Upper bound on the decay of correlations in a general class of O(N)-symmetric models

Maxime Gagnebin, Yvan Velenik

Published 2013-09-10, updated 2013-12-13Version 2

We consider a general class of two-dimensional spin systems, with continuous but not necessarily smooth, possibly long-range, $O(N)$-symmetric interactions, for which we establish algebraically decaying upper bounds on spin-spin correlations under all infinite-volume Gibbs measures. As a by-product, we also obtain estimates on the effective resistance of a (possibly long-range) resistor network in which randomly selected edges are shorted.