Pantheon SEMPARIS Le serveur des séminaires parisiens Paris

Statut Confirmé
Série IPHT-HEP
Domaines hep-ph
Date Mardi 28 Mars 2023
Heure 14:45
Institut IPHT
Salle Salle Claude Itzykson, Bât. 774
Nom de l'orateur Enrico Pajer
Prenom de l'orateur
Addresse email de l'orateur
Institution de l'orateur University of Cambridge
Titre Recent Progress on the Cosmological Bootstrap
Résumé In this talk, I will review the (boostless) cosmological bootstrap approach to the study of cosmological correlators from inflation, in which symmetries and general physical principles such as causality, unitarity and locality substitute the traditional model-building and lead to a variety of general results and new predictions for primordial signals. The object of study is the field theoretic wavefunction and its wavefunctions coefficients, from which all correlators can be (perturbatively) derived. Wavefunction coefficients are the close analog of amplitudes in flat space and many results for amplitudes have avatars in the cosmological bootstrap. In the first part of the talk, I will review a few core results: (i) Causality implies that "off-shell" wavefunction coefficients (a.k.a. cosmological "in-out" Green's function) are analytic functions of off-shell energies (non-perturbatively) in the lower-half complex plane, whose singularity on the negative real axis are classified. (ii) Unitarity implies an infinite set of relations between higher and lower order contributions in perturbation theory known collectively as the cosmological optical theorem. (iii) Manifest locality constrains wavefunction coefficients in the form of analytically-continued soft limits. In the second part of the talk, I discuss four phenomenological results recently derived with these techniques: (1) The tree-level scalar bispectrum to all orders in derivatives both assuming scale invariant and oscillations (resonant non-Gaussianity)
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