Singular fate of the universe in modified theories of gravity

TL;DR

This paper investigates the ultimate fate of the universe within modified gravity theories, focusing on future singularities and their characteristics through curvature analysis and observer-based schemes.

Contribution

It introduces a detailed analysis of future singularities in modified gravity, considering both theoretical models and phenomenological examples, extending previous work beyond general relativity.

Findings

Identification of different types of future singularities in modified gravity

Curvature scalar behavior indicates potential singularities

Observer-based analysis provides insights into physical implications

Abstract

In this paper we study the final fate of the universe in modified theories of gravity. As compared with general relativistic formulations, in these scenarios the Friedmann equation has additional terms which are relevant for low density epochs. We analyze the sort of future singularities to be found under the usual assumption the expanding Universe is solely filled with a pressureless component. We report our results using two schemes: one concerned with the behavior of curvature scalars, and a more refined one linked to observers. Some examples with a very solid theoretical motivation and some others with a more phenomenological nature are used for illustration.