  We study atomic Bloch oscillations in an ensemble of one-dimensional tilted
superfluids in the Bose-Hubbard regime. For large values of the tilt, we
observe interaction-induced coherent decay and matter-wave quantum phase
revivals of the Bloch oscillating ensemble. We analyze the revival period
dependence on interactions by means of a Feshbach resonance. When reducing the
value of the tilt, we observe the disappearance of the quasi-periodic phase
revival signature towards an irreversible decay of Bloch oscillations,
indicating the transition from regular to quantum chaotic dynamics.
