Deformed general relativity and scalar-tensor models

TL;DR

This paper derives the most general scalar-tensor action with deformed covariance, explores its cosmological implications, and introduces a new bounce-generating model with non-minimal coupling.

Contribution

It provides a comprehensive framework for scalar-tensor theories with deformed covariance and introduces a novel bouncing model within this framework.

Findings

General conditions for inflation or a bounce in scalar-tensor models.

A new non-minimally coupled scalar model that produces a bounce.

Method to construct similar bouncing models.

Abstract

We calculate the most general action for a scalar-tensor model up to quadratic order in derivatives with deformed general covariance and non-minimal coupling. We demonstrate how different choices of the free functions recover specific well known scalar-tensor models. We look at the cosmological dynamics and find the general conditions for either inflation or a big bounce. Using this we present a novel non-minimally coupled scalar model which produces a bounce, and describe how to find similar models.