Abstract
In this lecture, we introduced the notion of "two-dimensional quantum fluid". Most of the lesson was devoted to the case of the perfect gas governed by the Bose-Einstein statistics. We looked successively at the uniform case, for which there is no condensation at the thermodynamic limit, and the case of a trapped gas, for which condensation can occur. We then describe experiments carried out on a cavity photon assembly illustrating this prediction. In a final section, we set up the formalism for taking into account interactions between two-dimensional particles, by focusing on a binary collision between identical atoms.
