Oscillation frequencies as a function of the parameter P for negative scattering length with each G = −0.03, 0, 0.03 with λz = 117/163
Figure 12. Oscillation frequencies as a function of the parameter P for negative scattering length with each G = −0.03, 0, 0.03 with λz = 117/163. The labels on the curves refer to different oscillation modes (see text).
We take into account the higher-order corrections in two-body scattering interactions within a mean-field description, and investigate the stability conditions and collective excitations of a harmonically trapped Bose–Einstein condensate (BEC). Our results show that the presence of higher-order corrections causes drastic changes to the stability condition of a BEC. In particular, we predict that with the help of the higher-order interaction, a BEC can now collapse even for positive scattering lengths; whereas, a usually unstable BEC with a negative scattering length can be stabilized by positive higher-order effects. The low-lying collective excitations are significantly modified as well, compared to those without the higher-order corrections. The conditions for a possible experimental scenario are also proposed.