Erlangen 2018 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 59: Quantum Gases (Bosons) VI

Q 59.4: Vortrag

Donnerstag, 8. März 2018, 11:15–11:30, K 2.020

Self-consistent spin texture in a quantum gas through opto-magnetical effects — Katrin Kröger, •Manuele Landini, Lorenz Hruby, Nishant Dogra, Tobias Donner, and Tilman Esslinger — Institute for Quantum Electronics, ETH Zurich, 8093 Zurich, Switzerland

We experimentally realize opto-magnetic coupling between a multilevel atomic BEC and a single mode of a high-finesse optical cavity. We focus on the role of the vectorial component of the polarizability tensor for spinful condensed atoms. We develop a theory in the context of a modified Dicke model and can explain the observed threshold power for the self-organization phase transition as well as the phase of the light in the organized phase depending on the internal state. When preparing a spin mixture, we identify two distinct regimes of coupling. In the regime of density coupling, the self-organization process generates density modulations in the atomic system. By increasing the ratio of the vectorial over the scalar coupling beyond a critical point, we observe the appearance of a new self-organization pattern consisting of magnetization modulations, a spin texture. Our findings demonstrate a direct competition between self-organization patterns in a single mode optical cavity, paving the way to the exploitation of opto-magnetic effects for quantum simulation of long-range magnetic interactions.