Credit: Yujun Wang, Kansas State University.
Probability density — given by the radius of the surface points to the origin — of an Efimov trimer state at different three-body geometries that are characterized by the polar angle — indicated by the trimer legends. The azimuthal angle characterizes the permutation of three atoms. The key feature in the probability density is that unlike ordinary molecular binding that mostly has a single geometry, the Efimov trimer covers have a broad range of geometries. The atoms in such states behave more like in a fluid drop.