Aspects of non-singular bounce in modified gravity theories

TL;DR

This paper explores three classical modified gravity models that naturally produce non-singular bouncing cosmologies, avoiding the big bang singularity without quantum effects, and discusses their constraints.

Contribution

It introduces three classical, geometrically motivated approaches within modified gravity theories that inherently generate bounce scenarios without external sources.

Findings

Models successfully produce non-singular bounces.

Constraints for viable bouncing models are discussed.

Approaches remain within classical gravity, avoiding quantum assumptions.

Abstract

Scenario of a bouncing universe is one of the most active area of research to arrive at singularity free cosmological models. Different proposals have been suggested to avoid the so called 'big bang' singularity through the quantum aspect of gravity which is yet to have a proper understanding. In this work, on the contrary, we consider three different approaches, each of which goes beyond General Relativity but remain within the domain of classical cosmological scenario, to address this problem. The hallmark of all these approaches is that the origin of the bouncing mechanism is somewhat natural within the geometrical framework of the model without any need of incorporating external source by hand. In the context of these scenarios ,we also discuss various constraints that these viable cosmological models need to satisfy.