Fluctuations of the Lyapunov exponent in 2D disordered systems
  We report a numerical investigation of the fluctuations of the Lyapunov exponent of a two dimensional non-interacting disordered system. While the ratio of the mean to the variance of the Lyapunov exponent is not constant, as it is in one dimension, its variation is consistent with the single parameter scaling hypothesis. 
K. Slevin, Y. Asada and L. I. Deych