Flat Monodromies and a Moduli Space Size Conjecture

TL;DR

This paper explores how flux-induced monodromies in type IIB string theory can produce long axionic trajectories, revealing mathematical structures and proposing a conjecture about the size of moduli spaces relevant for inflation.

Contribution

It introduces the concept of 'Monodromic Moduli Space' generated by flux, analyzes the constraints on geodesic lengths, and formulates a new 'Moduli Space Size Conjecture' with mathematical insights.

Findings

Flux generates flat monodromies in moduli space.

Long axionic trajectories are non-geodesic and constrained.

Mathematical structures involve fundamental domains of modular subgroups.

Abstract

We investigate how super-Planckian axions can arise when type IIB 3-form flux is used to restrict a two-axion field space to a one-dimensional winding trajectory. If one does not attempt to address notoriously complicated issues like Kahler moduli stabilization, SUSY-breaking and inflation, this can be done very explicitly. We show that the presence of flux generates flat monodromies in the moduli space which we therefore call 'Monodromic Moduli Space'. While we do indeed find long axionic trajectories, these are non-geodesic. Moreover, the length of geodesics remains highly constrained, in spite of the (finite) monodromy group introduced by the flux. We attempt to formulate this in terms of a 'Moduli Space Size Conjecture'. Interesting mathematical structures arise in that the relevant spaces turn out to be fundamental domains of congruence subgroups of the modular group. In addition, new perspectives on inflation in string theory emerge.