Late time accelerated scaling attractors in DGP (Dvali-Gabadadze-Porrati) braneworld

TL;DR

This paper explores how specific interactions in DGP braneworld models with scalar fields can produce stable late-time accelerated scaling attractors, potentially addressing the Coincidence problem in cosmology.

Contribution

It demonstrates the existence of late-time accelerated scaling solutions in DGP braneworld with interacting scalar fields, a feature absent in non-interacting models.

Findings

Late-time accelerated scaling solutions are possible with exponential potentials.

One specific interaction yields stable scaling solutions for phantom fields.

The identified scaling solutions are classically stable.

Abstract

In the evolution of late universe, the main source of matter are Dark energy and Dark matter. They are indirectly detected only through their gravitational manifestations. So the possibility of interaction with each other without violating observational restrictions is not ruled out. With this motivation, we investigate the dynamics of DGP braneworld where source of dark energy is a scalar field and it interacts with matter source. Since observation favours phantom case more, we have also studied the dynamics of interacting phantom scalar field. In non interacting DGP braneworld there are no late time accelerated scaling attractors and hence cannot alleviate Coincidence problem. In this paper, we shall show that it is possible to get late time accelerated scaling solutions. The phase space is studied by taking two categories of potentials (Exponential and Non exponential functions). The stability of critical points are examined by taking two specific interactions. The first interaction gives late time accelerated scaling solution for phantom field only under exponential potential, while for second interaction we do not get any scaling solution. Furthermore, we have shown that this scaling solution is also classically stable.