Reconstructing cosmic acceleration from f(R) modified gravity

TL;DR

This paper develops reconstruction methods for f(R) gravity to model cosmic acceleration, comparing two schemes and illustrating a transient phantom behavior without matter, highlighting potential non-equivalence of different frames.

Contribution

It introduces two novel reconstruction schemes for f(R) gravity and compares their physical implications, especially regarding frame equivalence and phantom behavior.

Findings

Reconstruction schemes in terms of e-foldings and scalar fields are formulated.

An example model exhibits transient phantom behavior without matter.

Comparison suggests potential non-equivalence of different frames.

Abstract

A variant of the accelerating cosmology reconstruction program is developed for $f(R)$ gravity. Reconstruction schemes in terms of e-foldings and by using an auxiliary scalar field are developed. An example of a model with a transient phantom behavior without real matter is explicitly discussed in both schemes. Detailed comparison of the two schemes of reconstruction is presented. It seems to support physical non-equivalence of the two frames.