Creation of vortex states in trapped condensates
To create a vortex state from a resting condensate one obviously has to transfer angular momentum to the atoms. We examined whether this can be achieved by using laser light.
One idea to transfer angular momentum to the atoms was
to use Laguerre-Gaußian laser beams which already have an orbital
We proposed to use a Raman transition between to hyperfine levels of the
atoms to transfer the resting condensate in the
| m = -1 > hyperfine state to a condensate in the | m = +1 > state forming a vortex.
Due to the interaction between the atoms the efficiency of this process is usually not very large since the interaction energy drives the transition out of resonance. We showed theoretically that this energy shift can be compensated by varying the frequency difference between the two Laguerre-Gaußian laser beams linearly in time.
In the same paper we also proposed a scheme based on the Doppler effect to detect a vortex state.