Quintessence and (Anti-)Chaplygin Gas in Loop Quantum Cosmology

TL;DR

This paper explores various scalar field models, including Chaplygin gas and quintessence, within loop quantum cosmology, analyzing their singularities, bounces, and classical behavior near the big bang.

Contribution

It introduces and compares four scalar field models in loop quantum cosmology, highlighting their singularity structures and bounce behaviors.

Findings

Anti-Chaplygin gas models exhibit type II singularities and possible bounces.

Other models behave classically far from the big bang and bounce at critical density.

Different scalar fields influence the universe's evolution distinctly.

Abstract

The concordance model of cosmology contains several unknown components such as dark matter and dark energy. Many proposals have been made to describe them by choosing an appropriate potential for a scalar field. We study four models in the realm of loop quantum cosmology (LQC): the Chaplygin gas, an inflationary and radiation-like potential, quintessence and an anti-Chaplygin gas. For the latter we show that all trajectories start and end with a type II singularity and, depending on the inital value, may go through a bounce. On the other hand the evolution under the influence of the first three scalar fields behaves classically at times far away from the big bang singularity and bounces as the energy density approaches the critical density.