Non-minimally coupled f(R) Cosmology

TL;DR

This study explores how non-minimal gravitational coupling affects cosmic evolution, showing it leads to a slower Hubble parameter evolution and different parameter constraints compared to minimal coupling, based on supernova and BAO data.

Contribution

It introduces a detailed analysis of non-minimal coupling effects on cosmology and constrains model parameters using observational data, highlighting differences from minimal coupling.

Findings

Hubble parameter evolves more slowly with non-minimal coupling.

Universe accelerates around present time in both models.

Non-minimal coupling allows a range of parameter values, unlike minimal coupling.

Abstract

We investigate the consequences of non-minimal gravitational coupling to matter and study how it differs from the case of minimal coupling by choosing certain simple forms for the nature of coupling, The values of the parameters are specified at $z=0$ (present epoch) and the equations are evolved backwards to calculate the evolution of cosmological parameters. We find that the Hubble parameter evolves more slowly in non-minimal coupling case as compared to the minimal coupling case. In both the cases, the universe accelerates around present time, and enters the decelerating regime in the past. Using the latest Union2 dataset for supernova Type Ia observations as well as the data for baryon acoustic oscillation (BAO) from SDSS observations, we constraint the parameters of Linder exponential model in the two different approaches. We find that there is a upper bound on model parameter in minimal coupling. But for non-minimal coupling case, there is range of allowed values for the model parameter.