The most advanced quantum communication network yet sprawls through the city of Hefei, China. Comprising three quantum devices and a central server, it is as close to an unhackable quantum internet as we have gotten yet.
Built by Jian-Long Liu at the University of Science and Technology of China and his colleagues, the network shares some features with conventional communication networks, such as transmitting information through optical fibres. But the light travelling in the quantum network comes in chunks whose quantum states encode the information and have properties not…