We address the microscopic origin of the universal three-body parameter that fixes the spectrum of three-atom systems in the Efimov regime. We identify it with the van der Waals two-body correlation, which causes the three-atom system to deform when the three atoms come within the distance of the van der Waals length, effectively preventing them from coming closer due to the kinetic-energy cost associated with three-body deformation. This deformation mechanism explains the universal ratio of the scattering length at the triatomic resonance to the van der Waals length observed in several experiments and confirmed by numerical calculations.
|Journal||Physical Review A - Atomic, Molecular, and Optical Physics|
|Publication status||Published - 2014 Aug 11|
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics