Entangling three qubits without ever touching

TL;DR

This paper demonstrates how to generate tripartite entangled states like GHZ and W without particles physically interacting, using the inherent correlations of identical particles in linear optical setups, applicable to bosons, fermions, or anyons.

Contribution

It introduces operational schemes for creating entanglement among three particles without contact, leveraging indistinguishability as a resource in linear optical systems.

Findings

Successful protocols for GHZ and W state generation without particle contact

Equal efficiency across bosons, fermions, and anyons

Indistinguishability as a practical entanglement resource

Abstract

All identical particles are inherently correlated from the outset, regardless of how far apart their creation took place. In this paper, this fact is used for extraction of entanglement from independent particles unaffected by any interactions. Specifically, we are concerned with operational schemes for generation of all tripartite entangled states, essentially the GHZ state and the W state, which prevent the particles from touching one another over the entire evolution. The protocols discussed in the paper require only three particles in linear optical setups with equal efficiency for boson, fermion or anyon statistics. Within this framework indistinguishability of particles presents itself as a useful resource of entanglement accessible for practical applications.