Density Functional Theory for Field Theorists I

TL;DR

This paper reinterprets Density Functional Theory (DFT) using quantum field theory language, proposing new systematic approximation methods and highlighting computational advantages within the large K approximation.

Contribution

It introduces novel ideas for constructing systematic density functional approximations and connects the quantum effective action of the Coulomb photon to DFT in a new way.

Findings

New systematic approximation methods for DFT.

Simplified computation of the quantum effective action in large K limit.

Enhanced understanding of DFT through quantum field theory techniques.

Abstract

I summarize Density Functional Theory (DFT) in a language familiar to quantum field theorists, and introduce several apparently novel ideas for constructing {\it systematic} approximations for the density functional. I also note that, at least within the large $K$ approximation ($K$ is the number of electron spin components), it is easier to compute the quantum effective action of the Coulomb photon field, which is related to the density functional by algebraic manipulations in momentum space.