LIGHT-CONE QUANTIZATION AND 1/N EXPANSION

For the phi4 scalar field theory with O(N) symmetry we exploit the possibility of a 1/N expansion to solve the equations of motion for the field operators in the framework of light cone quantization in the symmetric phase. Due to the triviality of the light cone vacuum the field operators can be explicitly constructed order by order in 1/square-root N. This is at variance with the conventional treatment where the appearance of non-trivial vacuum states renders the corresponding expansion practically very difficult beyond the 1/N correction. We argue that the proposed scheme will also be very useful for the treatment of the broken phase.