Showing papers by "Yaron Oz published in 2005"
TL;DR: In this article, the authors consider the topology of event horizons in higher dimensions and show that the integrated Ricci scalar curvature with respect to the induced metric on the event horizon is positive also for higher dimensions.
Abstract: In four dimensions the topology of the event horizon of an asymptotically flat stationary black hole is uniquely determined to be the two-sphere $S^2$. We consider the topology of event horizons in higher dimensions. First, we reconsider Hawking's theorem and show that the integrated Ricci scalar curvature with respect to the induced metric on the event horizon is positive also in higher dimensions. Using this and Thurston's geometric types classification of three-manifolds, we find that the only possible geometric types of event horizons in five dimensions are $S^3$ and $S^2 \times S^1$. In six dimensions we use the requirement that the horizon is cobordant to a four-sphere (topological censorship), Friedman's classification of topological four-manifolds and Donaldson's results on smooth four-manifolds, and show that simply connected event horizons are homeomorphic to $S^4$ or $S^2\times S^2$. We find allowed non-simply connected event horizons $S^3\times S^1$ and $S^2\times \Sigma_g$, and event horizons with finite non-abelian first homotopy group, whose universal cover is $S^4$. Finally, following Smale's results we discuss the classification in dimensions higher than six.
55 citations
TL;DR: In this article, a duality between perturbed type II strings and the topological B-model on deformed Calabi-Yau singularities was proposed based on the ground ring structure.
Abstract: We consider type IIA/B strings in two-dimensions and their projection with respect to the nilpotent space-time supercharge. Based on the ground ring structure, we propose a duality between perturbed type II strings and the topological B-model on deformed Calabi-Yau singularities. Depending on the type II spectra, one has either the conifold or the suspended pinch point geometry. Using the corresponding quiver gauge theory, obtained by D-branes wrapping in the resolved suspended pinch point geometry, we propose the all orders perturbative partition function.
18 citations
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TL;DR: In this article, a covariant description of non-critical superstrings in even dimensions is given, where supersymmetric hybrid type variables are constructed in a linear dilaton background, and an underlying N = 2 twisted superconformal algebra structure.
Abstract: We construct a covariant description of non-critical superstrings in even dimensions. We construct explicitly supersymmetric hybrid type variables in a linear dilaton background, and study an underlying N = 2 twisted superconformal algebra structure. We find similarities between non-critical superstrings in 2n + 2 dimensions and critical superstrings compactified on CY4−n manifolds. We study the spectrum of the non-critical strings, and in particular the Ramond-Ramond massless fields. We use the supersymmetric variables to construct the non-critical superstrings σ-model action in curved target space backgrounds with coupling to the Ramond-Ramond fields. We consider as an example non-critical type IIA strings on AdS2 background with Ramond-Ramond 2-form flux.
16 citations
TL;DR: In this article, a duality between perturbed type II strings and the topological B-model on deformed Calabi-Yau singularities was proposed based on the ground ring structure.
Abstract: We consider type IIA/B strings in two-dimensions and their projection with respect to the nilpotent space-time supercharge. Based on the ground ring structure, we propose a duality between perturbed type II strings and the topological B-model on deformed Calabi-Yau singularities. Depending on the type II spectra, one has either the conifold or the suspended pinch point geometry. Using the corresponding quiver gauge theory, obtained by D-branes wrapping in the resolved suspended pinch point geometry, we propose the all orders perturbative partition function.
12 citations
TL;DR: In this paper, the authors studied closed N = 2 strings on orbifolds of the form T4/2 and 2/2, and proved the modular invariance of the torus partition function.
Abstract: We study closed N = 2 strings on orbifolds of the form T4/2 and 2/2 . We compute the torus partition function and prove its modular invariance. We analyze the BRST cohomology of the theory, construct the vertex operators, and compute three and four point amplitudes of twisted and untwisted states. We introduce a background of D-branes, and compute twist states correlators.
6 citations
TL;DR: The general form of the meson correlation functions in the presence of graviphoton background with or without gravity is obtained in this article. And the perturbation theory scheme of computing these correlation functions is discussed.
Abstract: We consider = 1 SU(Nc) supersymmetric gauge theory with chiral matter multiplets in the fundamental representation of the gauge group. The general form of the meson correlation functions in the presence of graviphoton background with or without gravity is obtained. Finally, the perturbation theory scheme of computing these correlation functions is discussed.
4 citations
TL;DR: The general form of the meson correlation functions in the presence of graviphoton background with or without gravity is obtained in this article. And the perturbation theory scheme of computing these correlation functions is discussed.
Abstract: We consider N=1 SU(N_c) supersymmetric gauge theory with chiral matter multiplets in the fundamental representation of the gauge group The general form of the meson correlation functions in the presence of graviphoton background with or without gravity is obtained Finally, the perturbation theory scheme of computing these correlation functions is discussed
2 citations
TL;DR: In this article, the authors studied closed N = 2 strings on orbifolds of the form T^4/Z_2 and C^2/Z-2 and proved their modular invariance.
Abstract: We study closed N=2 strings on orbifolds of the form T^4/Z_2 and C^2/Z_2. We compute the torus partition function and prove its modular invariance. We analyse the BRST cohomology of the theory, construct the vertex operators, and compute three and four point amplitudes of twisted and untwisted states. We introduce a background of D-branes, and compute twist states correlators.