Hubbard--Heisenberg Thermodynamic Comparison at Half Filling in a Fixed Staggered Field
The study compares the thermodynamic properties of a repulsive Hubbard model at half filling with a staggered magnetic field to an effective Heisenberg model at the Heisenberg scale J0(U) = 4t^2/U. The analysis uses strong-coupling transformations to show that for large U, charge fluctuations are suppressed, meaning low-energy physics is governed by antiferromagnetic spin degrees of freedom.