It is shown that by an appropriate modification of the trapping potential, one may create collective excitation in a cold atom Bose-Einstein condensate. The proposed method is complementary to earlier suggestions. It seems to be feasible experimentally—it requires only a proper change in time of the potential in atomic traps, as realized in laboratories already.

• Received 2 February 2001

DOI:https://doi.org/10.1103/PhysRevA.63.061601