单模热腔场中两原子的纠缠演化动力学

Evolution of Entanglement for Two Atoms Interacting with a Thermal Field

在考虑内禀消相干影响下,通过使用部分转置的负本征值(NPT)和共生纠缠度来度量原子间的纠缠.研究了两个二能级原子与初态为热态的单模光场相互作用系统中,两原子间的纠缠随时间演化问题.讨论了内禀消相干和平均光子数等对纠缠度的影响.结果表明:存在内禀消相干时随着时间的演化,原子间的纠缠逐渐减小到一个确定值.通过对两种不同的纠缠度量方法的比较,可以看出NPT和共生纠缠度的时间演化有相似的规律,能够度量同类系统的纠缠.

Considering by means of nonpositivity of the partial transposition （NPT） and concurrence, the entanglement dynamic of two two-level atoms interacting with a single-mode optical field, which is prepared initially in the thermal state. The results show that entanglement of the atoms is very sensitive to the intrinsic decoherence coefficient and the photon number of cavity field. The evolution of NPT for the two atoms exhibits similar behaviors as that of their concurrence, and thus both are well-established measure of entanglement in such system.