Quantum Critical Transport and the Hall Angle
  In this letter we study the Hall conductivity in holographic models where translational invariance is broken by a lattice. We show that generic holographic theories will display a different temperature dependence in the Hall angle as to the DC conductivity. Our results suggest a general mechanism for obtaining an anomalous scaling of the Hall angle in strongly interacting quantum critical systems. 
Mike Blake, Aristomenis Donos
hep-th cond-mat.str-el