Suppression of collapse for matter waves with orbital angular momentum

We explore the influence of the orbital angular momentum on the collapse of vortex-free elliptic clouds of Bose–Einstein condensates with a negative scattering length trapped in a radially symmetric harmonic potential. We show that the number of trapped ultracold atoms corresponding to the collapse threshold can be radically increased for such rotating nonlinear matter waves. Below the threshold the elliptic mode is stable and exhibits periodic oscillations around a stationary rotating state. The frequency of these oscillations is independent of the number of particles and is determined solely by the trapping potential.