Dresden 2011 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 3: Cold Molecules 1

Q 3.3: Vortrag

Montag, 14. März 2011, 11:00–11:15, BAR Schön

Semiclassical model for the formation of Rydberg molecules — •Andrej Junginger, Jörg Main, and Günter Wunner — 1. Institut für Theoretische Physik, Universität Stuttgart

In cold gases ultra-long range Rydberg molecules have been predicted theoretically [1] and recently observed experimentally [2]. The bond is caused by a scattering process of the Rydberg electron at the ground state atom. In a mean-field approximation this can be explained by a Fermi pseudo-potential which well describes the bound states but, as a conservative potential, is not able to explain the process of capturing the ground state atom.

We present a new model based on scattering theory and a semiclassical approximation which is capable of describing the formation of the Rydberg molecule by decelerating the ground state atom. From the infinite set of Kepler ellipses we select a finite number passing through the ground state atom. At the position of the latter the ellipses are approximated by plane waves, and the s-wave scattering of the Rydberg electron at the ground state atom then leads to a dissipative force. Solving the classical equations of motion, we find that a ground state atom with kinetic energy E_kin>0 in the order of the magnitude of the binding energy will always be decelerated. Depending on the initial conditions it can even come to rest, so that this dissipative process may play an important role in the formation of the Rydberg molecule.

[1] C. H. Green et al., Phys. Rev. Lett. 85, 2458 (2000).

[2] V. Bendkowsky et al., Nature 458, 1005 (2009).