arXiv:cond-mat/0009024 · Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics
Exact amplitude ratio and finite-size corrections for the M×N square lattice Ising model
N. Sh. Izmailian, Chin‐Kun Hu
Abstract
Let $f, U,$ and C represent, respectively, the free energy, the internal energy, and the specific heat of the critical Ising model on the $M\ifmmode\times\else\texttimes\fi{}N$ square lattice with periodic boundary conditions, and ${f}_{\ensuremath{\infty}}$ represents f for fixed $M/N$ and $\stackrel{\ensuremath{\rightarrow}}{N}\ensuremath{\infty}.$ We find that $f, U,$ and C can be written as $N(f\ensuremath{-}{f}_{\ensuremath{\infty}})={\ensuremath{\sum}}_{i=1}^{\ensuremath{\infty}}{f}_{2i\ensuremath{-}1}{/N}^{2i\ensuremath{-}1}, U=\ensuremath{-}\sqrt{2}+{\ensuremath{\sum}}_{i=1}^{\ensuremath{\infty}}{u}_{2i\ensuremath{-}1}{/N}^{2i\ensuremath{-}1},$ and $C=8\mathrm{ln}N/\ensuremath{\pi}+{\ensuremath{\sum}}_{i=0}^{\ensuremath{\infty}}{c}_{i}{/N}^{i},$ i.e., $\mathrm{Nf}$ and U are odd functions of ${N}^{\ensuremath{-}1}.$ We also find that ${u}_{2i\ensuremath{-}1}{/c}_{2i\ensuremath{-}1}=1/\sqrt{2}$ and ${u}_{2i}{/c}_{2i}=0$ for $1<~i<\ensuremath{\infty}$ and obtain closed form expressions for $f, U,$ and C up to orders ${1/N}^{5}, {1/N}^{5},$ and ${1/N}^{3},$ respectively, which implies an analytic equation for ${c}_{5}.$