COLLAPSE AND REVIVALS OF WAVE-PACKETS IN OPTICAL LATTICES

We study the effects of dispersion, tunneling, and dissipation on wave -packet oscillations resembling coherent states of atoms in optical la ttices. The wave packets are prepared by suddenly shifting the lattice after equilibration of the atoms at the lattice sites. The atoms osci llate in the light-shift potential wells, which exert a force arising from photon redistribution between lattice beams. We measure the resul tant periodic intensity exchange between the beams, obtaining informat ion on the wave-packet evolution. We observe a strong impact of dissip ation on the overall shape and the time of revivals, as well as a supp ression of tunneling by weak magnetic fields. [S0031-9007(98)07414-6].