Three-Body Interactions in Liquid and Solid Helium

Abstract

We have calculated the contribution of the triple-dipole three-body interactions to the ground-state energy of liquid ${\mathrm{He}}^4$ and solid He. The liquid calculation was done by a Monte Carlo method using a variationally determined product wave function, and the solid calculation by evaluating the triple-dipole sum in the static lattice for several crystal lattices. The triple-dipole term is found to be quite small, of the order of 2% of the ground-state energy of liquid ${\mathrm{He}}^4$.