Molecule-molecule and atom-molecule collisions in an ultracold ensemble of bosonic ²³Na³⁹K molecules

Understanding and controlling collisions in ultracold gases of all-ground state molecules is of great importance in particular in view of possible applications of the molecules for quantum-many-body physics and precision measurements. Here, we report the preparation of an ultracold gas of  bosonic polar ²³Na³⁹K molecules in a specific hyperfine state of their rovibronic ground state.  We analyze the two-body decay of a pure molecular sample and in various atom-molecule mixtures. In particular, we find an unexpectedly low two-body decay coefficient for collisions between molecules and ³⁹K atoms in a selected hyperfine state [1].  Finally, we report about our recent studies of  photoinduced-loss processes for the chemically stable ²³Na³⁹K molecules [2].