Decay of covariances, uniqueness of ergodic component and scaling limit for a class of \nablaφsystems with non-convex potential

Codina Cotar, Jean-Dominique Deuschel

Published 2008-07-16, updated 2011-08-12Version 4

We consider a gradient interface model on the lattice with interaction potential which is a nonconvex perturbation of a convex potential. Using a technique which decouples the neighboring vertices sites into even and odd vertices, we show for a class of non-convex potentials: the uniqueness of ergodic component for \nabla\phi-Gibbs measures, the decay of covariances, the scaling limit and the strict convexity of the surface tension.