Magnetic blackbody shift of hyperfine transitions for atomic clocks

TL;DR

This paper derives a detailed expression for the magnetic blackbody shift affecting hyperfine transitions in atomic clocks, highlighting its temperature dependence and implications for cesium and p_1/2 transitions.

Contribution

It provides a new, comprehensive formula for the magnetic blackbody shift, including effects of fine-structure interactions, for improved atomic clock accuracy.

Findings

The shift depends on temperature in a complex way, approximating T^2 at high temperatures.

Interaction with p_3/2 fine-structure multiplet can dominate the shift in certain transitions.

The derived expressions can improve the precision of atomic clock frequency standards.

Abstract

We derive an expression for the magnetic blackbody shift of hyperfine transitions such as the cesium primary reference transition which defines the second. The shift is found to be a complicated function of temperature, and has a T^2 dependence only in the high-temperature limit. We also calculate the shift of ground-state p_1/2 hyperfine transitions which have been proposed as new atomic clock transitions. In this case interaction with the p_3/2 fine-structure multiplet may be the dominant effect.