Conductance and statistical properties of chaotic and integrable electron waveguides

We show that the S-matrix for electrons propagating in a waveguide has diff erent statistical properties depending on whether the waveguide cavity shap e gives rise to chaotic or integrable behavior classically. We obtain distr ibutions of energy level spacings for integrable and chaotic billiards shap ed like the waveguide cavity. We also obtain distributions for Wigner delay times and resonance widths for the waveguide, for integrable and chaotic c avity geometries. Our results, obtained by direct numerical calculation of the electron wave function, are consistent with the predictions of random m atrix theory.