Confluent corrections to scaling in the isotropic Heisenberg model

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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.