Abstract

Title : Quantum Correlations vs. Classical Correlations MR14 , 4pm

Abstract: In this talk, we discuss equivalences and inequivalences between quantum and classical correlations.

First, we prove that secrecy can be established by sending non-secret correlations through a private channel, deriving the classical analog of the quantum scenario, that separable states can be used to distribute distillable entanglement in [PRL 91 037902 (2003)]. The derivation is based on a conceptually natural equivalence between quantum and classical operations.

Then, we characterize the cryptographic properties of quantum channels in the realistic scenario where the two honest parties employ prepare and measure protocols and the known two-way communication reconciliation techniques. We obtain a necessary and sufficient condition for key distillation, in arbitrary dimension. This may imply existence of weakly entangled states from which a secret key cannot be distilled.