Energy eigenvalues and string tension in the Schwinger model

We exactly evaluate the energy eigenvalues of the Schwinger model, and find that due to a nontrivial cancellation the fermion eigenvalues are eliminated. The eigenspectrum of the interacting theory reduces to that of a free massive boson field. We then exactly evaluate the energy of the fermion-string-antifermion state and the string tension. We discuss the relation of the string tension to the Wilson criterion of confinement