Entanglement distribution and quantum discord

TL;DR

This paper reviews the fundamental properties of entanglement and quantum discord, focusing on recent advances in entanglement distribution methods, including the role of quantum discord and the potential benefits of indirect distribution protocols.

Contribution

It provides a comprehensive review of entanglement and quantum discord, highlighting recent results and open problems in entanglement distribution, especially with separable states and indirect protocols.

Findings

Entanglement distribution can be achieved with separable states.

Quantum discord plays a significant role in entanglement distribution.

Open problems include the potential advantages of indirect over direct distribution.

Abstract

Establishing entanglement between distant parties is one of the most important problems of quantum technology, since long-distance entanglement is an essential part of such fundamental tasks as quantum cryptography or quantum teleportation. In this lecture we review basic properties of entanglement and quantum discord, and discuss recent results on entanglement distribution and the role of quantum discord therein. We also review entanglement distribution with separable states, and discuss important problems which still remain open. One such open problem is a possible advantage of indirect entanglement distribution, when compared to direct distribution protocols.