title: Experimental demonstration of a nondestructive controlled-NOT quantum gate for two independent photon qubits.
abstract: Universal logic gates for two quantum bits (qubits) form an essential ingredient of quantum information processing. However, photons, one of the best candidates for qubits, suffer from a lack of strong nonlinear coupling, which is required for quantum logic operations. Here we show how this drawback can be overcome by reporting a proof-of-principle experimental demonstration of a nondestructive controlled-NOT (CNOT) gate for two independent photons using only linear optical elements in conjunction with single-photon sources and conditional dynamics. Moreover, we exploit the CNOT gate to discriminate all four Bell states in a teleportation experiment.
authors.affiliation: Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Zhao
authors.forename: An-Ning
authors.initials: AN
authors.lastname: Zhang
authors.forename: Yu-Ao
authors.initials: YA
authors.lastname: Chen
authors.forename: Han
authors.initials: H
authors.lastname: Zhang
authors.forename: Jiang-Feng
authors.initials: JF
authors.lastname: Du
authors.forename: Tao
authors.initials: T
authors.lastname: Yang
authors.forename: Jian-Wei
authors.initials: JW
authors.lastname: Pan