Quantum key distribution1, 2 (QKD) is the first commercial application in the new field of quantum information, with first routine applications in government and financial sectors3 and with successful demonstrations of trusted node networks4, 5. Today, the main goal is efficient long-range key distribution via either quantum repeaters6 or satellites7, 8, 9, with a view to enabling global secure communication. En route to achieving QKD via satellites, a free-space demonstration of secure key distribution was performed between two ground stations10, over a distance of 144 km. This scenario is comparable to links between satellites in low Earth orbit and ground stations with respect to both attenuation and fluctuations. However, key exchange with rapidly moving platforms remained to be demonstrated. Here, we prove, for the first time, the feasibility of BB84 QKD between an aeroplane and a ground station. By establishing a stable and low-noise quantum communication channel with the aeroplane moving at 290 km h−1 at a distance of 20 km—that is, 4 mrad s−1—our results are representative of typical communication links to satellites11 or to high-altitude platforms.
At a glance
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