An efficient quantum light-matter interface with sub-second lifetime

TL;DR

This paper demonstrates an efficient quantum light-matter interface with a sub-second lifetime, enabling long-distance quantum communication and advancing the development of quantum repeaters.

Contribution

It introduces a novel light-matter interface with high efficiency and long storage time using laser-cooled atoms in a 3D optical lattice and a ring cavity.

Findings

Achieved 76% initial retrieval efficiency.

Realized a 0.22 s 1/e lifetime.

Supported sub-Hz entanglement distribution over 1000 km.

Abstract

Quantum repeater holds the promise for scalable long-distance quantum communication. Towards a first quantum repeater based on memory-photon entanglement, significant progresses have made in improving performances of the building blocks. Further development is hindered by the difficulty of integrating key capabilities such as long storage time and high memory efficiency into a single system. Here we report an efficient light-matter interface with sub-second lifetime by confining laser-cooled atoms with 3D optical lattice and enhancing the atom-photon coupling with a ring cavity. An initial retrieval efficiency of 76(5)% together with an 1/e lifetime of 0.22(1) s have been achieved simultaneously, which already support sub-Hz entanglement distribution up to 1000 km through quantum repeater. Together with an efficient telecom interface and moderate multiplexing, our result may enable a first quantum repeater system that beats direct transmission in the near future.