Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Kinetic energies for systems formed from He-4 atoms at T=0 in the solid and liquid phases are reported. The "exact" results are obtained by an extension of the diffusion Monte Carlo method. The overall agreement of the results with experimental values and calculations at finite temperatures is very good.16241732154159Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)