Inflationary f(R) cosmologies

TL;DR

This paper presents a method to reconstruct f(R) gravity models from exact cosmological solutions, enabling the modeling of inflationary scenarios consistent with observational data like Planck.

Contribution

It introduces a procedure to derive f(R) models from known inflationary solutions and demonstrates their consistency with observational parameters.

Findings

Reconstructed f(R) models match inflationary expansion

Calculated slow-roll parameters align with Planck data

Provided a systematic approach for f(R) inflationary cosmologies

Abstract

This paper discusses a simple procedure to reconstruct f (R)-gravity models from exact cosmological solutions of the Einstein field equations with a noninteracting classical scalar field-and-radiation background. From the kind of inflationary scenario we want, we show how the potential functions can be obtained. We then show how an f (R) gravitational Lagrangian density that mimics the same cosmological expansion as the scalar field-driven inflation of General Relativity can be reconstructed. As a demonstration, we calculate the slow-roll parameters (the spectral index n s and the tensor-to-scalar ratio r) and compare them to the Planck data.