  We investigate the effect of temperature on resonant and antiresonant
dynamics in a dilute atomic gas kicked periodically by a standing wave laser
field. Our numerical calculations are based on a Monte Carlo method for an
incoherent mixture of non-interacting plane waves, and show that the atomic
dynamics are highly sensitive to the initial momentum width of the gas. We
explain this sensitivity by examining the time evolution of individual atomic
centre of mass momentum eigenstates with varying quasimomentum, and we have
determined analytic expressions for the evolution of the second-order momentum
moment to illustrate the range of behaviours.
