Heterotic Duals Research Articles

String-string dualities in D=6,4 dimensions

We study heterotic E8 × E8 models that are dual to compactifications of F-theory and type IIA string on certain classes of elliptically fibered Calabi-Yau manifolds. Different choices for the specific torus in the fibration have heterotic duals that are most easily understood in terms of E8 × E8 models with gauge backgrounds of type H × U(1)8-d, where H is a non-Abelian factor. The case with d = 8 corresponds to the well known E8 × E8 compactifications with non-Abelian instanton backgrounds (k1, k2) whose F-theory duals are built through compactifications on fibrations of the torus P(1,2,3)2[6] over Fn. The new cases with d

Non-perturbative properties of heterotic string vacua compactified on K3 × T2

Using the heterotic-type II duality of N = 2 string vacua in four space-time dimensions we study non-perturbative couplings of toroidally compactified six-dimensional heterotic vacua. In particular, the heterotic-heterotic S-duality and the Coulomb branch of tensor multiplets observed in six dimensions are studied from a four-dimensional point of view. We explicitly compute the couplings of the vector multiplets of several type II vacua and investigate the implications for their heterotic duals.

New branches of string compactifications and their F-theory duals

We study heterotic E 8 × E 8 models that are dual to compactifications of F-theory and type IIA string on certain classes of elliptically fibered Calabi-Yau manifolds. Different choices for the specific torus in the fibration have heterotic duals that are most easily understood in terms of E 8 × E 8 models with gauge backgrounds of type H × U (1) 8− d , where H is a non-Abelian factor. The case with d = 8 corresponds to the well-known E 8 × E 8 compactifications with non-Abelian instanton backgrounds ( k 1 , k 2 ) whose F-theory duals are built through compactifications on fibrations of the torus P 2 (1,2,3) over F n . The new cases with d < 8 correspond to other choices for the elliptic fiber over the same base and yield unbroken U (1)′ s , some of which are anomalous and acquire a mass by swallowing zero-modes of the antisymmetric B MN field. We also study transitions to models with no tensor multiplets in D = 6 and find evidence of E d instanton dynamics. We also consider the possibility of conifold transitions among spaces with different realization of the elliptic fiber.

Heterotic gauge structure of type II K3 fibrations

We show that certain classes of K3 fibered Calabi-Yau manifolds derive from orbifolds of global products of K3 surfaces and particular types of curves. This observation explains why the gauge groups of the heterotic duals are determined by the structure of a single K3 surface and provides the dual heterotic picture of conifold transitions between K3 fibrations. Abstracting our construction from the special case of K3 hypersurfaces to general K3 manifolds with an appropriate automorphism, we show how to construct Calabi-Yau threefold duals for heterotic theories with arbitrary perturbative gauge groups. This generalization reveals that the previous limit on the Euler number of Calabi-Yau manifolds is an artifact of the restriction to the framework of hypersurfaces.

Chains of N = 2, D = 4 heterotic/type II duals

We report on a search for N = 2 heterotic strings that are dual candidates of type II compactifications on Calabi-Yau threefolds described as K3 fibrations. We find many new heterotic duals by using standard orbifold techniques. The associated type II compactifications fall into chains in which the proposed duals are heterotic compactifications related one another by a sequential Higgs mechanism. This breaking in the heterotic side typically involves the sequence SU(4) → SU(3) → SU(2) → ), while in the type II side the weights of the complex hypersurfaces and the structure of the K3 quotient singularities also follow specific patterns. Some qualitative features of the relationship between each model and its dual can be understood by fiber-wise application of string-string duality.