We Probably Live On An Inflating Brane-World

TL;DR

This paper explores brane-world cosmology, proposing that our universe is a 4D de Sitter space embedded in a 5D de Sitter space, offering insights into late-time cosmic acceleration.

Contribution

It introduces a model where a 4D de Sitter universe in 5D de Sitter space explains cosmic acceleration, contrasting with the anti de Sitter background used in AdS/CFT.

Findings

A 5D de Sitter background yields a finite 4D Newton constant.

Normalizable zero-mode graviton wave function is found in this setup.

The model provides a framework for late epoch acceleration of the universe.

Abstract

Brane-world models where observers are trapped within the thickness of a 3-brane offer novel perspectives on gravitation and cosmology. In this essay, I would argue that the problem of a late epoch acceleration of the universe is well explained in the framework of a 4-dimensional de Sitter universe embedded in a 5-dimensional de Sitter spacetime. While a 5D anti de Sitter space background is important for studying conformal field theories -- for its role in the AdS/CFT correspondence -- the existence of a 5-dimensional de Sitter space is crucial for finding an effective 4D Newton constant that remains finite and a normalizable zero-mode graviton wave function.