BEIJING, Aug. 10 (Xinhua) — Chinese scientists have become the first to realize quantum key distribution from a satellite to the ground, laying the foundation for building a hack-proof global quantum communication network.
The achievement based on experiments conducted with the world’ s first quantum satellite, Quantum Experiments at Space Scale (QUESS), was published in the authoritative academic journal Nature on Thursday.
The Nature reviewers commented that the experiment was an impressive achievement, and constituted a milestone in the field.
Nicknamed “Micius,” after a 5th Century B.C. Chinese philosopher and scientist who has been credited as the first person ever to conduct optical experiments, the 600-kilogram-plus satellite was sent into a sun-synchronous orbit at an altitude of 500 kilometers on Aug. 16, 2016.
Pan Jianwei, lead scientist of QUESS and an academician of the Chinese Academy of Sciences (CAS), said the satellite sent quantum keys to ground stations in Xinglong, in north China’s Hebei Province, and Nanshan, near Urumqi, capital of northwest China’s Xinjiang Uygur Autonomous Region.
The communication distance between the satellite and the ground station varies from 645 kilometers to 1,200 kilometers, and the quantum key transmission rate from satellite to ground is up to 20 orders of magnitude more efficient than that expected using an optical fiber of the same length, said Pan.
When the satellite flies over China, it provides an experiment window of about 10 minutes. During that time, the 300 kbit secure key can be generated and sent by the satellite, according to Pan.
“That, for instance, can meet the demand of making an absolute safe phone call or transmitting a large amount of bank data,” Pan said.
“Satellite-based quantum key distribution can be linked to metropolitan quantum networks where fibers are sufficient and convenient to connect numerous users within a city over 100 km. We can thus envision a space-ground integrated quantum network, enabling quantum cryptography- most likely the first commercial application of quantum information- useful at a global scale,” Pan said.
The establishment of a reliable and efficient space-to-ground link for faithful quantum state transmission paves the way to global-scale quantum networks, he added.
By harnessing quantum entanglement, the quantum key technology is used in quantum communications, ruling out the possibility of wiretapping and perfectly securing the communication.
BREAKING LIMITS IN SPACE
Scientists expect quantum communications to fundamentally change human development in the next two or three decades, as there are enormous prospects for applying the new generation of communication in fields like defense, military and finance.
CHINA’S QUANTUM LEAP
Karl Ziemelis, chief physical sciences editor at Nature, said that with the publication of these new papers, Pan and his colleagues have completed their demonstration of a trio of quantum experiments that will be central to any global space-based quantum Internet.
“I mean you could say that the sky’s the limit for quantum technologies, but that is a little bit conservative actually. They’ve gone beyond the sky with these latest experiments. And it’s a testament to China’s investments and significant efforts in the physical sciences that this group has been able to push research in practical quantum communication technologies to such an astronomical height,” said Ziemelis.
CAS president Bai Chunli said the achievements show China has reached a leading position in the field of quantum communication research.
“Micius has ushered in the construction of global quantum communication, the study of space quantum physics and experimental verification of quantum gravity theories. It helps China’s race to control the command point of quantum science and technology, and enables China to become a leader in the field,” Bai said.
Full article: China Focus: China’s satellite sends unbreakable cipher from space (XinhuaNet)