2008/09/17 by Ulrike Herzog, János A. Bergou, Janos A. Bergou · 1 citation
Computer Science · Physics and Astronomy · #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Mechanics and Applications #quant-ph
paper · pdf · doi:10.1103/physreva.78.032320
published as Phys. Rev. A 78, 032320 (2008), Erratum: Phys. Rev. A 78, 069902 (2008) · A reference has been included and a sign error has been corrected that propagated and affected the final result and is unfortunately also present in the printed journal version
openalex publication_date 2008/09/17 · arxiv created 2008/11/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We address the problem of unambiguously identifying the state of a probe qudit with the state of one of d reference qudits. The d reference states are assumed pure and linearly independent but we have no knowledge of them. The state of the probe qudit is assumed to coincide equally likely with either one of the d unknown reference states. We derive the optimum measurement strategy that maximizes the success probability of unambiguous identification and find that the optimum strategy is a generalized measurement. We give both the measurement operators and the optimum success probability explicitly. Technically, the problem we solve amounts to the optimum unambiguous discrimination of d known mixed quantum states.