title: Generating superposition of up-to three photons for continuous variable quantum information processing.
abstract: We develop an experimental scheme based on a continuous-wave (cw) laser for generating arbitrary superpositions of photon number states. In this experiment, we successfully generate superposition states of zero to three photons, namely advanced versions of superpositions of two and three coherent states. They are fully compatible with developed quantum teleportation and measurement-based quantum operations with cw lasers. Due to achieved high detection efficiency, we observe, without any loss correction, multiple areas of negativity of Wigner function, which confirm strongly nonclassical nature of the generated states.
authors.affiliation: Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Mitsuyoshi
authors.initials: M
authors.lastname: Yukawa
authors.forename: Kazunori
authors.initials: K
authors.lastname: Miyata
authors.forename: Takahiro
authors.initials: T
authors.lastname: Mizuta
authors.forename: Hidehiro
authors.initials: H
authors.lastname: Yonezawa
authors.forename: Petr
authors.initials: P
authors.lastname: Marek
authors.forename: Radim
authors.initials: R
authors.lastname: Filip
authors.forename: Akira
authors.initials: A
authors.lastname: Furusawa