  We present a holographic model of a Weyl semi-metal. We show that upon
varying a mass parameter the model undergoes a quantum phase transition from a
topologically non-trivial state to a trivial one. The order parameter for this
phase transition is the anomalous Hall effect (AHE). We give an interpretation
of the results in terms of a holographic RG flow and compare to a weakly
coupled field theoretical model. Since there are no quasiparticle excitations
in the strongly coupled holographic model the topological phase can not be
bound to notions of topology in momentum space.
