Molecular Theory for Precision Measurement and Laser Cooling

The proposed research will develop new theoretical and computational methods to accelerate the discovery of molecules and solid-state materials for precision measurements that probe new fundamental physics beyond the Standard Model. Although the Standard Model successfully explains a wide range of fundamental phenomena, it cannot account for one of the most profound mysteries in nature: the overwhelming dominance of matter over antimatter in the observed universe. Addressing this question requires searches for new sources of symmetry violation that lie beyond the Standard Model. Tabletop precision measurements using molecules have emerged as one of the most sensitive approaches for searching for new fundamental physics. Heavy-atom-containing molecules and solid-state systems can greatly amplify tiny symmetry-violating interactions, making them exceptionally powerful probes of new physics. The proposed work focuses on highly accurate theoretical predictions aiming to identify the most promising candidate systems and interpret experimental results. Beyond advancing fundamental physics, the project will produce broadly applicable computational tools for studying heavy-element molecules and materials, benefiting research in chemistry, physics, and materials science. The project will also provide interdisciplinary training for students and early-career researchers at the interface of quantum chemistry, atomic and molecular physics, and precision measurement science. This project will develop new relativistic quantum-chemical methods capable of accurately describing the coupling between electronic and nuclear motions, as well as predicting the molecular sensitivity parameters that determine a system's response to fundamental symmetry-violating interactions. These new theoretical tools will be applied to radioactive molecules, particularly those containing radium, and to emerging solid-state platforms for precision measurements. The project will provide the first relativistic all-electron first-principles predictions for key time-reversal-symmetry-violating sensitivity factors in several experimentally relevant systems. Close collaboration with experimental groups pursuing laser cooling and precision spectroscopy will enable the theoretical developments to directly guide ongoing efforts to discover new physics beyond the Standard Model. 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.