Density Dependence of Two-Body Interactions for Beyond Mean-Field   Calculations
  This paper deals with the theoretical foundation of effective two-body forces for the Generator Coordinate Method (GCM) and the projected mean-field method. The first aim of this paper is to reduce into various local-densities the in-medium content of a generalized $G$ matrix removing the hard core problem in this extended context. Then, we consider the possible renormalization of multi-body forces through a density-dependent two-body interaction in the context of configuration mixing calculations. A density dependence of the form $\rho^{\sigma}$, as used in Skyrme and Gogny forces, is successfully interpreted as doing so when the mixed density is used. Finally, we propose a simple extension of the Skyrme force dedicated to the calculation of matrix elements between non-orthogonal product states, which are needed to evaluate the correlated energy. 
T. Duguet and P. Bonche