Smilansky's model of irreversible quantum graphs, I: the absolutely continuous spectrum

In the model suggested by Smilansky one studies an operator describing the interaction between a quantum graph and a system of $K$ one-dimensional oscillators attached at several different points in the graph. The present paper is the first one in which the case $K>1$ is investigated. For the sake of simplicity we consider K=2, but our argument is of a general character. In this first of two papers on the problem, we describe the absolutely continuous spectrum. Our approach is based upon scattering theory

Smilansky's model of irreversible quantum graphs, II: the point spectrum

In the model suggested by Smilansky one studies an operator describing the interaction between a quantum graph and a system of K one-dimensional oscillators attached at different points of the graph. This paper is a continuation of our investigation of the case K>1. For the sake of simplicity we consider K=2, but our argument applies to the general situation. In this second paper we apply the variational approach to the study of the point spectrum.Comment: 18 page