# ^{27}Al^{+} Quantum-Logic Clock with a Systematic Uncertainty below 10^{-18}.

@article{Brewer201927AlQC,
title={^\{27\}Al^\{+\} Quantum-Logic Clock with a Systematic Uncertainty below 10^\{-18\}.},
author={S. Brewer and J.-S. Chen and A. Hankin and E. Clements and C. Chou and D. Wineland and D. Hume and D. Leibrandt},
journal={Physical review letters},
year={2019},
volume={123 3},
pages={
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… Expand
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