On the way from matter-dominated era to dark energy universe

TL;DR

This paper develops a unified scalar-tensor framework to describe the transition from matter dominance to dark energy-driven acceleration, consistent with observational data, and explores implications for galaxy rotation curves.

Contribution

It provides a general reconstruction method for scalar-tensor theories that unify matter and dark energy epochs, including explicit potentials and models with observational consistency.

Findings

Explicit scalar potentials for matter-dark energy transition

Models where dark energy dominance follows matter dominance

Modified Newtonian potential explaining galaxy rotation curves

Abstract

We develop the general program of the unification of matter-dominated era with acceleration epoch for scalar-tensor theory or dark fluid. The general reconstruction of single scalar-tensor theory is fulfilled. The explicit form of scalar potential for which the theory admits matter-dominated era, transition to acceleration and (asymptotically deSitter) acceleration epoch consistent with WMAP data is found. The interrelation of the epochs of deceleration-acceleration transition and matter dominance-dark energy transition for dark fluids with general EOS is investigated. We give several examples of such models with explicit EOS (using redshift parametrization) where matter-dark energy domination transition may precede the deceleration-acceleration transition. As some by-product, the reconstruction scheme is applied to scalar-tensor theory to define the scalar potentials which may produce the dark matter effect. The obtained modification of Newton potential may explain the rotation curves of galaxies.