Stability of attractive bosonic cloud with van der Waals interaction

TL;DR

This paper studies the stability of a Bose-Einstein condensate of lithium atoms considering realistic van der Waals interactions, revealing a new high-density stable state and analyzing effects of trap size and collision losses.

Contribution

It introduces a detailed analysis of condensate stability with realistic interactions and identifies a novel high-density stable branch not previously characterized.

Findings

Discovery of a high-density stable branch in the condensate

Comparison between local and non-local interaction models

Analysis of trap size effects on stability and transition

Abstract

We investigate the structure and stability of Bose-Einstein condensate of $^{7}$Li atoms with realistic van der Waals interaction by using the potential harmonic expansion method. Besides the known low-density metastable solution with contact delta function interaction, we find a stable branch at a higher density which corresponds to the formation of an atomic cluster. Comparison with the results of non-local effective interaction is also presented. We analyze the effect of trap size on the transition between the two branches of solutions. We also compute the loss rate of a Bose condensate due to two- and three-body collisions.