Using Energy Conditions to Distinguish Brane Models and Study Brane Matter

TL;DR

This paper uses energy conditions to differentiate brane models and analyze the matter content on the brane, including normal and nonnormal matter like dark energy, to understand universe acceleration.

Contribution

It introduces a method to distinguish brane models based on energy conditions and examines the impact of various matter components on universe acceleration.

Findings

Normal matter on the brane satisfies energy conditions and implies a pressureless universe.

Nonnormal matter, such as dark energy with w<-1/3, leads to accelerated expansion.

Energy conditions can effectively differentiate between different brane cosmological models.

Abstract

Current universe (assumed here to be normal matter on the brane) is pressureless from observations. In this case the energy condition is $\rho_0\geq0$ and $p_0=0$. By using this condition, brane models can be distinguished. Then, assuming arbitrary component of matter in DGP model, we use four known energy conditions to study the matter on the brane. If there is nonnormal matter or energy (for example dark energy with $w<-1/3$) on the brane, the universe is accelerated.