Long-Distance Free-Space Twin-Field Quantum Key Distribution towards Satellite-based Quantum Network

Authors

• M. Wang

Abstract

Twin-field quantum key distribution (TF-QKD) offers inherent immunity to all measurement-device attacks and scales the secure key rate from a linear to a square-root dependence on channel loss. It is essential to implement TF-QKD in the future global-scale quantum communication network. Toward this goal, we investigate the feasibility of implementing single-photon interference and TF-QKD with moving satellites, carefully considering the influence of orbital-induced Doppler shift. We report an experimental demonstration of TF-QKD over a 14.2 km atmospheric channel, featuring physical emulation and active compensation of the Doppler shift. The achieved secure key rate surpasses the repeaterless capacity bound, marking a pivotal advance toward deploying satellite-based quantum networks.