Electrodynamics effects in 3+1 dimensions induced by interactions in   Topological Insulators
  We investigate the effect of interactions in the Topological Insulator in 3+1 dimensions. We show that for a particular type of interactions, the Electrodynamics response is equivalent to the response of non-interacting Topological Insulator in 4+1 dimensions. 
D.Schmeltzer
cond-mat.str-el