Séminaire / Seminar GReCO |
| « Cosmological correlators with Laplace transforms » |
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Nathan Belrhali |
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The generation of primordial density inhomogeneities from inflaton quantum
fluctuations is a crucial prediction of inflation. The correlation functions of these fluctuations, called cosmological correlators, can be studied in a perturbative framework where the quantum fluctuations can be described as quantum fields that propagate in a curved space-time. However, this propagation has a complex time and kinematic dependence due to broken Lorentz invariance, implying technical difficulties for analytical correlator computations. In this talk, after reviewing the essential features of the physics of inflation and cosmological correlators, I will present a new framework to study the analytical properties of these correlators. It is based on the use of Laplace transforms to decompose the mode functions that encode the propagation of fields in curved geometry in terms of their flat-space counterpart, which are plane waves. Following simple diagrammatic rules, any cosmological correlator can then be written from integrating the corresponding flat-space one against a Laplace space kernel. As an illustration, I will show new analytical results obtained with this framework for cosmological correlators with massive exchanges and for the cosmological collider at strong mixing. |
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lundi 9 novembre 2026 - 11:00 Salle des séminaires Évry Schatzman Institut d'Astrophysique de Paris |
| Pages web du séminaire / Seminar's webpage |