Chinese Scientists Achieve Twin-Field Quantum Key Distribution (TF-QKD) Thru 511-km Optical Fiber Linking Two Distant Areas

(Shine.cn) Chinese scientists have achieved twin-field quantum key distribution (TF-QKD) through a 511-km optical fiber linking two distant metropolitan areas, proving the technical feasibility in a practical environment and paving the way toward a long-haul fiber quantum network.
Led by Pan Jianwei from the University of Science and Technology of China, the field test was conducted through a channel between Qingdao and Jinan in east China’s Shandong Province.
Twin-field QKD is a new technology that may realize long-haul fiber QKD theoretically. The research team had already realized TF-QKD of 500 km in their lab, but human voice or other activities cannot be forbidden in a real environment, which can interfere with quantum stability. Therefore, putting the experiment to a field test is not only necessary to prove its feasibility, but also an important step for exploring the possibilities of future global QKD networks.
The work proves the feasibility of TF-QKD in a practical environment and paves the way toward long-haul fiber quantum networks. We expect that the techniques developed in this work will find immediate use in more general applications such as quantum repeaters and phase-based architecture for the quantum Internet, said the groups research paper in Nature.