双模场与原子相互作用中的量子纠缠和内禀退相干

Entanglement and intrinsic decoherence in the interaction between two-mode field and atom

通过求解系统的Milburn方程,研究了两能级原子与双模SU(1,1)相干态光场发生相互作用系统中,原子与场的纠缠及双模SU(1,1)相干态场的模间纠缠随时间的演化问题,讨论了内禀退相干、双模光子数差等对纠缠度的影响.结果表明,存在内禀退相干时,随着时间的演化,场-原子纠缠逐渐减小到一个确定值,而模间纠缠逐渐增大到一个确定值,两者演化的最终值只取决于双模光子数差和平均光子数,而与内禀退相干因子无关.

Considering the interaction between two-mode SU（ 1,1 ） coherence states and a two-level atom, we find an exact solution of the Milbum equation for the system . We investigate the time evolution of the entanglement of field-atom and one of two modes of field using the quantum-reduced entropy and quantum relative entropy, respectively. The influences of intrinsic decoherence and two-mode photon number difference on the evolution of the entanglement of field-atom and one of two modes of field are discussed. It is shown that the entanglement of field-atom reduces to a stationary value with time evolution and the entanglement between two modes increases to another stationary value with intrinsic decoherence, and the values only depend on the two-mode photon number and mean photon number.