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DC Field  Value  Language 
contributor.advisor  Bianchi, Massimo   
contributor.author  Zapata, Oswaldo   
date.accessioned  20060308T12:01:48Z   
date.available  20060308T12:01:48Z   
date.issued  20060308T12:01:48Z   
identifier.uri  http://hdl.handle.net/2108/229   
description.abstract  Strings on AdS_3 x S^3 and the Plane Wave Limit
Oswaldo Zapata
The AdS_{d+1}/CFT_d holographic correspondence suggests a relationship between string theory, the only known consistent formulation of quantum gravity, and a superconformal field theory where gravity is absent. In this correspondence the strings live in a tendimensional spacetime given by a direct product of an anti deSitter space (AdS), a space with negative cosmological constant, and a sphere (S). On the other hand the conformal field theory is only defined on the boundary of such an AdS space.
In the last years this conjecture has passed a large number of tests, especially in the AdS_5/CFT_4 case, and it continues to be intensively studied, in part due to the weak/strong coupling connection that links the two sides of the correspondence. Another realization of the correspondence is given by superstrings living on a AdS_3 x S ^3 x M_4 bulk space and a twodimensional superconformal boundary field theory that is expected to be a nonlinear sigmamodel on a symmetric orbifold. The bosonic case is relatively well known (WZW model) and it provides by itself useful insight into some basic aspects of holography, nevertheless it is not completely satisfactory and new issues should come from the study of the superstring. So far we have made some progress in understanding and extending the bosonic results to the full fermionic string ( M. Bianchi, and O. Zapata, to appear soon ).
An interesting limit of AdS x S is the plane wave background (ppwave), which corresponds to the local background seen by an observer moving at the speed of light in the AdS x S space. This process of zoomingin around a null geodesic is known as Penrose limit. In the line of what we said above we expect string theory in this ppwave background to be described by a special kind of WZW model. In particular, for the Penrose limit of AdS_3 x S ^3 the worldsheet current model is a generalization of the NappiWitten (NW) model.
Using powerful CFT techniques we have been able to give explicit expressions for the string amplitudes (two, three and four insertions) in the relevant ppwave background. Moreover, we have found a relationship between string amplitudes in the ppwave and the correlators coming from the original formulation in the AdS space. Preliminary results suggest that in the boundary theory the correlation functions should mimic what has been done in the bulk side ( M. Bianchi, G. D'Appollonio, E. Kiritsis and O. Zapata, [arXiv:~hepth/0402004], published in JHEP 0404:074,2004).
We are convinced that following this approach we will be able to show how holography precisely works after the Penrose limit has been taken on both sides of the correspondence, something that has so far remained unclear. Then, by studying a simpler case (AdS_3/CFT_2) we hope to shed light on the understanding of ppholography in the more realistic and complicated AdS_5/CFT_4 duality.
A general overview of the PPwave/CFT holographic correspondence and some preliminary results were presented in the `Tenth Marcel Grossmann Meeting', 2026 July 2003, CBPFICRA, Rio de Janeiro, Brazil [arXiv: hepth/0312316].  en 
format.extent  738501 bytes   
format.mimetype  application/pdf   
language.iso  en  en 
title  Strings on AdS_3 x S^3 and the Plane Wave Limit  en 
type  Thesis  en 
degree.name  Tesi di Dottorato in Fisica  en 
degree.level  Dottorato  en 
degree.discipline  Facoltà di Scienze Matematiche Fisiche e Naturali  en 
degree.grantor  Università degli studi di Roma Tor Vergata  en 
date.dateofdefense  2004/2005  en 
Appears in Collections:  Tesi di dottorato in scienze matematiche e fisiche

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