Dark Energy and Modified Scale Covariant Theory of Gravitation

TL;DR

This paper investigates four cosmological models within a modified scale covariant theory of gravitation, analyzing dark energy's role in universe acceleration and its interaction with matter, revealing that dark energy is a significant contributor to accelerated expansion.

Contribution

It introduces four cosmological models in a modified scale covariant framework, highlighting dark energy's persistent role and its interaction with matter, with some models predicting future singularities.

Findings

Dark energy contributes to accelerated expansion in all models.

Dark energy models resemble $\\Lambda$CDM and quintessence types.

One model predicts a future big rip singularity.

Abstract

Taking up four model universes we study the behaviour and contribution of dark energy to the accelerated expansion of the universe, in the modified scale covariant theory of gravitation. Here, it is seen that though this modified theory may be a cause of the accelerated expansion it cannot totally outcast the contribution of dark energy in causing the accelerated expansion. In one case the dark energy is found to be the sole cause of the accelerated expansion. The dark energy contained in these models come out to be of the $\Lambda$CDM type and quintessence type comparable to the modern observations. Some of the models originated with a big bang, the dark energy being prevalent inside the universe before the evolution of this era. One of the models predicts big rip singularity, though at a very distant future. It is interestingly found that the interaction between the dark energy and the other part of the universe containing different matters is enticed and enhanced by the gauge function $\phi(t)$ here.