English

Scalar spectral measures associated with an Operator-Fractal

Spectral Theory 2012-04-24 v1 Operator Algebras

Abstract

We examine the operator U5U_5 defined on L2(μ14)L^2(\mu_{\frac14}) where μ14\mu_{\frac14} is the 1/4 Cantor measure. The operator U5U_5 scales the elements of the canonical exponential spectrum for L2(μ14)L^2(\mu_{\frac14}) by 5 --- that is, Ueγ=e5γUe_{\gamma} = e_{5\gamma} where eγ(t)=e2πiγte_{\gamma}(t) = e^{2\pi i \gamma t}. It is known that U5U_5 has a self-similar structure, which makes its spectrum, which is currently unknown, of particular interest. In order to better understand the spectrum of U5U_5, we demonstrate a decomposition of the projection valued measures and scalar spectral measures associated with U5U_5. We are also able to compute associated Radon-Nikodym derivatives between the scalar measures. Our decomposition utilizes a system of operators which form a representation of the Cuntz algebra O2\mathcal{O}_2.

Keywords

Cite

@article{arxiv.1204.5116,
  title  = {Scalar spectral measures associated with an Operator-Fractal},
  author = {Palle E. T. Jorgensen and Keri A. Kornelson and Karen L. Shuman},
  journal= {arXiv preprint arXiv:1204.5116},
  year   = {2012}
}