Optimal super dense coding over memory channels

TL;DR

This paper explores the limits of super dense coding capacity when using quantum channels with correlated noise, analyzing both unitary and non-unitary encoding methods, and providing explicit results for Pauli channels.

Contribution

It introduces a comprehensive analysis of super dense coding over memory channels, including explicit capacity formulas and the impact of non-unitary encoding.

Findings

Non-unitary encoding can improve capacity in certain memory channels.

Explicit capacity formulas derived for Pauli channels.

Example demonstrating capacity enhancement with non-unitary encoding.

Abstract

We study the super dense coding capacity in the presence of quantum channels with correlated noise. We investigate both the cases of unitary and non-unitary encoding. Pauli channels for arbitrary dimensions are treated explicitly. The super dense coding capacity for some special channels and resource states is derived for unitary encoding. We also provide an example of a memory channel where non-unitary encoding leads to an improvement in the super dense coding capacity.