The frozen phase of F-theory
Lakshya Bhardwaj, David R. Morrison, Yuji Tachikawa, Alessandro Tomasiello
TL;DR
This work extends F-theory to include frozen O7_+ planes, clarifying how gauge algebras and matter arise on seven-branes and their intersections in six dimensions. By introducing frozen divisors and a generalized Green–Schwarz framework, the authors realize 6d SCFTs that were previously inaccessible, including theories with hypermultiplets in the symmetric representation of $rak{su}$. They develop perturbative and duality tools to read off spectra, analyze anomaly cancellation with frozen singularities, and construct both noncompact and compact models that exhibit novel tensor and conformal-matter sectors. The results show that frozen branes modify canonical gauge assignments, enable new tensor branches, and connect to perturbative string realizations through dual frames, with implications for the 6d SCFT landscape and its heterotic/IIA connections.
Abstract
We study the interpretation of O7+ planes in F-theory, mainly in the context of the six-dimensional models. In particular, we study how to assign gauge algebras and matter content to seven-branes and their intersections, and the implication of anomaly cancellation in our construction, generalizing earlier analyses without any O7+ planes. By including O7+ planes we can realize 6d superconformal field theories hitherto unobtainable in F-theory, such as those with hypermultiplets in the symmetric representation of su. We also examine a couple of compact models. These reproduce some famous perturbative models, and in some cases enhance their gauge symmetries non-perturbatively.
