2003/09/02 by Luca Salasnich
Physics and Astronomy · #cond-mat.soft #cond-mat.stat-mech
published as Laser Physics, vol. 14, N. 2, 291-294 (2004) · presented to the XII International Laser Physics Workshop, August 24-29 2003, Hamburg (Germany); to be published in Laser Physics
arxiv created 2003/09/02 · arxiv updated 2009/12/01
Formation of multi-solitons and vortex bright solitons in Bose-condensed alkali-metal atoms is analyzed by using the nonpolynomial Schordinger equation. A train of bright solitons is obtained from an axially homogeneous Bose-Einstein condensate by a sudden change of the scattering length from repulsive to attractive. We derive an analytical expression for the number of bright solitons generated by using this mechanism. The formula generalizes a previous formula obtained with the 1D Gross-Pitaevskii equation. In the second part we consider vortex bright solitons, namely cigar-shaped bright solitons with a nonzero angular quantum number k along the axial direction. By using a variational approach we determine the shape of vortex bright solitons, showing that the critical number of atoms for the collapse of the vortex soliton increases with a larger k. Finally we calculate monopole and quadrupole collective oscillations of these vortex bright solitons.