Einstein-Podolsky-Rosen Entanglement between Separated Atomic Ensembles

TL;DR

This paper demonstrates the successful creation of EPR entanglement in position and momentum between two separated atomic ensembles using quantum storage, advancing quantum communication and fundamental physics research.

Contribution

It is the first to establish true position-momentum EPR entanglement between separated atomic ensembles through quantum storage techniques.

Findings

EPR entanglement in position and momentum was experimentally demonstrated.

Inseparability criterion was satisfied confirming entanglement.

Quantum ghost-imaging and ghost-interference experiments validated the results.

Abstract

The Einstein-Podolsky-Rosen (EPR) entanglement is of special importance not only for fundamental research in quantum mechanics, but also for quantum information processing. Establishing EPR entanglement between two memory systems, such as atomic ensembles, nitrogen-vacancy centers, and rare-earth-ion-doped solids is promising for realizing spatial-multimode based quantum communication, quantum computation, and quantum imaging. To date, there have been few reports on realizing EPR entanglement between physical systems in true position and momentum. Here we describe successfully establishing such entanglement between two separated atomic ensembles by using quantum storage. We clearly prove the existence of EPR entanglement in position and momentum between two memories by demonstrating the satisfying of the inseparability criterion with the aid of quantum ghost-imaging and ghost-interference experiments.