LOCAL DYNAMICS OF LASER COOLING IN AN OPTICAL LATTICE

Using the basis of Wannier states, we study the local dynamics of pola rization gradient cooling for an atom driven on a J(g)=2-->J(e)=3 tran sition by a one-dimensional optical lattice. This analysis allows us t o formulate a physical picture of the cooling mechanism, analogous to Sisyphus cooling for a J(g)=1/2-->J(e)=3/2 atom, which depends strongl y on coherences in the Zeeman sublevels of the ground state. In additi on, we are able to explain the steady-state properties of the laser-co oled atoms in a regime where the standard semiclassical analysis break s down.