Exhibition Program

We investigate a counter-intuitive phenomenon of quantum state discrimination that the success probability of identifying all the unknown quantum states increases even when the number of unknown states increases. The phenomenon is known for vulnerability of quantum secret sharing (QSS), which enables one to distribute a secret amongst untrusted participants securely, however, the necessary and sufficient condition for the phenomenon was unknown. We show the condition for a specific discrimination task and construct a practical method to realize the phenomenon. These results advance the analysis of the phenomenon and reveal the vulnerability of QSS. Since quantum state discrimination lies at the heart of many quantum information processing tasks, our research widely contributes to the future information society based on quantum technologies, where people would obtain the benefits from genuine quantum information processing.