Photoinduced two-body loss of ultracold molecules

Ultracold polar molecules are a promising platform for applications such as precision measurement, quantum computing, and quantum simulation. In typical experiments, the molecules’ lifetime is limited by loss due to molecule-molecule collisions. Surprisingly, collisional loss is observed even for chemically stable molecules, and cannot be explained by “sticky collisions”, proposed previously \footnote{Mayle, Ruzic, and Bohn, \emph{Phys. Rev. A}, {\bf 85}, 062712 (2013)}. Instead, we show that excitation of collision complexes by the laser used to trap the molecules leads to the effective two-body loss observed experimentally \footnote{Christianen, Zwierlein, Groenenboom, and Karman, \emph{Phys. Rev. Lett.}, {\bf 123}, 123402 (2019)}