Stability of Weyl semimetals with quasiperiodic disorder

Weyl semimetals are phases of matter with excitations effectively described by massless Dirac fermions. Their critical nature makes unclear the persistence of such a phase in the presence of disorder. We present a theorem ensuring the stability of the semimetallic phase in the presence of weak quasiperiodic disorder. The proof relies on the subtle interplay of the relativistic quantum field theory description combined with number-theoretical properties used in Kolmogorov-Arnold-Moser theory.