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Time-delayed single satellite quantum repeater node for global quantum communications

M. Gündoğan1, J.S. Sidhu2, M. Krutzik1,3, and D.K.L. Oi2,4

Published in:

Optica Quantum, vol. 2, no 3, pp. 140-147, doi:10.1364/OPTICAQ.517495 (2024).


Global-scale quantum networking faces significant technical and scientific obstacles. Quantum repeaters (QRs) have been proposed to overcome the inherent direct transmission range limit through optical fiber. However, QRs are typically limited to a total distance of a few thousand kilometers and/or require extensive hardware overhead. Recent proposals suggest that strings of space-borne QRs with on-board quantum memories (QMs) are able to provide global coverage. Here, we propose an alternative to such repeater constellations using a single satellite with two QMs that effectively acts as a time-delayed version of a single QR node. By physically transporting stored qubits, our protocol improves long-distance entanglement distribution with reduced system complexity over previous proposals. We estimate the amount of secure key in the finite block regime and demonstrate an improvement of at least three orders of magnitude over prior single-satellite methods that rely on a single QM, while simultaneously reducing the necessary memory capacity similarly. We propose an experimental platform to realize this scheme based on rare-earth ion doped crystals with appropriate performance parameters. By exploiting recent advances in quantum memory lifetimes, we are able to significantly reduce system complexity while achieving high key rates, bringing global quantum networking closer to implementation.

1 Institut für Physik and IRIS Adlershof Humboldt-Universität zu Berlin, Newtonstr. 15, Berlin 12489, Germany
2 SUPA Department of Physics, University of Strathclyde, John Anderson Building, 107 Rottenrow East, Glasgow, G4 0NG, UK
3 Ferdinand-Braun-Institut (FBH), Gustav-Kirchoff-Str. 4, Berlin 12489, Germany
4 Walton Institute for Information and Communication Systems Science, South East Technological University, Waterford, X91 P20H, Ireland

Related Topics:

Entanglement distribution, Photonic entanglement, Quantum communications, Quantum technology, Wavelength division multiplexing

Published by Optica Publishing Group under the terms of the Creative Commons Attribution 4.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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