Emergent cosmic space in Rastall theory

TL;DR

This paper explores the emergent cosmic space concept within Rastall theory, proposing a modified energy concept and deriving the Friedmann equation, thus linking emergent space ideas with modified gravity.

Contribution

It introduces a modified Komar energy and derives the Friedmann equation in Rastall theory using Padmanabhan's emergent space framework.

Findings

Derived a new form of Komar energy for Rastall theory

Reobtained Friedmann equations from emergent space principles

Linked Rastall gravity with emergent cosmic space concept

Abstract

Padmanabhan's emergent cosmic space proposal is employed to study the Rastall theory which involves modifying the conservation law of energy-momentum tensor. As a necessary element for this approach, we firstly propose a modified Komar energy which reflects the evolution of the energy-momentum itself in the case of a perfect fluid. After that, an expansion law is invoked to reobtain the Friedmann equation in this theory.