Optimal trading of classical communication, quantum communication, and entanglement

We provide a solution for the most general setting of information processing in the quantum Shannon-theoretic sense by giving optimal trade-offs between classical communication, quantum communication, and entanglement. We begin by showing that a combination of teleportation, superdense coding, and entanglement distribution is the optimal strategy for transmission of information when only the three noiseless resources of classical communication, quantum communication, and entanglement are available. Next, we provide a solution for the scenario where a large number of copies of a noisy bipartite state are available (in addition to consumption or generation of the above three noiseless resources). The coding strategy is an extension of previous techniques in the quantum Shannon-theoretic literature. We finally provide a solution to the scenario where a large number of uses of a noisy quantum channel are available in addition to the consumption or generation of the three noiseless resources. The coding strategy here is the classically-enhanced father protocol, a protocol which we discussed in a previous paper. Our results are of a multi-letter nature, meaning that there might be room for improvement in the coding strategies presented here. © 2009 Springer-Verlag