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

• DOI: 10.1364/opticaq.517495
• Publication Date: 2024-04-10T12:00:13Z
• Authors: Mustafa Gündoǧan; Jasminder S. Sidhu; Markus Krutzik; Daniel K. L. Oi
• Keywords: Repeater (horology); Communications satellite

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