Dark energy from cosmological fluids obeying a Shan-Chen non-ideal equation of state

TL;DR

This paper explores a cosmological model where a non-ideal fluid with Shan-Chen equation of state naturally evolves into a universe dominated by dark energy, eliminating the need for a cosmological constant.

Contribution

It introduces a fluid dynamical model with asymptotic freedom behavior that explains dark energy emergence without a cosmological constant.

Findings

Fluid models evolve into dark energy-dominated universe

No need for cosmological constant in this model

Provides a quantitative measure of darkness abundance

Abstract

We consider a Friedmann-Robertson-Walker universe with a fluid source obeying a non-ideal equation of state with "asymptotic freedom," namely ideal gas behavior (pressure changes directly proportional to density changes) both at low and high density regimes, following a fluid dynamical model due to Shan and Chen. It is shown that, starting from an ordinary energy density component, such fluids naturally evolve towards a universe with a substantial "dark energy" component at the present time, with no need of invoking any cosmological constant. Moreover, we introduce a quantitative indicator of darkness abundance, which provides a consistent picture of the actual matter-energy content of the universe.