Quantum networks boosted by entanglement with a control system

TL;DR

This paper demonstrates that quantum correlations between data and control in quantum networks enable secure communication and entanglement distribution tasks that are impossible without prior entanglement, highlighting the advantages of quantum control.

Contribution

It reveals the power of quantum correlations in network control, showing new communication protocols enabled by entanglement with a controller.

Findings

Quantum correlations enable secure classical communication.

Entanglement with a controller allows establishing multipartite entanglement.

Prior entanglement is necessary for certain information processing tasks.

Abstract

Networks of quantum devices with coherent control over their configuration offer promising advantages in quantum information processing. So far, the investigation of these advantages assumed that the control system was initially uncorrelated with the data processed by the network. Here, we explore the power of quantum correlations between data and control, showing two communication tasks that can be accomplished with information-erasing channels if and only if the sender shares prior entanglement with a third party (the ``controller'') controlling the network configuration. The first task is to transmit classical messages without leaking information to the controller. The second task is to establish bipartite entanglement with a receiver, or, more generally, to establish multipartite entanglement with a number of spatially separated receivers.