Inflation with scalar-tensor theory of gravity

TL;DR

This paper investigates inflation within a scalar-tensor gravity framework, using symmetry to determine model parameters, and finds that several potentials satisfy observational constraints and end inflation gracefully.

Contribution

It introduces a method to fix parameters in scalar-tensor inflation models using symmetry, demonstrating compatibility with observational data for multiple potentials.

Findings

All tested potentials satisfy Planck 2018 constraints.

Models successfully exit inflation smoothly.

The symmetry approach effectively constrains model parameters.

Abstract

The latest released data from Planck in 2018, put up tighter constraints on inflationary parameters. In the present article, the in-built symmetry of the non-minimally coupled scalar-tensor theory of gravity is used to fix the coupling parameter, the functional Brans-Dicke parameter, and the potential of the theory. It is found that all the three different power-law potentials and one exponential, pass these constraints comfortably, and also gracefully exit from inflation.