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Dr. Francesca Ferlaino

Institute of Experimental Physics, University of Innsbruck

Monday, October 17th, 2011 at 02:00:00 PM

Conference room Querzoli - LENS - via Nello Carrara 1 - Sesto Fiorentino (Florence)

Published on-line at 12:18:47 PM on Friday, October 7th, 2011

Latest news from ultracold Bose gas experiments in Innsbruck

Three very cold experiences from Innsbruck: cold atoms to study universal few-body physics, interspecies scattering properties and Erbium condensates.

I will present new results from three different experiments on cold and ultracold Bose gases in Innsbruck, operating on cesium atoms, rubidium-cesium mixtures, and erbium atoms, respectively.

In a first experiment, we investigate universal few-body physics with ultracold cesium atoms. We detect various Efimov resonances in a magnetic field range up to 1000 G by measuring atomic loss rates in three-body recombination processes. We find in total five distinct Efimov resonances in the same spin channel, all resulting from different Feshbach resonances. Surprisingly, all Efimov resonances occur at the same value of the scattering length, which points to universality across all Feshbach resonances and rules out a significant variation of the three-body parameter.

In a second experiment, we produce a degenerate or near-degenerate ultracold mixture of 87Rb and 133Cs atoms. We investigate the interspecies scattering properties by Feshbach spectroscopy and we determine the background inter-species scattering length to be unusually large and positive. Starting with magneto-associated Feshbach molecules, we perform spectroscopic measurements on the two-photon optical transition that will serve to transfer RbCs molecules to the rovibronic ground state via a STIRAP transfer scheme. This work constitutes a first step towards the production of a quantum gas of ground-state polar molecules.

Finally, I will present results from the newest experiment in Innsbruck, which aims to Bose condense a novel and highly exotic atomic species: erbium. In particular, we reached magneto-optical trapping of erbium atoms using a comparatively narrow laser cooling transition. This provides the first important step towards quantum degeneracy.

For further informations, please contact Dr. Francesco Minardi.