Influence of boundary conditions on random unfrustrated magnetic systems

Abstract

The size dependence of the sensitivity of the free energy to a change in the boundary conditions is investigated for disordered unfrustrated systems. Characteristically different dependencies are found in the high- and low-temperature phases and an estimate of the lower critical dimensionality of the system may be obtained from the low-temperature behavior. Results of studies of random Heisenberg and Ising ferromagnets with periodic and antiperiodic boundary conditions and with random boundary conditions are presented.