Dynamics of the universe as a "test 3-brane" in a 5D bulk

TL;DR

This paper models our universe as a test 3-brane in a five-dimensional bulk space-time, showing that its acceleration and crossing of the phantom divide line are driven by the bulk's geometry.

Contribution

It introduces a novel 5D bulk space-time framework where the universe's acceleration arises from geometric effects, treating the universe as a test brane with negligible physical properties.

Findings

Universe experiences acceleration due to bulk geometry

Equation of state crosses the phantom divide line

Model provides geometric explanation for cosmic acceleration

Abstract

In this paper we study the dynamics of a 5D bulk space-time with our universe as a "test 3-brane" located in the bulk, an idealized model of a topological object whose physical properties is negligible in comparison with that of the bulk. Our universe experiences acceleration and its equation of state parameter crosses the phantom divide line due to the geometry of the bulk space-time.