Neutron matter in the hole-line expansion

We calculate the binding energy of pure neutron matter up to third order in the Brueckner-Bethe-Goldstone hole-line expansion, employing various modern nucleon-nucleon potentials. At that order all results appear well converged to within a few percent up to a density of 0.8 fm(-3). We analyze the potentials in terms of the strength of their hard core. Comparison with results of other theoretical methods is made.