We present a calculation of the energy-density correlation $d_{\mathrm{-}}$(r,h) of the two-dimensional Ising model in a magnetic field under the limit T→$T_c$-, H→0, and R→∞ where h=const×H‖T-$T_c$${\Vert }^{\mathrm{-}15/8}$ is fixed and small, while r=R‖T-$T_c$‖ is fixed and large. We find ${\mathit{d}}_{\mathrm{-}}$(r,h)∼2${\mathrm{\pi }}^{\mathrm{-}1/2}$${\mathrm{hr}}^{\mathrm{-}1/2}$${\mathrm{e}}^{\mathrm{-}2}$, where ${\lambda }_l$ are the positive solutions of ${\mathit{J}}_{1/3}$(${\lambda }_{\mathrm{l}}$/3)+${\mathrm{J}}_{\mathrm{-}1/3}$ (${\lambda }_{1/3}$)=0.

• Received 23 November 1987

DOI:https://doi.org/10.1103/PhysRevB.38.9152