Trapped Bose gases with large positive scattering lengthM. Thøgersen, D. V. Fedorov and A. S. Jensen
IFA, Aarhus University - 8000 Aarhus C, Denmark
received 30 May 2007; accepted in final form 26 June 2007; published August 2007
published online 19 July 2007
We calculate the energy and the condensate fraction of a system of trapped bosons interacting via a short-range two-body potential with positive scattering length. The potential is attractive and has a two-body bound state. When the scattering length is small compared to the trap length the system is model independent: all potential models -attractive, repulsive and zero-range- provide similar results. When the scattering length is large the attractive model differs qualitatively from the repulsive and zero-range models. In this regime the system with attractive potential becomes independent of the scattering length, with both the energy and the condensate fraction converging towards finite constants.
03.75.Hh - Static properties of condensates; thermodynamical, statistical, and structural properties.
03.75.Nt - Other Bose-Einstein condensation phenomena.
21.45.+v - Few-body systems.
© Europhysics Letters Association 2007