Cosmological perturbations in theories with non-minimal coupling between curvature and matter

TL;DR

This paper investigates how non-minimal coupling between curvature and matter influences cosmological perturbations and structure formation, providing analytical solutions that support models compatible with late-time cosmic acceleration.

Contribution

It offers new analytical insights into the evolution of matter overdensities in theories with curvature-matter coupling, constraining the coupling terms based on structure growth.

Findings

Coupling affects the growth rate of matter perturbations.

Analytical solutions are derived during the matter-dominated era.

Results support coupling functions compatible with cosmic acceleration.

Abstract

In this work, one examines how the presence of a non-minimal coupling between the spacetime curvature and matter affects the evolution of cosmological perturbations around a homogeneous and isotropic Universe and hence the formation of large-scale structure. This framework places constraints on the terms which arise due to the coupling with matter and, in particular, on the modification in the growth of matter density perturbations. One obtains approximate analytical solutions for the evolution of matter overdensities during the matter dominated era and shows that these favor the presence of a coupling function that is compatible with the late-time cosmic acceleration.