Observation of resonant scattering between ultracold heteronuclear Feshbach molecules

TL;DR

This paper reports the first observation of a resonant inelastic collision between ultracold heteronuclear Feshbach molecules, revealing a crossing with a tetramer state and enabling tunable interactions in ultracold molecular systems.

Contribution

It provides the first experimental evidence of a heteronuclear dimer-dimer inelastic resonance linked to a tetramer state crossing, advancing understanding of four-body heteronuclear systems.

Findings

Observation of a pronounced inelastic loss peak at the resonance

Modification of temperature dependence of dimer-dimer scattering near resonance

Insight into heteronuclear four-body interactions

Abstract

We report the observation of a dimer-dimer inelastic collision resonance for ultracold Feshbach molecules made of bosonic sodium and rubidium atoms. This resonance, which we attribute to the crossing of the dimer-dimer threshold with a heteronuclear tetramer state, manifests itself as a pronounced inelastic loss peak of dimers when the interspecies scattering length between the constituent atoms is tuned. Near this resonance, a strong modification of the temperature dependence of the dimer-dimer scattering is observed. Our result provides insight into the heteronuclear four-body system consisting of heavy and light bosons and offers the possibility of investigating ultracold molecules with tunable interactions.