TROJAN WAVE-PACKETS - MATHIEU THEORY AND GENERATION FROM CIRCULAR STATES

We present an analytic theory of three-dimensional Trojan (stable nons preading) wave packets. The theory is valid beyond the harmonic approx imation presented previously. We show that electron wave packets that are both radially and angularly well localized can be generated from a n angularly completely delocalized state (a circular Rydberg state) by adiabatic switching of a circularly polarized electric field. Confine ment of the Rydberg electron results from the suppression of the nonli nearity of the Coulomb spectrum, the same nonlinearity that is respons ible for wave-packet spreading and revivals in the absence of the appl ied field. A comparison with the harmonic approach is also presented, as well as the results of numerical experiments based on integration o f the time-dependent and field-dependent Schrodinger equation for the electron.