Positivity of Lyapunov exponents for a continuous matrix-valued Anderson model

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We study a continuous matrix-valued Anderson-type model. Both leading Lyapunov exponents of this model are proved to be positive and distinct for all ernergies in (2,+∞) except those in a discrete set, which leads to absence of absolutely continuous spectrum in (2,+∞). This result is an improvement of a previous result with Stolz. The methods, based upon a result by Breuillard and Gelander on dense subgroups in semisimple Lie groups, and a criterion by Goldsheid and Margulis, allow for singular Bernoulli distributions.