Relevance of disorder for dirac fermions with imaginary vector potentials

We consider the effects of disorder in a Dirac-like Hamiltonian. In order to use conformal field theory techniques, we argue that one should consider disorder in an imaginary vector potential. This affects significantly the signs of the lowest order beta functions. We present evidence for the existence of two distinct universality classes, depending on the relative strengths of the gauge field verses impurity disorder strengths. In one class all disorder is made irrelevant by the gauge field disorder.