Systematics of Entanglement Distribution by Separable States

TL;DR

This paper demonstrates a method for sharing multipartite entangled states, like GHZ and Bell states, between distant labs using only separable mediating particles, with potential applications in quantum networks.

Contribution

It introduces a constructive protocol for entanglement distribution via separable states, generalizable to any number of parties and dimensions.

Findings

GHZ states shared with probability 1/7

Method extends to arbitrary dimensions and parties

Facilitates multi-node quantum network construction

Abstract

Three distant labs A, B and C, having no prior entanglement can establish a shared GHZ state, when one of them say A sends two particles to B and C for their local actions. The mediating particles remain separable from each other and from the particles of A, B and C. We prove that in this way, GHZ states are shared with a probability $\frac{1}{7}$. We also show how separable particles can be mediated to establish arbitrary $d-$ dimensional Bell states between distant labs. Our method is constructive and allows generaization of GHZ sharing between any number of parties and in any dimension. The proposed method may facilitate the construction of multi-node quantum networks and many other processes which use multi-partite entangled states.