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A: Atomphysik

A 3: Ultrakalte Atomphysik I: Plasmen und Rydbergsysteme

A 3.4: Vortrag

Montag, 13. März 2006, 17:30–17:45, H6

Ionization processes induced by ultralong-range interactions in an ultracold Rydberg gas — •T. Amthor¹, M. Reetz-Lamour¹, S. Westermann¹, J. Denskat¹, J. Deiglmayr¹, A.L. de Oliveira^2,3, 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

In early investigations of many-body effects in an ultracold Rydberg gas, the atoms were considered to be at rest (”frozen gas”) [1]. It was soon found that this cloud of Rydberg atoms can spontaneously evolve into a quasi-neutral plasma [2]. While the low temperature excludes any considerable thermal motion, the attractive interaction between the atoms can lead to acceleration, collisions, and finally Penning ionization [3]. This process can trigger the efficient ionization of the whole cloud.
We present spectroscopically resolved measurements of the ionization dynamics of different Rydberg states in an initially cold sample, which provide information about long-range interaction potentials.

[1] Anderson et al., PRA 80, 249 (1998), Mourachko et al., PRA 80, 253 (1998)

[2] Gallagher et al., JOSA B 20, 1091 (2003)

[3] Li et al., PRL 94, 173001 (2005)