Browsing by Subject "String theory"
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Item Dynamics of asymptotically AdS spaces and holography(2015-08) Pedraza Avella, Juan Felipe; Fischler, Willy; Distler, Jacques; Kilic, Can; Neitzke, Andrew; Paban, SoniaThis thesis presents a series of studies on the evolution and out-of-equilibrium dynamics of strongly coupled quantum field theories by means of the AdS/CFT correspondence. We use a handful of analytic and semi-analytic techniques to investigate the response of the system due to different types of perturbations, some of them leading to thermalization, cooling down or coherent oscillations of the quantum fields. We characterize the processes by studying the evolution of non-local observables such as two-point functions, Wilson loops and entanglement entropy. Our results may be relevant to heavy-ion collision and condensed matter physics experiments.Item Non-supersymmetric holographic engineering and U-duality(2012-08) Young, Stephen Christopher; Fischler, Willy; Caceres, Elena; Paban, Sonia; Dicus, Duane; Freed, DanIn this Ph.D. thesis, we construct and study a number of new type IIB supergravity backgrounds that realize various flavored, finite temperature, and non-supersymmetric deformations of the resolved and deformed conifold geometries. We make heavy use of a U-duality solution generating procedure that allows us to begin with a modification of a family of solutions describing the backreaction of D5 branes wrapped on the S^2 of the resolved conifold, and generate new backgrounds related to the Klebanov-Strassler background. We first construct finite temperature backgrounds which describe a configuration of N_c D5 branes wrapped on the S^2 of the resolved conifold, in the presence of N_f flavor brane sources and their backreaction i.e. N_f/N_c ~ 1. In these solutions the dilaton does not blow up at infinity but stabilizes to a finite value. The U-duality procedure is then applied to these solutions to generate new ones with D5 and D3 charge. The resulting backgrounds are a non-extremal deformation of the resolved deformed conifold with D3 and D5 sources. It is tempting to interpret these solutions as gravity duals of finite temperature field theories exhibiting phenomena such as Seiberg dualities, Higgsing and confinement. However, a first necessary step in this direction is to investigate their stability. We study the specific heat of these new flavored backgrounds and find that they are thermodynamically unstable. Our results on the stability also apply to other non-extremal backgrounds with Klebanov-Strassler asymptotics found in the literature. In the second half of this thesis, we apply the U-duality procedure to generate another class of solutions which are zero temperature, non-supersymmetric deformations of the baryonic branch of Klebanov-Strassler. We interpret these in the dual field theory by the addition of a small gaugino mass. Using a combination of numerical and analytical methods, we construct the backgrounds explicitly, and calculate various observables of the field theory.Item The deconstruction of orbifold fixed points in heterotic M-theory(2016-08) Claussen, Jacob Cole; Kaplunovsky, Vadim; Distler, Jacques; Fischler, Willy; Neitzke, Andrew; Paban, SoniaThe compactification of E8 X E8 heterotic string theory on orbifolds of the form T6=ZN produces a 4D spectrum of untwisted states and twisted states. Unlike the untwisted states, the twisted states are confined to the fixed points of the ZN action and can be charged under subgroups of both E8 gauge groups simultaneously. While insignificant in the string theory case, dualizing to heterotic M-theory yields a peculiar phenomenon. Specifically, in heterotic M-theory the E8 gauge groups are isolated from each other by an extra dimension with 11D supergravity in the bulk between them. Determining how states can be charged across this bulk becomes a highly nontrivial problem to solve. We propose a procedure that utilizes deconstruction to probe these fixed points and build the appropriate states in the continuum limit. We then analyze and apply this procedure to the Z3, Z4, Z6-I, and Z7 orbifolds.Item Tinkertoys for Gaiotto duality(2011-08) Chacaltana Alarcon, Oscar Chacaltana; Distler, Jacques; Kaplunovsky, Vadim; Paban, Sonia; Fischler, Willy; Freed, DanielWe describe a procedure for classifying 4D N=2 superconformal theories of the type introduced by Davide Gaiotto. Any punctured curve, C, on which the 6D (2,0) SCFT is compactified, may be decomposed into 3-punctured spheres, connected by cylinders. The 4D theories, which arise, can be characterized by listing the ``matter" theories corresponding to 3-punctured spheres, the simple gauge group factors, corresponding to cylinders, and the rules for connecting these ingredients together. Different pants decompositions of C correspond to different S-duality frames for the same underlying family of 4D \mathcal{N}=2 SCFTs. We developed such a classification for the A_{N-1} and the D_N series of 6D (2,0) theories. We outline the procedure for general A_{N-1} and D_N, and construct, in detail, the classification through A_4 and D_4, respectively.