title: Certifying the Presence of a Photonic Qubit by Splitting It in Two.
abstract: We present an implementation of photonic qubit precertification that performs the delicate task of detecting the presence of a flying photon without destroying its qubit state, allowing loss-sensitive quantum cryptography and tests of nonlocality even over long distance. By splitting an incoming single photon in two via parametric down-conversion, we herald the photon's arrival from an independent photon source while preserving its quantum information with up to (92.3±0.6)% fidelity. With reduced detector dark counts, precertification will be immediately useful in quantum communication.
authors.affiliation: Institute for Quantum Computing and Department of Physics and Astronomy, University of Waterloo, 200 University Ave W, Waterloo, Ontario, Canada N2L 3G1.
authors.forename: Evan
authors.initials: E
authors.lastname: Meyer-Scott
authors.affiliation: Institute for Quantum Computing and Department of Physics and Astronomy, University of Waterloo, 200 University Ave W, Waterloo, Ontario, Canada N2L 3G1.
authors.forename: Daniel
authors.initials: D
authors.lastname: McCloskey
authors.affiliation: Institute for Quantum Computing and Department of Physics and Astronomy, University of Waterloo, 200 University Ave W, Waterloo, Ontario, Canada N2L 3G1.
authors.forename: Klaudia
authors.initials: K
authors.lastname: Gołos
authors.affiliation: Institute for Quantum Computing and Department of Physics and Astronomy, University of Waterloo, 200 University Ave W, Waterloo, Ontario, Canada N2L 3G1.
authors.forename: Jeff Z
authors.initials: JZ
authors.lastname: Salvail
authors.affiliation: Institute for Quantum Computing and Department of Physics and Astronomy, University of Waterloo, 200 University Ave W, Waterloo, Ontario, Canada N2L 3G1.
authors.forename: Kent A G
authors.initials: KA
authors.lastname: Fisher
authors.affiliation: Département de physique et d'astronomie, Université de Moncton, 18 avenue Antonine-Maillet, Moncton, New Brunswick, Canada E1A 3E9.
authors.forename: Deny R
authors.initials: DR
authors.lastname: Hamel
authors.affiliation: Departamento de Física Aplicada II, Universidad de Sevilla, E-41012 Sevilla, Spain.
authors.forename: Adán
authors.initials: A
authors.lastname: Cabello
authors.affiliation: Institute for Quantum Computing and Department of Physics and Astronomy, University of Waterloo, 200 University Ave W, Waterloo, Ontario, Canada N2L 3G1.
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Resch
authors.affiliation: Institute for Quantum Computing and Department of Physics and Astronomy, University of Waterloo, 200 University Ave W, Waterloo, Ontario, Canada N2L 3G1.|Quantum Information Science Program, Canadian Institute for Advanced Research, Toronto, Ontario, Canada M5G 1Z8.
authors.forename: Thomas
authors.initials: T
authors.lastname: Jennewein