title: Exploring a new regime for processing optical qubits: squeezing and unsqueezing single photons.
abstract: We implement the squeezing operation as a genuine quantum gate, deterministically and reversibly acting "online" upon an input state no longer restricted to the set of Gaussian states. More specifically, by applying an efficient and robust squeezing operation for the first time to non-Gaussian states, we demonstrate a two-way conversion between a particlelike single-photon state and a wavelike superposition of coherent states. Our squeezing gate is reliable enough to preserve the negativities of the corresponding Wigner functions. This demonstration represents an important and necessary step towards hybridizing discrete and continuous quantum protocols.
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: Yoshichika
authors.initials: Y
authors.lastname: Miwa
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: Jun-ichi
authors.initials: J
authors.lastname: Yoshikawa
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: Noriaki
authors.initials: N
authors.lastname: Iwata
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: Mamoru
authors.initials: M
authors.lastname: Endo
authors.affiliation: Department of Optics, Palacký University, 17. listopadu 1192/12, 771 46 Olomouc, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Marek
authors.affiliation: Department of Optics, Palacký University, 17. listopadu 1192/12, 771 46 Olomouc, Czech Republic.
authors.forename: Radim
authors.initials: R
authors.lastname: Filip
authors.affiliation: Institute of Physics, Staudingerweg 7, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: van Loock
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: Akira
authors.initials: A
authors.lastname: Furusawa