Laser-induced rotation of a trapped Bose-Einstein condensate

Atom optic techniques are proposed to control the excitation of a Bose-Einstein condensate in an atomic trap. We show that by employing the dipole potential induced by four highly detuned traveling-wave laser beams with appropriate phases and frequencies, one can coherently excite a trapped Bose-Einstein condensate composed of ultracold alkali-metal atoms into a state rotating around the trap center. Pure vortex states can be created with this scheme if the condensate is trapped in an anharmonic trap.