An Aufbau-Ansatz for Geminal Functional Theory

Geminal functional theory (GFT) is related to reduced density matrices (RDMs) in quantum mechanics and inspired by density functional theory (DFT). It is based on the realization that all physical properties can be described by the second order RDM and a reduced two-particle operator. The proposed Aufbau-Ansatz is an iterative method to compute the second order RDM for an antisymmetrized product of arbitrary geminals (APG). This circumvents the need to represent the wavefunction in its full dimensionality. Since GFT relies on two-electron interactions, the electron-electron cusp needs special consideration. It is shown that an appropriate choice of basis set eliminates this necessity. Furthermore, we compare the Aufbau-Ansatz with GFT as introduced by D. A. Mazziotti [J. Chem. Phys., 112(23), 2000, 10125-10130]