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09/03/2015, 10:00 — 11:00 — Room P3.10, Mathematics Building

Hugo Terças, *Institute for Theoretical Physics, University of Innsbruck*

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Strong coupling in quantum optics: exciton-polaritons and phonon-polaritons

Strong coupling in quantum mechanical systems occurs when the strength of the coupling is much larger than losses. Such a feature can be found in optical cavities, where the atoms strongly couple to the cavity photonic modes (cavity QED). The same occurs in semi-conductor microcavities, where excitons strongly couple to photons. In these systems, the resulting quasi-particle, the so-called polariton, results from the hybridisation of a typical excitation with photons. In this talk, I will discuss two examples involving ultracold atoms where strong coupling involves a phonon mode, giving rise to an acoustic-like quasi-particle: the phonon-polariton. Some relations with the research in the domain of exciton-polaritons and its applications will be drawn.