K. Liang

Geopotential measurement with a robust, transportable Ca+ optical clock

K. Gao, S. Cao, Tianchu Li, 2020 .

Hertz-level measurement of the Ca-40(+) 4s S-2(1/2)-3d D-2(5/2) clock transition frequency with respect to the SI second through the Global Positioning System

K. Gao, X. Huang, P. Liu, 2011, 1111.5174.

A comparison of two 40Ca+ single-ion optical frequency standards at the 5 × 10−17 level and an evaluation of systematic shifts

K. Gao, Yisheng Huang, Longsheng Ma, 2017 .

Frequency Comparison of Two (40)Ca(+) Optical Clocks with an Uncertainty at the 10(-17) Level.

K. Gao, P. Liu, H. Guan, 2016, Physical review letters.

Absolute frequency measurement of an Yb optical clock at the 10−16 level using International Atomic Time

Xinye Xu, Tianchu Li, H. Qiao, 2020, Metrologia.