Sharp $\frac12$-Hölder continuity of the Lyapunov exponent at the bottom of the spectrum for a class of Schrödinger cocycles

Jordi-Lluís Figueras, Thomas Ohlson Timoudas

Published 2018-09-14Version 1

We consider a similar type of scenario for the disappearance of uniform of hyperbolicity as in Bjerkl\"ov and Saprykina (2008, Nonlinearity 21), where it was proved that the minimum distance between invariant stable and unstable bundles has a linear power law dependence on parameters. In this scenario we prove that the Lyapunov exponent is sharp $\frac12$-H\"older continuous. In particular, we show that the Lyapunov exponent of Schr\"odinger cocycles with a potential having a unique non-degenerate minimum, is sharp $\frac12$-H\"older continuous below the lowest energy of the spectrum, in the large coupling regime.