A joint China-Austria team has performed quantum key distribution between the quantum-science satellite Micius and multiple ground stations located in Xinglong, Nanshan, and Graz.
Such experiments demonstrate the secure satellite-to-ground exchange of cryptographic keys during the passage of the satellite Micius over a ground station. In contrast, quantum key distribution uses individual light quanta in quantum superposition states to guarantee unconditional security between distant parties.
“A cross-disciplinary multi-institutional team of scientists from the Chinese Academy of Sciences, led by Professor Jian-Wei Pan, has spent more than 10 years developing a sophisticated satellite, Micius, dedicated to quantum science experiments, which was launched on August 2016 and orbits at an altitude of ~500 km.
Within a year after launch, three key milestones for a global-scale quantum internet were achieved: satellite-to-ground decoy-state QKD with kHz rate over a distance of ~1200 km; satellite-based entanglement distribution to two locations on the Earth separated by ~1200 km and Bell test, and ground-to-satellite quantum teleportation.
To further demonstrate the Micius satellite as a robust platform for quantum key distribution with different ground stations on Earth, QKD from the Micius satellite to Garz ground station near Vienna has also been performed successfully this June in collaboration with Professor Anton Zeilinger of Austrian Academy of Sciences.
A picture of Micius was transmitted from Beijing to Vienna, and a picture of Schrödinger from Vienna to Beijing, using approximately 80 kbit secure quantum key for one-time-pad encoding.