Note on the stability of a confined Bose gas: Comment on quant-ph/9712030 by L. Salasnich

We demonstrate analytically that a Bose-Einstein condensate confined in a harmonic trap with zero-range attractive interparticle interactions is unstable if there is more than 1 boson. Replacing the zero-range interaction by a short-range attractive interaction lifts the instability, and leads to a pronounced clustering, by which the particles leak out of the condensate.