Additional clock transitions in neutral ytterbium bring new possibilities for testing physics beyond the Standard Model

TL;DR

This paper explores new ytterbium clock transitions that could enhance tests of fundamental physics beyond the Standard Model, by analyzing their properties and potential for ultra-high precision measurements.

Contribution

It identifies and evaluates additional clock transitions in ytterbium, demonstrating their suitability for high-precision tests of fundamental physics.

Findings

Both transitions support ultra-high accuracy similar to existing ytterbium clocks.

The states have favorable lifetimes and sensitivities for detecting variations in fundamental constants.

The transitions can improve searches for physics beyond the Standard Model.

Abstract

We study the prospects of using transitions from the ytterbium ground state to metastable states $^3{\rm P}^{\rm o}_2$ at $E=19\,710.388~$cm$^{-1}$ and $4f^{13}5d6s^2\,(J=2)$ at $E=23\,188.518~$cm$^{-1}$ as clock transitions in an optical lattice clock. Having more than one clock transition in Yb could benefit the search for new physics beyond the Standard Model via studying the non-linearity of King's plot or the time-variation of the ratio of the frequencies of two clock transitions. We calculate the lifetime of the states, relevant transition amplitudes, systematic shifts, and the sensitivities of the clock transitions to a variation of the fine structure constant and to the gravitational potential. We find that both transitions can probably support ultra-high accuracy, similar to what is already achieved for the $^1$S$_0$ - $^3$P$^{\rm o}_0$ clock transition.