Long-lived metastable states in the 4f$^{13}$5d6s configuration of Yb$^+$

TL;DR

This study investigates long-lived metastable states in Yb$^+$ ions, measuring their lifetimes and identifying decay pathways, with implications for quantum information and precision timekeeping.

Contribution

The paper reports the first experimental measurement of metastable state lifetimes in Yb$^+$ and confirms these with atomic structure calculations, revealing states useful for quantum and clock applications.

Findings

Measured metastable state lifetimes of 0.92 s and 9.8 s.

Evidence for a metastable state with lifetime > 30 s.

Atomic structure calculations support observed decay paths.

Abstract

We study the occurrence of long-lived metastable states in the 4f$^{13}$5d6s electron configuration of Yb$^+$. By optical pumping of a single trapped ion on the $^2F^\text{o}_{7/2}\rightarrow (7/2,0)_{7/2}$ transition at 377.5 nm, we prepare a wide range of metastable electronic states. We use a co-trapped control ion to sympathetically cool the spectroscopy ion, allowing us to accurately time its subsequent decay. We record a strong decay signal corresponding to a lifetime of 0.92(8) s, a weaker decay signal with lifetime 9.8(+2.9, -2.0) s, and find evidence for a much longer lifetime, $>$ 30 s. We identify the metastable states with these lifetimes qualitatively, and corroborate our results with atomic structure calculations that support the observed lifetimes and decay paths. These long-lived states provide new opportunities in qubit and qudit state detection and optical clocks.