Atom-dimer and dimer-dimer scattering in fermionic mixtures near a narrow Feshbach resonance

TL;DR

This paper develops a diagrammatic method to analyze atom-dimer and dimer-dimer scattering in heteronuclear fermionic mixtures near a narrow Feshbach resonance, revealing strong angular momentum effects and providing scattering parameters.

Contribution

It introduces a novel diagrammatic approach for few-body problems in heteronuclear fermionic mixtures near narrow Feshbach resonances, including detailed scattering phase shifts and relaxation rates.

Findings

Strong angular momentum dependence in atom-dimer interactions.

Pronounced interference between s- and p-waves in 40K-(40K-6Li) collisions.

Calculated dimer-dimer scattering length and relaxation rate constants.

Abstract

We develop a diagrammatic approach for solving few-body problems in heteronuclear fermionic mixtures near a narrow interspecies Feshbach resonance. We calculate s-, p-, and d-wave phaseshifts for the scattering of an atom by a weakly-bound dimer. The fermionic statistics of atoms and the composite nature of the dimer lead to a strong angular momentum dependence of the atom-dimer interaction, which manifests itself in a peculiar interference of the scattered s- and p-waves. This effect strengthens with the mass ratio and is remarkably pronounced in 40K-(40K-6Li) atom-dimer collisions. We calculate the scattering length for two dimers formed near a narrow interspecies resonance. Finally, we discuss the collisional relaxation of the dimers to deeply bound states and evaluate the corresponding rate constant as a function of the detuning and collision energy.