Spectrum of the Dirac Operator and Inversion Algorithms with Dynamical   Staggered Fermions
  Complete spectra of the staggered Dirac operator $\Dirac$ are determined in four-dimensional $SU(2)$ gauge fields with and without dynamical fermions.   An attempt is made to relate the performance of multigrid and conjugate gradient algorithms for propagators with the distribution of the eigenvalues of~$\Dirac$. 
Thomas Kalkreuter