Absolute continuity of the spectrum in a twisted Dirichlet-Neumann waveguide

Quantum waveguides with the shape of a planar infinite straight strip and combined Dirichlet and Neumann boundary conditions on the opposite half-lines of the boundary are considered. The absence of the point as well as of the singular continuous spectrum is proved.Quantum waveguides with the shape of a planar infinite straight strip and combined Dirichlet and Neumann boundary conditions on the opposite half-lines of the boundary are considered. The absence of the point as well as of the singular continuous spectrum is proved.