1 Spin susceptibility of neutron matter at zero temperature

The Auxiliary Field Diffusion Monte Carlo method is applied to compute the spin susceptibility and the compressibility of neutron matter at zero temperature. Results are given for realistic interactions which include both a two–body potential of the Argonne type and the Urbana IX three–body potential. Simulations have been carried out for about 60 neutrons. We find an overall reduction of the spin susceptibilty by about a factor of 3 with respect to the Pauli susceptibility for a wide range of densities. Results for the compressibility of neutron matter are also presented and compared with other available estimates obtained for semirealistic nucleon–nucleon interactions and with more traditional many–body techniques, like Brueckner's or Correlated Basis Function theories.