QUANTUM-THEORY OF SOLID-LIQUID COEXISTENCE AND INTERFACE IN HE-4

We present a variational Monte Carlo simulation of solid-liquid coexis tence and interface in He-4 at T = 0 K. We employ a new, generalized f orm of the shadow wave function in which intershadow correlations are made explicitly dependent on a local density operator. This form allow s for a unique representation of the ground state for the whole range of density extending over the two phases. In the phase transition regi on the stable state consists of a slab of crystal coexisting with the fluid. We obtain the local density, the order parameter, and the inter facial energy for the {100} surface of an fcc crystal.