QLunch: Quantum correlations under restricted transfer of information

Speaker: Jonatan Bohr Brask from DTU

Title: Quantum correlations under restricted transfer of information

Abstract: Quantum communication leads to stronger correlations than what is classically possible, when the amount of communication is restricted. The study of such correlations provide fundamental insight into the structure of quantum physics, and they also enables semi-device-independent information processing, where security can be guaranteed with only partially characterised devices. Various types of communication restrictions have been considered, including limiting the dimension of the transmitted system, their entropy, or their energy. In this talk, I will discuss a new alternative, instead upper-bounding the one-shot accessible information. We provide a characterisation of the set of classical correlations and show that quantum correlations are stronger. We also show that limiting information rather than dimension increases the strength of quantum correlations, and we present a fully device independent test for lower-bounding the information given observed correlations. Finally, we show that when limiting the information, quantum communication is at least as strong a resource as classical communication assisted by pre-shared entanglement.