Remark on the momentum dependence of the magnetic catalysis in QED - art. no. 067702

We propose a new derivation of the fermion dynamical mass generated in four -dimensional QED in the presence of an external constant magnetic field, ta king into account the momentum dependence of the fennion self-energy. The r esult confirms previous analytical studies, and we extend the computation t o the finite temperature case where we find that the critical temperature i s of the order of the dynamical mass at zero temperature.