Constraints on Singular Evolution from Gravitational Baryogenesis

TL;DR

This paper explores how gravitational baryogenesis constrains Type IV singularities in cosmological models, particularly within modified gravity frameworks, ensuring the baryon-to-entropy ratio remains finite during different cosmic eras.

Contribution

It demonstrates that gravitational baryogenesis imposes constraints on Type IV singularities in modified gravity models, preventing singularities in the baryon-to-entropy ratio during key cosmological periods.

Findings

Type IV singularities at matter and radiation eras are constrained by baryogenesis.

Models cannot be realized in Einstein-Hilbert gravity, only in $F(R)$ or modified gravity.

Baryon-to-entropy ratio remains finite despite singularities.

Abstract

We investigate how the gravitational baryogenesis mechanism can potentially constrain the form of a Type IV singularity. Specifically, we study two different models with interesting phenomenology, that realize two distinct Type IV singularities, one occurring at the end of inflation and one during the radiation domination era or during the matter domination era. As we demonstrate, the Type IV singularities occurring at the matter domination era or during the radiation domination era, are constrained by the gravitational baryogenesis, in such a way so that these do not render the baryon to entropy ratio singular. Both the cosmological models we study cannot be realized in the context of ordinary Einstein-Hilbert gravity, and hence our work can only be realized in the context of $F(R)$ gravity and more generally in the context of modified gravity only.