Instanton Action for Type II Hypermultiplets

TL;DR

This paper studies the hypermultiplet moduli space in type IIA string theory compactified on Calabi-Yau threefolds, focusing on non-perturbative membrane-fivebrane instanton effects and their impact on the scalar field identifications.

Contribution

It constructs the membrane-fivebrane instanton action and analyzes its implications for the moduli space geometry and flux quantization in type IIA compactifications.

Findings

Membrane-fivebrane instanton action is explicitly constructed.

Discrete identifications of scalar fields are derived from flux quantization.

Non-perturbative corrections modify the classical moduli space structure.

Abstract

We analyze the hypermultiplet moduli space describing the universal sector of type IIA theory compactified on a Calabi-Yau threefold. The classical moduli space is described in terms of the coset $SU(2,1)/U(2)$. The flux quantization condition of the antisymmetric tensor field of M-theory implies discrete identifications for the scalar fields describing this four- dimensional quaternionic geometry. Non-perturbative corrections of the classical theory are described in terms of a membrane- fivebrane instanton action which we construct herein.