The reporter learned from the University of Science and Technology of China on January 25 that a research team composed of Pan Jianwei, Chen Yuao, Dai Hanning and others from the school successfully developed a 10,000-second stability and uncertainty better than 5×10-18 (equivalent to billions of A strontium atomic optical lattice clock with an error of less than one second per year. According to publicly published data, this system is not only the current optical clock with the best comprehensive indicators in the country, but also makes our country the second country to achieve the above-mentioned comprehensive indicators.

It is understood that based on previous work, the research team achieved laser cooling of strontium atoms and bound them in a long-lived one-dimensional optical lattice, using a beam of ultra-stable laser pre-locked to the ultra-stable cavity to explore The strontium atomic clock state transitions and realizes the closed-loop operation of the optical clock. Frequency comparison measurements were made through two independent sets of strontium atomic optical lattice clocks, and it was found that the stability of a single set of optical clocks reached 4×10-18 at an integration time of 10,000 seconds and 2.1×10-18 at an integration time of 47,000 seconds. . On this basis, the research team also conducted an item-by-item assessment of the system frequency shift factors of the Sr1 optical clock, and finally found that its system uncertainty is 4×10-18, which is equivalent to a deviation of only 1 second in 7.2 billion years. The above performance indicators indicate that the optical clock system has partially met the requirements for the redefinition of "seconds".

According to the researchers, this achievement lays an important technical foundation for the future realization of long-distance optical clock comparisons, the establishment of ultra-high-precision optical frequency standard benchmarks and a global optical clock network, and for the future construction of a new generation of global time benchmarks and even the provision of gravitational waves. New methods for detection and dark matter search are of great value.

Relevant results were recently published in the authoritative international academic journal "Econometrics".