http://arxiv.org/abs/1506.08575
We show that very general scalar-tensor theories of gravity (including, e.g., Horndeski models) are generically invariant under disformal transformations. However there is a special subset, when the transformation is not invertible, that yields new equations of motion which are a generalization of the so-called “mimetic” dark matter theory recently introduced by Chamsedinne and Mukhanov. These new equations of motion can also be derived from an action containing an additional Lagrange multiplier field. The general mimetic scalar-tensor theory has the same number of derivatives in the equations of motion as the original scalar-tensor theory. As an application we show that the simplest mimetic scalar-tensor model is able to mimic the cosmological background of a flat FLRW model with an irrotational barotropic perfect fluid with any constant equation of state.
F. Arroja, N. Bartolo, P. Karmakar, et. al.
Tue, 30 Jun 15
14/75
Comments: 14 pages, 1 figure
You must be logged in to post a comment.