Operational interpretations of quantum discord

TL;DR

This paper provides the first operational interpretation of quantum discord, linking it to entanglement consumption in quantum state merging and relating its asymmetry to performance in quantum protocols.

Contribution

It introduces an operational meaning of quantum discord through entanglement costs and connects its asymmetry to protocol performance, advancing understanding of quantum correlations.

Findings

Quantum discord is interpreted via entanglement consumption.

Asymmetry of quantum discord relates to performance imbalance.

Provides new insights into quantum correlations beyond entanglement.

Abstract

Quantum discord quantifies non-classical correlations going beyond the standard classification of quantum states into entangled and unentangled ones. Although it has received considerable attention, it still lacks any precise interpretation in terms of some protocol in which quantum features are relevant. Here we give quantum discord its first operational meaning in terms of entanglement consumption in an extended quantum state merging protocol. We further relate the asymmetry of quantum discord with the performance imbalance in quantum state merging and dense coding.