利用线性光学器件实现三体纠缠相干态的纠缠交换

利用一个两体最大纠缠相干态作为量子通道，通过线性光学器件实现了连续变量纠缠态的纠缠交换方案。我们采用分束器和相移器这两种线性光学器件，借助量子隐形传态的思想，实现了三体纠缠相干态的纠缠交换，这一纠缠交换只有一种测量过程是失败的，但几率很小。详细的分析显示，当光场平均光子数大于2，成功纠缠交换任意三体纠缠相干态的概率和总平均最小保真度接近1。

Entanglement swapping of tripartite entangled coherent state by linear optics devices

A scheme for the entanglement swapping of entangled states with continuous variable is presented, in which the bipartite maximally entangled coherent state serves as the quantum channel. With the help of the idea of teleportation, using beam splitter and phase-shifter, entanglement swapping of tripartite entangled coherent state can be realized. In this scheme, the entanglement swapping is failure only for one measurement process. The failure probability is very small. The detail results show that the probability and the minimum of total average fidelity for successful swapping an arbitrary tripartite entangled coherent state is nearly 1 when the mean number of photons is larger than 2.