Effective fluid mixture of tensor-multi-scalar gravity

We apply to tensor-multi-scalar gravity the effective fluid analysis based on the representation of the gravitational scalar field as a dissipative effective fluid. This generalization poses new challenges as the effective fluid is now a complicated mixture of individual fluids mutually coupled to each other, and many reference frames are possible for its description. They are all legitimate, although not all convenient for specific problems, and they give rise to different physical interpretations. Two of these frames are highlighted, and implications for cosmology are pointed out.

Automated summary

In this paper, we apply the effective fluid analysis to tensor-multi-scalar gravity by representing the gravitational scalar field as a dissipative effective fluid. This generalization poses new challenges as the effective fluid becomes a complicated mixture of mutually coupled individual fluids, with different possible reference frames for its description. Two of these frames are highlighted, and their implications for cosmology are discussed.