Submission + - China's Experiment Clears Major Hurdle in Ultrasecure Quantum Communication (nature.com)
hackingbear writes: China’s Quantum Experiments at Space Scale (QUESS) mission, also known as Micius after an ancient Chinese philosopher who performed the world's first light splitting experiment, successfully sends entangled photons — which could underpin quantum-based data encryption — over 1,200km between ground station at Delingha, on the northern Tibetan Plateau, and Gaomeigu Observatory in Lijiang, Yunnan province. The researchers had a window of less than 5 minutes each night when the satellite, which orbits at an altitude of about 500 kilometres, was in view of both observatories. Within weeks of launch, they were able to transmit a pair of entangled photons per second — a rate ten times faster than they had hoped. They want to launch a second, improved, quantum satellite in two years. Similar missions in the planning stages — such as Canada’s Quantum Encryption and Science Satellite (QEYSSat) — use a simpler approach, creating the entangled photons on Earth and beaming them to a satellite. Thomas Jennewein, who is at the University of Waterloo in Canada and part of the Candanian mission, says that his group and others around the world are now racing to catch up with the Chinese effort. “They are now clearly the world leader in quantum satellites,” he says.