%0 Journal Article
%T Ornstein-Zernike Theory for the finite range Ising models above T_c
%A M. Campanino
%A D. Ioffe
%A Y. Velenik
%J Mathematics
%D 2001
%I arXiv
%R 10.1007/s00440-002-0229-z
%X We derive precise Ornstein-Zernike asymptotic formula for the decay of the two-point function in the general context of finite range Ising type models on Z^d. The proof relies in an essential way on the a-priori knowledge of the strict exponential decay of the two-point function and, by the sharp characterization of phase transition due to Aizenman, Barsky and Fernandez, goes through in the whole of the high temperature region T > T_c. As a byproduct we obtain that for every T > T_c, the inverse correlation length is an analytic and strictly convex function of direction.
%U http://arxiv.org/abs/math/0111274v1