ROLE OF ZERO MODES IN THE CANONICAL QUANTIZATION OF HEAVY-FERMION QEDIN LIGHT-CONE COORDINATES

Four-dimensional heavy-fermion QED is studied in light-cone coordinate s with (anti)periodic field boundary conditions. We carry out a consis tent light-cone canonical quantization of this model using the Dirac a lgorithm for a system with first- and second-class constraints. To exa mine the role of the zero modes, we consider the quantization procedur e in the zero mode and the nonzero-mode sectors separately. In both se ctors we obtain the physical variables and their canonical commutation relations. The physical Hamiltonian is constructed via a step-by-step exclusion of the unphysical degrees of freedom. An example using this Hamiltonian in which the zero modes play a role is the verification o f the correct Coulomb potential between two heavy fermions.