Hannover 2016 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 36: Ultra-cold atoms, ions and BEC IV (with Q)
A 36.3: Vortrag
Donnerstag, 3. März 2016, 15:00–15:15, f303
On the heteronuclear Efimov effect with van der Waals interactions — •Juris Ulmanis1, Stephan Häfner1, Rico Pires1, Yujun Wang2, Chris H. Greene3, Eva D. Kuhnle1, and Matthias Weidemüller1 — 1Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 226, 69120 Heidelberg, Germany — 2Department of Physics, Kansas State University, 116 Cardwell Hall, Manhattan, KS 66506, USA — 3Department of Physics, Purdue University, West Lafayette, Indiana, 47907-2036, USA
Ultracold Bose-Fermi mixture of 133Cs and 6Li atoms constitutes a prototypical system with mass imbalance that allows thorough exploration of the heteronuclear Efimov effect – the formation of an infinite geometrical series of bound three-body states for resonant two-body interactions. Here we present our measurements and analysis of three-body recombination spectra of Li+Cs+Cs close to two broad Li-Cs Feshbach resonances. Two series of consecutive Efimov resonances, each characterized by different sign and magnitude of Cs-Cs s-wave scattering length, are observed, showing deviations from the geometric scaling law. For positive Cs-Cs scattering lengths the three-body resonance that is associated to the Efimov ground state is missing. This is in agreement with the spinless van der Waals theory that predicts the transformation of the Efimov ground state into the Li + Cs2 scattering channel, and modification of the scaling factors via short-range effects. These findings provide a comprehensive picture of universal and non-universal features in the heteronuclear Efimov scenario.