Related papers: Structure Formation with Two Periods of Inflation:…
The motion of a pseudo-scalar field $X$ during inflation naturally induces a significant amplification of the gauge fields to which it is coupled. The amplified gauge fields can source characteristic scalar and tensor primordial…
In an alternative mechanism recently proposed, adiabatic cosmological perturbations are generated at the decay of the inflaton field due to small fluctuations of its coupling to matter. This happens whenever the coupling is governed by the…
Inflation may provide unique insight into the physics at the highest available energy scales that cannot be replicated in any realistic terrestrial experiment. Features in the primordial power spectrum are generically predicted in a wide…
Heavy scalar fields can undergo an instability during inflation as a result of their kinetic couplings with the inflaton. This is known as the geometrical destabilization of inflation, as it relies on the effect of the negative curvature of…
Cosmological inflation models with modifications to include recent cosmological observations has been an active area of research after WMAP 3 results, which have given us information about the composition of dark matter, normal matter and…
We have studied modulated inflation that generates curvature perturbation from light-field fluctuation. As discussed in previous works, even if the fluctuation of the inflaton itself does not generate the curvature perturbation at the…
Since it became evident that the CDM model for cosmic structure formation predicts smaller power on large scales than observed, many alternatives have been suggested. Among them, the existence of late decaying particle can cure it by…
Doppler peaks in the cosmic microwave background may allow us to distinguish among the two classes of theories-inflationary models and topological defect scenarios-which attempt to explain the origin of structure formation in the universe.…
Using the techniques of out-of-equilibrium field theory, we study the influence on the properties of cosmological perturbations generated during inflation on observable scales coming from fluctuations corresponding today to scales much…
We present two- and three-dimensional simulations of the growth of quantum fluctuations of the scalar fields in supersymmetric hybrid inflation models. For a natural range of couplings, sub-horizon quantum fluctuations undergo rapid growth…
We consider the formation of topological defects after inflation. In order to take into account the effects of the rescattering of fluctuations, we integrate the classical equation that describes the evolution of a complex scalar field on…
In this paper we will discuss analytically the perturbations created from a slowly rolling subdominant spectator field which decays much before the end of inflation. The quantum fluctuations of such a spectator field can seed perturbations…
It is well known that damped superimposed oscillations at large scales in the primordial power spectrum can be generated in both single field and two field models. In single field inflationary models, these features typically arise due to…
It has been shown that the observed dark matter (DM) abundance can be produced by amplification of quantum fluctuations of an energetically subdominant scalar field during inflation. In this paper, we study the robustness of this "spectator…
Inflation has the potential to seed the galactic magnetic fields observed today. However, there is an obstacle to the amplification of the quantum fluctuations of the electromagnetic field during inflation: namely the conformal invariance…
We have evaluated the observational constraints on the spectral index $n$, in the context of a $\Lambda$CDM model. For $n$ scale-independent, as predicted by most models of inflation, present data require $n\simeq 1.0 \pm 0.1$ at the…
We present an alternative scenario for cosmic structure formation where initial fluctuations are due to Kalb-Ramond axions produced during a pre-big bang phase of inflation. We investigate whether this scenario, where the fluctuations are…
Typically the fluctuations generated from a decaying field during inflation do not contribute to the large scale structures. In this paper we provide an example where it is possible for a field which slowly rolls and then decays during…
We reconsider the observed CMB dipolar asymmetry in the context of open inflation, where a supercurvature mode might survive the bubble nucleation. If such a supercurvature mode modulates the amplitude of the curvature power spectrum, it…
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…