Synchronous Comparison of Two Thulium Optical Clocks

TL;DR

This paper reports on the synchronous comparison of two thulium optical lattice clocks, achieving high precision and stability, and demonstrating the potential for systematic shift studies with very low uncertainty.

Contribution

It introduces a method for synchronous comparison of two thulium optical clocks using a single ultrastable laser, reducing measurement errors and enabling long-term systematic shift analysis.

Findings

Achieved a relative measurement error of 10^{-16} after 500 seconds.

Demonstrated a relative instability of 2×10^{-15}/√τ.

Enabled systematic shift studies with an uncertainty of 10^{-17}.

Abstract

The experimental comparison of two thulium optical lattice clocks in a time interval of up to one hour has been carried out. The synchronous comparison of a clock transition in two independent atomic ensembles using a single ultrastable laser has allowed us to eliminate fluctuations of the laser frequency from the measured frequency difference and to reach a relative measurement error of $10^{-16}$ after 500-s averaging, which corresponds to a relative instability of $2\times10^{-15}/\sqrt{\tau}$. The successful demonstration of the long-term operation of two systems using the synchronous comparison of clock transitions opens the possibility of studying systematic shifts in thulium optical clocks with an uncertainty of $10^{-17}$.