Realization of a time-scale with an accurate optical lattice clock

TL;DR

This paper demonstrates the creation of a highly reliable optical clock-based timescale that surpasses caesium clocks in accuracy, supporting the potential redefinition of the SI second and confirming the consistency of strontium lattice clocks.

Contribution

It introduces a method to establish a continuous, reliable optical clock timescale, overcoming previous reliability issues and validating the clocks' international consistency.

Findings

Optical clock timescale exceeds caesium clock performance.

Achieved continuous realization of an optical timescale.

Confirmed $10^{-16}$ accuracy level of strontium lattice clocks.

Abstract

Optical clocks are not only powerful tools for prime fundamental research, but are also deemed for the re-definition of the SI base unit second as they now surpass the performance of caesium atomic clocks in both accuracy and stability by more than an order of magnitude. However, an important obstacle in this transition has so far been the limited reliability of the optical clocks that made a continuous realization of a timescale impractical. In this paper, we demonstrate how this situation can be resolved and that a timescale based on an optical clock can be established that is superior to one based on even the best caesium fountain clocks. The paper also gives further proof of the international consistency of strontium lattice clocks on the $10^{-16}$ accuracy level, which is another prerequisite for a change in the definition of the second.