Systematic evaluation of an atomic clock at 2e-18 total uncertainty

TL;DR

This paper reports a significant improvement in the accuracy and stability of an 87Sr optical lattice clock, achieving a total uncertainty of 2.1e-18, advancing precision in atomic timekeeping.

Contribution

The work demonstrates a systematic evaluation and reduction of uncertainties in an optical lattice clock, setting a new record for clock accuracy at 2.1e-18.

Findings

Achieved fractional stability of 2.2e-16 at 1 second

Reduced systematic uncertainties in key measurement parameters

Set a new record for clock accuracy at 2.1e-18

Abstract

The pursuit of better atomic clocks has advanced many research areas, providing better quantum state control, new insights in quantum science, tighter limits on fundamental constant variation, and improved tests of relativity. The record for the best stability and accuracy is currently held by optical lattice clocks. This work takes an important step towards realizing the full potential of a many-particle clock with a state-of-the-art stable laser. Our 87Sr optical lattice clock now achieves fractional stability of 2.2e-16 at 1 s. With this improved stability, we perform a new accuracy evaluation of our clock, reducing many systematic uncertainties that limited our previous measurements, such as those in the lattice ac Stark shift, the atoms' thermal environment, and the atomic response to room-temperature BBR. Our combined measurements have reduced the total uncertainty of the JILA Sr clock to 2.1e-18 in fractional frequency units.