The Efimov effect in lithium 6

TL;DR

This paper investigates the Efimov effect in lithium-6 atoms, analyzing recent experiments and highlighting the need for non-universal corrections for accurate quantitative descriptions at negative energies.

Contribution

It provides a detailed analysis of experimental data on lithium-6, emphasizing the importance of non-universal corrections for modeling the Efimov effect.

Findings

Qualitative agreement with Efimov physics observed.

Quantitative discrepancies at negative energies identified.

Energy-dependent parameters improve data fitting.

Abstract

We analyse the recent experiments investigating the low-energy physics of three lithium 6 atoms in different internal states with resonant two-body scattering lengths. All observed features are qualitatively consistent with the expected Efimov effect, i.e. the effective universal three-body attraction that arises for large values of the scattering lengths. However, we find that a quantitative description at negative energy requires non-universal two- and three-body corrections due to presently unknown behaviour at short distance. An attempt to implement these corrections is made through energy-dependent parameters fitted to the experimental data.