Absolutely Continuous Spectrum of Multifrequency Quasiperiodic Schrödinger operator
arXiv:2004.04409
Abstract
In this paper, we prove that for any -frequency analytic quasiperiodic Schrödinger operator, if the frequency is weak Liouvillean, and the potential is small enough, then the corresponding operator has absolutely continuous spectrum. Moreover, in the case , we even establish the existence of ac spectrum under small potential and some super-Liouvillean frequency, and this result is optimal due to a recent counterexample of Avila and Jitomirskaya.