High-precision ultracold-molecule spectroscopy for metrology and new physics

Ultracold molecules offer a rich platform for precision measurements of fundamental interactions, metrology, and quantum chemistry. We employ an optical lattice to trap ultracold $^{\mathrm{88}}$Sr$_{\mathrm{2}}$ molecules with the goal of probing fundamental molecular structure and studying new, beyond-the-Standard-Model physics, including enhanced constraints on nanometer-scale gravity. Improvements to \textit{ab-initio} theory models are crucial in order to select optimal clock states and to develop predictive models to guide the experiment. In the most recent experimental work, we measured the binding energies and transition strengths for both deeply and weakly bound vibrational levels in the ground and first excited states via light shifts and Autler-Townes spectroscopy. These measurements inform theory and improve our current predictive models and understanding of the underlying molecular structure, enabling us to design a molecular clock with longer quantum-state coherence.