Atomic, Molecular, and Optical Physics Seminar
Raman-Sideband Cooling and Cold Atomic Collisions in Optical Lattices
Dr. Andrew J.
Department of Physics
The next generation of atomic frequency standards, atom-interferometers, and Bose-Einstein condensation experiments can benefit from enhanced laser-cooling methods capable of preparing a high flux of atoms at high phase-space density. We have demonstrated such a method, known as Raman-sideband cooling, which we have used to produce atomic samples at temperatures near the single-photon recoil limit, and at phase-space densities within a factor of 30 of Bose-Einstein condensation. This method involves stimulated Raman transitions between the well-resolved, quantized vibrational levels of atoms in the tightly confining potential of an optical lattice.
We have also used this technique to prepare high densities of trapped cesium atoms to study their ultracold collisions. These interactions are the dominant stability limit for advanced cesium frequency standards, and are also important for Bose-Einstein condensation and cold-atom based realizations of quantum phase-transitions and quantum computation schemes. We have observed a large number of narrow resonances in the elastic and inelastic collision cross-sections, arising from an effect known as Feshbach resonance, where two atoms form a weakly-bound virtual molecule during a collision. From our observations, a fully predictive model of ultracold cesium collisions can for the first time be constructed.
Monday, January 27, 2003
Gant Science Complex