English

The absolutely continuous spectrum of the almost Mathieu operator

Dynamical Systems 2008-10-17 v1 Mathematical Physics math.MP Spectral Theory

Abstract

We prove that the spectrum of the almost Mathieu operator is absolutely continuous if and only if the coupling is subcritical. This settles Problem 6 of Barry Simon's list of Schr\"odinger operator problems for the twenty-first century.

Keywords

Cite

@article{arxiv.0810.2965,
  title  = {The absolutely continuous spectrum of the almost Mathieu operator},
  author = {Artur Avila},
  journal= {arXiv preprint arXiv:0810.2965},
  year   = {2008}
}

Comments

22 pages

R2 v1 2026-06-21T11:31:35.813Z