Jing-Jing Xia

In this paper, we propose a method for identifying the contribution of various sources of noise to the instability of an optical lattice clock. These sources include Dick noise, quantum projection noise, shot noise, and technical noise. By measuring the clock instability at four different sets of parameters, we can determine the frequency fluctuations due to each type of noise separately. Furthermore, we can accurately extract the absolute number of atoms, the photon number detected per atom by the photoelectric detector, and the root mean square fluctuations of the atom number. We demonstrate the effectiveness of our approach through numerical simulations, showcasing the ability to determine these parameters with an uncertainty of less than 10%. Specifically, a remarkable uncertainty of 1% can be achieved when determining the atom number.

Optical clocks have been applied to the generation of time scales since they provide superb uncertainty and instability in recent years. This paper presents the simulations about the impact of the optical clock’s operational strategies on the performance of the generated time scale through two distinct steering algorithms. By post-processing the measured frequency difference between the 87Sr optical lattice clock and the hydrogen maser at the National Time Service Center, we realized an “optically steered” time scale TS(Sr), and the variation of the time difference TT(BIPM22)-TS(Sr) is 0.1 ns during the modified Julian date 59794–59819.