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 $0.8\phantom{\rule{0.28em}{0ex}}{\mathrm{fm}}^{\ensuremath{-}3}$. We analyze the potentials in terms of the strength of their hard core. Comparison with results of other theoretical methods is made.