English

Renormalization and universality of the Hofstadter spectrum

Mathematical Physics 2020-08-26 v1 math.MP Spectral Theory Quantum Physics

Abstract

We consider a renormalization transformation RR for skew-product maps of the type that arise in a spectral analysis of the Hofstadter Hamiltonian. Periodic orbits of RR determine universal constants analogous to the critical exponents in the theory of phase transitions. Restricting to skew-product maps over a circle-rotations by the golden mean, we find several periodic orbits for RR, and we conjecture that there are infinitely many. Interestingly, all scaling factors that have been determined to high accuracy appear to be algebraically related to the circle-rotation number. We present evidence that these values describe (among other things) local scaling properties of the Hofstadter spectrum.

Keywords

Cite

@article{arxiv.1911.09172,
  title  = {Renormalization and universality of the Hofstadter spectrum},
  author = {Hans Koch and Sasha Kocic},
  journal= {arXiv preprint arXiv:1911.09172},
  year   = {2020}
}