  We examine the dynamics of ultracold atoms held in optical lattice
potentials. By controlling the switching of a periodic driving potential we
show how a phase-induced renormalization of the intersite tunneling can be used
to produce directed motion and control wavepacket spreading. We further show
how this generation of a synthetic gauge potential can be used to split and
recombine wavepackets, providing an attractive route to implementing quantum
computing tasks.
