Warped compactification to de Sitter space

TL;DR

This paper investigates warped supergravity models with noncompact extra dimensions that can produce a four-dimensional de Sitter universe, challenging previous no-go theorems and providing explicit solutions with localized gravity.

Contribution

It demonstrates the existence of warped supergravity models with noncompact dimensions that yield a finite 4D Newton constant and localized graviton, broadening the scope of viable cosmological models.

Findings

Existence of warped supergravity solutions with noncompact extra dimensions.

Localization of a massless 4D graviton on an inflating universe.

Explicit solutions with constant radial dimension in large volume limit.

Abstract

We explore in detail the prospects of obtaining a four-dimensional de Sitter universe in classical supergravity models with warped and time-independent extra dimensions, presenting explicit cosmological solutions of the $(4+n)$-dimensional Einstein equations with and without a bulk cosmological constant term. For the first time in the literature we show that there may exist a large class of warped supergravity models with a noncompact extra dimension which lead to a finite 4D Newton constant as well as a massless 4D graviton localised on an inflating four-dimensional FLRW universe. This result helps establish that the `no-go' theorem forbidding acceleration in `standard' compactification of string/M-theory on physically compact spaces should not apply to a general class of warped supergravity models that allows at least one noncompact direction. We present solutions for which the size of the radial dimension takes a constant value in the large volume limit, providing an explicit example of spontaneous compactification.