An atomic clock with $1\times 10^{-18}$ room-temperature blackbody Stark uncertainty

TL;DR

This paper presents a room-temperature blackbody radiation shield for an ytterbium optical lattice clock, achieving an unprecedented BBR Stark shift uncertainty of 1×10⁻¹⁸, significantly improving atomic clock precision.

Contribution

Introduction of an in-vacuum radiation shield that precisely characterizes the BBR environment, reducing the BBR Stark shift uncertainty in atomic clocks.

Findings

Achieved BBR Stark shift uncertainty of 1×10⁻¹⁸ at room temperature.

Demonstrated the ability to measure BBR shift temperature dependence.

Validated the consistency between BBR environment and atomic response.

Abstract

The Stark shift due to blackbody radiation (BBR) is the key factor limiting the performance of many atomic frequency standards, with the BBR environment inside the clock apparatus being difficult to characterize at a high level of precision. Here we demonstrate an in-vacuum radiation shield that furnishes a uniform, well-characterized BBR environment for the atoms in an ytterbium optical lattice clock. Operated at room temperature, this shield enables specification of the BBR environment to a corresponding fractional clock uncertainty contribution of $5.5 \times 10^{-19}$. Combined with uncertainty in the atomic response, the total uncertainty of the BBR Stark shift is now $1\times10^{-18}$. Further operation of the shield at elevated temperatures enables a direct measure of the BBR shift temperature dependence and demonstrates consistency between our evaluated BBR environment and the expected atomic response.