On the recently proposed Mimetic Dark Matter

Understand

Recently, an interesting gravitational model was proposed in order to mimic the effect of Dark Matter.

• Chamseddine and Mukhanov in the arXiv preprint 1308.5410 have separated the conformal mode of a physical metric in the form of a squared gradient of an auxiliary scalar field.
• Notably, the variational principle has given a more general equation of motion than that of purely Einsteinian relativity theory, with a possibility of reproducing an effective Dark Matter.
• In this short paper, we explain the nature of this phenomenon in terms of the class of functions on which the variation takes place.