中文摘要：

基于弱非线性及线性光学元件提出非破坏性测量两光子Bell态及三光子Greenberger-Horne-Zeilinger（GHZ）态方案.方案中,首先应用光束分束器及交叉克尔非线性介质对两光子Bell态进行对称性分析,进而结合控制非门提出三光子分析方案实现对八个三光子GHZ态完全且非破坏性区分.

英文摘要：

The scheme for quantum nondemolition measurement of two-photon Bell-state and three-photon Greenberger-Horne-Zeilinger（GHZ）-state is proposed based on weak nonlinearities and linear-optics elements.We first describe a scheme of the symmetry analyzer for two-photon Bell-state by using beam splitters and cross-Kerr nonlinear medium.According to this symmetry analyzer for twophoton Bell-state and the controlled-NOT gates we construct a three-photon state analyzer which can completely and nondestructively discriminate eight three-photon GHZ states.