$^{87}$Sr 1D Optical Lattice Clock With a 124 K Silicon Cavity: Full Systematic Evaluation and Record Precision

We report on the full systematic evaluation of the JILA Sr1 optical lattice clock using a laser stabilized to a 124 K silicon cavity. This evaluation resulted in a factor of 10 improvement over our previous evaluation of JILA Sr1 for the systematic uncertainty [1]. After the systematic evaluation of the JILA Sr2 clock at 2.1$\times 10^{-18}$ [2], it is now operating in a 3D lattice configuration. We perform an extensive comparison between JILA Sr1 and Sr2 clocks and determine independent clock stability of 4.8$\times 10^{-17}$ at 1 s. With synchronous clock operation we achieve stability of 3.5$\times 10^{-17}$ at 1 s and a precision of 6$\times 10^{-19}$ in 1 hour of measurement. The state-of-the-art precision and accuracy of this clock enables measurements for wide-ranging applications, from searches for dark matter to relativistic geodesy. \newline \noindent [1] Bloom, B. J., et al. "An optical lattice clock with accuracy and stability at the 10$^{-18}$ level." Nature 506.7486 (2014): 71. \noindent [2] Nicholson, T. L., et al. "Systematic evaluation of an atomic clock at 2$\times 10 ^{-18}$ total uncertainty." Nature communications 6 (2015): 6896.