Observation of Collisions between Two Ultracold Ground-State CaF Molecules

Abstract

We measure inelastic collisions between ultracold CaF molecules by combining two optical tweezers, each containing a single molecule. We observe collisions between ${}^2\Sigma$ CaF molecules in the absolute ground state $|X,v=0,N=0,F=0⟩$, and in excited hyperfine and rotational states. In the absolute ground state, we find a two-body loss rate of $7(4)\times 10^{-11}{\text{cm}}^3/\text{s}$, which is below, but close to the predicted universal loss rate.

5 pages, 4 figures