Universal coding for classical-quantum channel

TL;DR

This paper develops a universal coding scheme for stationary, memoryless classical-quantum channels, adapting classical universal coding techniques to the quantum setting using representation theory and quantum information spectrum methods.

Contribution

It introduces a novel quantum universal coding construction that combines irreducible representations, quantum information spectrum decoding, and packing lemma techniques.

Findings

Achieves universal coding for classical-quantum channels

Uses quantum information spectrum for decoding

Employs representation theory and packing lemma

Abstract

We construct a universal code for stationary and memoryless classical-quantum channel as a quantum version of the universal coding by Csisz\'{a}r and K\"{o}rner. Our code is constructed by the combination of irreducible representation, the decoder introduced through quantum information spectrum, and the packing lemma.