JILA SrI Optical Lattice Clock with Uncertainty of $2.0 \times 10^{-18}$

We report on an improved systematic evaluation of the JILA SrI optical lattice clock, achieving a nearly identical uncertainty compared to the previous strontium record set by the JILA SrII optical lattice clock at 2.1 × 10−18. This improves upon the previous evaluation of the JILA SrI optical lattice clock in 2013, and we achieve a more than twenty-fold reduction in systematic uncertainty to 2.0 × 10−18. A seven-fold improvement in clock...