Discriminating Single-Photon States Unambiguously in High Dimensions

Megan Agnew, Eliot Bolduc, Kevin J. Resch, Sonja Franke-arnold, Jonathan Leach

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)
87 Downloads (Pure)


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.
Original languageEnglish
Article number020501
JournalPhysical Review Letters
Issue number2
Publication statusPublished - 7 Jul 2014


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