Thermodynamics of spin glasses in the Hartree-Fock approximation

Abstract

The thermodynamics of a short-ranged spin glass, described by the soft-spin version of the Heisenberg model, is studied in a Hartree-Fock-type approximation. This approximation is derived here by considering the limit in which the number of spin components n becomes infinite. In this limit, our equations are exact. These equations are numerically solved for small systems in two and three dimensions; free energy and a variety of susceptibilities, including all the eigenvalues of the susceptibility matrix, are evaluated in the high-temperature phase.