Schwinger- Dyson Equations and Dynamical Symmetry Breaking in Quantum   R^2- gravity
  The dymamical chiral symmetry breaking in higher- derivative quantum gravity has been investigated on the flat background. The Schwinger- Dyson equations numerical solutions have been found in the ladder approximation. Both two- and four- dimensional cases have been considered. The dymamical fermion mass generation accompanied by the second- order phase transition has been shown to take place in a different gauges. 
Y. I. Shil'nov, V. V. Chitov, A.T. Kotwicki