Effective range from tetramer dissociation data for cesium atoms

TL;DR

This paper develops a method to extract the effective range correction from tetramer dissociation data in ultracold cesium gases, improving understanding of four-body interactions near Feshbach resonances.

Contribution

It introduces a novel approach to determine the effective range correction from experimental tetramer dissociation peaks in cold atom systems.

Findings

Effective range correction is approximately 3.9 times the van der Waals length.

The method aligns with the van der Waals potential tail for cesium.

Applicable to other cold atom experiments for four-body interaction analysis.

Abstract

The shifts in the four-body recombination peaks, due to an effective range correction to the zero-range model close to the unitary limit, are obtained and used to extract the corresponding effective range of a given atomic system. The approach is applied to an ultracold gas of cesium atoms close to broad Feshbach resonances, where deviations of experimental values from universal model predictions are associated to effective range corrections. The effective range correction is extracted, with a weighted average given by 3.9$\pm 0.8 R_{vdW}$, where $R_{vdW}$ is the van der Waals length scale; which is consistent with the van der Waals potential tail for the $Cs_2$ system. The method can be generally applied to other cold atom experimental setups to determine the contribution of the effective range to the tetramer dissociation position.