Renormalization of the Effective Action
In the previous chapter, we derived the effective action of <p4 theory (6.36) in the rather symbolic form as an infinite sum of diagrams (equations (6.75) - (6.78) with the graphical representation given in fig. 29). In this chapter, we shall learn how to calculate the contribution of the diagrams. We shall analyze the explicit form of the corresponding integrals, some of which will appear to diverge, and find out the source and the structure of the divergences. After the renormalization, we shall get a finite result for the one-loop propagator and discuss the structure of the next terms of the effective action which apper in fig. 29.