Scaling Regimes and the Singularity of Specific Heat in the 3D Ising Model

The singularity of specific heat CV of the three-dimensional Ising model is studied based on Monte Carlo data for lattice sizes L≤1536.Fits of two data sets,one corresponding to certain value of the Binder cumulant and the other-to the maximum of CV,provide consistent values of C0 in the ansatz CV(L)=C0+AL^(a/n) at large L,if a/n=0.196(6).However,a direct estimation from our Cmax V data suggests that a/n,most probably,has a smaller value(e.g.,a/n=0.113(30)).Thus,the conventional power-law scaling ansatz can be questioned because of this inconsistency.We have found that the data are well described by certain logarithmic ansatz.