CATALYSIS OF DYNAMICAL SYMMETRY-BREAKING BY A MAGNETIC-FIELD

A constant magnetic field in 3+1 and 2+1 dimensions is a strong cataly st of dynamical chiral symmetry breaking, leading to the generation of a fermion dynamical mass even at the weakest attractive interaction b etween fermions. The essence of this effect is the dimensional reducti on D --> D - 2 in the dynamics of fermion pairing in a magnetic held. The effect is illustrated in the Nambu-Jona-Lasinio (NJL) model and QE D. Possible applications of this effect and its extension to inhomogen eous held configurations are discussed.