Towards a unified interpretation of the early Universe in $R^2$-corrected dark energy model of $F(R)$ gravity

Abstract

$R^2$-corrected dark energy (DE) models in $F(R)$ gravity have been widely investigated in recent years, which not only removes the weak singularity potentially present in DE models but also provide us with a unified picture of the cosmic history, including the inflationary and DE epochs. Towards the unified interpretation of dynamical DE all over the cosmic history in the class of $R^2$-corrected DE models, we explore the universal features of the scalaron dynamics in the radiation-dominated epoch, along with the chameleon mechanism, by keeping our eyes on the inflationary and DE epochs. We show that the scalaron evolution does not follow a \textit{surfing solution} and is mostly adiabatic before big bang nucleosynthesis (BBN), even properly including the \textit{kick} by the nonperturbative QCD phase transition, hence a catastrophic consequence claimed in the literature is not applied to this class of DE models. This is due to the presence of the gigantic scale hierarchy between $R^2$ correction and DE, so is the universal feature for the class of $R^2$-corrected DE models. The prospects for the post- or onset-inflationary epoch would be pretty different from what the standard $R^2$ inflationary scenario undergoes due to the presence of the chameleon mechanism.

24 pages, 10 figures, 1 data file; Version to appear in Chinese Physics C with few references added

References in corpus (13)

• Nonperturbative Dynamics Of Reheating After Inflation: A Review
• The QCD equation of state in background magnetic fields
• A Singularity Problem with f(R) Dark Energy
• Dark Matter from R^2-gravity
• On Effective Degrees of Freedom in the Early Universe
• Unifying of Inflation with Early and Late Dark Energy Epochs in Axion $F(R)$ Gravity
• Aspects of cosmological expansion in F(R) gravity models
• Unification of Inflation with Dark Energy in $f(R)$ Gravity and Axion Dark Matter
• Geometric Inflation and Dark Energy with Axion $F(R)$ Gravity
• Can higher curvature corrections cure the singularity problem in f(R) gravity?
• Inflation and dark energy from f(R) gravity
• $R^2$ Inflation Revisited and Dark Energy Corrections
• ${\mathcal{R}}^2$ Quantum Corrected Scalar Field Inflation

Cited by in corpus (1)

• Revisiting compact star in $F(R)$ gravity: Roles of chameleon potential and energy conditions