Hannover 2016 – scientific programme
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A: Fachverband Atomphysik
A 16: Collisions, scattering and correlation phenomena II
A 16.2: Talk
Tuesday, March 1, 2016, 15:00–15:15, f142
Universal three-body recombination and Efimov resonances in an ultracold Li-Cs mixture — •Stephan Häfner1, Juris Ulmanis1, Rico Pires1, Felix Werner2, Dmitry S. Petrov3, Eva D. Kuhnle1, and Matthias Weidemüller1 — 1Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 226, 69120 Heidelberg, Germany — 2Laboratoire Kastler Brossel, ENS-PSL, UPMC-Sorbonne Université, Collège de France, CNRS, 24 rue Lhomond, 75231 Paris Cedex 05, France — 3LPTMS, CNRS, Univ. Paris Sud, Université Paris-Saclay, 91405 Orsay, France
Universality of few-body systems has been a driving force in fundamental quantum physics. One paradigm is the Efimov effect, where a infinite geometical progession of bound three-body states emerges from pairwise resonantly interacting particles. In an ultracold Bose-Fermi mixture of 133Cs and 6Li the scaling factor is drastically reduced due to its large mass imbalance, making it an indeal system for the experimental observation of a series of Efimov resonances. Here we present our recent measurements of the three-body event rate constant of the Li+Cs+Cs scattering channel close to a broad Feshbach resonance. We observe a series of three consecutive Efimov resonances at temperatures of 450nK and 120nK and compare the recombination spectra with the universal zero-range theory at finite temperature [1]. For the first and second excited Efimov resonance, located in the window of universality, good agreement is found, whereas for the ground state deviations from universality become apparent.
[1] D.S. Petrov and F. Werner, Phys. Rev. A 92, 022704 (2015)