Observation of an Efimov resonance in an ultracold mixture of atoms and weakly bound dimers

TL;DR

This paper reports the experimental observation of an Efimov resonance in an ultracold mixture of cesium atoms and dimers, providing insights into universal and non-universal few-body quantum phenomena.

Contribution

It presents the first observation of an atom-dimer Efimov resonance in an ultracold atomic mixture, including analysis of universal and non-universal states and comparison with theoretical models.

Findings

Observation of an Efimov resonance in an ultracold Cs mixture

Comparison of experimental results with effective field theory

Analysis of universal and non-universal dimer states

Abstract

We discuss our recent observation of an atom-dimer Efimov resonance in an ultracold mixture of Cs atoms and Cs_2 Feshbach molecules [Nature Phys. 5, 227 (2009)]. We review our experimental procedure and present additional data involving a non-universal g-wave dimer state, to contrast our previous results on the universal s-wave dimer. We resolve a seeming discrepancy when quantitatively comparing our experimental findings with theoretical results from effective field theory.