title: Discriminating single-photon states unambiguously in high dimensions.
abstract: The ability to uniquely identify a quantum state is integral to quantum science, but for nonorthogonal states, quantum mechanics precludes deterministic, error-free discrimination. However, using the nondeterministic protocol of unambiguous state discrimination enables the error-free differentiation of states, at the cost of a lower frequency of success. We discriminate experimentally between nonorthogonal, high-dimensional states encoded in single photons; our results range from dimension d=2 to d=14. We quantify the performance of our method by comparing the total measured error rate to the theoretical rate predicted by minimum-error state discrimination. For the chosen states, we find a lower error rate by more than 1 standard deviation for dimensions up to d=12. This method will find immediate application in high-dimensional implementations of quantum information protocols, such as quantum cryptography.
authors: Department of Physics & Astronomy and Institute for Quantum Computing, University of Waterloo, Waterloo N2L 3G1, Canada and SUPA, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom.
authors: Megan
authors: M
authors: Agnew
authors: SUPA, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom.
authors: Eliot
authors: E
authors: Bolduc
authors: Department of Physics & Astronomy and Institute for Quantum Computing, University of Waterloo, Waterloo N2L 3G1, Canada.
authors: Kevin J
authors: KJ
authors: Resch
authors: SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom.
authors: Sonja
authors: S
authors: Franke-Arnold
authors: SUPA, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom.
authors: Jonathan
authors: J
authors: Leach