  It is often said that interactions destroy the particle nature of
excitations. We report that, in holographic theory adding interaction term can
create a new quasi particle spectrum, on the contrary. We show this by
calculating the optical conductivity in a model with exact background solution
and finding a new quasi-particle spectrum. We argue that such new poles are
generic consequence of any non-minimal interaction like Chern-Simon term. The
interaction driven metal-insulator transition and the pinning effect in
holography are examples of this phenomena. We also point out that the origin of
the pinning peak is the vortex formation by the anomalous magnetic moment
induced by the interaction term.
