Source Compression with a Quantum Helper

TL;DR

This paper investigates classical source coding with quantum side-information, revealing that measurement compression is essential for optimal rates, and provides a single-letter characterization of the achievable rate region.

Contribution

It introduces a single-letter characterization of the rate region for source coding with a quantum helper, emphasizing the importance of measurement compression over separate measurement and compression schemes.

Findings

Measurement compression is necessary for optimal rate region.

Separate measurement and compression schemes are suboptimal.

Derived a single-letter characterization of the achievable rate region.

Abstract

We study classical source coding with quantum side-information where the quantum side-information is observed by a helper and sent to the decoder via a classical channel. We derive a single-letter characterization of the achievable rate region for this problem. The direct part of our result is proved via the measurement compression theory by Winter. Our result reveals that a helper's scheme that separately conducts a measurement and a compression is suboptimal, and the measurement compression is fundamentally needed to achieve the optimal rate region.