Aligned Natural Inflation in String Theory

TL;DR

This paper presents a string theory-based model for large-field inflation using aligned axions, achieved through gaugino condensation on D7-branes, enabling super-Planckian decay constants in Calabi-Yau compactifications.

Contribution

It introduces a novel string theory construction for aligned natural inflation with controllable large decay constants via gaugino condensation on D7-branes.

Findings

Large effective decay constants are achievable in Calabi-Yau orientifolds.

The mechanism is a string-theoretic realization of the Kim-Nilles-Peloso alignment.

Controllable points in moduli space support super-Planckian decay constants.

Abstract

We propose a scenario for realizing super-Planckian axion decay constants in Calabi-Yau orientifolds of type IIB string theory, leading to large-field inflation. Our construction is a simple embedding in string theory of the mechanism of Kim, Nilles, and Peloso, in which a large effective decay constant arises from alignment of two smaller decay constants. The key ingredient is gaugino condensation on magnetized or multiply-wound D7-branes. We argue that, under very mild assumptions about the topology of the Calabi-Yau, there are controllable points in moduli space with large effective decay constants.