Spectral Structure of Quantum Line with a Defect

Abstract

We study the spectral properties of one-dimensional quantum wire with a single defect. We reveal the existence of the non-trivial topological structures in the spectral space of the system, which are behind the exotic quantum phenomena that have lately been found in the system.Comment: 4 pages, LaTeX, To appear in Proc. International Symposium on Foundation of Quantum Mechanics, Tokyo, Aug.26-30, 2001 (ISQM-Tokyo 01