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An 27Al+ quantum-logic clock with systematic uncertainty below 10-18



Samuel M. Brewer, Jwo-Sy Chen, Aaron M. Hankin, Ethan Clements, Chin-wen Chou, David J. Wineland, David Hume, David Leibrandt


We describe an optical atomic clock based on quantum-logic spectroscopy of the 1S0 <- -> 3P0 transition in 27Al+ with a systematic uncertainty of 9.0 x 10-19 and a frequency stability of 1.2 X 10-15/(T1/2). A 25Mg+ ion is simultaneously trapped with the 27Al+ ion and used for sympathetic cooling and state readout during clock operation. Improvements in a new trap have led to reduced secular motion heating, compared to previous 27Al+ clocks, enabling clock operation with ion motion near the three-dimensional ground state. Operating the clock with a lower trap drive frequency has reduced excess micromotion, compared to previous 27Al+ clocks, leading 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.
Physical Review Letters


Atomic clocks, lattic clocks, optical clocks, Precision Measurements, Trapped ions


Brewer, S. , Chen, J. , Hankin, A. , Clements, E. , Chou, C. , Wineland, D. , Hume, D. and Leibrandt, D. (2019), An <sup>27</sup>Al+ quantum-logic clock with systematic uncertainty below 10<sup>-18</sup>, Physical Review Letters, [online], (Accessed May 20, 2024)


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Created July 15, 2019, Updated April 23, 2021