# The matter-ekpyrotic bounce scenario in Loop Quantum Cosmology

## TL;DR

This paper analyzes a matter-ekpyrotic bounce scenario within Loop Quantum Cosmology, demonstrating its viability for producing a nearly scale-invariant power spectrum and successful reheating consistent with observational data.

## Contribution

It provides a detailed dynamical systems analysis of the matter-ekpyrotic bounce in Loop Quantum Cosmology, including particle production and perturbation spectra.

## Key findings

- Universe transitions from matter domination to ekpyrotic phase in contraction
- Reheating occurs via production of heavy and massless particles
- Perturbation spectra are nearly scale-invariant and compatible with PLANCK data

## Abstract

We will perform a detailed study of the matter-ekpyrotic bouncing scenario in Loop Quantum Cosmology using the methods of the dynamical systems theory. We will show that when the background is driven by a single scalar field, at very late times, in the contracting phase, all orbits depict a matter dominated Universe, which evolves to an ekpyrotic phase. After the bounce the Universe enters in the expanding phase, where the orbits leave the ekpyrotic regime going to a kination (also named deflationary) regime. Moreover, this scenario supports the production of heavy massive particles conformally coupled with gravity, which reheats the universe at temperatures compatible with the nucleosynthesis bounds and also the production of massless particles non-conformally coupled with gravity leading to very high reheating temperatures but ensuring the nucleosynthesis success. Dealing with cosmological perturbations, these background dynamics produce a nearly scale invariant power spectrum for the modes that leave the Hubble radius, in the contracting phase, when the Universe is quasi-matter dominated, whose spectral index and corresponding running is compatible with the recent experimental data obtained by PLANCK's team.