Source: People’s Daily
Beijing, April 13 (Reporter Wang Haonan) The reporter recently learned from Beijing Institute of Quantum Information Science: Professor Long Guilu of Beijing Institute of Quantum Information Science and Tsinghua University The team cooperated with Professor Lu Jianhua’s team to design and implement a new quantum direct communication system with mixed encoding of phase quantum states and timestamp quantum states, and successfully achieved 100-kilometer quantum direct communication. This is currently the longest quantum direct communication distance in the world.
“Such an indicator can realize point-to-point quantum direct communication between some cities without relays, and can support some applications of wide-area quantum networks based on secure classical relays.” Long Guilu Introduced, in previous systems, sampling detection and information transmission all use phase quantum states. The new system adopts the mixed encoding of phase quantum state and time stamp quantum state, and the time stamp quantum state is used for sampling detection, which greatly reduces the influence of noise. The communication still uses the phase quantum state with self-compensation performance, so the new system has a high degree of stability and a very low intrinsic bit error rate (bit error rate without eavesdropping). The code rate LDBCH coding effectively improves the security communication capacity, distance and rate.
Long Guilu said that the new system still has a lot of room for improvement in laser pulse frequency, and the corresponding communication distance and speed are expected to be further improved to meet the application requirements of some scenarios.
It is understood that Beijing Institute of Quantum Information Science was established on December 24, 2017, by the Beijing Municipal Government and the Chinese Academy of Sciences, Tsinghua University, Peking University and other colleges and universities.
People’s Daily (13 edition on April 14, 2022)