NSF Award
2409425
The PI and her research team will theoretically model an extremely powerful new platform to study novel symmetry-violating forces beyond those in the Standard Model of particle physics. The study of these phenomena is needed to explain the observed cosmological asymmetry between matter and antimatter. Priority in the proposed research will be given to a platform based on milli-Kelvin, trapped 223FrAg, francium-silver molecules, which takes advantage of their enhanced sensitivity to the symmetry-violating effects. The shape or charge distribution of the unstable 223Fr nucleus is octupole deformed (pear-like) promoting increases in sensitivity to symmetry breakdowns. In addition, the electron bonding between Fr and Ag can lead to a strong, effective internal electric field along the axis connecting the two atoms at the positions of the nuclei magnifying the effects of externally applied fields. The research team’s primary goal is to provide guidance to experimental groups for “building” this novel molecular sensor with revolutionary sensitivity to symmetry-violations from its constituent atoms Fr and Ag. Both atoms have already been cooled with lasers to milli-Kelvin temperatures. Binding the two cold atoms together, also using lasers, however, has never been done before and, specifically, calculating the rate at which this can be achieved will help determine the success of the sensor. The precise determination of the rates with calculations spearheaded by the students are crucial to advance the field and will be performed in coordination with an experimental group building the apparatus led by Dr. D. DeMille at the University of Chicago.<br/><br/>The technical research of the proposal has several components. Firstly, electronic states and radiative transition dipole moments of the FrAg diatomic molecule must be precisely determined. An important element of this proposal is the development of a state-of-the-art relativistic configuration-interaction valence-bond method for precise first-principle numerical calculations of di-atomic molecules. The valence-bond method is unique among molecular electronic structure methods as it is well suited for the larger internuclear separations, where the overlap of the electron wavefunction of the two atoms is relatively small. Secondly, the PI and her team will use numerical quantum scattering models to describe the relative motion of the two ultracold atoms in the presence of magnetic fields and laser radiation of multiple colors to assemble FrAg molecules. At cold temperatures molecular forces operating at large interatomic separations dominate the physics of the motion. Resonant scattering phenomena in the presence of a magnetic field can enhance the molecular formation rates. Finally, once FrAg has been formed in its energetically lowest rovibrational state, the research will characterize the light shifts on eigen states of FrAg due to the laser light that traps them. These forces, while essential for the experiment, will also be detrimental for precision measurements looking for small symmetry breaking effects. The light forces are classified as scalar, vector, and tensor light shifts in order of decrease size.<br/><br/>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.
