Quantum nondemolition measurement of two-photon Bell-state and three-photon Greenberger-Horne-Zeilinger-state based on weak nonlinearities
Ding Dong, Yan Feng-Li · Acta Physica Sinica · 2013
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 two-photon 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.