Matter Bounce Scenario in F(T) gravity

TL;DR

This paper explores how teleparallel $F(T)$ gravity combined with Loop Quantum Cosmology can support a Matter Bounce Scenario, offering a viable alternative to inflation with specific observational and theoretical conditions.

Contribution

It demonstrates the viability of Matter Bounce Scenario in $F(T)$ gravity with holonomy corrections, including power spectrum calculations and discussion of associated challenges.

Findings

Power spectrum and tensor-to-scalar ratio calculated for matter-dominated background.

Conditions for compatibility with PLANCK data summarized.

Challenges like non-gaussianities and instabilities discussed.

Abstract

It is shown that teleparallel $F(T)$ theories of gravity combined with holonomy corrected Loop Quantum Cosmology (LQC) support a Matter Bounce Scenario (MBS) which is a potential alternative to the inflationary paradigm. The Matter Bounce Scenario is reviewed and, according to the current observational data provided by PLANCK's team, we have summarized all the conditions that it has to satisfy in order to be a viable alternative to inflation, such as to provide a theoretical value of the spectral index and its running compatible with the latest PLANCK data, to have a reheating process via gravitational particle production, or to predict some signatures in the non-gaussianities of the power spectrum. The calculation of the power spectrum for scalar perturbations and the ratio of tensor to scalar perturbations has been done, in the simplest case of an exact matter dominated background, for both holonomy corrected LQC and teleparallel $F(T)$ gravity. Finally, we have discussed the challenges (essentially, dealing with non-gaussianities, the calculation of the 3-point function in flat spatial geometries for theories beyond General Relativity) and problems (Jeans instabilities in the case of holonomy corrected LQC or local Lorentz dependence in teleparallelism) that arise in either bouncing scenario.