Supergravity description of spacetime instantons

Classical and Quantum Gravity (Impact Factor: 3.56). 08/2006; DOI: 10.1088/0264-9381/24/3/001
Source: arXiv

ABSTRACT We present and discuss BPS instanton solutions that appear in type II string theory compactifications on Calabi-Yau threefolds. From an effective action point of view these arise as finite action solutions of the Euclidean equations of motion in four-dimensional N=2 supergravity coupled to tensor multiplets. As a solution generating technique we make use of the c-map, which produces instanton solutions from either Euclidean black holes or from Taub-NUT like geometries.

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    ABSTRACT: We study a class of supersymmetric spinning particle models derived from the radial quantization of stationary, spherically symmetric black holes of four dimensional [TEX equation: {{\mathcal N} = 2}] supergravities. By virtue of the c-map, these spinning particles move in quaternionic Kähler manifolds. Their spinning degrees of freedom describe mini-superspace-reduced supergravity fermions. We quantize these models using BRST detour complex technology. The construction of a nilpotent BRST charge is achieved by using local (worldline) supersymmetry ghosts to generate special holonomy transformations. (An interesting byproduct of the construction is a novel Dirac operator on the superghost extended Hilbert space.) The resulting quantized models are gauge invariant field theories with fields equaling sections of special quaternionic vector bundles. They underly and generalize the quaternionic version of Dolbeault cohomology discovered by Baston. In fact, Baston’s complex is related to the BPS sector of the models we write down. Our results rely on a calculus of operators on quaternionic Kähler manifolds that follows from BRST machinery, and although directly motivated by black hole physics, can be broadly applied to any model relying on quaternionic geometry.
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    Journal of High Energy Physics 08/2009; 2009(08):098. · 5.62 Impact Factor
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    ABSTRACT: We investigate quantum corrections to the hypermultiplet moduli space M \mathcal{M} in Calabi-Yau compactifications of type II string theories, with particular emphasis on instanton effects from Euclidean NS5-branes. Based on the consistency of D- and NS5-instanton corrections, we determine the topology of the hypermultiplet moduli space at fixed string coupling, as previewed in [1]. On the type IIB side, we compute corrections from (p, k)-fivebrane instantons to the metric on M \mathcal{M} (specifically, the correction to the complex contact structure on its twistor space Z \mathcal{Z} ) by applying S-duality to the D-instanton sum. For fixed fivebrane charge k, the corrections can be written as a non-Gaussian theta series, whose summand for k = 1 reduces to the topological A-model amplitude. By mirror symmetry, instanton corrections induced from the chiral type IIA NS5-brane are similarly governed by the wave function of the topological B-model. In the course of this investigation we clarify charge quantization for coherent sheaves and find hitherto unnoticed corrections to the Heisenberg, monodromy and S-duality actions on M \mathcal{M} , as well as to the mirror map for Ramond-Ramond fields and D-brane charges. KeywordsNonperturbative Effects–Discrete and Finite Symmetries–Topological Strings–String Duality
    Journal of High Energy Physics 2011(3):1-74. · 5.62 Impact Factor


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