Wolfgang Lerche

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We show how the Riemann surface Σ of N = 2 Yang-Mills field theory arises in type II string compactifications on Calabi-Yau threefolds. The relevant local geometry is given by fibrations of ALE spaces. The 3-branes that give rise to BPS multiplets in the string descend to self-dual strings on the Riemann surface, with tension determined by a canonically(More)
We present a first step towards generalizing the work of Seiberg and Witten on N=2 supersymmetric Yang-Mills theory to arbitrary gauge groups. Specifically, we propose a particular sequence of hyperelliptic genus n−1 Riemann surfaces to underly the quantum moduli space of SU(n) N = 2 supersymmetric gauge theory. These curves have an obvious generalization(More)
We investigate B-type topological Landau-Ginzburg theory with one variable, withD2-brane boundary conditions. We find that the allowed brane configurations are determined in terms of the possible factorizations of the superpotential, and compute the corresponding open string chiral rings. These are characterized by bosonic and fermionic generators that(More)
Using heterotic/type II string duality, we obtain exact nonperturbative results for the point particle limit (α → 0) of some particular four dimensional, N = 2 supersymmetric compactifications of heterotic strings. This allows us to recover recent exact nonperturbative results on N = 2 gauge theory directly from tree-level type II string theory, which(More)
We give a systematic derivation of the consistency conditions which constrain open-closed disk amplitudes of topological strings. They include the A∞ relations (which generalize associativity of the boundary product of topological field theory), as well as certain homotopy versions of bulk-boundary crossing symmetry and Cardy constraint. We discuss(More)
We study the open string extension of the mirror map for N = 1 supersymmetric type II vacua with D-branes on non-compact Calabi-Yau manifolds. Its definition is given in terms of a system of differential equations that annihilate certain period and chain integrals. The solutions describe the flat coordinates on the N = 1 parameter space, and the exact disc(More)