Density Functional Theory for quasiparticle properties

A framework is proposed to construct the ground-state energy and density matrix of an N-electron system by solving self-consistently a set of single-particle equations. The method is based on separating the Green's function into a quasi-particle part and a background part, and expressing only the background part as a functional of the local density or the density matrix. The calculated single-particle energies and wave functions have a clear physical interpretation as quasiparticle energies and orbitals. Apart from Hartree-Fock, also the standard Kohn-Sham DFT scheme is embedded as a special case. Several advantages of such an approach are pointed out, and possible implementations are explored.