Effect of interaction strength on gap solitons of Bose--Einstein condensates in optical lattices

We have developed a systematic analytical approach to the study onthe dynamic properties of the linear and the nonlinear excitationsfor quasi-one-dimensional Bose--Einstein condensate trapped inoptical lattices. A novel linear dispersion relation and an algebraicsoliton solution of the condensate are derived analytically underconsideration of Bose--Einstein condensate with a periodic potential.By analysing the soliton solution, we find that the interatomicinteraction strength has an important effect on soliton dynamicproperties of Bose--Einstein condensate.