Nuclear Density Functional Theory (DFT)

The present chapter is devoted to explaining the basics of nuclear Density Functional Theory (DFT). At the start, a reminder is provided of some of the many empirical pieces of evidence that point to the fact that a description of the atomic nucleus in terms of independent particles is a reasonable approximation. Accordingly, Hartree-Fock (HF) has been one of the most widely used methods throughout the second half of the last century. However, HF has been successful (mainly) in connection with density-dependent Hamiltonians; then, at a given point, it has been concluded that this is a mere realization of DFT in nuclear physics, as explained in the text. The chapter also focuses on recent developments that include avoiding underlying Hamiltonians and building functionals with diverse densities, implementing new symmetry-breaking formulations, or improving the pairing sector. DFT for Coulomb systems will be used as a paradigm: similarities and differences will be pointed out. The chapter deals only with nonrelativistic DFT and single-reference implementations, as other topics will be covered in other chapters.