Séminaire Doctorants / Seminar PhD students |
| « De Sitter momentum space » |
|
Arthur Poisson |
| In many inflationary scenarios, primordial correlation functions are encoded in late-time observables in de Sitter spacetime, where even the simplest processes already involve highly nontrivial time integrals. I will show that this difficulty can be overcome by introducing a new momentum-space representation adapted to de Sitter isometries. This construction is based on diagonalizing the Casimir operator rather than the Hamiltonian, effectively trading the usual (d+1)-dimensional Fourier space for the Kontorovich–Lebedev–Fourier (KLF) space. I will also show practical advantages of this description: quadratic dynamics provide a simple propagator analogous to flat space, and the nested time integrals turn into frequency-space integrals over meromorphic functions. |
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vendredi 20 mars 2026 - 16:00 Salle des séminaires Évry Schatzman, Institut d'Astrophysique |
| Page web du Séminaire / Seminar's webpage |