%0 Journal Article
%T The absolutely continuous spectrum of the almost Mathieu operator
%A Artur Avila
%J Mathematics
%D 2008
%I arXiv
%X 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.
%U http://arxiv.org/abs/0810.2965v1