Journal of Physics A Mathematical and General
Confluent corrections to scaling in the isotropic Heisenberg model
William J. Camp, John P. VAN DYKE
Abstract
Confluent corrections to scaling are explicitly incorporated in the analysis of high-temperature series for the S= 1 / 2 (quantum-mechanical) and S= infinity (classical) isotropic Heisenberg models on the FCC lattice. For S= infinity , strong confluent corrections are found in the susceptibility, the second moment of the correlation function, as well as the anisotropy crossover function. No evidence for confluent, non-analytic corrections to scaling is found in the analysis of the S= 1 / 2 susceptibility. The best value for the S= infinity susceptibility exponent is gamma ( infinity )=1.42 -0.01 +0.02 , which-taken with the best previous estimate gamma ( 1 / 2 )=1.43-is consistent with universality. However, for S= 1 / 2 , it is felt that (because of apparent non-confluent singularities) gamma is known no better than gamma ( 1 / 2 ) approximately=1.41-1.51. The S= infinity correlation-length exponent is estimated to be nu =0.725+or-0.015, and the crossover exponent is estimated to be phi =1.30+or-0.03. Finally, the S= infinity correction-to-scaling exponent is found to be Delta 1 =0.54+or-0.10.