Isotope shifts for ${}^1S_0-{}^3P_{0,1}^o$ Yb lines from multi-configuration Dirac-Hartree-Fock calculations

TL;DR

This study uses advanced relativistic atomic calculations to analyze isotope shifts in ytterbium, providing improved nuclear charge parameters and predicting unknown clock transition frequencies relevant for fundamental physics tests.

Contribution

The paper presents new relativistic multiconfiguration Dirac-Hartree-Fock calculations of isotope shifts in ytterbium, including improved nuclear charge parameters and predictions for unknown transition frequencies.

Findings

Calculated mass and field shift parameters for Yb lines.

Provided improved estimates of nuclear charge differences.

Predicted unknown clock line frequencies for bosonic Yb isotopes.

Abstract

Relativistic multiconfiguration Dirac-Hartree-Fock (MCDHF) calculations with configuration interaction (CI) are carried out for the $^{1}S_{0}$ and $^{3}P_{0,1}^o$ states in neutral ytterbium by use of the available GRASP2018 package. From the resultant atomic state functions and the RIS4 extension, we evaluate the mass and field shift parameters for the $^{1}S_{0}-\,^{3}P_{0}^o$ (clock) and $^{1}S_{0}-\,^{3}P_{1}^o$ (intercombination) lines. We present improved estimates of the nuclear charge parameters, $\lambda^{A,A'}$, and differences in mean-square charge radii, $\delta\langle r^2\rangle^{A,A'}$, and examine the second-order hyperfine interaction for the $^{3}P_{0,1}^o$ states. Isotope shifts for the clock transition have been estimated by three largely independent means from which we predict the unknown clock line frequencies in bosonic Yb isotopes. Knowledge of these line frequencies has implications for King plot nonlinearity tests and the search for beyond Standard-Model signatures.