two atoms. For typical experimental data, the critical temperature is on the order of 10 -5K. In addition, there exists the quantum phase transition in this Jaynes-Cummings model.