An approximate many-body calculation for trapped bosons with attractive interaction

TLDR: In this paper, the stability of trapped interacting bosons with attractive interactions is studied using an approximate many-body calculation using PHEM instead of using the traditional hyperspherical harmonics expansion method (PHEM), and the justification of the use of PHEM in connection with dilute condensates is presented.

Abstract: The stability of trapped interacting bosons with attractive interactions is studied using an approximate many-body calculation. Instead of using the traditional hyperspherical harmonics expansion method we prescribe a potential harmonics expansion method (PHEM). The justification of the use of PHEM in connection with dilute condensates is presented. The choice of a correlation function is justified as it correctly reproduces the short-range two-body correlation in the wavefunction as also the correct value of the s-wave scattering length (as). Applications to 7Li and 85Rb condensates with the realistic van der Waals interaction give good agreement with the Rice and JILA experiments, respectively. The JILA experiment used controlled collapse of the 85Rb condensate for different values of as. Our calculations agree with the experimental results within the experimental error bars.