Ground-state properties of the free surface of liquidHe4

Abstract

We report quantum-mechanical calculations of the properties of the ground state of a slab of ${}_{}{}^4{}_{}{}^{}\mathrm{He}$. Both variational Monte Carlo and Green's-function Monte Carlo (GFMC) methods are applied to systems of different sizes. The values for the surface tension at zero temperature obtained with different estimators give excellent agreement with experimental results. The density distributions and the thickness of the interface are also studied. We conclude that the He-He potential is accurate enough and GFMC precise enough to calculate a nontrivial inhomogeneous system.