原子的选择测量对原子纠缠特性和场熵的影响*

考虑初始处于W态的三个二能级原子，将其中两个原子同时注入处于真空态的单模腔中，并与光场发生共振相互作用的情况。采用数值计算方法，通过对是否进行原子态选择性测量情况下，腔内原子间的纠缠性质和场熵的比较，讨论了对腔外原子的态选择性测量对腔内原子间的纠缠性质和场熵演化的影响。研究结果表明：对腔外原子的选择性测量，可增强腔内原子间的纠缠，但会减弱腔內原子与光场的关联。

The influences of the selective atomic measurement on entanglement

Considering three two-level atoms initially in the W state, two atoms of the three atoms are put into initially empty cavity and made resonant interaction. The two-atom entanglement evolution inside cavity and entropy of field are investigated. The influences of state-selective measurement of the atom outside cavity and the coupling coefficient between atoms inside cavity on the two-atom entanglement evolution inside cavitiy are discussed. The results obtained using the numerical method show that the two-atom entanglement inside cavity is strengthened through the state-selective measurement of the atom outside the cavity. On the other hand, the coupling coefficient between atoms inside cavity also influences the two-atom entanglement properties and entropy evolution of field.