The Efimov effect in lithium 6

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.Comment: 12 pages, 8 figures. Same as published version. Contains additions detailing the derivation of some formulae; http://dx.doi.org/10.1016/j.crhy.2010.12.00