Non-perturbative monodromies in N=2 heterotic string vacua

TL;DR

This work analyzes non-perturbative monodromies in four-dimensional $N=2$ heterotic string vacua, demonstrating that each perturbative line of enhanced gauge symmetry splits into two loci where monopoles or dyons become massless. By constructing explicit perturbative $Sp(8,\mathbb{Z})$ monodromies and applying a consistent truncation to the rigid Seiberg–Witten theory, the authors reproduce SW results and illuminate how dilaton dynamics affect the rigid limit. They then propose a framework where the semiclassical monodromies decompose into monopole and dyon non-perturbative monodromies, derive concrete non-perturbative matrices for the $SU(2)$ lines, and show how these reduce to the known rigid SW monodromies upon truncation. The work also discusses the relation to Type II/Calabi–Yau duals and notes potential gravitational non-perturbative effects at finite $S$. Overall, it provides a coherent string-theoretic origin for Seiberg–Witten dynamics and clarifies how non-perturbative string effects organize around lines of enhanced gauge symmetry.

Abstract

We address non-perturbative effects and duality symmetries in $N=2$ heterotic string theories in four dimensions. Specifically, we consider how each of the four lines of enhanced gauge symmetries in the perturbative moduli space of $N=2$ $T_2$ compactifications is split into 2 lines where monopoles and dyons become massless. This amounts to considering non-perturbative effects originating from enhanced gauge symmetries at the microscopic string level. We show that the perturbative and non-perturbative monodromies consistently lead to the results of Seiberg-Witten upon identication of a consistent truncation procedure from local to rigid $N=2$ supersymmetry.