Atomic quantum revivals produced by ultrashort laser pulses: The effect of energy discretization

We study atomic quantum revivals initiated by ultrashort laser pulses. The large energy spread of these pulses requires the use of atoms with high Z to limit the number of states excited. Yet the desired range of excitation energies must be accessible by state-of-the-art ultrashort laser pulses. This leads to Z ~ 8 and an interesting regime of a relatively small number k of states in the wave packet in the range 2 < k < 6. Under these circumstances the traditional harmonic expansion for the energy fails. We propose a method for calculating the periods of the system using the explicit values of the energies, with no harmonic expansion. Our method coincides in the limit of long pulses and high atomic number with the traditional one.