  We demonstrate a new class of "coherent" metamaterials, where a regular
ensemble of meta-molecules shows a collective, i.e. coherent, narrow band
resonant response, while disordering the ensemble leads to broadening and
eventually disappearance of the resonance. We draw parallels between the
observed collective behavior of meta-molecules and the Mossbauer effect and
notice certain remarkable similarities with the phase transitions of
ferromagnetic systems.
