Diederik Roest - Isocurvature modes during turns and their imprint on the CMB скачать в хорошем качестве

Diederik Roest - Isocurvature modes during turns and their imprint on the CMB

Abstract: We discuss the bispectrum shapes resulting from a multi-field EFT of fluctuations, which describes different multi-field inflationary models, where we largely focuss on the case where the background trajectory experiences turns in field space. This can give rise to a transient instability in isocurvature modes, which in turn imprints a specific signature on CMB bispectra. We discuss the salient features of these bispectra for both heavy and light modes, and compare to the single-field EFT and to angular inflation. Finally, we discuss the complementary case of massless isocurvature modes and no turns, as arises in modular inflation, and the fate of isocurvature perturbations after inflation.