Wigner-Dyson statistics from the Keldysh sigma-model

Phys Rev Lett. 2000 Dec 25;85(26 Pt 1):5615-8. doi: 10.1103/PhysRevLett.85.5615.

Abstract

The level statistics of disordered metallic grains with broken time reversal invariance is obtained from the Keldysh nonlinear sigma-model. The basic strategy of the approach--a nonperturbative integration over all saddle points of the sigma-model manifold--might prove useful in the analysis of problems involving disorder and interactions.