Non-Perturbative Renormalization Group Analysis of the Chiral Critical   Behaviors in QED
  We study the chiral critical behaviors of QED by using Non-Perturbative Renormalization Group (NPRG). Taking account of the non-ladder contributions, our flow equations are free from the gauge parameter ($\alpha$) dependence. We clarify the chiral phase structure, and calculate the anomalous dimension of $\bar\psi\psi$, which is enhanced compared to the ladder approximation. We find that the cutoff scheme dependence of the physical results is very small. 
Ken-Ichi Aoki, Keiichi Morikawa, Jun-Ichi Sumi, Haruhiko Terao,   Masashi Tomoyose