  We present calculations of the energy per particle of pure neutron and
symmetric nuclear matter with simplified Argonne nucleon-nucleon potentials for
different many-body theories. We compare critically the Brueckner-Hartree-Fock
results to other formalisms, such as the Brueckner-Bethe-Goldstone expansion up
to third order, Self-Consistent Green's Functions, Auxiliary Field Diffusion
Monte Carlo, and Fermi Hyper Netted Chain. We evaluate the importance of
spin-orbit and tensor correlations in the equation of state and find these to
be important in a wide range of densities.
