Higher moments of spin-spin correlation functions for the ferromagnetic random bond Potts model

Laboratoire de Physique Théorique et des Hautes Energies Universités Pierre et Marie Curie (Paris VI ) et Denis Diderot (Paris VII ) Boite 126, Tour 16, 1er étage, 4 pl. Jussieu, 75251 Paris Cedex 05, France

Received: 1 December 1997
Accepted: 28 May 1998

Abstract

Using conformal field theory techniques, we compute the disorder-averaged p-th power of the spin-spin correlation function () for the ferromagnetic random bond Potts model. We thus generalize the calculations of Dotsenko, Dotsenko and Picco (hep-th/9709136, 1997), where the case p=2 was considered, and of Ludwig ( Nucl. Phys. B, 85 (1987) 97, 330 (1990) 639), where first-order computations where made for general p. Perturbative calculations are made up to second order in ϵ (ϵ being proportional to the central charge deviation of the pure model from the Ising model value). The explicit dependence of the correlation function on p gives an upper bound for the validity of the ϵ-expansion, which seems to be valid, in the three-states case, only if .