Quantum motion of atoms confined in an optical lattice

An optical lattice is a periodic array of potential wells for atoms, formed by the interference of several laser beams. These lattices have interesting similarities to and differences from solid crystal lattices. We study the motion of atoms trapped and laser-cooled in such lattices by measuring the atomsʹ temperature when released, by examining the spectrum of light emitted by the atoms, and by Bragg scattering of light from the lattice. We find results that are in good quantitative agreement with detailed quantum mechanical calculations.