Brewer S M, Chen J-S, Hankin A M, Clements E R, Chou C W, Wineland D J, Hume D B, Leibrandt D R
Time and Frequency Division, National Institute of Standards and Technology, Boulder, Colorado 80305, USA.
Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.
Phys Rev Lett. 2019 Jul 19;123(3):033201. doi: 10.1103/PhysRevLett.123.033201.
We describe an optical atomic clock based on quantum-logic spectroscopy of the ^{1}S_{0}↔^{3}P_{0} transition in ^{27}Al^{+} with a systematic uncertainty of 9.4×10^{-19} and a frequency stability of 1.2×10^{-15}/sqrt[τ]. A ^{25}Mg^{+} ion is simultaneously trapped with the ^{27}Al^{+} ion and used for sympathetic cooling and state readout. Improvements in a new trap have led to reduced secular motion heating, compared to previous ^{27}Al^{+} clocks, enabling clock operation with ion secular motion near the three-dimensional ground state. Operating the clock with a lower trap drive frequency has reduced excess micromotion compared to previous ^{27}Al^{+} clocks. Both of these improvements have led to a reduced time-dilation shift uncertainty. Other systematic uncertainties including those due to blackbody radiation and the second-order Zeeman effect have also been reduced.
我们描述了一种基于(^{27}Al^{+})中(^{1}S_{0}\leftrightarrow^{3}P_{0})跃迁的量子逻辑光谱学的光学原子钟，其系统不确定度为(9.4×10^{-19})，频率稳定性为(1.2×10^{-15}/\sqrt{τ})。一个(^{25}Mg^{+})离子与(^{27}Al^{+})离子同时被俘获，并用于交感冷却和状态读出。与之前的(^{27}Al^{+})时钟相比，新陷阱的改进导致了长期运动加热的减少，使得时钟能够在接近三维基态的离子长期运动下运行。与之前的(^{27}Al^{+})时钟相比，以较低的陷阱驱动频率操作时钟减少了多余的微运动。这两项改进都导致了时间膨胀偏移不确定度的降低。包括黑体辐射和二阶塞曼效应引起的其他系统不确定度也有所降低。
