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Accueil > Événements > Séminaires 2016

Production of dual Bose-Einstein condensates of 39K and 41K. Towards the study of the Bose polaron

Pierrick Cheiney

29 février 2016 à 11 heures

Quantum mixtures are versatile systems for the study of a broad range of phenomena, including both few- and many-body physics. In particular, we are interested in the Bose polaron, an impurity immersed in a Bose gas and dressed by it. Although it is a paradigmatic and conceptually simple problem of many-body physics, its properties (mass, energy) are difficult to predict in the strongly interacting case. In certain regimes, they should stem from the interplay of Efimov and many-body physics, a situation very different from the Fermi polaron (an impurity inmersed in a Fermi gas) which has been studied up to now.

During my talk, I will introduce a new experimental setup designed to produce ultracold Bose-Bose or Bose-Fermi mixtures of potassium isotopes that possess favourable Feshbach resonances to address this question. In particular, I will focus on our latest results : the production of a large 41K Bose-Einstein condensate (BEC) by evaporative cooling in a hybrid trap, of a dual BEC of 39K and 41K by sympathetic cooling, and the very recent observation of the miscible- immiscible quantum phase transition in the binary condensate mixture. I will then present our latest progress on the Feshbach spectroscopy of the mixture which is a prerequisite to the study of the Bose polaron.