Hole transitions in multiply-charged ions for precision laser spectroscopy and searching for alpha-variation

TL;DR

This paper explores electron hole transitions in multiply-charged ions that are suitable for high-precision spectroscopy and fundamental physics tests, highlighting their high sensitivity to variations in the fine-structure constant.

Contribution

It introduces the concept of using hole transitions in multiply-charged ions for precision measurements and demonstrates their potential for detecting alpha-variation with unprecedented sensitivity.

Findings

Hole transitions can be within optical clock range due to level-crossing.

Strong E1 transitions enable laser cooling and trapping.

Transitions show high sensitivity to alpha-variation.

Abstract

We consider transitions of electron holes (vacancies in otherwise filled shells of atomic systems) in multiply-charged ions that, due to level-crossing of the holes, have frequencies within the range of optical atomic clocks. Strong E1 transitions provide new options for laser-cooling and trapping, while narrow transitions can be used for high-precision spectroscopy and tests of fundamental physics. We show that hole transitions can have extremely high sensitivity to alpha-variation due to large relativistic corrections, and propose candidate transitions that have much larger alpha-sensitivities than any previously seen in atomic systems.