CROSSOVER DRIVEN BY TIME-REVERSAL SYMMETRY-BREAKING IN QUANTUM CHAOS

Parametric correlations of the energy spectra of quantum chaotic syste ms are presented in the presence of time-reversal symmetry-breaking pe rturbations. The spectra disperse as a function of two external pertur bations, one of which preserves time-reversal symmetry, while the othe r violates it. Exact analytical expressions for the parametric two-poi nt autocorrelation function of the density of states are derived in th e crossover region by means of the supermatrix method. For the orthogo nal-unitary crossover, the velocity distribution is determined and sho wn to deviate from Gaussian.