Quintom dark energy in DGP braneworld cosmology

TL;DR

This paper investigates how a quintom dark energy fluid in a 5D DGP braneworld influences cosmic acceleration, revealing conditions for late-time self-inflation and static universe solutions.

Contribution

It derives the effective Einstein equations in a DGP braneworld with quintom dark energy, considering cases with bulk or brane-confined quintom fields, and analyzes resulting cosmological behaviors.

Findings

Self-inflationary solutions in the positive branch.

Asymptotically static universe in the negative branch.

Time-dependent bulk quintom induces a dynamic cosmological constant.

Abstract

In this paper we consider a $Z_2$ symmetrical 3-brane embedded in a 5-dimensional spacetime. We study the effective Einstein equation and acceleration condition in presence of the quintom dark energy fluid as the bulk matter field. It is shown that the time-dependent bulk quintom field induces a time-dependent cosmological constant on the brane. In the framework of the DGP model, the effective Einstein equation is obtained in two different cases: i) where the quintom field is considered as the bulk matter field and the brane is empty and, ii) where the quintom dark energy is confined on the brane and the bulk is empty. We show that in both cases one could obtain a self-inflationary solution at late time in positive branch $\epsilon=1$, and an asymptotically static universe in negative branch $\epsilon=-1$.