Remote Entanglement between a Single Atom and a Bose-Einstein Condensate

TL;DR

This paper demonstrates the experimental creation of remote entanglement between a single atom and a Bose-Einstein condensate, showcasing a significant step towards quantum networks with high fidelity and long-lived entanglement.

Contribution

It reports the first experimental generation of matter-matter entanglement between a single atom and a BEC via photon mediation, with high fidelity and extended entanglement lifetime.

Findings

Matter-matter entanglement lifetime of 100 microseconds

Total operation fidelity of 95%

Conversion of atom-photon to photon-photon entanglement

Abstract

Entanglement between stationary systems at remote locations is a key resource for quantum networks. We report on the experimental generation of remote entanglement between a single atom inside an optical cavity and a Bose-Einstein condensate (BEC). To produce this, a single photon is created in the atom-cavity system, thereby generating atom-photon entanglement. The photon is transported to the BEC and converted into a collective excitation in the BEC, thus establishing matter-matter entanglement. After a variable delay, this entanglement is converted into photon-photon entanglement. The matter-matter entanglement lifetime of 100 $\mu$s exceeds the photon duration by two orders of magnitude. The total fidelity of all concatenated operations is 95%. This hybrid system opens up promising perspectives in the field of quantum information.