Related papers: Inflation Dynamics and Reheating
Coupled, multi-field models of inflation can provide several attractive features unavailable in the case of a single inflaton field. These models have a rich dynamical structure resulting from the interaction of the fields and their…
We consider the non-equilibrium evolution of the inflaton field coupled to both lighter scalars and fermions. The dissipational dynamics of this field is studied and found to be quite different than that believed in inflationary models. In…
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 $N_\mathrm{field}-1$…
Inflation is studied in the context of induced gravity (IG) $\gamma \sigma^2 R$, where $R$ is the Ricci scalar, $\sigma$ a scalar field and $\gamma$ a dimensionless constant, and diverse symmetry-breaking potentials $V(\sigma)$ are…
We investigate whether the predictions of single-field models of inflation are robust under the introduction of additional scalar degrees of freedom, and whether these extra fields change the potentials for which the data show the strongest…
Taking field theory seriously, inflation model-building is difficult but not impossible. The observed value of the spectral index of the adiabatic density perturbation is starting to discriminate between models, and may well pick out a…
A model of cosmological inflation is proposed in which field space is a hyperbolic plane. The inflaton never slow-rolls, and instead orbits the bottom of the potential, buoyed by a centrifugal force. Though initial velocities redshift away…
We study the post-inflation dynamics of multifield models involving nonminimal couplings using lattice simulations to capture significant nonlinear effects like backreaction and rescattering. We measure the effective equation of state and…
We study the two-phase scenario following inflation, where the initial step is preheating, accompanied by a step of perturbative reheating at which inflaton field decays transferring all of its energy to create relativistic particles, the…
This PhD thesis presents a study of the effect and generation of non-adiabatic perturbations in Cosmology. We study adiabatic (curvature) and entropy (isocurvature) perturbations produced during a period of cosmological inflation that is…
Preheating after inflation may lead to nonthermal phase transitions with symmetry restoration. These phase transitions may occur even if the total energy density of fluctuations produced during reheating is relatively small as compared with…
In this article, we review how strong dynamics can be efficiently employed as a viable alternative to study the mechanism of cosmic inflation. We examine single-field inflation in which the inflaton emerges as a bound state stemming from…
Several recent proposals to embed inflation into high-energy physics rely on inflationary dynamics characterized by a strongly non-geodesic motion in negatively curved field space. This naturally leads to a transient instability of…
A pressing problem in comparing inflationary models with observation is the accurate calculation of correlation functions. One approach is to evolve them using ordinary differential equations ("transport equations"), analogous to the…
We investigate the importance of local gravity during preheating, the non-linear dynamics that may be responsible for starting the process of reheating the universe after inflation. We introduce three numerical methods that study a simple…
We develop a cosmological model where primordial inflation is driven by a 'solid', defined as a system of three derivatively coupled scalar fields obeying certain symmetries and spontaneously breaking a certain subgroup of these. The…
We investigate density perturbations generated through modulated reheating while inflation is driven by a conformally coupled scalar field. A large running of the spectral index is obtained, which reflects the basic nature of conformal…
We present a new general mechanism for generating curvature perturbations after inflation. Our model is based on the simple assumption that a field that starts to oscillate after inflation has a potential characterized by an underlying…
We study adiabatic and isocurvature perturbation spectra produced by a period of cosmological inflation driven by two scalar fields. We show that there exists a model-independent consistency condition for all two-field models of slow-roll…
We analyse models of inflation in which isocurvature perturbations present during inflation are converted into the primordial curvature perturbation during instant preheating. This can be due to an asymmetry between the fields present…