Finite-element quantum electrodynamics. II. Lattice propagators, current   commutators, and axial-vector anomalies
  We apply the finite-element lattice equations of motion for quantum electrodynamics given in the first paper in this series to examine anomalies in the current operators. By taking explicit lattice divergences of the vector and axial-vector currents we compute the vector and axial-vector anomalies in two and four dimensions. We examine anomalous commutators of the currents to compute divergent and finite Schwinger terms. And, using free lattice propagators, we compute the vacuum polarization in two dimensions and hence the anomaly in the Schwinger model. A discussion of our choice of gauge-invariant current is provided. 
Dean Miller, Kimball A. Milton, and Stephan Siegemund-Broka