Eight-dimensional non-geometric heterotic strings and enhanced gauge groups

Some constructions in string theory are linked to noncommutative geometry. Non-geometric strings among such constructions. related a torus. In this article, we discuss some aspects of non-geometric heterotic strings. We review the construction eight-dimensional (8D) strings, proposed by Malmendier and Morrison, which do not allow for geometric interpretation. construction, $$\mathfrak {e}_8\oplus \mathfrak {e}_7$$ gauge algebra is unbroken. The moduli space 8D theories arising can be analyzed studying geometries elliptically fibered K3 surfaces with global section applying F-theory/heterotic duality. addition, results points unbroken algebra, at non-Abelian groups maximally enhanced. At these points, formed perturbative interpretation perspective. However, from dual F-theory perspective, deformations stable degenerations that arise coincident 7-branes. On side, enhancements understood as non-perturbative effect 5-brane insertions.