The Spectrum of the Dirac Operator in the Linear Sigma Model with Quarks
  We derive the spectrum of the Dirac operator for the linear sigma-model with quarks in the large N_c approximation using renormalization group flow equations. For small eigenvalues, the Banks-Casher relation and the vanishing linear term are recovered. We calculate the coefficient of the next to leading term and investigate the spectrum beyond the low energy regime. 
T. Spitzenberg, K. Schwenzer and H.-J. Pirner