Fluids in cosmology

TL;DR

This paper reviews the role of fluids and scalar fields in cosmology, covering their dynamics, thermodynamics, and perturbations, with emphasis on parameter constraints from recent observations.

Contribution

It provides a comprehensive overview of fluid and scalar field applications in cosmology, including recent constraints from observational data.

Findings

Relativistic and non-relativistic fluids influence universe evolution.

Scalar fields can drive inflation and late-time acceleration.

Recent cosmological probes constrain fluid and scalar field parameters.

Abstract

We review the role of fluids in cosmology by first introducing them in General Relativity and then by applying them to a FRW Universe's model. We describe how relativistic and non-relativistic components evolve in the background dynamics. We also introduce scalar fields to show that they are able to yield an inflationary dynamics at very early times (inflation) and late times (quintessence). Then, we proceed to study the thermodynamical properties of the fluids and, lastly, its perturbed kinematics. We make emphasis in the constrictions of parameters by recent cosmological probes.