Related papers: Gravitons and Temperature Fluctuation Correlations…
We compute the primordial scalar, vector and tensor metric perturbations arising from quantum field inflation. Quantum field inflation takes into account the nonperturbative quantum dynamics of the inflaton consistently coupled to the…
Within the framework of metric-affine theories of gravity, where both the metric and connection are treated as independent variables, we consider actions quadratic in the Ricci scalar curvature coupled non-minimally to a scalar field…
A second-order expansion for the quantum fluctuations of the matter field was considered in the framemork of the warm inflation scenario. The friction and Hubble parameters were expanded by means of a semiclassical approach. The…
We present the general discussion on the inflection point inflation with small or large inflaton fields and show the effects of reheating dynamics on the inflationary predictions. In order to compare the model predictions with precisely…
(abridged)We present a model which predicts inflation without the presence of inflaton fields, based on the \epsilon R^2 and Starobinsky models. It links the above models to the observable universe, in particular, to the ratio r of tensor…
We compute the primordial scalar, vector and tensor metric perturbations arising from quantum field inflation. Quantum field inflation takes into account the nonperturbative quantum dynamics of the inflaton consistently coupled to the…
The determination of the inflationary energy scale represents one of the first step towards the understanding of the early Universe physics. The (very mild) non-Gaussian signals that arise from any inflation model carry information about…
We consider the potential problems due to the production of inflatinos and gravitinos after inflation. Inflationary models with a single scale set by the microwave background anisotropies have a low enough reheat temperature to avoid…
Recent released WMAP data show a low value of quadrupole in the CMB temperature fluctuations, which confirms the early observations by COBE. In this paper we consider a model of two inflatons with different masses, $V(\phi_1,\phi_2)={1\over…
Measurements of CMB temperature fluctuations by the Wilkinson Microwave Anisotropy Probe (WMAP) indicate that the fluctuation amplitude in one half of the sky differs from the amplitude in the other half. We show that such an asymmetry…
We study the scalar and tensor perturbations generated by the fragmentation of the inflaton condensate into oscillons or transients after inflation, using nonlinear classical lattice simulations. Without including the backreaction of metric…
During thermal inflation, the temperature determines the number of e-folds of expansion of the universe and so thermal fluctuations are magnified into curvature perturbations. We use classical thermodynamics to calculate the subhorizon…
We consider the production of matter and radiation during reheating after inflation, restricting our attention solely to gravitational interactions. Processes considered are the exchange of a graviton, $h_{\mu \nu}$, involved in the…
We study the large scale power spectrum of gravitational wave perturbations of the microwave background in the context of single-bubble open inflation models. We compute the ratio of tensor to scalar contributions to the CMB anisotropies as…
It is sometimes argued that observation of tensor modes from inflation would provide the first evidence for quantum gravity. However, in the usual inflationary formalism, also the scalar modes involve quantised metric perturbations. We…
We propose a qualitatively new mechanism for generating cosmological fluctuations from inflation. The non-equilibrium excitation of interacting scalar fields often evolves into infra-red (IR) and ultra-violet (UV) cascading, resulting in an…
The decoherence of quantum fluctuations into classical perturbations during inflation is discussed. A simple quantum mechanical argument, using a spatial particle wavefunction rather than a field description, shows that observable…
We present a description of CMB anisotropies generated by tensor perturbations in f(R) theories of gravity. The temperature power spectrum in the special case of $f(R)=R^n$ is computed using a modified version of CAMB package.
We consider the abundance of gravitinos created from the vacuum fluctuation, in a class of `new' inflation models for which global supersymmetry is a good approximation. Immediately after inflation, gravitinos are produced, with number…
We analyze the spectrum of gravitational waves generated by the induced spectrum of tensor fluctuation during warm natural inflation. In our previous work it has been demonstrated that an epoch of warm natural inflation can lead to…