Holographic model of the S^{+/-} multiband superconductor
  We construct the holographic model of an $S^\pm$ multiband superconductor. This system is a candidate to explain the anomalous features of the iron-based superconductors (e.g. LaFeAsO, BFe2As2, and other pnictides and arsenides). We study the framework, which allows formation of the sign-interchanging order parameter. We also calculate the electric AC conductivity and study its features, related to the interband interaction. 
A. Krikun, V. P. Kirilin, A. V. Sadofyev
hep-th cond-mat.supr-con