Collisional properties of weakly bound heteronuclear dimers

B. Marcelis 1, 2, S. J. J. M. F. Kokkelmans 1, G. V. Shlyapnikov 2, 3, D. S. Petrov 2, 4

Physical Review A: Atomic, Molecular and Optical Physics 77 (2008) 032707

We consider collisional properties of weakly bound heteronuclear molecules (dimers) formed in a two-species mixture of atoms with a large mass difference. We focus on dimers containing light fermionic atoms as they manifest collisional stability due to an effective dimer-dimer repulsion originating from the exchange of the light atoms. In order to solve the dimer-dimer scattering problem we develop a theoretical approach, which provides a physically transparent and quantitative description of this four-atom system in terms of three- and two-body observables. We calculate the elastic scattering amplitude and the rates of inelastic processes such as the trimer formation and the relaxation of dimers into deeply bound molecular states. Irrespective of whether the heavy atoms are bosons or fermions, the inelastic rate can be significantly lower than the rate of elastic collisions. Moreover, the measurement of the inelastic rate which is a four-body observable, can be an efficient and precise tool for determining three-body observables such as the three-body parameter, positions of Efimov states and their lifetimes.

  • 1. Eindhoven University of Technology (TUE),
    Eindhoven University of Technology
  • 2. Laboratoire de Physique Théorique et Modèles Statistiques (LPTMS),
    CNRS : UMR8626 – Université Paris XI - Paris Sud
  • 3. Van der Waals-Zeeman Institute,
    University of Amsterdam
  • 4. National Research Centre "Kurchatov Institute" (NRC KI),
    University of Moscow