Density functionals derived from Feynman diagrams

Abstract

We construct a stationary density functional for the partition function from a chosen set of one (boson) line irreducible Feynman diagrams. The construction does not proceed by the inversion of a Legendre transform. It is formulated for fermions with Coulomb interactions, in which case a stationary functional of the particle density is contructed, as well as for nucleons interacting with mesons, which involves a stationary functional of several densities. The use of Kohn-Sham orbits is shown to be an unnecessary complication.