Transport in Locally Perturbed Tubes

Abstract

Quantum motion in a non-straight tube represents a particular case of scattering with a finite number of open channels corresponding to transverse modes with the energy below that of the incident particle. Resonances in such systems are of particular interest. They may arise from a violation of a symmetry preventing passages between certain transverse modes. They may appear also in other situations, for instance, in thin bent tubes where they are situated in the vicinity of the transverse thresholds and their widths are exponentially small in terms of the tube diameter.