IIB String Theory and Sequestered Inflation

TL;DR

This paper constructs sequestered inflation models within type IIB string theory compactified on a specific orientifold, deriving inflationary potentials with string-theoretic origins and analyzing their cosmological implications.

Contribution

It introduces a novel framework for string-inspired inflation models using flux compactifications and nilpotent multiplets to realize $ ext{alpha}$-attractor potentials.

Findings

Inflationary potentials with $ ext{alpha}$-attractor form derived from string theory.

Heavy moduli and extra dimensions remain stable during inflation.

Cosmological predictions depend on hyperbolic geometry from string compactification.

Abstract

We develop sequestered inflation models, where inflation occurs along flat directions in supergravity models derived from type IIB string theory. It is compactified on a ${\mathbb{T}^6 \over \mathbb{Z}_2 \times \mathbb{Z}_2}$ orientifold with generalized fluxes and O3/O7-planes. At Step I, we use flux potentials which 1) satisfy tadpole cancellation conditions and 2) have supersymmetric Minkowski vacua with flat direction(s). The 7 moduli are split into heavy and massless Goldstone multiplets. At Step II we add a nilpotent multiplet and uplift the flat direction(s) of the type IIB string theory to phenomenological inflationary plateau potentials: $\alpha$-attractors with 7 discrete values $3\alpha = 1, 2, 3, ..., 7$. Their cosmological predictions are determined by the hyperbolic geometry inherited from string theory. The masses of the heavy fields and the volume of the extra dimensions change during inflation, but this does not affect the inflationary dynamics.