  We calculate the time evolution of a far-from-equilibrium initial state of a
non-relativistic ultracold Bose gas in one spatial dimension. The
non-perturbative approximation scheme is based on a systematic expansion of the
two-particle irreducible effective action in powers of the inverse number of
field components. This yields dynamic equations which contain direct
scattering, memory and off-shell effects that are not captured in mean-field
theory.
