Geometric Constructions of Nongeometric String Theories

TL;DR

This paper introduces a framework for constructing perturbative closed string compactifications without large-radius limits by incorporating string duality symmetries into fibrations, expanding the landscape of string vacua.

Contribution

It proposes a novel method to build nongeometric string theories through monodromy group enlargements, demonstrated with explicit six-dimensional (1,0) supersymmetric vacua.

Findings

Detailed analysis of six-dimensional (1,0) vacua from two-torus fibrations.

Construction of examples over four-dimensional bases.

Discussion on extending the framework to other fibrations.

Abstract

We advocate a framework for constructing perturbative closed string compactifications which do not have large-radius limits. The idea is to augment the class of vacua which can be described as fibrations by enlarging the monodromy group around the singular fibers to include perturbative stringy duality symmetries. As a controlled laboratory for testing this program, we study in detail six-dimensional (1,0) supersymmetric vacua arising from two-torus fibrations over a two-dimensional base. We also construct some examples of two-torus fibrations over four-dimensional bases, and comment on the extension to other fibrations.