Efimov-van-der-Waals universality for ultracold atoms with positive scattering lengths

Understand

We study the universality of the three-body parameters for systems relevant for ultracold quantum gases with positive $s$-wave two-body scattering lengths.

• Our results account for finite-range effects and their universality is tested by changing the number of deeply bound diatomic states supported by our interaction model.
• We find that the physics controlling the values of the three-body parameters associated with the ground and excited Efimov states is constrained by a variational principle and can be strongly affected by $d$-wave interactions that prevent both trimer states from merging into the atom-dimer continuum.
• Our results enable comparisons to current experimental data and they suggest tests of universality for atomic systems with{positive scattering lengths.