An ion ring in a linear multipole trap for optical frequency metrology

TL;DR

This paper explores a ring-shaped ion crystal in a linear multipole trap as a stable optical frequency standard, demonstrating improved short-term stability and reduced sensitivity to ion number fluctuations through analytical and simulation studies.

Contribution

It introduces a novel ring configuration of ions in a multipole trap for optical frequency metrology, analyzing its stability and systematic shifts with new insights.

Findings

Ring of 10 or 20 ions achieves better short-term stability than a single ion.

Configuration reduces frequency sensitivity to ion number fluctuations.

Systematic shifts for calcium ion transitions are evaluated.

Abstract

A ring crystal of ions trapped in a linear multipole trap is studied as a basis for an optical frequency standard. The equilibrium conditions and cooling possibilities are discussed through an analytical model and molecular dynamics simulations. A configuration which reduces the frequency sensitivity to the fluctuations of the number of trapped ions is proposed. The systematic shifts for the electric quadrupole transition of calcium ions are evaluated for this ring configuration. This study shows that a ring of 10 or 20 ions allows to reach a short term stability better than for a single ion without introducing limiting long term fluctuations.