תקציר:

We develop a semiclassical theory for the spectral statistics of quasi-one-dimensional systems that show chaotic diffusion on the classical level and Anderson-localized quantal eigenstates. It relates the spectral two-point correlations to the classical probability for periodic motion. We obtain analytical expressions for the spectral form factor, defining a novel, one-parameter spectral universality class which spans the transition from Poissonian spectra in the limit corresponding to disordered systems in the isolating regime, to GOE statistics in the opposite (ballistic) regime. Our analytical predictions are confirmed by a numerical study of quasi-one-dimensional billiard chains.