title: Demonstration of a controlled-phase gate for continuous-variable one-way quantum computation.
abstract: We experimentally demonstrate a controlled-phase gate for continuous variables using a cluster-state resource of four optical modes. The two independent input states of the gate are coupled with the cluster in a teleportation-based fashion. As a result, one of the entanglement links present in the initial cluster state appears in the two unmeasured output modes as the corresponding entangling gate acting on the input states. The genuine quantum character of this gate becomes manifest and is verified through the presence of entanglement at the output for a product two-mode coherent input state. By combining our gate with the recently reported module for single-mode Gaussian operations [R. Ukai et al., Phys. Rev. Lett. 106, 240504 (2011)], it is possible to implement any multimode Gaussian operation as a fully measurement-based one-way quantum computation.
authors.affiliation: Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Tokyo 113-8656, Japan.
authors.forename: Ryuji
authors.initials: R
authors.lastname: Ukai
authors.forename: Shota
authors.initials: S
authors.lastname: Yokoyama
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Yoshikawa
authors.forename: Peter
authors.initials: P
authors.lastname: van Loock
authors.forename: Akira
authors.initials: A
authors.lastname: Furusawa