MERCREDI 23 SEPTEMBRE 2009 14 heures Salle Séminaire 5 Centre de Physique Théorique Marseille-Luminy Daniel Ueltschi Dept of Mathematics, University of Warwick, United Kingdom Title: The Critical Temperature of Dilute Bose Gases Abstract: Predicted by Einstein in 1924, the Bose-Einstein condensation is a striking phase transition that takes place in certain systems of quantum bosonic particles. The dependence of the critical temperature on the interparticle interactions has been a controversial issue in the physics community. I will review the mathematical setting and the literature, and I will describe a non-rigorous but hopefully exact way to compute the lowest order correction to the change of the critical temperature of dilute systems. The approach is based on "spatial random permutations". (This is joint work with V. Betz.)