Talk by Riccardo Laurenza on Tue 11 July

Riccardo Laurenza, from the University of York, is giving a talk on Tue 11 July 2017, 2.30 PM, QO room at LITA 5th floor

Teleportation stretching and its finite-resource version for continuous-variable systems

We first discuss how adaptive protocols for quantum and private communication over quantum channels can be simplified into a much simpler block version. This reduction procedure, dubbed teleportation stretching, stems from the combination of two main ingredients. The first one is given by the simulation of quantum channels by means of local operations, classical communication and suitable resource states, while the second ingredient is represented by the relative entropy of entanglement.  With these tools we are able to derive weak converse upper bounds for the secret-key capacity of a wide class of either qubit and bosonic channels. We then consider the finite-energy simulation of Gaussian channels recently introduced by [Liuzzo-Scorpo et al., arXiv:1705.03017] providing weak converse upper bounds for the secret-key capacity of phase-insensitive Gaussian channel, which closely approximate the optimal limit for infinite energy.