Properties of universal bosonic tetramers

Abstract

The system of four identical bosons is studied using momentum-space equations for the four-particle transition operators. Positions, widths and existence limits of universal unstable tetramers are determined with high accuracy. Their effect on the atom-trimer and dimer-dimer scattering observables is discussed. We show that a universal shallow tetramer intersects the atom-trimer threshold twice leading to resonant effects in ultracold atom-trimer collisions.

Comments: accepted for publication in special issue of Few-Body Systems devoted to Critical Stability 2011