Related papers: Non-linear Dynamics and Primordial Curvature Pertu…
This contribution gives an overview on primordial non-Gaussianities from a theoretical perspective. After presenting a general formalism to describe nonlinear cosmological perturbations, several classes of models, illustrated with examples,…
A new class of non-Gaussian curvature fluctuations \zeta_{pr} (\bx) \equiv \delta N(\chi_i) arises from the post-inflation preheating behaviour of a non-inflaton field \chi_i. Its billiard-like chaotic dynamics imprints regular log-spaced…
The purpose of these lectures is to give a pedagogical introduction to inflation and the production of primordial perturbations, as well as a review of some of the latest developments in this domain. After a short introduction, we review…
We study, analytically and with lattice simulations, the decay of coherent field oscillations and the subsequent thermalization of the resulting stochastic classical wave-field. The problem of reheating of the Universe after inflation…
We propose a new mechanism of non-thermal particle production during inflation based on a narrow parametric resonance, akin to the dynamics of post-inflationary preheating. The mechanism is based on the production of scalar particles with a…
We study the non-perturbative evolution of inflationary fluctuations during preheating using fully non-linear general-relativistic field-theory simulations. We choose a single-field inflationary model that is consistent with observational…
Quantum diffusion describes the inflow of vacuum quantum fluctuations as they get amplified by gravitational instability, and stretched to large distances during inflation. In this picture, the dynamics of the universe's expansion becomes…
We investigate the inflaton decay and reheating period after the end of inflation in the non-minimal derivative coupling (NDC) model with chaotic potential. In general, this model is known to provide an enhanced slow-roll inflation caused…
We study (p)reheating in alpha-attractor T-models of inflation, taking into account both scalar fields present in these models: the inflaton and the spectator. The two-field model has a negative field-space curvature which, at the end of…
Since a positive future detection of non-linearity in the cosmic microwave background anisotropy pattern might allow to descriminate among different mechanisms giving rise to cosmological adiabatic perturbations, we study the evolution of…
This paper concludes our semi-analytic study of preheating in inflationary models comprised of multiple scalar fields coupled nonminimally to gravity. Using the covariant framework of paper I in this series, we extend the rigid-spacetime…
A recent variant of the inflationary paradigm is that the ``primordial'' curvature perturbations come from quantum fluctuations of a scalar field, subdominant and effectively massless during inflation, called the ``curvaton'', instead of…
One of the fundamental problems of modern cosmology is to explain the origin of all the matter and radiation in the Universe today. The inflationary model predicts that the oscillations of the scalar field at the end of inflation will…
In many theories of reheating starting from the classical spatially homogeneous inflaton field, its accompanying inhomogeneous part (which arises from primordial quantum fluctuations) is treated as a first order perturbation. We examine…
We develop a non-linear framework for describing long-wavelength perturbations in multiple-field inflation. The basic variables describing inhomogeneities are defined in a non-perturbative manner, are invariant under changes of time slicing…
Warm inflation is an interesting possibility of describing the early universe, whose basic feature is the absence, at least in principle, of a preheating or reheating phase. Here we analyze the dynamics of warm inflation generalizing the…
Understanding the physics of inflaton condensate fragmentation in the early Universe is crucial as the existence of fragments in the form of non-topological solitons (oscillons or Q-balls) may potentially modify the evolution of the…
This thesis is dedicated to studying cosmological inflation, which is a period of accelerated expansion in the very early Universe that is required to explain the observed anisotropies in the cosmic microwave background. Inflation, when…
Inflation universally produces classical almost scale free Gaussian inhomogeneities of any light scalars. Assuming the coupling constants at the time of inflation depend on some light moduli fields, we encounter the generation of modulated…
In higher-curvature inflation models ($R+\alpha_n R^n$), we study a parametric preheating of a scalar field $\chi$ coupled non-minimally to a spacetime curvature $R$ ($\xi R \chi^2$). In the case of $R^2$-inflation model, efficient…