Inflation on the resolved warped deformed conifold

TL;DR

This work analyzes inflation driven by a D3-brane moving in the resolved warped deformed conifold, focusing on how four-dimensional curvature alters the inflaton dynamics. By constructing a de-Sitter deformation of the background within Type IIB supergravity, the authors derive the IR and UV asymptotics and obtain a D3-brane effective action that yields an inflaton potential with a second derivative giving a slow-roll parameter ${\eta}$ of order ${2/3}$, i.e., fast-roll deep in the warped throat. The key result is that curvature-induced conformal coupling imparts a Hubble-scale mass to the inflaton, rendering standard slow-roll inflation unattainable in this setup unless compensating fluxes or alternative mechanisms are introduced. The findings place concrete constraints on realizing slow-roll inflation in strongly warped string backgrounds and highlight the need for additional ingredients to achieve viable inflation in such geometries.

Abstract

Braneworld inflation on the resolved warped deformed conifold is represented by the dynamics of a D3-brane probe with the world volume of a brane spanning the large dimensions of the observable Universe. This model was recently proposed as a string theory candidate for slow-roll inflationary cosmology in hep-th/0511254. During inflation, the scalar curvature of the Universe is determined by the Hubble scale. We argue that taking into account the curvature of the inflationary Universe renders dynamics of the D3-brane fast-roll deep inside the warped throat.