Power-law solutions for TeVeS

TL;DR

This paper analyzes the cosmological solutions of TeVeS, showing that it can produce power-law expansion and contraction, with the scalar field acting as dark matter and matter mimicking dark energy.

Contribution

It derives explicit power-law solutions for TeVeS in a homogeneous universe, revealing the scalar field's role as dark matter and the matter component's dark energy mimicry.

Findings

Power-law solutions in physical frame are found.

Scalar field acts as dark matter.

Matter mimics phantom dark energy.

Abstract

The dynamics of TeVeS in a homogeneous and isotropic universe is shown to be equivalent to the dynamics of an interacting two-component system, consisting of a scalar field and a "fluid", related to the matter part, with explicitly given coupling term. Scaling solutions (solutions with a constant ratio of the energy densities of both components) in the "Einstein frame" are found which are exponentially expanding or contracting with no remaining freedom for Bekenstein's $F$ function. In the "physical frame" these solutions are of the power-law type. An equivalent General Relativity (GR) picture of the dynamics suggests that it is the scalar field which plays the role of dark matter, while the "matter" has to mimic (phantom-type) dark energy.