Frankfurt 2006 – scientific programme

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Q: Quantenoptik und Photonik

Q 16: Quanteneffekte II

Q 16.5: Talk

Monday, March 13, 2006, 18:00–18:15, HII

Dynamics of resonant energy transfer processes in an ultracold gas of Rydberg atoms — •S. Westermann¹, T. Amthor¹, A.L. de Oliveira^2,3, J. Deiglmayr¹, M. Reetz-Lamour¹, and M. Weidemüller¹ — ¹Physikalisches Institut Universität Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg — ²Universidade do Estado de Santa Catarina, Departamento de Física, Joinville, SC 89223-100, Brazil — ³Universidade de São Paulo, Instituto de Física, São Carlos, SP 13560-970, Brazil

Rydberg atoms can be seen as a prototype system to investigate resonant energy transfer processes, which play an important role e.g. in many biological sytems (Förster processes). Due to the strong interactions of Rydberg atoms with external fields, one can use moderate electric fields of a few V/cm to tune the atom pair states | nP,nP > and | nS,(n+1)S > of ⁸⁷Rb into degeneracy. In an ultracold gas of Rb atoms excited into the 32P Rydberg state, one finds after a few µs many atoms in the 33S state due to the resonant energy transfer | 32P,32P > → | 32S,33S >.
The dependence of this process on the applied electric field can be mainly explained by many-body effects in a stationary gas [1]. We present a model extending the approach of Ref. [1] and density-dependent measurements. Both show that the time dependence can be explained in a stationary picture, underlining the coherent character of the resonant energy transfer in an ultracold Rydberg gas [2].

[1] Mourachko et al., PRA 70 (2004) 031401R

[2] S.Westermann et al., Eur.Phys.J.D subm.