  Existence of the eigenvalues of the discrete-time quantum walks is deeply
related to localization of the walks. We revealed the distributions of the
eigenvalues given by the splitted generating function method (the SGF method)
of the quantum walks we had treated in our previous studies. In particular, we
focused on two kinds of the Hadamard walk with one defect models and the
two-phase QWs that have phases at the non-diagonal elements of the unitary
transition operators. As a result, we clarified the characteristic parameter
dependence for the distributions of the eigenvalues with the aid of numerical
simulation.
