  For an attractive trapped Bose-Einstein condensate an imaginary three-body
recombination loss term and an imaginary linear source term are usually
included in the Gross-Pitaevskii (GP) equation for a proper account of
dynamics. Under the action of an impulsive force, generated by suddenly
changing the atomic interaction or the trapping potential, the solution of this
complex GP equation for attractive interaction is found to lead to a very long
term chaotic oscillation.
