# Nonsingular Universes in Gauss-Bonnet Gravity's Rainbow

## TL;DR

This paper investigates how rainbow gravity deformations, inspired by gamma-ray burst spectra, can eliminate singularities in Friedmann-Robertson-Walker cosmology within Einstein and Gauss-Bonnet gravity frameworks.

## Contribution

It demonstrates that rainbow deformations can remove cosmological singularities and explores how Gauss-Bonnet gravity alters the conditions for nonsingular universes.

## Key findings

- Rainbow deformation removes FRW singularity.
- Gauss-Bonnet gravity changes nonsingularity constraints.
- Explicit demonstration with gamma-ray burst motivated functions.

## Abstract

In this paper, we will study the rainbow deformation of the FRW cosmology in both Einstein gravity and Gauss-Bonnet gravity. We will demonstrate that the singularity in the FRW cosmology can be removed because of the rainbow deformation of the FRW metric. We will obtain the general constraints required for the FRW cosmology to be free from singularities. It will be observed that the inclusion of Gauss-Bonnet gravity can significantly change the constraints required to obtain a nonsingular universes. We will use a rainbow functions motivated from the hard spectra of gamma-ray bursts to deform the FRW cosmology, and it will be explicitly demonstrated that such a deformation removes the singularity in the FRW cosmology.