Linear Paul trap design for an optical clock with Coulomb crystals

TL;DR

This paper presents a design for a linear Paul trap optimized for optical clocks using Coulomb crystals, focusing on minimizing systematic shifts and micromotion to achieve extremely high frequency stability.

Contribution

It introduces a scalable trap design with precise electric field calculations that reduces excess micromotion, enabling fractional frequency uncertainties of 10^-18.

Findings

Finite element method used for electric field calculations

Trap design minimizes excess micromotion below 10^-18

Achieves high stability for optical clock applications

Abstract

We report on the design of a segmented linear Paul trap for optical clock applications using trapped ion Coulomb crystals. For an optical clock with an improved short-term stability and a fractional frequency uncertainty of 10^-18, we propose 115In+ ions sympathetically cooled by 172Yb+. We discuss the systematic frequency shifts of such a frequency standard. In particular, we elaborate on high precision calculations of the electric radiofrequency field of the ion trap using the finite element method. These calculations are used to find a scalable design with minimized excess micromotion of the ions at a level at which the corresponding second- order Doppler shift contributes less than 10^-18 to the relative uncertainty of the frequency standard.