Non-perturbative heterotic duals of M-theory on G 2 orbifolds

Abstract

Abstract By fibering the duality between the E 8 × E 8 heterotic string on T 3 and M-theory on K3, we study heterotic duals of M-theory compactified on G 2 orbifolds of the form T 7 / ℤ 2 3 $$ {\mathbb{Z}}_2^3 $$ . While the heterotic compactification space is straightforward, the description of the gauge bundle is subtle, involving the physics of point-like instantons on orbifold singularities. By comparing the gauge groups of the dual theories, we deduce behavior of a “half-G 2” limit, which is the M-theory analog of the stable degeneration limit of F-theory. The heterotic backgrounds exhibit point-like instantons that are localized on pairs of orbifold loci, similar to the “gauge-locking” phenomenon seen in Hořava-Witten compactifications. In this way, the geometry of the G 2 orbifold is translated to bundle data in the heterotic background. While the instanton configuration looks surprising from the perspective of the E 8 × E 8 heterotic string, it may be understood as T-dual Spin(32)/ℤ2 instantons along with winding shifts originating in a dual Type I compactification.

Keywords

• M-Theory
• String Duality
• Superstrings and Heterotic Strings