Topological properties of superconducting junctions
D. I. Pikulin+, Y. V. Nazarov*
+Instituut-Lorentz, Universiteit Leiden, 2300 RA Leiden, Netherlands
*Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, Netherlands
Abstract
Motivated by recent developments in the field of one-dimensional
topological superconductors, we investigate the topological properties of
s-matrix of generic superconducting junctions where dimension should not
play any role. We argue that for a finite junction the s-matrix is always
topologically trivial. We resolve an apparent contradiction with the previous
results by taking into account the low-energy resonant poles of s-matrix.
Thus no common topological transition occur in a finite junction. We reveal a
transition of a different kind that concerns the configuration of the
resonant poles.