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Phase Diagram of a Three Orbital Model for the high-T$_c$ cuprates

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.