Quantum transport of atoms in an optical lattice

Abstract

Quantum-mechanical transport of atoms in an optical lattice in one dimension is described in an exactly solvable model. The atoms are tightly bound and they are sufficiently cooled so that they are restricted only to the lowest Bloch band in a single adiabatic potential. The coherent spreading of an atomic wave packet by tunneling is counteracted by the localizing effect of photon emission that accompanies optical pumping. The time evolution of the quasimomentum distribution, the coherence length, and the spatial width of the atomic state are evaluated analytically. These quantities depend strongly on the statistics of photon emissions.