Speaker
Description
In this talk Il present exact analytic solutions for the linear dynamics of a two-field inflationary system in which the primordial curvature perturbation $\zeta$ is coupled to an isocurvature perturbation $\sigma$ of entropy mass $\mu$. The solutions are valid for arbitrary values of $\mu$ and of the dimensionless interaction strength $\lambda$, within a quasi-de Sitter background. They therefore provide analytic control over the strongly coupled regime in which $\zeta$ interacts with light isocurvature fields, commonly associated with rapid-turn inflation. As a first application, I show how to derive the amplitude of the primordial power spectrum in closed form, obtaining an expression that interpolates between the weakly coupled, strongly coupled, light-field, and heavy-field regimes. I will also show how to derive analytic expressions for the bispectrum, opening the way to systematic studies of multifield observables beyond the power spectrum, including non-Gaussianity, particle production, and loop corrections.