Non-singular modified gravity: the unification of the inflation, dark energy and dark mater

TL;DR

This paper explores non-singular modified gravity theories that unify early inflation and late-time acceleration, showing how they can resolve future singularities and improve cosmological models.

Contribution

It introduces conditions for avoiding future singularities in modified gravity and demonstrates how non-singular models can unify inflation with dark energy.

Findings

Non-singular modified gravity can unify inflation and dark energy.

Adding non-singular theories can cure singularities in combined models.

The approach applies to both early-time inflation and late-time acceleration.

Abstract

Using the fluid representation, we formulate the conditions for the appearance of all four types finite-time future singularity in modified gravity in accelerating FRW universe. It stressed that number of standard quintessence/phantom DE theories (including scalar, fluid, DBI ones, etc) brings the accelerating cosmology to future singularity precisely in the same way as singular modified gravity DE. The viable non-singular modified gravity unifying the early-time inflation with late-time acceleration is considered. It is shown that adding such non-singular theory to another realistic singular modified gravity which has the accelerating solution with future singularity may cure the singularity of resulting combined model. This universal scenario may be naturally applied to standard singular DE models as well as to inflationary theories with initial singularity. This suggests the additional fundamental reasoning for modification of General Relativity.