Coding Theorem and Strong Converse for Quantum Channels

TL;DR

This paper provides a new proof of Holevo's coding theorem and its strong converse for quantum channels, utilizing a combinatorial approach inspired by Wolfowitz, and offers a novel proof of Holevo's information bound.

Contribution

It introduces a new combinatorial proof technique for quantum channel coding theorems, independent of previous methods, and establishes the strong converse.

Findings

New proof of Holevo's coding theorem

New proof of the strong converse for quantum channels

Alternative proof of Holevo's information bound

Abstract

In this correspondence we present a new proof of Holevo's coding theorem for transmitting classical information through quantum channels, and its strong converse. The technique is largely inspired by Wolfowitz's combinatorial approach using types of sequences. As a by-product of our approach which is independent of previous ones, both in the coding theorem and the converse, we can give a new proof of Holevo's information bound.