Hi all,
Apologies for the late email. This afternoon Diane Saint Aubin will tell us about her semester project, entitled "Lower and upper bounds on quantum key distribution protocols". See below for the abstract. We'll start as usual at 2pm in/at https://ethz.zoom.us/j/362994444.
Best,
Joe
Abstract:
The 3-state quantum key distribution protocol has two entanglement-based descriptions, raising the question of which one is best used to compute the key rate. We show that the descriptions are equivalent, and that symmetrising the state used in the protocol can give a lower bound on the secret key rate. In addition, we provide an upper bound for the BB84 protocol using the intrinsic information which just outperforms a recent bound by Xing Wang. For the device independent protocol based on the CHSH game, thresholds on the key rate are found depending on the observed parameters. We find an upper bound for protocols using one way-classical communication, which is much tighter than the previous two-way classical communication bound for low values of the Bell violation.