  We apply wave packet methods to study an ion-trap system in the strong
excitation regime imposing neither the rotating wave nor the Lamb-Dicke
approximations. By this approach we show the existence of states with
restricted phase space evolution, as a genuine consequence of quantum
interference between wave packet fractions. A particular instance of such a
state oscillates between maximal entanglement and pure disentanglement between
the constitute subsystems. The characteristic crossover time is very rapid
making them suitable for state preparations of EPR or Schrodinger cat states.
Over longer time periods the dynamics of these states exhibits collapse-revival
patterns with well resolved fractional revivals in autocorrelation, inversion
and entanglement.
