Mardi 15 janvier 2013 à 10h00
Salle 234, Ecole de Physique

Two-dimensional Bose gases near resonance: competing two and three-body effects

Jean-Sebastien Bernier, Ecole Polytechnique, France

I present the results of a recent investigation of 2D Bose gases beyond the dilute limit emphasizing the role played by three-body scattering events. In this work, we demonstrated that a competition between three-body attractive interactions and two-body repulsive forces results in the chemical potential of 2D Bose gases to exhibit a maximum at a critical scattering length beyond which these quantum gases possess a negative compressibility. For larger scattering lengths, the increasingly prominent role played by three-body attractive interactions leads to an onset instability at a second critical value. The three-body effects studied here are fully characterized by the effective 2D scattering length and are, in comparison to the 3D case, independent of three-body ultraviolet physics.