Detection of genuine tripartite entanglement by multiple sequential observers

TL;DR

This paper explores whether multiple sequential observers can detect genuine tripartite entanglement from a single shared entangled state, using correlation inequalities and witness operators, demonstrating the possibility of multiple detections.

Contribution

It introduces a method to allow multiple independent observers to sequentially detect genuine tripartite entanglement from one shared state, expanding the understanding of entanglement sharing.

Findings

More than one Charlie can detect genuine tripartite entanglement.

Correlation inequalities can certify genuine tripartite entanglement in a device-independent manner.

Maximum number of Charlies able to detect entanglement is determined.

Abstract

Due to the difficulties present in experimentally preparing genuine tripartite entanglement, it is important to explore the possibility of multiple usage of a single genuine entangled state. In the present paper, we present one such possibility by considering a scenario consisting of three spin-$\frac{1}{2}$ particles shared between Alice, Bob and multiple Charlies. Alice performs measurements on the first particle, Bob performs measurements on the second particle and multiple Charlies perform measurements on the third particle sequentially and independently. In this scenario, we investigate whether more than one Charlie can detect genuine tripartite entanglement, and we answer this question affirmatively. In order to probe genuine entanglement, we use correlation inequalities whose violations certify genuine tripartite entanglement in a device-independent way. We extend our investigation by using appropriate genuine tripartite entanglement witness operators. Using each of these different tools for detecting genuine tripartite entanglement, we find out the maximum number of Charlies who can detect genuine entanglement in the above scenario.