Exhibition Program

Science of Communication and Computation


New secrets threaten past secrets

- Vulnerability assessment of quantum secret sharing -


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.


  • [1] S. Akibue, G. Kato, “Bipartite discrimination of independently prepared quantum states as a counterexample to a parallel repetition conjecture,” Physical Review A, Vol. 97, No. 10, 042309, 2018.




Seiseki Akiube, Theory Research Group, Media Information Laboratory