Theory of the ac Hall response of a model with X-ray edge Singularities   in infinite dimensions
  We study the ac magnetotransport in a non-Fermi liquid metal, which possesses explicit x-ray edge singularities in $d=\infty$. Specifically, we compute the ac conductivity tensor in a formalism that becomes exact in this limit. The ac Hall constant and Hall angle reveal features that are in striking qualitative agreement with those observed in optical transmission experiments carried out on $YBa_{2}Cu_{3}O_{7}$ thin films. Our results provide a concrete realization of the two-relaxation time picture proposed to explain magnetotransport anomalies in the normal state of cuprate superconductors. 
Mukul S. Laad and Luis Craco