On Magnetic Catalysis and Gauge Symmetry Breaking

Non-perturbative effects of constant magnetic fields in a Higgs-Yukawa gauge model are studied using the extremum equations of the effective action for composite operators. It is found that the magnetic field induces a Higgs condensate, a fermion-antifermion condensate, and a fermion dynamical mass, hence breaking the discrete chiral symmetry of the theory. The results imply that for a non-simple group extension of the present model, the external magnetic field would either induce or reinforce gauge symmetry breaking. Possible cosmological applications of these results in the electroweak phase transition are suggested.