On The Inflaton Potential From Antibranes in Warped Throats

TL;DR

This work investigates whether flux-dissolved charge screens the brane/antibrane force in warped flux backgrounds, a question with direct implications for the inflaton potential in string cosmology. It presents two parallel calculations—treating antibranes as probes in backreacted brane backgrounds and vice versa—for anti-D3 in KS and anti-M2 in warped Stenzel—and finds exact agreement in the resulting force, indicating no screening. The results yield the exact functional form of the inflaton potential up to an overall normalization, strengthening the reliability of brane/antibrane inflation scenarios like KKLMMT. By providing explicit expressions for the forces in both IIB and M-theory realizations, the paper supports the broader applicability of these methods to flux compactifications and early-universe phenomenology.

Abstract

We compute the force between a stack of smeared antibranes at the bottom of a warped throat and a stack of smeared branes at some distance up the throat, both for anti-D3 branes and for anti-M2 branes. We perform this calculation in two ways: first, by treating the antibranes as probes in the background sourced by the branes and second, by treating the branes as probes in the candidate background sourced by the antibranes. These two very different calculations yield exactly the same expression for the force, for all values of the brane-antibrane separation. This indicates that the force between a brane and an antibrane is not screened in backgrounds where there is positive charge dissolved in flux, and gives a way to precisely compute the inflaton potential in certain string cosmology scenarios.