No-Go theorems for ekpyrosis from ten-dimensional supergravity

TL;DR

This paper demonstrates that embedding the ekpyrotic scenario into ten-dimensional supergravity faces fundamental obstacles, as flux compactifications do not produce suitable scalar potentials for ekpyrosis due to their universal scaling properties.

Contribution

It provides a no-go theorem showing that flux compactifications in ten-dimensional supergravity cannot support ekpyrotic cosmology.

Findings

Flux compactifications do not yield suitable potentials for ekpyrosis.

Universal scaling of scalar potential constrains ekpyrotic scenarios.

Strong constraints from fast-roll conditions rule out ekpyrosis in this framework.

Abstract

In this note we investigate whether the new ekpyrotic scenario can be embedded into ten-dimensional supergravity. We use that the scalar potential obtained from flux compactifications of type II supergravity with sources has a universal scaling with respect to the dilaton and the volume mode. Similar to the investigation of inflationary models, we find very strong constraints ruling out ekpyrosis from analysing the fast-roll conditions. We conclude that flux compactifications tend to provide potentials that are neither too flat and positive (inflation) nor too steep and negative (ekpyrosis).