AC conductivity for a holographic Weyl Semimetal
  We study the AC electrical conductivity at zero temperature in a holographic model for a Weyl semimetal. At small frequencies we observe a linear dependence in the frequency. The model shows a quantum phase transition between a topological semimetal (Weyl semimetal phase) with a non vanishing anomalous Hall conductivity and a trivial semimetal. The AC conductivity has an intermediate scaling due to the presence of a quantum critical region in the phase diagram of the system. The phase diagram is reconstructed using the scaling properties of the conductivity. We compare with the experimental data of [1502.03807] obtaining qualitative agreement. 
Gianluca Grignani, Andrea Marini, Francisco Pena-Benitez, Stefano   Speziali
cond-mat.str-el hep-th