Statut | Confirmé |
Série | STR-LPT-ENS-HE |
Domaines | hep-th |
Date | Vendredi 11 Décembre 2020 |
Heure | 14:00 |
Institut | LPTENS |
Salle | GoToMeeting |
Nom de l'orateur | Paulos |
Prenom de l'orateur | Miguel |
Addresse email de l'orateur | |
Institution de l'orateur | ENS, CNRS |
Titre | Landau diagrams in AdS and S-matrices from conformal correlators |
Résumé | Quantum field theories in AdS generate conformal correlation functions on the boundary, and in the limit where AdS is nearly flat one should be able to extract an S-matrix from such correlators. We discuss a particularly simple position-space procedure to do so. It features a direct map from boundary positions to (on-shell) momenta and thereby relates cross ratios to Mandelstam invariants. This recipe succeeds in several examples, includes the momentum-conserving delta functions, and can be shown to imply the two proposals in arXiv:1607.06109 based on Mellin space and on the OPE data. Interestingly the procedure does not always work: the Landau singularities of a Feynman diagram are shown to be part of larger regions, to be called `bad regions', where the flat-space limit of the Witten diagram diverges. To capture these divergences we introduce the notion of Landau diagrams in AdS. As in flat space, these describe on-shell particles propagating over large distances in a complexified space, with a form of momentum conservation holding at each bulk vertex. As an application we recover the anomalous threshold of the four-point triangle diagram at the boundary of a bad region. |
Numéro de preprint arXiv | 2007.13745 |
Commentaires | https://global.gotomeeting.com/join/261832861 |
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