Enhanced sensitivity to the fine-structure constant variation in Th IV atomic clock transition

TL;DR

This paper identifies a specific transition in Th^{3+} ion that is highly sensitive to changes in the fine-structure constant alpha, proposing it as a promising candidate for detecting potential variations over time.

Contribution

It demonstrates the enhanced sensitivity of a Th^{3+} atomic clock transition to alpha variation and suggests its use in experimental searches for fundamental constant changes.

Findings

The 5f_5/2-7s_1/2 transition in Th^{3+} is highly sensitive to alpha variation.

The transition is narrow, laser-coolable, and suitable for precision measurements.

A reference line with positive sensitivity is identified for comparison.

Abstract

Our calculations have shown that the 5f_5/2-7s_1/2 23131 cm^{-1} transition from the ground state in the ion Th^{3+} is very sensitive to the temporal variation of the fine structure constant alpha (q=-75300 cm^{-1}). The line is very narrow, the ion has been trapped and laser cooled and the positive shifter line 5f_5/2-5f_7/2 4325 cm^{-1} (q=+2900 cm^{-1}) may be used as a reference. A comparison may also be made with a positive shifter in another atom or ion. This makes Th^{3+} a good candidate to search for the alpha variation.