Hopping-parameter expansion and the Schwinger model with Wilson fermions

The hopping-parameter expansion method is used to study the Euclidean lattice Schwinger model with Wilson fermions. The effect of virtual fermion loops is also analyzed. The relation between the (bar psi psi) operators in the continuum and on the lattice is constructed. Our result shows satisfactory scaling behavior and reproduces well the exactly calculable value for the fermion condensate in the continuum.