Simulation of Gaussian channels via teleportation with applications to error correction and secret-key capacities.

Gaussian channels are the typical way to model the decoherence in continuous-variable quantum states. It is known that those channels can be simulated by a teleportation protocol using as a resource state either a maximally entangled state passing through the same channel, i.e., the Choi-state, or a state that is entangled at least as much as the Choi-state. Since the construction of the Choi-state requires infinite mean energy and entanglement, i.e. it is unphysical, we derive instead every physical state able to simulate a given channel through teleportation with finite resources. Finally, we use those states to generalize a previously known error correction protocol by making it able to correct noise coming from thermal loss channels, and we also show how finite-energy resource states are able to provide tight upper bounds to the secret-key capacity of Gaussian channels.

arXiv.1803.03516 (Accepted - PRA)
arXiv.1808.00608 (Under Review - PRA)