  Systems involving N-identical interacting particles under quantum confinement
appear in many areas of physics, including chemical, condensed matter, and
atomic physics. We discuss a beyondmean- field perturbation method that is
applicable to weakly, intermediate and strongly-interacting systems. Group
theory is used to derive an analytic beyond-mean-field correlated wave function
at zeroth order for a system under spherical confinement. We derive the
corresponding zeroth-order analytic density profile and apply it to the example
of a Bose-Einstein condensate.
