Séminaire / Seminar GReCO |
| « Inflationary trispectrum of gauge fields from scalar and tensor exchanges » |
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Haridev S R |
| I will present our study of the inflationary trispectrum of primordial gauge fields generated through scalar and tensor exchanges in models with spectator U(1) gauge fields kinetically coupled to the inflaton. Using the in-in formalism, we obtain exact analytical expressions for the connected four-point correlation function of both electric and magnetic fields. For the scalar exchange, we find that the trispectrum signal in the equisided configuration grows with the exchange momentum and reaches its maximum in the flattened limit. However, in the counter collinear limit, we show that the non-linearity parameter associated with the trispectrum scales quadratically with the corresponding parameter of the cross-correlation bispectrum of magnetic fields and curvature perturbations, thereby establishing a hierarchical relation between the higher- and lower-order correlation functions. For the tensor exchange, the trispectrum shows a rich angular dependence, sensitive to the orientation of the momentum quadrilateral with respect to the tensor polarisation. These angular modulations represent distinct observational signatures. Detecting such patterns in future high-precision cosmological data could provide new insights into tensor-mediated interactions during inflation. |
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lundi 24 novembre 2025 - 11:00 Salle des séminaires Évry Schatzman Institut d'Astrophysique de Paris |
| Pages web du séminaire / Seminar's webpage |