Highly charged ions of heavy actinides as sensitive probes for time variation of the fine structure constant

TL;DR

This paper theoretically identifies highly charged heavy actinide ions with optical transitions sensitive to variations in the fine structure constant, proposing their use as precise probes in fundamental physics tests.

Contribution

It discovers specific ions and transitions that can serve as optical clocks with high sensitivity to changes in the fine structure constant, advancing experimental tests of fundamental physics.

Findings

Identified promising ions with sensitive optical transitions

Found multiple clock transitions with different sensitivities

Proposed ions suitable for fundamental physics experiments

Abstract

Highly charged ions of heavy actinides from uranium to einsteinium are studied theoretically to find optical transitions sensitive to the variation of the fine structure constant. A number of promising transitions have been found in ions with ionisation degree $\sim$~10. All these transitions correspond in single-electron approximation to the $6p$ - $5f$ transitions. Many of the transitions are between ground and excited metastable states of the ions which means that they can probably be used as optical clock transitions. Some of the ions have more than one clock transition with different sensitivity to the variation of the fine structure constant $\alpha$. The most promising systems include the Np$^{10+}$, Np$^{9+}$, Pu$^{11+}$, Pu$^{10+}$, Pu$^{9+}$, Pu$^{8+}$, Bk$^{15+}$, Cm$^{12+}$, and Es$^{15+}$ ions.