On the triviality of QED with a large number of flavors

We consider quantum electrodynamics with a variable number of flavors Nf. We argue that the theory becomes trivial for Nf finite but large. At strong coupling (β=1/g2=0.0) we find that the lattice regulated theory does not break chiral symmetry if Nf> or approx.30. At Nf=8 we find a chiral phase transition at finite coupling but it is compatible with mean field behavior and in the simplest scenario would define only a free field theory in the lattice theory's continuum limit. These results are discussed from the prospective of the competition of the 'collapse' mechanism that drives the chiral transition in the quenched theory and 'screening' that accompanies dynamical fermions. We also find that the chiral transition at β=0.0 is first order while at Nf=8 it is second order suggesting the existence of a tricritical point in between. (orig.)