标题： 两种未知部分纠缠态的量子纠缠浓缩方案与交叉克尔非线性 显示英文标题

标题： Schemes for quantum entanglement concentration of two unknown partially entangled states with cross-Kerr nonlinearity

摘要： 我们提出了利用交叉Kerr非线性对一对未知的部分纠缠Bell态和三光子W态进行浓缩的实用方案。 在这些方案中，利用局部操作和经典通信，两个分离的参与者可以从之前共享的两个部分纠缠光子对中获得一个最大纠缠光子对，三个分离的参与者可以从两个相同的部分纠缠三光子W态中以一定的成功概率获得一个最大纠缠三光子W态和一个最大纠缠簇态。 最后，我们讨论了误差源和退相干对这些方案的影响。 所提出的装置非常简单，仅使用一些线性光学元件和交叉Kerr介质，这大大简化了这些方案的实验实现。 这些方案在当前实验技术下是可行的。 显示英文摘要

摘要： We propose practical schemes for concentrating entanglement of a pair of unknown partially entangled Bell states and three-photon W states with cross-Kerr nonlinearity. In the schemes, utilizing local operations and classical communication, two separated parties can obtain one maximally entangled photon pair from two previously shared partially entangled photon pairs, and three separated parties can obtain one maximally entangled three-photon W state and a maximally entangled cluster state from two identical partially entangled three-photon W state with a certain success probability. Finally, we discuss the influences of sources of errors and decoherence on the schemes. The proposed setup is very simple, just employing some linear optical elements and cross-Kerr medium, which greatly simplifies the experimental realization of the schemes. The schemes are feasible within current experimental technology