Erlangen 2018 – scientific programme

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MO: Fachverband Molekülphysik

MO 15: Complex Systems in the Gas Phase

MO 15.6: Talk

Wednesday, March 7, 2018, 15:15–15:30, PA 1.150

Many-body resonances in dilute gas-phase systems — •Lukas Bruder¹, Marcel Binz¹, Ulrich Bangert¹, Markus Schulz-Weiling², and Frank Stienkemeier¹ — ¹Physikalisches Institut, Universität Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg — ²Department of Chemistry, University of British Columbia, Vancouver British Columbia, Canada V6T 1Z1

We investigate the collective behavior of atomic gases at low density and ambient temperature. In this regime, interatomic interactions are small and collective effects are masked by inhomogeneous broadening. Therefore, collective signatures are hard to detect with frequency domain methods. To this end, we have developed a highly efficient time-domain detection method based on a nonlinear femtosecond pump probe excitation scheme [1]. With this method, we detected, for the first time, four-body resonances in a rubidium vapor at densities down to 10⁸ cm⁻³. Furthermore, we observe phase shifts in the absorption spectrum that are connected to the hyperfine levels of the system. Our findings are surprising considering the weak interparticle interaction present at the studied conditions, which has triggered some interest from theory to explain our results [2,3].

[1] L. Bruder, M. Binz, and F. Stienkemeier, Phys. Rev. A 92, 053412 (2015) [2] S. Mukamel, J. Chem. Phys. 145, 041102 (2016) [3] Z.-Z. Li, L. Bruder, F. Stienkemeier, and A. Eisfeld, Phys. Rev. A 95, 052509 (2017)