title: Linear optics controlled-phase gate made simple.
abstract: Linear optics quantum logic gates are the best tool to generate multiphoton entanglement. Simplifying a recent approach, we were able to implement the conditional phase gate with only one second-order interference at a polarization dependent beam splitter, thereby significantly increasing its stability. The improved quality of the gate is evaluated by analyzing its entangling capability and by performing full process tomography. The achieved results ensure that this device is well suited for implementation in various multiphoton quantum information protocols.
authors.affiliation: Max-Planck-Institut für Quantenoptik, D-85748 Garching, Germany and Department für Physik, Ludwig-Maximilians-Universität, D-80797 München, Germany.
authors.forename: Nikolai
authors.initials: N
authors.lastname: Kiesel
authors.forename: Christian
authors.initials: C
authors.lastname: Schmid
authors.forename: Ulrich
authors.initials: U
authors.lastname: Weber
authors.forename: Rupert
authors.initials: R
authors.lastname: Ursin
authors.forename: Harald
authors.initials: H
authors.lastname: Weinfurter