2004/10/31 by Chi Zhang, Yuan Feng, Mingsheng Ying +1 · 2 citations
Computer Science · Physics and Astronomy · #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Mechanics and Applications #quant-ph
paper · pdf · doi:10.1016/j.physleta.2005.12.097
published as Phys. Lett. A, 353, 300-306 (2006) · 7 pages
openalex publication_date 2006/01/07 · arxiv created 2006/10/16 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In this paper, we consider the problem of unambiguous discrimination between a set of mixed quantum states. We first divide the density matrix of each mixed state into two parts by the fact that it comes from ensemble of pure quantum states. The first part will not contribute anything to the discrimination, the second part has support space linearly independent to each other. Then the problem we consider can be reduced to a problem in which the strategy of set discrimination can be used in designing measurements to discriminate mixed states unambiguously. We find a necessary and sufficient condition of unambiguous mixed state discrimination, and also point out that searching the optimal success probability of unambiguous discrimination is mathematically the well-known semi-definite programming problem. A upper bound of the optimal success probability is also presented. Finally, We generalize the concept of set discrimination to mixed state and point out that the problem of discriminating it unambiguously is equivalent to that of unambiguously discriminating mixed states.