On the Existence of Quantum Electrodynamics

We explain from an intuitive renormalization-group perspective how "collapse of the wave function" in quenched quantum electrodynamics leads to coupling-constant renormalization and an interacting ultraviolet stable fixed point. A diagrammatic expansion in $N_f$, the number of fermion species, suggests that vacuum polarization leads the fixed point of the quenched model stable, and computer-simulation data support this possibility. The scaling region of the quenched lattice model is discovered numerically.