Scattering halos in strongly interacting Feshbach molecular Bose-Einstein condensates

TL;DR

This paper studies scattering halos in molecular Bose-Einstein condensates, revealing how interactions influence collision processes and introducing a universal relation between scattering factors and halo ratios.

Contribution

It introduces a scattering factor and a universal relation for scattering halos, and compares perturbative and non-perturbative models with experimental data.

Findings

Interactions significantly affect scattering halo formation.

A universal relation between scattering factor and halo ratio is established.

Simulations reveal discrepancies under non-perturbative conditions.

Abstract

We investigate the scattering halos resulting from collisions between discrete momentum components in the time-of-flight expansion of interaction-tunable $^6\rm Li_2$ molecular Bose-Einstein condensates. A key highlight of this study is the observation of the influence of interactions on the collisional scattering process. We measure the production of scattering halos at different interaction levels by varying the number of particles and the scattering length, and quantitatively assess the applicability of perturbation theory. To delve into a general theory of scattering halos, we introduce a scattering factor and obtain a universal relation between it and the halo ratio. Furthermore, we simulate the formation of scattering halos under non-perturbative conditions and analyze the discrepancies between simulation results and experiments through a return pulse experiment. This study enhances our understanding of the physical mechanisms underlying scattering processes in many-body systems and provides new perspectives for further theoretical research.