Branes, graphs and singularities

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2009.

Bibliographic Details
Main Author: Vegh, David
Other Authors: John McGreevy.
Format: Thesis
Language:eng
Published: Massachusetts Institute of Technology 2011
Subjects:
Online Access:http://hdl.handle.net/1721.1/63007
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author Vegh, David
author2 John McGreevy.
author_facet John McGreevy.
Vegh, David
author_sort Vegh, David
collection MIT
description Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2009.
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spelling mit-1721.1/630072019-04-12T09:38:18Z Branes, graphs and singularities Vegh, David John McGreevy. Massachusetts Institute of Technology. Dept. of Physics. Massachusetts Institute of Technology. Dept. of Physics. Physics. Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2009. Cataloged from PDF version of thesis. Includes bibliographical references (p. 341-354). In this thesis, we study various aspects of string theory on geometric and nongeometric backgrounds in the presence of branes. In the first part of the thesis, we study non-compact geometries. We introduce "brane tilings" which efficiently encode the gauge group, matter content and superpotential of various quiver gauge theories that arise as low-energy effective theories for D-branes probing singular non-compact Calabi-Yau spaces with toric symmetries. Brane tilings also offer a generalization of the AdS/CFT correspondence. A technique is developed which enables one to quickly compute the toric vacuum moduli space of the quiver gauge theory. The equivalence of this procedure and the earlier approach that used gauged linear sigma models is explicitly shown. As an application of brane tilings, four dimensional quiver gauge theories are constructed that are AdS/CFT dual to infinite families of Sasaki-Einstein spaces. Various checks of the correspondence are performed. We then develop a procedure that constructs the brane tiling for an arbitrary toric Calabi-Yau threefold. This solves a longstanding problem by computing superpotentials for these theories directly from the toric diagram of the singularity. A different approach to the low-energy theory of D-branes uses exceptional collections of sheaves associated to the base of the threefold. We provide a dictionary that translates between the language of brane tilings and that of exceptional collections. Geometric compactifications represent only a very small subclass of the landscape: the generic vacua are non-geometric. In the second part of the thesis, we study perturbative compactifications of string theory that rely on a fibration structure of the extra dimensions. Non-geometric spaces preserving .A = 1 supersymmetry in four dimensions are obtained by using T-dualities as monodromies. Several examples are discussed, some of which admit an asymmetric orbifold description. We explore the possibility of twisted reductions where left-moving spacetime fermion number Wilson lines are turned on in the fiber. by David Vegh. Ph.D. 2011-05-23T18:01:04Z 2011-05-23T18:01:04Z 2009 2009 Thesis http://hdl.handle.net/1721.1/63007 720743119 eng M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 354 p. application/pdf Massachusetts Institute of Technology
spellingShingle Physics.
Vegh, David
Branes, graphs and singularities
title Branes, graphs and singularities
title_full Branes, graphs and singularities
title_fullStr Branes, graphs and singularities
title_full_unstemmed Branes, graphs and singularities
title_short Branes, graphs and singularities
title_sort branes graphs and singularities
topic Physics.
url http://hdl.handle.net/1721.1/63007
work_keys_str_mv AT veghdavid branesgraphsandsingularities