Environment-assisted bosonic quantum communications

We consider a quantum relay which is used by two parties to perform several continuous-variable protocols of communication, from entanglement distribution (swapping and distillation), teleportation, key distribution. The theory these suitably extended non-Markovian model decoherence characterized correlated Gaussian noise in the bosonic environment. In worst case scenario where bipartite completely lost at relay, we show that various can be reactivated assistance classical (separable) correlations fact, above critical amount, are able guarantee weaker form (quadripartite), localized into stronger (bipartite) exploitable parties. Our findings confirmed proof-of-principle experiment show, for first time, memory effects environment drastically enhance performance well beyond single-repeater bound private communications.