Blocking transformation in field theory

The renormalization group of the field theory which was found when dealing with ultraviolet divergences has wider origin and implications. In this paper, the blocking approach to the renormalization group by Kadanoff and Wilson is presented in the loop expansion. The blocking procedure in investigated in a four-dimensional model and scalar quantum electrodynamics in the one loop approximation. It generates the local irrelevant operators as well and makes the investigation of the infrared fixed point possible in a systematical manner. 7 refs., 4 figs