Quantum discord as a resource in quantum communication

TL;DR

This paper explores quantum discord as a resource in quantum communication, linking it to protocol performance under noise and highlighting its role alongside entanglement in practical quantum technologies.

Contribution

It establishes a quantitative relation between quantum discord and the efficiency of noisy quantum communication protocols, advancing understanding of quantum resources in realistic settings.

Findings

Quantum discord quantifies the advantage of quantum coherence in noisy communication.

Quantum discord relates to the performance of the fully quantum Slepian-Wolf protocol under noise.

Discussions on the role of quantum discord in teleportation, super-dense coding, and entanglement distillation.

Abstract

As quantum technologies move from the issues of principle to those of practice, it is important to understand the limitations on attaining tangible quantum advantages. In the realm of quantum communication, quantum discord captures the damaging effects of a decoherent environment. This is a consequence of quantum discord quantifying the advantage of quantum coherence in quantum communication. This establishes quantum discord as a resource for quantum communication processes. We discuss this progress, which derives a quantitative relation between the yield of the fully quantum Slepian-Wolf protocol in the presence of noise and the quantum discord of the state involved. The significance of quantum discord in noisy versions of teleportation, super-dense coding, entanglement distillation and quantum state merging are discussed. These results lead to open questions regarding the tradeoff between quantum entanglement and discord in choosing the optimal quantum states for attaining palpable quantum advantages in noisy quantum protocols.