  An extended electron model fully recovers many of the experimental results of
quantum mechanics while it avoids many of the pitfalls and remains generally
free of paradoxes. The formulation of the many-body electronic problem here
resembles the Kohn-Sham formulation of standard density functional theory.
However, rather than referring electronic properties to a large set of single
electron orbitals, the extended electron model uses only mass density and field
components, leading to a substantial increase in computational efficiency. To
date, the Hohenberg-Kohn theorems have not been proved for a model of this
type, nor has a universal energy functional been presented. In this paper, we
address these problems and show that the Hohenberg-Kohn theorems do also hold
for a density model of this type. We then present a proof-of-concept practical
implementation of this method and show that it reproduces the accuracy of more
widely used methods on a test-set of small atomic systems, thus paving the way
for the development of fast, efficient and accurate codes on this basis.
