Robust quantum repeater with atomic ensembles and single-photon sources

TL;DR

This paper introduces a robust quantum repeater protocol utilizing atomic ensembles, linear optics, and single-photon sources to achieve high-fidelity entanglement distribution over long distances more efficiently than previous methods.

Contribution

It proposes a new quantum repeater scheme that is robust against phase fluctuations and significantly faster at establishing entanglement over 1280 km compared to prior protocols.

Findings

Achieves higher fidelity entanglement over 1280 km

Speeds up quantum communication by about 2 orders of magnitude

Robust against phase fluctuations in quantum channels

Abstract

We present a quantum repeater protocol using atomic ensembles, linear optics and single-photon sources. Two local 'polarization' entangled states of atomic ensembles $u$ and $d$ are generated by absorbing a single photon emitted by an on-demand single-photon sources, based on which high-fidelity local entanglement between four ensembles can be established efficiently through Bell-state measurement. Entanglement in basic links and entanglement connection between links are carried out by the use of two-photon interference. In addition to being robust against phase fluctuations in the quantum channels, this scheme may speed up quantum communication with higher fidelity by about 2 orders of magnitude for 1280 km compared with the partial read (PR) protocol (Sangouard {\it et al.}, Phys. Rev. A {\bf77}, 062301 (2008)) which may generate entanglement most quickly among the previous schemes with the same ingredients.