String theory on G2 manifolds based on Gepner construction

Abstract

We study the type II string theories compactified on manifolds of G 2 holonomy of the type (Calabi–Yau 3 -fold×S 1)/ Z 2 where CY 3 sectors realized by the Gepner models. We construct modular invariant partition functions for G 2 manifold for arbitrary Gepner models of the Calabi–Yau sector. We note that the conformal blocks contain the tricritical Ising model and find extra massless states in the twisted sectors of the theory when all the levels k i of minimal models in Gepner constructions are even.