Excessive distribution of quantum entanglement

TL;DR

This paper classifies entanglement distribution protocols, identifying excessive ones that surpass traditional bounds, demonstrating their effectiveness especially in noisy environments where they can be the only means to increase entanglement.

Contribution

It introduces the concept of excessive entanglement distribution protocols and provides examples and analysis of their advantages in noisy quantum communication scenarios.

Findings

Excessive protocols can significantly increase entanglement beyond traditional bounds.

In noisy environments, excessive protocols outperform non-excessive ones.

Some scenarios rely solely on excessive protocols for entanglement gain.

Abstract

We classify protocols of entanglement distribution as excessive and non-excessive ones. In a non-excessive protocol, the gain of entanglement is bounded by the amount of entanglement being communicated between the remote parties, while excessive protocols violate such bound. We first present examples of excessive protocols that achieve a significant entanglement gain. Next we consider their use in noisy scenarios, showing that they improve entanglement achieved in other ways and for some situations excessive distribution is the only possibility of gaining entanglement.