Einstein-Podolsky-Rosen Entanglement of Narrowband Photons from Cold Atoms

TL;DR

This paper reports the first experimental demonstration of EPR position-momentum entanglement of narrowband photon pairs generated from cold atoms, confirmed through ghost imaging and interference, with potential applications in quantum information processing.

Contribution

First experimental demonstration of EPR entanglement in narrowband photons from cold atoms using ghost imaging and interference techniques.

Findings

Narrowband photon pairs violate separability criterion.

Explicit confirmation of EPR entanglement through ghost imaging.

Demonstration of continuous variable EPR steering.

Abstract

Einstein-Podolsky-Rosen (EPR) entanglement introduced in 1935 deals with two particles that are entangled in their positions and momenta. Here we report the first experimental demonstration of EPR position-momentum entanglement of narrowband photon pairs generated from cold atoms. By using two-photon quantum ghost imaging and ghost interference, we demonstrate explicitly that the narrowband photon pairs violate the separability criterion, confirming EPR entanglement. We further demonstrate continuous variable EPR steering for positions and momenta of the two photons. Our new source of EPR-entangled narrowband photons is expected to play an essential role in spatially-multiplexed quantum information processing, such as, storage of quantum correlated images, quantum interface involving hyper-entangled photons, etc.