Cosmological consequences of the redistribution of energy between matter components in the very early universe

TL;DR

This paper investigates how energy redistribution between matter components in the early universe affects its evolution, deriving analytical solutions and exploring transitions between different cosmological phases.

Contribution

It introduces a new constraint linking the universe's geometry and matter content during energy transfer, with analytical solutions for various evolutionary phases.

Findings

Derived analytical solutions of Einstein equations for matter with energy exchange

Identified conditions for matter production and radiation-dominated phases

Discussed the transition dynamics between inflationary and other phases

Abstract

The evolution of matter in the expanding FRW universe during the time interval between the end of inflation and the beginning of the radiation-dominated era is studied. A constraint between the global geometry and total amount of matter in the universe as a whole, which is valid during the phase of an intensive transfer of energy to the matter degrees of freedom, is introduced. The matter is considered as a perfect fluid with two components between which there is energy exchange. The analytical solutions of the Einstein equations are found. The limiting cases of the the Hubble expansion rate and the total energy density, which correspond to matter production, pressure-free and radiation-dominated phases are investigated. The transition to the inflationary phase and a unidirectional evolution of matter in the universe at all phases are discussed.