Coherent laser spectroscopy of highly charged ions using quantum logic

TL;DR

This paper demonstrates a significant advancement in laser spectroscopy of highly charged ions by achieving unprecedented precision using quantum-logic techniques, enabling new tests of fundamental physics and potential applications in quantum information.

Contribution

The authors introduce coherent laser spectroscopy on highly charged ions with an eight orders of magnitude increase in precision, including cooling and probing techniques for $^{40}$Ar$^{13+}$.

Findings

Achieved lowest reported temperatures for trapped HCI.

Performed quantum-logic spectroscopy on forbidden optical transition.

Measured excited-state lifetime and g-factor of $^{40}$Ar$^{13+}$.

Abstract

Precision spectroscopy of atomic systems is an invaluable tool for the advancement of our understanding of fundamental interactions and symmetries. Recently, highly charged ions (HCI) have been proposed for sensitive tests of physics beyond the Standard Model and as candidates for high-accuracy atomic clocks. However, the implementation of these ideas has been hindered by the parts-per-million level spectroscopic accuracies achieved to date. Here, we cool a trapped HCI to the lowest reported temperatures, and introduce coherent laser spectroscopy on HCI with an eight orders of magnitude leap in precision. We probe the forbidden optical transition in $^{40}$Ar$^{13+}$ at 441 nm using quantum-logic spectroscopy and measure both its excited-state lifetime and $g$-factor. Our work ultimately unlocks the potential of HCI, a large, ubiquitous atomic class, for quantum information processing, novel frequency standards, and highly sensitive tests of fundamental physics, such as searching for dark matter candidates or violations of fundamental symmetries.