Gauged NJL model at strong curvature
  We investigate the gauged NJL--model in curved spacetime using the RG formulation and the equivalency with the gauge Higgs--Yukawa model in a modified 1/N_c -expansion. The strong curvature induced chiral symmetry breaking is found in the non-perturbative RG approach (presumably equivalent to the ladder Schwinger--Dyson equations). Dynamically generated fermion mass is explicitly calculated and inducing of Einstein gravity is briefly discussed. This approach shows the way to the non-perturbative study of the dynamical symmetry breaking at external fields. 
B. Geyer and S.D. Odintsov