LOOP EXPANSION IN LIGHT-CONE PHI(4) FIELD-THEORY

Based on the path integral quantization of the light-cone phi(4) field theory in 1+1 dimensions, a loop expansion is implemented. The effect ive potential as a function of the zero-mode held omega is calculated up to two-loop order and its derivative with respect to omega is used to determine the vacuum expectation value of the field phi. The critic al coupling constant at the occurrence of the spontaneous symmetry bre aking is consistent with that obtained in the ordinary instant-form he ld theory. The critical exponents which describe the behavior of the s usceptibility and the vacuum expectation value of phi near the critica l point ark evaluated from the effective potential. The one-loop diagr ams for the connected Green's function are calculated in momentum spac e. The relevant equal-time correlation function is shown to be closely related.