关于光-原子相互作用中光场的约化密度算符的主方程，范洪义等已经用他们提出的热纠缠态表象给出了新解法，以及不少新的光场密度矩阵解（例如关联二项-负二项式光场，拉盖尔权重热光场等）。本申请将继续用这个思路发明求解原子的约化密度算符主方程新方法，并用于多种原子初态在多种物理过程中的演化的研究中，包括二能级原子的自发辐射，二能级原子在压缩真空中的衰变等，并推广到三能级原子的相应情况。我们给出的解法不但能解出以前难以求解的原子的约化密度算符主方程，而且有简捷、普适的特点，能较好的地反映光-原子相互作用中量子退相干和量子纠缠等现象。

Regarding to solving the master equation of optical field's reduced density operator Fan Hon-yi et al have proposed a method by virtue of the thermo entangled state representation, in so doing, some new photon field density operators are discovered, such as binomial-;;negative binomial correlated photon field, Laguerre polynomial weighted chaotic photon field, etc. In this application, we shall develop this approach to tackle the master equation of atom's reduced density operator with a new method, in this new way, we shall study various atomic systems' time evolution in some physical processes, including two-level atom's spontaneously radiation, decaying in squeezed vacuum, etc, and generalize these topics to three-level atom syetems. Our new method not only solve some difficult master equations, but also exhibit concise and novel characters, and demonstrating clearly quantum entanglement and decoherence in light-atom interations.