Dynamics of a BEC bright soliton in an expulsive potential
  We theoretically investigate the dynamics of a matter-wave soliton created in a harmonic potential, which is attractive in the transverse direction but expulsive in the longitudinal direction. This Bose-Einstein-condensate (BEC) bright soliton made of $^7$Li atoms has been observed in a recent experiment (Science {\bf 296}, 1290 (2002)). We show that the non-polynomial Schr\"odinger equation, an effective one-dimensional equation we derived from the three-dimensional Gross-Pitaevskii equation, is able to reproduce the main experimental features of this BEC soliton in an expulsive potential. 
Luca Salasnich (INFM and Univ. Milano)