Generalized Chaplygin Gas, Accelerated Expansion and Dark Energy-Matter Unification

TL;DR

This paper explores a generalized Chaplygin gas model derived from a d-brane dynamics, which unifies dark matter and dark energy, explaining the universe's transition from matter domination to accelerated expansion.

Contribution

It introduces a generalized equation of state for a d-brane system and analyzes conditions for homogeneity and cosmic evolution, unifying dark matter and dark energy.

Findings

The model describes a universe transitioning from matter-dominated to dark energy-dominated phases.

It provides conditions for homogeneity in the generalized Chaplygin gas scenario.

The effective equation of state evolves from $p = ho$ to $p = -A/ ho^{eta}$.

Abstract

We consider the scenario emerging from the dynamics of a generalized $d$-brane in a $(d+1, 1)$ spacetime. The equation of state describing this system is given in terms of the energy density, $\rho$, and pressure, $p$, by the relationship $p = - A/\rho^{\alpha}$, where $A$ is a positive constant and $0 < \alpha \le 1$. We discuss the conditions under which homogeneity arises and show that this equation of state describes the evolution of a universe evolving from a phase dominated by non-relativistic matter to a phase dominated by a cosmological constant via an intermediate period where the effective equation of state is given by $p = \alpha \rho$.