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We consider D-branes wrapped around supersymmetric cycles of Calabi-Yau manifolds from the viewpoint of N = 2 Landau-Ginzburg models with boundary as well as by consideration of boundary states in the corresponding Gepner models. The Landau-Ginzburg approach enables us to provide a target space interpretation for the boundary states. The boundary states are… (More)

We construct a linear sigma model for open-strings ending on special Lagrangian cycles of a Calabi-Yau manifold. We illustrate the construction for the cases considered by Aganagic and Vafa(AV). This leads naturally to concrete models for the moduli space of open-string instantons. These instanton moduli spaces can be seen to be intimately related to… (More)

Motivation There has been tremendous progress in providing a microscopic counting of states that contribute to the entropy of supersymmetric black holes. More generally, one is interested in understanding the number of BPS states in different contexts such as chiral primaries in CFT's, black hole entropy. As the amount of supersymmetry is reduced, these… (More)

We show how the double cohomology of the String and Felder BRST charges naturally leads to the ring structure of c < 1 strings. The chiral ring is a ring of polynomials in two variables modulo an equivalence relation of the form x p ≃ y p+1 for the (p+1, p) model. We also study the states corresponding to the edges of the conformal grid whose inclusion is… (More)

We show that the generating function of electrically charged 1 2-BPS states in N = 4 supersymmetric CHL Z N orbifolds of the heterotic string on T 6 are given by multiplicative η-products. The η-products are determined by the cycle shape of the corresponding symplectic involution in the dual type II picture. This enables us to complete the construction of… (More)

We present a method based on mutations of helices which leads to the construction (in the large volume limit) of exceptional coherent sheaves associated with the (a l a = 0) orbits in Gepner models. This is explicitly verified for a few examples including some cases where the ambient weighted projective space has singularities not inherited by the… (More)

We study both A-type and B-type D-branes in the gauged linear sigma model by considering worldsheets with boundary. The boundary conditions on the matter and vector multiplet fields are first considered in the large-volume phase/non-linear sigma model limit of the corresponding Calabi-Yau manifold, where we also find that we need to add a contact term on… (More)

We construct boundary conditions in the gauged linear sigma model for B-type D-branes on Calabi-Yau manifolds that correspond to coherent sheaves given by the cohomology of a monad. This necessarily involves the introduction of boundary fields, and in particular, boundary fermions. The large-volume monodromy for these D-brane configurations is implemented… (More)

We show how to compute terms in an expansion of the world-volume superpotential for fairly general D-branes on the quintic Calabi-Yau using linear sigma model techniques, and show in examples that this superpotential captures the geometry and obstruction theory of bundles and sheaves on this Calabi-Yau.

- Bobby Ezhuthachan, Suresh Govindarajan
- 2005

We study fractional 2p-branes and their intersection numbers in non-compact orbifolds as well the continuation of these objects in Kähler mod-uli space to coherent sheaves in the corresponding smooth non-compact Calabi-Yau manifolds. We show that the restriction of these objects to compact Calabi-Yau hypersurfaces gives the new fractional branes in LG… (More)