Hannover 2010 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 5: Ultra-Cold Atoms: Rydberg Gases / Miscellaneous (with Q)
A 5.2: Vortrag
Montag, 8. März 2010, 17:00–17:15, A 320
Coherent population trapping with controlled interparticle interactions — •Georg Günter1, Hanna Schempp1, Christian Giese1, Sebastian Saliba1, Christoph Hofmann1, Brett D. DePaola1, Sevilay Sevincli2, Thomas Pohl2, Thomas Amthor1, and Matthias Weidemüller1 — 1Physikalisches Institut, Universität Heidelberg, Philosophenweg 12, 69120 Heidelberg — 2Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, 01187 Dresden
Coherent population trapping (CPT) and the related phenomenon of a "dark resonance" is a paradigm for quantum interference. Intense studies of this phenomenon have led to intriguing effects like electromagnetically induced transparency, lasing without inversion, adiabatic population transfer and subrecoil cooling. Whereas CPT is generally described within a single-atom framework, the situation becomes more involved when interparticle interactions have to be considered. To address this question, we investigate CPT in a strongly interacting, ultracold Rydberg-gas. In our experiment we tune the interaction strength by choosing the Rydberg state and control interactions effects using the ground state density. Even in the blockade regime we observe a resonance with sub-natural linewidth at the single-particle resonance frequency despite the strong van der Waals interactions among Rydberg atoms. Due to the correlations among the atoms the experimental observations cannot be explained within a meanfield model. A theoretical model that includes interparticle correlations is presented and nicely reproduces the observed features.