Unambiguous Discrimination Between Mixed Quantum States Based on Programmable Quantum State Discriminators
We discuss the problem of designing an unambiguous programmable discriminator for mixed quantum states. We prove that there does not exist such a universal unambiguous programmable discriminator for mixed quantum states that has two program registers and one data register. However, we find that we can use the idea of programmable discriminator to unambiguously discriminate mixed quantum states. The research shows that by using such an idea, when the success probability for discrimination reaches the upper bound, the success probability is better than what we do not use the idea to do, except for some special cases.
KeywordsUnambiguous discrimination Mixed quantum state Programmable discriminator
This work is supported in part by the National Natural Science Foundation (Nos. 61572532, 61272058), the Natural Science Foundation of Guangdong Province of China (No. 2017B030311011), and the Fundamental Research Funds for the Central Universities of China (Nos. 17lgjc24) and Mateus and Qiu are also funded by FCT project UID/EEA/50008/2013.