Reporter:Prof.Matthias Weidemüller
Affiliation: Physics Institute and Heidelberg Center for Quantum Dynamics, Heidelberg University
Time: At 10:00AM, March 25, 2016
Place: Yizhi Meeting Room

Abstract

The Efimov scenario, where pairwise resonantly interacting particles form an infinite geometrical　　series of bound three-body states, the Efimov states, is one of the most fundamental effects in　modern few-body quantum physics. The theoretical understanding and experimental observation of　　such progressions in both homonuclear and heteronuclear systems has been a longstanding　challenge that requires exquisite control and tuning of mutual particle interactions and appropriate　treatment of internal and external degrees of freedom. Here, employing a drastic reduction of the　geometrical scaling factor due to the high mass imbalance of Li and Cs atoms, we present the first　observation of three consecutive LiCsCs Efimov resonances via three-body recombination rate　measurements [1]. The previous analysis of Feshbach resonances [2] is extended with　radiofrequency association of LiCs Feshbach molecules to obtain precise mapping of the applied　magnetic field onto the scattering length [3]. This new parametrization of Li-Cs interaction　properties is used to compare the measured recombination spectra, including Efimov resonance　　positions and scaling factors, with state-of-the-art few-body theories. These findings are used to　　elucidate the connection between the universal regime that is excellently approximated by two-body　　contact interactions and the short range dominated regime, which is described by the van der Waals　　tails of pairwise interaction potentials [4,5].　

*Work done in collaboration with Juris Ulmanis, Stephan Hafner, Rico Pires, and Eva Kuhnle.

[1] R. Pires, J. Ulmanis, S. H ner, E. D. Kuhnle and M. Weidem ler, Phys. Rev. Lett. 112, 250404　　(2014).

[2] R. Pires, J. Ulmanis, M. Repp, E. D. Kuhnle, M. Weidem ler, T. Tiecke, B. Ruzic, C. Greene, J.　Bohn and E. Tiemann, Phys. Rev. A 90, 012710 (2014).

[3] J. Ulmanis, S. H ner, R. Pires, E. D. Kuhnle, M. Weidem ler, E. Tiemann, New J. Phys. 17,　　055009 (2015).

[4] J. Ulmanis et al., Phys. Rev. A 93, 022707 (2016).