A. Parola et al., STRUCTURE AND STABILITY OF BOSONIC CLOUDS - ALKAKI-METAL ATOMS WITH NEGATIVE SCATTERING LENGTH, Physical review. A, 57(5), 1998, pp. 3180-3183
We investigate the form and stability of a cloud of atoms confined in
a harmonic trap when the scattering length is negative. We find that,
besides the known low-density metastable solution, a different branch
of Bose condensate appears at higher density when nonlocality effects
in the attractive part are taken into account. The transition between
the two classes of solutions as a function of the number N of atoms ca
n be either sharp or smooth according to the strength and range of the
attractive interaction. Use of tight traps is favorable for investiga
ting the evolution of the system, as the strength of the effective int
eraction increases with N.