Autocorrelation function of level velocities for ray-splitting billiards

We study experimentally and theoretically the autocorrelation function of l evel velocities c(x) and the generalized conductance C(0) for classically c haotic ray-splitting systems. Experimentally, a Sinai ray-splitting billiar d was simulated by a thin microwave rectangular cavity with a quarter-circl e Teflon insert. For the theoretical estimates of the autocorrelator c(x) a nd the conductance C(0) we made parameter-dependent quantum calculations of eigenenergies of an annular ray-splitting billiard. Our experimental and n umerical results are compared to theoretical predictions of systems based o n the Gaussian orthogonal ensemble in random matrix theory.