title: Demonstration of coherent-state discrimination using a displacement-controlled photon-number-resolving detector.
abstract: We experimentally demonstrate a new measurement scheme for the discrimination of two coherent states. The measurement scheme is based on a displacement operation followed by a photon-number-resolving detector, and we show that it outperforms the standard homodyne detector which we, in addition, prove to be optimal within all Gaussian operations including conditional dynamics. We also show that the non-Gaussian detector is superior to the homodyne detector in a continuous variable quantum key distribution scheme.
authors.affiliation: Max Planck Institute for the Science of Light, Günther-Scharowsky-Strasse 1, Bau 24, 91058, Erlangen, Germany.
authors.forename: Christoffer
authors.initials: C
authors.lastname: Wittmann
authors.forename: Ulrik L
authors.initials: UL
authors.lastname: Andersen
authors.forename: Masahiro
authors.initials: M
authors.lastname: Takeoka
authors.forename: Denis
authors.initials: D
authors.lastname: Sych
authors.forename: Gerd
authors.initials: G
authors.lastname: Leuchs