Disordered systems and the metal-insulator transition: A super universality class

The critical behavior of three-dimensional disordered systems is investigated by analyzing the spectral fluctuations of the energy spectrum. Our results suggest that the initial symmetries (orthogonal, unitary, and symplectic) are broken by the disorder at the critical point. The critical behavior, determined by the symmetry at the critical point, should therefore be independent of the previous invariances and be described by a ``super'' universality class. This result is strongly supported by the fact that we obtain the same critical exponent ν1.35 in the three cases: orthogonal, unitary, and symplectic.