Observation of Collisions between Two Ultracold Ground-State CaF Molecules

Lawrence W. Cheuk, Loïc Anderegg, Yicheng Bao, Sean Burchesky, Scarlett S. Yu, Wolfgang Ketterle, Kang-Kuen Ni, and John M. Doyle

We measure inelastic collisions between ultracold CaF molecules by combining two optical tweezers, each containing a single molecule. We observe collisions between 2Σ 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)×10−11  cm3/s, which is below, but close to, the predicted universal loss rate.

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