推广的Jaynes-Cummings模型中原子纠缠的时间演化和热纠缠态

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

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 .

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.