Cosmological Inflation in a Generalized Unimodular Gravity

TL;DR

This paper investigates inflation within a generalized unimodular $f(R)$ gravity framework, analyzing model parameters against observational data to identify viable inflationary scenarios.

Contribution

It introduces a specific $f(R)$ model with a scalaron driving inflation in unimodular gravity and constrains its parameters using observational data.

Findings

Model consistent with observations for 1.89<n<1.918 at 60 e-folds.

Confronts theoretical predictions with observational constraints.

Provides bounds on the parameter n in the $f(R)$ function.

Abstract

We study some aspects of cosmological inflation in the framework of unimodular $f(R)$ gravity. To be more clarified, we consider a generic $f(R)$ of the type $f(R)=R+\alpha R^{n}$. By considering Einstein frame counterpart of the unimodular $f(R)$ gravity, we set the scalaron to be responsible for cosmological inflation in this setup. We confront our model parameters space with observational data and impose some constraints on the value of $n$ in this manner. We show that for the number of e-folds $N=60$, the model is consistent with observation if $1.89<n<1.918$.