Degenerate Raman sideband cooling of trapped cesium atoms at very high atomic densities

We trap 10(7) cesium atoms in a far red detuned 1D optical lattice. With de generate Raman sideband cooling we achieve a vibrational ground state popul ation of 80% for the steep trapping direction. Collisional coupling enables us to cool the spin-polarized gas in 3D without loss of atoms to a peak ph ase space density of 1/180 at a mean temperature of 2.8 mu K and a density of 1.4 x 10(13) cm(-3).