Ultimate limits for multiple quantum channel discrimination

Understand

Quantum hypothesis testing is a central task in the entire field of quantum information theory.

• Understanding its ultimate limits will give insight into a wide range of quantum protocols and applications, from sensing to communication.
• Although the limits of hypothesis testing between quantum states have been completely clarified by the pioneering works of Helstrom in the 70s, the more difficult problem of hypothesis testing with quantum channels, i.e., channel discrimination, is less understood.
• This is mainly due to the complications coming from the use of input entanglement and the possibility of employing adaptive strategies.