Ising-Model Critical Indices below the Critical Temperature

We review the estimates for the critical indices of the Ising model below TC and conclude (for 3 dimensions): α^'=0.066_-0.04^_+0.16, β=0.312_-0.005^_+0.002, γ^'=1.310_-0.05^_+0.04 for the specific heat, magnetization, and magnetic susceptibility, respectively. For 2 dimensions, we estimate γ^'=1.75_-0.00^_+0.01. In order to explain previous estimates of α^'=0, we point out that a low power can, in practice, look deceptively like a logarithm. Finally, we discuss the behavior of the specific heat at constant magnetization.