Detection of Genuine Multipartite Entanglement in Quantum Network Scenario

TL;DR

This paper proposes a protocol to detect genuine tripartite entanglement in quantum networks in a device-independent way, even when standard methods fail, by leveraging entanglement swapping.

Contribution

It introduces a novel protocol that enhances detection of genuine tripartite entanglement in mixed states using entanglement swapping within a device-independent framework.

Findings

Standard DIEWs fail to detect entanglement in certain mixed states.

Entanglement swapping enables detection of entanglement in these states.

Protocol improves robustness of entanglement detection in quantum networks.

Abstract

Experimental demonstration of entanglement needs to have a precise control of experimentalist over the system on which the measurements are performed as prescribed by an appropriate entanglement witness. To avoid such trust problem, recently device-independent entanglement witnesses (\emph{DIEW}s) for genuine tripartite entanglement have been proposed where witnesses are capable of testing genuine entanglement without precise description of Hilbert space dimension and measured operators i.e apparatus are treated as black boxes. Here we design a protocol for enhancing the possibility of identifying genuine tripartite entanglement in a device independent manner. We consider three mixed tripartite quantum states none of whose genuine entanglement can be detected by applying standard \emph{DIEW}s, but their genuine tripartite entanglement can be detected by applying the same when distributed in some suitable entanglement swapping network.