Dirac Operators with Exponentially Decaying Entropy

Abstract

We prove that the Weyl function of the one-dimensional Dirac operator on the half-line \({\mathbb {R}}_+\) with exponentially decaying entropy extends meromorphically into the horizontal strip \(\{0\geqslant \mathop {\textrm{Im}}\nolimits z > -\delta \}\) for some \(\delta > 0\) depending on the rate of decay. If the entropy decreases very rapidly then the corresponding Weyl function turns out to be meromorphic in the whole complex plane. In this situation we show that poles of the Weyl function (scattering resonances) uniquely determine the operator.