Detection of entanglement in asymmetric quantum networks and multipartite quantum steering

TL;DR

This paper introduces a method for certifying multipartite entanglement in asymmetric quantum networks, demonstrating its effectiveness experimentally and establishing a foundation for semi-device-independent quantum cryptography.

Contribution

It presents a novel approach to certify all types of multipartite entanglement in asymmetric scenarios, bridging standard and device-independent frameworks.

Findings

Successfully demonstrated entanglement certification experimentally

Defined a new concept of genuine multipartite quantum steering

Provided a basis for semi-device-independent cryptography in quantum networks

Abstract

The future of quantum communication relies on quantum networks composed by observers sharing multipartite quantum states. The certification of multipartite entanglement will be crucial to the usefulness of these networks. In many real situations it is natural to assume that some observers are more trusted than others in the sense that they have more knowledge of their measurement apparatuses. Here we propose a general method to certify all kinds of multipartite entanglement in this asymmetric scenario and experimentally demonstrate it in an optical experiment. Our results, which can be seen as a definition of genuine multipartite quantum steering, give a method to detect entanglement in a scenario in between the standard entanglement and fully device-independent scenarios, and provide a basis for semi-device-independent cryptographic applications in quantum networks.