Perfect fluids with $\omega=\mathrm{const}$ as sources of scalar cosmological perturbations

TL;DR

This paper generalizes a scalar perturbation scheme to include extended perfect fluids with constant equation of state, deriving a universal equation and showing structure growth suppression beyond a certain interaction range.

Contribution

It introduces a unified perturbation equation applicable to all scales for models with multiple perfect fluids, expanding previous models to more complex cosmological scenarios.

Findings

Derived a single scalar perturbation equation valid on all scales.

Defined a universal Yukawa interaction range for scalar perturbations.

Showed that structure growth is suppressed beyond this interaction range.

Abstract

We make a generalization of a self-consistent first-order perturbation scheme, being suitable for all (sub-horizon and super-horizon) scales, which has been recently constructed for the concordance cosmological model and discrete presentation of matter sources, to the case of extended models with extra perfect fluids and continuous presentation. Namely, we derive a single equation determining the scalar perturbation and covering the whole space as well as define the corresponding universal Yukawa interaction range. We also demonstrate explicitly that the structure growth is suppressed at distances exceeding this fundamental range.