Distributed quantum dense coding with two receivers in noisy environments

TL;DR

This paper explores how noise affects the capacity of distributed quantum dense coding with multiple senders and two receivers, establishing bounds and relations to multipartite entanglement.

Contribution

It provides bounds on the multipartite capacity in noisy environments and links genuine multipartite entanglement to dense coding capacity in such settings.

Findings

Upper bound on multipartite capacity in noisy channels

Covariant noisy channels tighten capacity bounds

GHZ states outperform many pure states in dense coding capacity

Abstract

We investigate the effect of noisy channels in a classical information transfer through a multipartite state which acts as a substrate for the distributed quantum dense coding protocol between several senders and two receivers. The situation is qualitatively different from the case with one or more senders and a single receiver. We obtain an upper bound on the multipartite capacity which is tightened in case of the covariant noisy channel. We also establish a relation between the genuine multipartite entanglement of the shared state and the capacity of distributed dense coding using that state, both in the noiseless and the noisy scenarios. Specifically, we find that in the case of multiple senders and two receivers, the corresponding generalized Greenberger-Horne-Zeilinger states possess higher dense coding capacities as compared to a significant fraction of pure states having the same multipartite entanglement.