An ${}^{27}$Al${}^{+}$ quantum-logic clock with systematic uncertainty below $10^{-18}$

Abstract

We describe an optical atomic clock based on quantum-logic spectroscopy of the ${}^1$S${}_0$ $\leftrightarrow$ ${}^3$P${}_0$ transition in ${}^{27}$Al${}^{+}$ with a systematic uncertainty of $9.4\times 10^{-19}$ and a frequency stability of $1.2\times 10^{-15}/\sqrt{\tau }$. 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.

5 pages 4 figures + supplemental material 9 pages 5 figures

References in corpus (6)

• Systematic evaluation of an atomic clock at 2e-18 total uncertainty
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Cited by in corpus (1)

• Measurements of ${}^{27}$Al${}^{+}$ and ${}^{25}$Mg${}^{+}$ magnetic constants for improved ion clock accuracy