Atomic Bose-Einstein condensation: Beyond mean-field theory

The hamiltonian describing the physics of atomic Bose gases is a many-body hamiltonian with a confining potential and two-particle repulsive interactions. Dealing with such a hamiltonian is difficult, even for dilute gases, at the level of mean-field theory, because of the very repulsive nature of the potential. It becomes even more difficult when the atomic density is increased and many-particle correlations need to be considered. In this article we overview the way in which density functional theory deals with both these problems.