Hamiltonian formulation of (2+1)-dimensional QED on the light cone

It is shown that an improper regularization in the light-cone quantization of field theories can introduce a violation of rotational invariance as well as spurious divergences. Several methods are developed to avoid or cure these problems, as required for a consistent renormalization procedure of gauge theories. Based on these methods, the light-cone Hamiltonian for (2+1)-dimensional QED is constructed. Extension to gauge theories in 3+1 physical dimensions is also discussed.