Energy-level correlations in chiral symmetric disordered systems: Corrections to the universal results - art. no. 214201

We investigate the deviation of the level-correlation functions from the un iversal form for the chiral symmetric classes. Using the supersymmetric non linear sigma model we formulate the perturbation theory. The large energy b ehavior is compared with the result of the diagrammatic perturbation theory . We have the diffuson and cooperon contributions even in the average densi ty of states. For the unitary and orthogonal classes we get the small energ y behavior that suggests a weakening of the level repulsion. For the symple ctic case we get a result with opposite tendency.