LIGHT-CONE QUANTIZATION APPROACH TO QUANTUM ELECTRODYNAMICS IN (2+1)-DIMENSIONS

Light-cone quantization techniques are applied to quantum electrodynamics in (2+1) dimensions with four-component spinors. The discretized light-cone Hamiltonian for the model is derived. Hence a Tamm-Dancoff integral equation for the 'positronium' bound states is obtained. It is shown that at weak couplings the integral equation reduces to the correct nonrelativistic Schrodinger equation, and accurate numerical solutions are obtained for the energy eigenvalues. At stronger couplings we find that the infrared divergences no longer cancel, which we attribute to a lack of gauge invariance in the approximation scheme. Possible remedies are discussed.