City-wide quantum data network in China is the largest ever built

By Matthew Sparkes

A city-wide quantum communications network in Hefei, China, that has been running for almost three years is the largest demonstration to date of how a future quantum internet might work.

The network, created by Teng-Yun Chen at the University of Science and Technology of China (USTC) and his colleagues, uses commercial fibre optics hardware to connect 40 computers at government buildings, banks and universities that are clustered into three subnetworks, each separated by around 15 kilometres.

In a traditional computer …