Chinese scientists have created a secure quantum link between the two cities, which are 511 km apart.
At the heart of quantum networks is such a physical phenomenon as quantum entanglement. As part of the experiments already carried out, Chinese scientists created pairs of entangled photons, and then fed one of them to the receiver, creating an encrypted line with a stable quantum key. Until now, the length of such lines has been limited, but Qiang Zhang of the University of Science and Technology of China and his colleagues figured out how to bypass the limitation using a repeater.
At the heart of quantum networks, there is such a physical phenomenon as quantum entanglement. In their experiments, Chinese scientists created pairs of entangled photons, and then fed one of them into the receiver. Thus, they created an encrypted line with a strong quantum key.
It is worth noting that recently the length of such lines was severely limited in length. Scientists from the University of Science and Technology of China have come up with a way to get around the limitation using a repeater.
Lasers from different sides of the fiber generate photons that rush towards each other and meet in the middle concentrator. The system registers this and alerts the sender and receiver of the data.
Thanks to the repeater, the line allows the exchange of quantum keys for secure data transmission. The authors of the work are confident that their experimental quantum data transmission line with a repeater will help in creating new safe and effective communications. In addition, they note that their work will not “go to the table”, but will become commercially successful.