Ising-Model Critical Indices in Three Dimensions from the Callan-Symanzik Equation

The coefficients in the Callan-Symanzik equations for a three-dimensional, continuous spin Ising model with an $\exp (-A{s}^4+B{s}^2)$ spin-weight factor are expanded in the dimensionless, renormalized coupling constant. These series are summed by the Padé-Borel method to yield the critical indices $\gamma =1.241\mathrm{}\pm 0.002$, $\eta =0.02\mathrm{}\pm 0.02$, $\nu =0.63\mathrm{}\pm 0.01$, and ${\Delta }_1=0.49\mathrm{}\pm 0.01$.