Gauge invariant variational approach with fermions: The Schwinger model

We extend the gauge invariant variational approach of I. Kogan and A. Kovner [Phys. Rev. D 51, 1948 (1995)] to theories with fermions. As the simplest example we consider the massless Schwinger model in 1+1 dimensions. We show that in this solvable model the simple variational calculation gives exact results. (c) 2000 The American Physical Society.