Excitation frequencies and stability regions for two-species Bose-Einsteincondensate in a triaxial magnetic trap

We have solved the coupled Gross-Pitaevskii equations for a two-species con densate confined within a fully anisotropic magnetic trap. Both variational and numerical methods are used to solve the Gross-Pitaevskii equations, an d the original numerical approach is discussed in more length. The calculat ion of the two-species excitation spectrum shows that the mode frequencies of the individual condensates are modified in a two-species condensate inte ratomic interaction, with new excitation modes present in the mixed system, The spatial distributions of the two condensates show deformations produce d by the interatomic interactions, with either compression of the atoms in the central region of the trap, or with a decrease of the atomic density in that region. (C) 1999 Published by Elsevier Science B.V. All rights reserv ed.