SINGLE LEVEL CURRENT AND CURVATURE DISTRIBUTIONS IN MESOSCOPIC SYSTEMS

Exact analytic results for single level current and curvature distribu tion functions are derived within the framework of a 2 x 2 random matr ix model. Current and curvature axe defined as the first and second de rivatives of energy with respect to a time-reversal symmetry breaking parameter (magnetic flux). The applicability of the obtained distribut ions for the spectral statistic of disordered metals is discussed. The most surprising feature of our results is the divergence of the secon d and higher moments of the curvature at zero flux. It is shown that t his divergence also appears in the general N x N random matrix model. Furthermore, we find an unusual logarithmic behavior of the two point current-current correlation function at small flux.