Critical exponents of the Gross-Neveu model from the effective average action

The phase transition of the Gross-Neveu model with N fermions is investigated by means of a non-perturbative evolution equation for the scale dependence of the effective average action. The critical exponents and scaling amplitudes are calculated for various values of N in d=3. It is also explicitely verified that the Neveu-Yukawa model belongs to the same universality class as the Gross-Neveu model.Comment: RevTeX, 4 pages, 2 figures, 1 table. Typos corrected in equation