  We present theoretical and numerical results on the dynamics of ultracold
atoms in an accelerated single- and double-periodic optical lattice. In the
single-periodic potential Bloch oscillations can be used to generate fast
directed transport with very little dispersion. The dynamics in the
double-periodic system is dominated by Bloch-Zener oscillations, i.e. the
interplay of Bloch oscillations and Zener tunneling between the subbands. Apart
from directed transport, the latter system permits various interesting
applications, such as widely tunable matter wave beam splitters and
Mach-Zehnder interferometry. As an application, a method for efficient probing
of small nonlinear mean-field interactions is suggested.
