Pantheon SEMPARIS Le serveur des séminaires parisiens Paris

Statut Confirmé
Domaines hep-th
Date Jeudi 10 Novembre 2022
Heure 10:00
Institut LPTHE
Salle Institut Henri Poincaré, Room 314
Nom de l'orateur Mason
Prenom de l'orateur Lionel
Addresse email de l'orateur
Institution de l'orateur Oxford
Titre Twistors and Lw_{1+infinity} symmetries in celestial formulations of 4d gravity
Résumé Recently in their celestial holography programme, Strominger and coworkers uncovered a hidden loop algebra version of w-infinity symmetry in the `celestial soft OPEs' for graviton scattering. This talk will explain the origin of this symmetry in terms of old ideas of Newman and Penrose based on light-cone cuts of null infinity and their description in terms of asymptotic twistors. W_n symmetries were introduced by Zamolodchikov as higher spin symmetries in 2d conformal field theories. These were given a geometric interpretation as for n=infinity as area-preserving diffeomorphisms of the plane. I will explain how the corresponding classical loop algebra becomes a hidden symmetry of self-dual gravity realized geometrically as the structure-preserving diffeomorphisms of Penrose's nonlinear graviton construction. This can be realized particularly cleanly by recasting the constructions in split signature. We introduce an open chiral sigma model with target the asymptotic twistor space. The full gravity tree-level S-matrix can then be obtained from tree correlators of this model. The action of the Lw_{1+\infty} symmetry on the tree-level S-matrix of full gravity beyond the self-dual sector is then realized by the action of certain vertex operators and act on the full amplitude. This is based on joint work with Tim Adamo and Atul Sharma and together with some more recent work.
Numéro de preprint arXiv 2110.06066
Fichiers attachés
  • 22-Paris.pdf (1235402 bytes) OPEN

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