BSM-PM: A Highly Charged Ion-Based Quantum-Logic Clock for Precision Tests of Fundamental Physics

For this project, the PI and collaborators will perform high-precision, quantum-enabled laser spectroscopy experiments on trapped, highly charged ions for the purpose of testing fundamental physics at low energy. Highly charged ions (atoms in which several electrons have been removed) are among the most sensitive systems to a possible time-variation of the fundamental physical constants. This high sensitivity, combined with laser-accessible transitions, makes them a unique platform for investigating predicted extensions to the standard model of particle physics. This project will focus on the development of an optical atomic clock based on trapped highly charged metal ions. The experiment will combine techniques that have been developed for ion trap-based quantum computing and optical frequency standards with a compact source of highly charged ions. This project will also provide training for undergraduate and graduate students in the fields of experimental atomic, molecular and optical physics, optical frequency metrology, and precision measurements. Several optical transitions in highly charged ions provide both an enhanced sensitivity to possible time-variation of the fine-structure constant (alpha) and favorable systematics as optical clocks when compared to singly charged ions and neutral atoms. In particular, these systems are immune to frequency shifts due to the presence of blackbody radiation (BBR). Using quantum-enabled spectroscopy techniques, the research team aims to develop an optical atomic clock based on narrow linewidth transitions in highly charged praseodymium ions (PrXI). A highly charged ion optical clock with a fractional systematic uncertainty at the level of one part in ten to the eighteen, when compared to an optical clock based on singly ionized ytterbium (YbII), could lead to a factor of one hundred improvement in the current laboratory limit on time-variation of alpha. Either an improved limit on the constancy of alpha, or a non-zero signal of the time-variation of alpha could be used to constrain physics beyond the standard model of particle physics. Results from this experimental work will be analyzed in the context of theoretical extensions to the standard model that propose new dark matter candidates and couplings that would lead to the observation of a non-zero value of the time-variation of alpha. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.