On Quantum Obstructions in Type IIA Orientifolds

TL;DR

This paper investigates quantum effects in Type IIA orientifolds, showing that quantum corrections prevent certain classical infinite distance limits in the moduli space, especially when uplifted to M-theory on G2 manifolds.

Contribution

It provides multiple independent arguments demonstrating the absence of quantum obstructions to infinite distance limits in Type IIA orientifolds, with insights from M-theory uplift.

Findings

Quantum corrections can remove classical infinite distance limits.

Uplift to M-theory on G2 manifolds offers a unified understanding.

Infinite distance limits are only possible when some moduli are finite.

Abstract

Quantum corrections can severely modify or even remove classical infinite distance limits in four-dimensional gravity theories with minimal N=1 supersymmetry. In this note we study this effect for infinite distance directions in the classical K\"ahler moduli sector of Type IIA orientifolds at fixed four-dimensional dilaton. We present several independent arguments why such infinite distance directions are absent at the quantum level. These involve the worldsheet theory of EFT strings and the putative asymptotically massless tower of particles. Key insights are provided by the uplift to M-theory on G2 manifolds, which allows for a unified treatment of quantum obstructions of seemingly different origin in the dual Type IIB/F-theory frame. Our results apply also to the Type IIA dual of infinite distance limits for which no quantum obstruction could be detected in the Type IIB frame in previous work. In conclusion, infinite distance limits in the part of the orientifold moduli space descending from a 4d N=2 vector multiplet sector are only possible at the quantum level if also some of the remaining moduli are taken to infinity.