Universal programmable devices for unambiguous discrimination

Journal Article · Sun Oct 15 04:00:00 EDT 2006 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.74.042308· OSTI ID:20857826

Chi, Zhang; Mingsheng, Ying ^[1]; Qiao, Bo ^[2]

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1. State Key Laboratory of Intelligent Technology and Systems, Department of Computer Science and Technology, Tsinghua University, Beijing 100084 (China)
2. Department of Fundamental Science, Tsinghua University, Beijina 100084 (China)

We discuss the problem of designing unambiguous programmable discriminators for any n unknown quantum states in an m-dimensional Hilbert space. The discriminator is a fixed measurement that has two kinds of input registers: the program registers and the data register. The quantum state in the data register is what users want to identify, which is confirmed to be among the n states in program registers. The task of the discriminator is to tell the users which state stored in the program registers is equivalent to that in the data register. First, we give a necessary and sufficient condition for judging an unambiguous programmable discriminator. Then, if m=n, we present an optimal unambiguous programmable discriminator for them, in the sense of maximizing the worst-case probability of success. Finally, we propose a universal unambiguous programmable discriminator for arbitrary n quantum states.

• OSTI ID: 20857826
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 4 Vol. 74; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
DISCRIMINATORS
ENERGY LEVELS
HILBERT SPACE
PROBABILITY
QUANTUM COMPUTERS
QUANTUM MECHANICS
QUANTUM NUMBERS