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Mechanical effect of van der Waals interactions observed in real time in an ultracold Rydberg gas

T. Amthor·M. Reetz-Lamour·S. Westermann·J. Denskat·M. Weidemüller
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Abstract

We present time-resolved spectroscopic measurements of Rydberg-Rydberg interactions in an ultracold gas, revealing the pair dynamics induced by long-range van der Waals interactions between the atoms. By detuning the excitation laser, a specific pair distribution is prepared. Penning ionization on a microsecond timescale serves as a probe for the pair dynamics under the influence of the attractive long-range forces. Comparison with a Monte Carlo model not only explains all spectroscopic features but also gives quantitative information about the interaction potentials. The results imply that the interaction-induced ionization rate can be influenced by the excitation laser. Surprisingly, interaction-induced ionization is also observed for Rydberg states with purely repulsive interactions.

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T. Amthor, M. Reetz-Lamour, S. Westermann, J. Denskat, M. Weidemüller. 2006-07-05. Mechanical effect of van der Waals interactions observed in real time in an ultracold Rydberg gas. https://doi.org/10.1103/physrevlett.98.023004

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