The equation of vacuum state and the structure formation in universe

TL;DR

This paper models the vacuum as a fluid derived from quantum fluctuations, deriving its properties and showing that early universe structure formation can occur without dark matter, suggesting a unification of dark energy and matter.

Contribution

It introduces a new framework for the vacuum as a fluid with an equation of state, explaining early universe structure formation without dark matter using a five-vector gravity theory.

Findings

Vacuum behaves as a fluid with specific equation of state

Early universe structure formation occurs without dark matter

Vacuum can unify dark energy and matter

Abstract

The vacuum is considered as some fluid emergent from the zero-point fluctuations of the quantum fields contributing to the vacuum energy density and pressure. The equation of vacuum state and the speed of vacuum sound-waves are deduced under the assumption of zero vacuum entropy. The evolution of the background space-time metric resembles that of the Milne's-like universe. In the framework of the five-vector theory of gravitation allowing an arbitrary choice of the energy density reference level, the dynamics of the vacuum, pressureless matter, and space-time metrics perturbations are traced under this background. The obtained results show the very early formation of the Universe structure without the need for dark matter. Thus, a vacuum can be considered as some of the dark-energy-matter unification.