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A: Fachverband Atomphysik

A 19: Ultracold Rydberg gases (jointly with Q)

A 19.4: Talk

Thursday, March 13, 2008, 09:15–09:30, 2G

Prospects for resonant energy transfer in structured ultracold Rydberg gases — •Christian Giese, Christoph Sebastian Hofmann, Wendelin Sprenger, Janne Denskat, Thomas Amthor, Markus Reetz-Lamour, and Matthias Weidemüller — Physikalisches Intitut, Universität Freiburg, Hermann-Herderstr. 3, 79104 Freiburg

Dynamics in cold Rydberg gases are entirely determined by long-range dipole-dipole and van der Waals interactions due to the negligible translational energy. A unique feature of the system is the tunability of these interactions in both strength and character. In this manner, two Rydberg pair states can be made energetically degenerate. This leads to energy and population transfer known as resonant energy transfer (RET) which plays an important role in the process of photosynthesis. In recent work , we have compared Monte Carlo simulations of this process to density dependent population measurements[1]. Coherent energy transfer occurs, but the signature is washed out by many-body diffusion and disorder. To overcome this, we plan to use beamshaping techniques for structuring the atomic cloud. Recently, the theoretical and experimental prospects of coherent exciton transport in linear chains in the presence of excitation traps were discussed[2]. We propose an experimental way of using cold, structured Rydberg gases as a model system for investigating the coherent and incoherent properties of this process when introducing different degrees of disorder.

[1] S. Westermann et al., Eur. J. Phys. D 40, 37 (2006)

[2] O. Mülken et al., Phys. Rev. Lett. 99, 090601 (2007)