Perturbation of an Eigen-Value from a Dense Point Spectrum : An Example

P. Duclos, P. Stovicek, M. Vittot

We study a perturbed Floquet Hamiltonian $K+\beta V$ depending on a coupling constant $\beta$. The spectrum $\sigma (K)$ is assumed to be pure point and dense. We pick up an eigen-value, namely $…