The effective potential of composite fields in weakly coupled QED in a   uniform external magnetic field
  The effective potential for the composite fields responsible for chiral symmetry breaking in weakly coupled QED in a magnetic field is derived. The global minimum of the effective potential is found to acquire a non-vanishing expectation value of the composite fields that leads to generating the dynamical fermion mass by an external magnetic field. The results are compared with those for the Nambu-Jona-Lasinio model. 
D.-S. Lee, P. N. McGraw, Y. J. Ng and I. A. Shovkovy