  We present a novel approach to modeling dynamics of trapped, degenerate,
weakly interacting Bose gases beyond the mean field limit. We transform a
many-body problem to the interaction representation with respect to a suitably
chosen part of the Hamiltonian and only then apply a multimode coherent-state
ansatz. The obtained equations are almost as simple as the Gross--Pitaevskii
equation, but our approach captures essential features of the quantum dynamics
such as the collapse of coherence.
