Berlin 2001 – scientific programme

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A: Atomphysik

A 1: Posters Monday (Cluster, Atoms in Fields)

A 1.24: Poster

Monday, April 2, 2001, 12:30–15:00, AT3

Lifetime clustering in Wannier-Stark systems — •F. Zimmer, M. Glück, A. R. Kolovsky, and H. J. Korsch — Fachbereich Physik, Universität Kaiserslautern

The quantum states of a particle in a periodic potential plus an external field form the famous Wannier-Stark ladder of resonances. Using a recently developed momentum space scattering approach we discuss the lifetime of these resonances as a function of the strength of the external field. Depending on the shape of the periodic potential the resonances tend to cluster in groups of approximately the same lifetime. This effect is explained by the structure of the field-free Bloch spectrum in combination with a Zener tunneling ansatz. A model description based on this explanation correctly reproduces the numerical data.