A Robust Atom-Photon Entanglement Source for Quantum Repeaters

TL;DR

This paper presents a robust and efficient method for creating atom-photon entanglement using a single laser beam and spatial modes, demonstrating long storage times and potential for quantum repeaters.

Contribution

A novel entanglement generation technique utilizing a single laser beam and spatial modes, with demonstrated long storage and applicability to quantum repeaters.

Findings

Entanglement persists after 20.5 μs storage time.

Violation of Bell's inequality confirms entanglement.

Method is extendable to high-dimensional entanglements.

Abstract

We demonstrate a novel way to efficiently and very robust create an entanglement between an atomic and a photonic qubit. A single laser beam is used to excite one atomic ensemble and two different spatial modes of scattered Raman fields are collected to generate the atom-photon entanglement. With the help of build-in quantum memory, the entanglement still exists after 20.5 $\mu$s storage time which is further proved by the violation of CHSH type Bell's inequality. Our entanglement procedure is the building block for a novel robust quantum repeater architecture [Zhao et al, Phys. Rev. Lett. 98, 240502 (2007)]. Our approach can be easily extended to generate high dimensional atom-photon entanglements.