  We introduce Gutzwiller conjugate gradient minimization (GCGM) theory, an ab
initio quantum many-body theory for computing the ground-state properties of
infinite systems. GCGM uses the Gutzwiller wave function but does not use the
commonly adopted Gutzwiller approximation (GA), which is a major source of
inaccuracy. Instead, the theory uses an approximation that is based on the
occupation probability of the on-site configurations, rather than
approximations that decouple the site-site correlations as used in the GA. We
test the theory in the one-dimensional and two-dimensional Hubbard models at
various electron densities and find that GCGM reproduces energies and double
occupancies in reasonable agreement with benchmark data at a very small
computational cost.
