The kicked Rydberg atom

Recent developments in experimental technique allow study of the ionization and excitation of Rydberg atoms by pulsed unidirectional electric fields, termed half-cycle pulses (HCPs), with duration T-p << T-n, where T-n is the classical electron orbital period. In this limit, each HCP simply delivers an impulsive momentum transfer or "kick" to the Rydberg electron. The opportunities provided by this are discussed with the aid of both theory and experiment. Single HCPs can be used to probe the momentum (and spatial) distribution of the excited electron. Atoms subject to a train of periodic HCPs provide an experimental realization of the kicked atom, a valuable test bed for the study of nonlinear dynamics in Hamiltonian systems. Studies of kicked atoms have furnished new insights into classical-quantum correspondence as well as a variety of phenomena such as dynamical stabilization and quantum localization which illuminate how the classical world emerges from the quantum world. Dynamical stabilization leads to strong transient periodic localization of the excited electron in phase-space and creation of periodic nondispersive wavepackets. The ability to manipulate the electron in phase-space can be extended by modulating the amplitude and frequency of the HCPs. Strong transient phase-space localization can also be generated using quasi-one-dimensional Rydberg atoms and a single HCP. Such localization provides new opportunities for control of the atomic wavefunction, i.e., for atomic engineering, by application of a carefully tailored sequence of HCPs to produce, for example, wavepackets whose behavior mimics that of a localized classical particle. Studies of the kicked Rydberg atom find application in a number of fields including fast ion-atom collisions, ion channeling in solids and exploring the behavior of atoms in ultra-fast, ultra-intense pulsed laser fields.