Darboux class of cosmological fluids with time-dependent adiabatic indices

TL;DR

This paper introduces a mathematical method using Darboux transformations to generate time-dependent adiabatic indices for cosmological fluids, offering a potential explanation for the universe's accelerated expansion.

Contribution

It presents a novel application of Darboux transformations to model cosmological fluids with variable adiabatic indices, expanding the theoretical framework for cosmology.

Findings

New class of cosmological fluids with time-dependent properties

Derivation of novel scale factors for universe expansion

Potential explanation for accelerated cosmic expansion

Abstract

A one-parameter family of time dependent adiabatic indices is introduced for any given type of cosmological fluid of constant adiabatic index by a mathematical method belonging to the class of Darboux transformations. The procedure works for zero cosmological constant at the price of introducing a new constant parameter related to the time dependence of the adiabatic index. These fluids can be the real cosmological fluids that are encountered at cosmological scales and they could be used as a simple and efficient explanation for the recent experimental findings regarding the present day accelerating universe. In addition, new types of cosmological scale factors, corresponding to these fluids, are presented