Gaussian quantum channels

TL;DR

This paper introduces Gaussian quantum channels, reviewing their capacities and related entropic properties, and extends some known results, including the maximization of quantum conditional entropy by Gaussian states.

Contribution

It provides an elementary overview of Gaussian channels and extends results on quantum conditional entropy maximization and additivity issues within this framework.

Findings

Quantum conditional entropy is maximized by Gaussian states.

Extensions of additivity results to Gaussian channels.

Review of capacities and entropic quantities for Gaussian channels.

Abstract

This article provides an elementary introduction to Gaussian channels and their capacities. We review results on the classical, quantum, and entanglement assisted capacities and discuss related entropic quantities as well as additivity issues. Some of the known results are extended. In particular, it is shown that the quantum conditional entropy is maximized by Gaussian states and that some implications for additivity problems can be extended to the Gaussian setting.