Non-Perturbative Analysis of the Coleman-Weinberg Phase Transition
  We perform a non-perturbative study of the Coleman-Weinberg phase transition in scalar QED. Our method permits a consistent treatment of the effective potential near the origin, a region not accessible to perturbation theory. As a result, we establish reliably the first order character of the phase transition for arbitrary values of the scalar coupling. 
D. Litim, C. Wetterich and N. Tetradis