Main research directions: Precision measurement physics, Gravitational Experiments, Measurement of gravitational constant G.

In the past 10 years, I focused on the big G measurement with the time-of-swing method in the cave laboratory in Huazhong University of Science and Technology:

Ø     My post-doctoral research work is measuring the gravitational constant G with time-of-swing method by using high-Q silica fibers. The main innovations include: 1). Coated silica fibers with Q factor of ~5*10⁴ are used in the experiment to reduce the anelastic effect. The silica fibers are pulled from 3-mm-diameter rods using oxygen-natural gas flame by hand. The fiber surface is coated with germanium and bismuth films with thickness of about 10 nm to make it ground; 2). The local background gravitational gradient is measured and then compensated with about 1 tons of lead blocks; 3). The coating effect of the pendulum is reduced by using aluminum coating layer to replace the Au/Cu coating layer; 4). The magnetic damper is optimized and its effect contributed to the value of G is reduced; 5). The updated three-point mounts are used to support the spherical source masses to improve the position stability and repeatability; 6). The measurements of G are conducted simultaneously on two sets of apparatus to verify the system effects related to the device. After several years of effort, the measurement of G has been performed with four silica fibers on two apparatus. We obtain seven values of G, which are consistent with each other. The uncertainty of the final combined G value is about 11.6 ppm (Nature, 2018, 560:582-588).

Ø     During my doctoral course, I participated in the measurement of G with the time-of-swing method by using the thoriated tungsten fiber. I repeated this experiment and finished the detailed introduction paper for the HUST-09 experiment, with 36 pages in length (Phys. Rev. D, 2010, 82:022001, second author). Participated in part in the experiment of measuring the anelastic effect of tungsten fiber with two disk pendulums under the help of a high-Q silica fiber (Phys. Rev. D, 2009, 80:122005).

Ø     Have measured the geomagnetic field fluctuation and the residual magnetic field of attracting mass in G measurement. The coefficient due to magnetic field influence was given by a modulation experiment, and the influence of geomagnetic field fluctuation on the measurement of G was evaluated.