The continuum limit of QED. Renormalization group analysis and the question of triviality

Recently there has been much interest in the chiral phase transition of QED and its implication for the continuum limit. In this letter we present the first lattice calculation of the renormalized charge and fermion mass. We use these results to derive the Callan-Symanzik fl-function. We find that the renormalized charge vanishes at the critical point, which indicates triviality. By examining different renormalization group trajectories we address the issue of whether QED can be viewed as a consistent cut-off theory. 1