  A condensate in an optical lattice, prepared in the ground state of the
superfluid regime, is stimulated first by suddenly increasing the optical
lattice amplitude and then, after a waiting time, by abruptly decreasing this
amplitude to its initial value. Thus the system is first taken to the Mott
regime and then back to the initial superfluid regime. We show that, as a
consequence of this nonadiabatic process, the system falls into a configuration
far from equilibrium whose superfluid order parameter is described in terms of
a particular superposition of Glauber coherent states that we derive. We also
show that the classical equations of motion describing the time evolution of
this system are inequivalent to the standard discrete nonlinear Schreodinger
equations. By numerically integrating such equations with several initial
conditions, we show that the system loses coherence, becoming insulating.
