Recently, the team led by Pan Jianwei from the University of Science and Technology of China used the "Mozi" quantum science experimental satellite to achieve the first principle experimental verification of quantum safe time transfer internationally, laying the foundation for building a safe and high-precision satellite navigation system in the future. This achievement was published online on May 11, 2020 in the internationally renowned academic journal Nature Physics.
Model of Mozi Quantum Communication Satellite
Time synchronization is the core technology for navigation, positioning, and other applications in daily life. The widely used time synchronization technologies at present mainly include satellite navigation and positioning system time synchronization, fiber optic network time synchronization, and other solutions. In recent years, the security of time synchronization has received widespread attention. Various network systems, such as computer networks, financial trading markets, power and energy networks, require a unified time reference. If these systems are subjected to malicious attacks, the resulting time errors can cause major security incidents such as network crashes and navigation positioning errors. However, the widely used time synchronization transmission technology currently faces potential risks of various attacks such as data tampering and signal deception.
Quantum communication technology has brought new solutions for secure time synchronization. Based on the principle of quantum unclonability, time transfer technology using single photon quantum states as carriers can fundamentally ensure the safety of signal transmission processes. The Pan Jianwei team has proposed for the first time a quantum secure time synchronization scheme based on bidirectional free space quantum key distribution technology. In this scheme, single photon quantum states serve as signal carriers for both time transfer and key distribution, performing time synchronization and key generation. The key generated during this process is used to encrypt classical time data, ensuring the secure transmission of time data.
Moreover, the Pan Jianwei team has overcome key technical challenges such as single photon time transfer between satellite and ground, high-speed bidirectional asynchronous laser time responders, and achieved technical verification of quantum safe time synchronization between satellite and ground. They have achieved a time transfer accuracy of up to 30ps, reaching the international advanced level of satellite ground laser time transfer.
The impact of this research achievement is profound, not only greatly promoting the research and application of quantum precision measurement related fields, but also laying the foundation for the construction of safe satellite navigation systems in the future. It has made significant breakthroughs in the safety and synchronization accuracy of satellite time synchronization, and is expected to be applied in time-frequency related fields in the future.