Statut  Confirmé 
Série  COURS 
Domaines  hepth 
Date  Vendredi 16 Mars 2018 
Heure  10:00 
Institut  IPHT 
Salle  Salle Claude Itzykson, Bât. 774 
Nom de l'orateur  Monica Guica 
Prenom de l'orateur  
Addresse email de l'orateur  
Institution de l'orateur  IPhT 
Titre  Asymptotic symmetries, black holes, and holography (2/5) 
Résumé  It is known since the work of Emmy Noether that continuous global symmetries lead to local conserved currents. In gauge theories such as electromagnetism or gravity, the currents associated to gauge transformations vanish because gauge symmetries are not physical symmetries, but rather redundancies of description. However, if the manifold on which the gauge theory is defined has a boundary and the gauge parameter does not vanish on it, then the associated conserved charge can be nonzero. Such gauge transformations that do not vanish at infinity are known as asymptotic symmetries and they act nontrivially on the space of states. \par Asymptotic symmetries make a natural appearance in holography, the proposed equivalence between a theory of quantum gravity on a given manifold and a field theory living on its boundary. More precisely, they should correspond to global symmetries of the dual field theory. Despite the huge success of the AdS/CFT holographic correspondence, holography for most spacetimes of interest remains very poorly understood. One may then hope that the study of asymptotic symmetries, especially when there is an infinite number of them, can shed light on the nature of the dual field theory. \par In this course, we will study several examples of gravitational backgrounds for which the group of asymptotic symmetries is infinitedimensional, such as AdS$_3$, the near horizon of extreme black holes, and flat space. In the latter case, a parallel development relates asymptotic symmetries to the soft behaviour of scattering amplitudes, providing a new perspective on these wellknown results. The black holes will always be lurking in the background. \\ \\ 1. Introduction to the covariant phase space formalism and construction of the conserved charges. \\ 2. Asymptotic symmetries of AdS$_3$ gravity and generalization to extreme Kerr black holes. \\ 3. Asymptotic symmetries of flat space: supertranslations, superrotations and the memory effect. \\ 4. Symmetries of scattering in flat space and relation to soft theorems. 
Numéro de preprint arXiv  
Commentaires  https://courses.ipht.cnrs.fr/?q=fr/node/196 
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