Curvature Quintessence

TL;DR

This paper explores how higher order gravity theories can explain cosmic acceleration and quintessence without scalar fields, providing exact solutions and analyzing their relation to standard models via conformal transformations.

Contribution

It introduces a framework using fourth order gravity theories to model quintessence and cosmic acceleration, offering exact solutions and connecting different theoretical frames.

Findings

Exact accelerated solutions in fourth order gravity theories.

Effective pressure and energy density linked to Ricci scalar.

Connections established between Jordan and Einstein frames.

Abstract

The issues of quintessence and cosmic acceleration can be discussed in the framework of higher order theories of gravity. We can define effective pressure and energy density directly connected to the Ricci scalar of curvature of a generic fourth order theory and then ask for the conditions to get an accelerated expansion. Exact accelerated expanding solutions can be achieved for several fourth order theories so that we get an alternative scheme to the standard quintessence scalar field, minimally coupled to gravity, usually adopted. We discuss also conformal transformations in order to see the links of quintessence between the Jordan and Einstein frames.