| Dynamics and interactions of atoms at low temperatures are quantum-mechanical in nature. Quantized motion in an optical trap can be resolved and manipulated by Raman transitions. A new cooling scheme, Raman-sideband cooling, is developed by pumping the atoms to the lowest vibrational level which dramatically reduces the temperature. After adiabatically releasing the atoms into the free space, a phase space density of 1/25 is observed, a factor of 104 improvement over the conventional optical molasses.; After cooling, up to 3 x 108 cesium atoms are transferred into a far-detuned dipole trap with a density as high as 1013cm -3. Multiple Feshbach resonances are discovered when the Cs 2 molecular bound states are tuned into degeneracy with the scattering state. The S-wave scattering length, which parameterizes the low energy scattering processes, varies dispersively about the Feshbach resonances and results in the observed collision anomalies. Based on the Feshbach spectroscopy, the cesium long range interactions are determined quantitatively for the first time: C6 = 6859(25)a.u., C8 = 8.6(8) x 10 5a.u., as = 280.37(12)a0, at = 2437(25)a 0 and Sc = 2.6(5).; When cold atoms are individually trapped and isolated in 3D optical lattices, they are immune from the collision events and a long coherence time is expected. Precision measurements on the electron's electric dipole moment and a scalable quantum computation scheme are proposed based on cold atoms in an optical lattice. |
