  Particles in a perfect lattice potential perform Bloch oscillations when
subject to a constant force, leading to localization and preventing
conductivity. For a weakly-interacting Bose-Einstein condensate (BEC) of Cs
atoms, we observe giant center-of-mass oscillations in position space with a
displacement across hundreds of lattice sites when we add a periodic modulation
to the force near the Bloch frequency. We study the dependence of these "super"
Bloch oscillations on lattice depth, modulation amplitude, and modulation
frequency and show that they provide a means to induce linear transport in a
dissipation-free lattice. Surprisingly, we find that, for an interacting
quantum system, super Bloch oscillations strongly suppress the appearance of
dynamical instabilities and, for our parameters, increase the phase-coherence
time by more than a factor of hundred.
