Progress on the <sup>40</sup>Ca<sup>+</sup> ion optical clock

Progress on the ⁴⁰Ca⁺ ion optical clock

Zhang Baolin^{1, 2, 3}, Huang Yao^{1, 2}, Zhang Huaqing^{1, 2, 3}, Hao Yanmei^{1, 2, 3}, Zeng Mengyan^{1, 2, 5}, Guan Hua^{1, 2, †}, Gao Kelin^{1, 2, 4, ‡}

Schematic diagram of the new linear Paul trap. V₀ cos (Ω t) is the RF potential. V₁ and V₂ are the horizontal and vertical compensation voltages, which are used to compensate for the static electric stray field at the center of the ion trap.