Related papers: Primordial Trispectrum from Entropy Perturbations …
We study the out of equilibrium dynamics of inflationary phase transitions and compute the resulting spectrum of metric perturbations relevant to observation. We show that simple single field models of inflation may produce an adiabatic…
We study adiabatic (curvature) and entropy (isocurvature) perturbations produced during a period of cosmological inflation that is driven by multiple scalar fields with an arbitrary interaction potential. A local rotation in field space is…
We show that the primordial curvature perturbations may originate not from the quantum fluctuations of inflaton during inflation but from isocurvature perturbations which are amplified during preheating after inflation. We consider a simple…
We study primordial perturbations in Higgs--$R^2$ inflation in the presence of non-minimal kinetic mixing between the Higgs field and the scalaron. By numerically solving the multifield background and linear perturbation equations, we…
We study the effects of a general type of features of the inflaton potential on the spectrum and bispectrum of primordial curvature perturbations. These features correspond to a discontinuity in the $n$-th order derivative of the potential…
We study non-linear primordial adiabatic and isocurvature perturbations and their non-Gaussianity. After giving a general formulation in the context of an extended delta N-formalism, we analyse in detail two illustrative examples. The first…
We study multifield aspects of Dirac-Born-Infeld (DBI) inflation. More specifically, we consider an inflationary phase driven by the radial motion of a D-brane in a conical throat and determine how the D-brane fluctuations in the angular…
We explore extensions of hybrid inflationary models in the context of supersymmetric D-term inflation. We point out that a large variety of inflationary scenarios can be encountered when the field content is extended. It is not only…
Non-adiabatic pressure perturbations naturally occur in models of inflation consisting of more than one scalar field. The amount of non-adiabatic pressure present at the end of inflation can have observational consequences through changes…
In the inflationary universe, there can be light fields other than the inflaton. We explore a possibility that such light fields source the primordial perturbations, while minimally affecting the inflaton dynamics. We show that during…
We show that multi-field inflationary models with negligible turning in field space during inflation can lead to an effective sourcing of adiabatic from entropic perturbations {\it after} the end of inflation. We illustrate this general…
We study single-field inflationary models with steep step-like features in the potential that lead to the temporary violation of the slow-roll conditions during the evolution of the inflaton. These features enhance the power spectrum of the…
Moduli with flat or run-away classical potentials are generic in theories based on supersymmetry and extra dimensions. They mix between themselves and with matter fields in kinetic terms and in the nonperturbative superpotentials. As the…
We present a method for the study of second-order superhorizon perturbations in multi field inflationary models with non trivial kinetic terms. We utilise a change of coordinates in field space to separate isocurvature and adiabatic…
We consider the pertubative consistency of inflationary models with features with effective field theory methods. By estimating the size of one-loop contributions to the three-point function, we find the energy scale where their…
The scalar perturbations in inflationary models, based on a two-component diagonal non-linear sigma model, are considered. For inhomogeneities generated at an inflationary stage, the law of motion of the comoving curvature ${\cal R}$ is…
We study non-Gaussianity generated by adiabatic and isocurvature primordial perturbations. We first obtain, in a very general setting, the non-linear perturbations, up to third order, for an arbitrary number of cosmological fluids, going…
We analytically compute the power spectrum of primordial curvature perturbations in Type III hilltop inflation models under the slow-roll approximation. The model parameters are constrained using current Cosmic Microwave Background (CMB)…
In this article, we study in detail the linear dynamics and cubic interactions for any number $N_\mathrm{field}$ of scalar fields during inflation, directly in terms of the observable curvature perturbation $\zeta$ and $N_\mathrm{field}-1$…
Multiple scalar fields nonminimally interacting through pure affine gravity are considered to generate primordial perturbations during an inflationary phase. The couplings considered give rise to two distinct sources of entropy…