Dark matter as the Bose–Einstein condensation in loop quantum cosmology

K Atazadeh,F Darabi,M Mousavi

doi:10.1140/epjc/s10052-016-4182-x

Abstract

We consider the FLRW universe in a loop quantum cosmological model filled with the radiation, baryonic matter (with negligible pressure), dark energy and dark matter. The dark matter sector is supposed to be of Bose-Einstein condensate type. The Bose-Einstein condensation process in a cosmological context by supposing it as an approximate first order phase transition, has been already studied in the literature. Here, we study the evolution of the physical quantities related to the early universe description such as the energy density, temperature and scale factor of the universe, before, during and after the condensation process. We also consider in detail the evolution era of the universe in a mixed normal-condensate dark matter phase. The behavior and time evolution of the condensate dark matter fraction is also analyzed.

Highlights

Loop quantum gravity (LQG) is one of the potential candidates for the study of quantum gravity [2]
We study the post condensation phase in loop quantum cosmology (LQC) model describing the evolution of the scale factor parameter under the effect of the existence of the Bose–Einstein Condensation (BEC) dark matter in LQC
We have studied the evolution during the Bose–Einstein condensation phase and found that this condensation process modifies the expansion rate of the universe

Summary

Introduction

Loop quantum gravity (LQG) is one of the potential candidates for the study of quantum gravity [2]. A Gauss–Bonnet extension of LQC, by introducing holonomy corrections in modified f (G) theories of gravity was developed, where the authors have provided a perturbative expansion in the critical density as well as a parameter characteristic of LQG, and one obtained leading-order corrections to the classical f (G) theories of gravity They presented a reconstruction method which makes possible to find the LQC corrected f (G) theory capable of realizing various cosmological scenarios [15]. We introduce the numerical values of the cosmological parameters at the condensation point, and obtain the important h(t) parameter as a volume fraction of matter in the Bose–Einstein condensed phase which explains the evolution of the dark matter energy density during the transition process, and extract the order of BEC time interval in LQC model.

Bose–Einstein condensate dark matter in the LQC universe

Loop quantum cosmological dynamics of the Bose–Einstein condensation

Cosmological parameters at the condensation point

The post-condensation phase in LQC model

Conclusions