Chinese scientists use Mozi quantum science experimental satellite for safe time transfer

Pan Jianwei of China University of Science and Technology and his colleagues Peng Chengzhi and Xu Feihu used the “Mozi” quantum science experimental satellite to realize the original rational experimental verification of quantum safe time transmission for the first time in the world, laying the foundation for the construction of a safe satellite navigation system for the future. The results were published online May 11, 2020 in Nature Physics, an international academic journal.

Original title: Chinese scientists use moko quantum science experimental satellite to achieve safe time transfer

Chinese scientists use Mozi quantum science experimental satellite for safe time transfer

Illustration of the experimental device

High-precision time transfer is the core technology of navigation, positioning and other applications in daily life. The time transmission technology widely used at this stage mainly includes the time transmission of satellite navigation and positioning system, the time transmission of optical fiber network and so on. In recent years, the security of time transfer has been widely concerned. Various network systems, such as computer networks, financial transactions markets, power and energy networks, all require uniform time benchmarks. If these systems are subjected to malicious attacks, time errors can cause major security incidents such as network crashes, navigation and positioning errors, and major security incidents. However, the current widely used time-transmission technology is exposed to the potential risk of various attacks, such as data tampering and signal spoofing.

Quantum communication technology brings new solutions for safe time transfer. Based on the principle of quantum non-clonability, the time transmission technology with single photon quantum state as the carrier can fundamentally guarantee the safety of the signal transmission process. For the first time, Pan Jianwei’s team proposed a quantum security time synchronization scheme based on two-way free space quantum key distribution technology. In this scheme, the single-photon quantum state acts as a signal carrier for time transmission and key distribution at the same time, and performs time synchronization and key generation. The key generated by this process is used to encrypt classic time data, ensuring the secure transfer of time data.

Based on the quantum science experimental satellite of “Mozi”, Pan Jianwei’s team broke through key technologies such as star-earth single photon time transfer and high-rate two-way asynchronous laser time transponder, realized the technical verification of the simultaneous time synchronization of the star-earth quantum security, and obtained the 30ps accuracy of the star-earth time transfer, which reached the international advanced level of star-earth laser time transfer. The work has been highly praised by reviewers, “the experiment in the field of space quantum experiments once again beyond the existing technical level”, which is essential for the practicalization of quantum technology, “the above results will greatly promote the research and application of quantum precision measurement related fields.” (Li Yi, CCTV reporter at The Station)