Double-Scaling Limit of Heterotic Bundles and Dynamical Deformation in CFT

We consider heterotic string theory on Eguchi–Hanson space, as a local model of a resolved A1 singularity in a six-dimensional flux compactification, with an Abelian gauge bundle turned on and non-zero torsion. We show that in a suitable double scaling limit, that isolates the physics near the non-vanishing two-cycle, a worldsheet conformal field theory description can be found. It contains a heterotic coset whose target space is conformal to Eguchi–Hanson. Starting from the blow-down limit of the singularity, it can be viewed as a dynamical deformation of the near-horizon fivebrane background. We analyze in detail the spectrum of the theory in particular examples, as well as the important role of worldsheet non-perturbative effects. Email: [email protected],[email protected],[email protected] Unité mixte de Recherche 7644, CNRS – École Polytechnique Unité mixte de Recherche 7095, CNRS – Université Pierre et Marie Curie