Critical Behavior of the Two-Dimensional Ising Susceptibility
Critical Behavior of the Two-Dimensional Ising Susceptibility
We report computations of the short- and long-distance (scaling) contributions to the square-lattice Ising susceptibility. Both computations rely on summation of correlation functions, obtained using nonlinear partial difference equations. In terms of a temperature variable $\ensuremath{\tau}$, linear in ${T/T}_{c}\ensuremath{-}1$, the short-distance terms have the form ${\ensuremath{\tau}}^{p}(\mathrm{ln}|\ensuremath{\tau}|{)}^{q}$ with $p\ensuremath{\ge}{q}^{2}$. A high- …