Towards brane-antibrane inflation in type $II_A$: The holographic MQCD model

TL;DR

This paper explores brane inflation models in type IIA string theory using holographic MQCD, relating them to type IIB models, and investigates their potential for realistic cosmological inflation with some unresolved issues.

Contribution

It introduces new type IIA brane inflation scenarios based on holographic MQCD, extending the framework of brane inflation models and analyzing their properties.

Findings

Good and generic inflationary models are obtained.

Models include both nonextremal and supersymmetric backgrounds.

Several unknowns and potential issues like volume stabilization remain.

Abstract

We describe type $II_A$ cosmological brane inflation scenarios based on the holographic MQCD model of Aharony et al \cite{Aharony:2010mi}. The scenarios can be related via T-duality to the type $II_B$ KKLMMT model \cite{Kachru:2003sx}. They describe a probe brane configuration of $p$ D4 branes stretching between an $NS5$ and $NS5'$ branes in the holographic background of large $N$ D4 branes. The resulting cosmological models have a Wick-rotated D4-brane metric, with transverse dimensions compactified, and a spiralling brane with flux $p$. In one model, the background has a small nonextremality, and the inflaton is provided by the position of a "sliding" D4-brane, and in the other, the background is supersymmetric, but with a sliding anti-D4-brane. We obtain good and generic inflationary models, though several unknowns remain, in particular about subleading corrections. The usual caveat of volume stabilization generically spoiling slow-roll still applies.