title: Universality class of the Nishimori point in the 2D +/- J random-bond Ising model.
abstract: We study the universality class of the Nishimori point in the 2D +/- J random-bond Ising model by means of the numerical transfer-matrix method. Using the domain-wall free energy, we locate the position of the fixed point along the Nishimori line at the critical concentration value p(c) = 0.1094 +/- 0.0002 and estimate nu = 1.33 +/- 0.03. Then, we obtain the exponents for the moments of the spin-spin correlation functions as well as the value for the central charge c = 0.464 +/- 0.004. The main qualitative result is the fact that percolation is now excluded as a candidate for describing the universality class of this fixed point.
authors.affiliation: Institut für Theoretische Physik, TU Braunschweig, Mendelssohnstrasse 3, 38106 Braunschweig, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Honecker
authors.forename: M
authors.initials: M
authors.lastname: Picco
authors.forename: P
authors.initials: P
authors.lastname: Pujol