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A: Atomphysik
A 12: Atomare Systeme in externen Feldern I
A 12.6: Vortrag
Mittwoch, 15. März 2006, 15:30–15:45, H6
Resonance-assisted decay of nondispersive wave packets in microwave-driven hydrogen Rydberg atoms — •Sandro Wimberger1, Peter Schlagheck2, Christopher Eltschka2, and Andreas Buchleitner3 — 1CNR-INFM and Dipartimento di Fisica E. Fermi, Universita degli Studi di Pisa, Largo Pontecorvo 3, I-56127 Pisa — 2Institut für Theoretische Physik, Universität Regensburg, D-93040 Regensburg — 3MPI für Physik komplexer Systeme, Nöthnitzerstr. 38, D-01187 Dresden
We present a quantitative semiclassical theory for the decay of nondispersive electronic wave packets that are formed in resonantly driven hydrogen Rydberg atoms. This decay is induced by a classically forbidden coupling process through the dynamical barriers of the regular island on which the wave packets are localized. The associated coupling rate is determined by the high-order nonlinear resonance that most dominantly manifests within this island. This resonance-assisted tunneling process is combined with quantum transport across a chaotic phase space region, and with the subsequent one-photon decay to the atomic continuum. We thus obtain an analytical semiclassical expression for the average decay rate of the wave packets, which is in excellent agreement with the exact rates obtained by a numerical diagonalization of the Floquet problem.