  We study the phase diagram of an effective three orbital model of the
cuprates using Variational Monte-Carlo calculations (VMC) on asymptotically
large lattices and exact diagonalization on a 24-site cluster. States with
ordered orbital current loops (LC), itinerant Anti-ferromagnetism (AFM), d-wave
superconductivity (SC), and the Fermi-liquid (FL) are investigated using
appropriate Slater determinants refined by Jastrow functions for on-site and
inter-site correlations. We find an LC state stable in the thermodynamic limit
for a range of parameters compatible with the Fermi surface of a typical hole
doped superconductors provided the transfer integrals between the oxygen atoms
have signs determined by the effects of indirect transfer through the Cu-4s
orbitals as suggested by O.K. Andersen. The results of the calculations are
that this phase gives way at lower dopings to an AFM phase and at larger
copings to a SC phase followed by a FL phase.
