Related papers: Mass Density Perturbations from Inflation with The…
A relaxed primordial power spectrum (PPS) of scalar perturbations arising from inflation can impact the dark radiation constraints obtained from Cosmic Microwave Background and other cosmological measurements. If inflation produces a…
In a recent paper, we suggested that the density fluctuation spectra arising from power-law (or extended) inflation, which are tilted with respect to the Harrison--Zel'dovich spectrum, may provide an explanation for the excess large scale…
We derive a general expression for the power spectra of scalar and tensor fluctuations generated during inflation given an arbitrary choice of boundary condition for the mode function at a short distance. We assume that the boundary…
We examine the calculation of density perturbation at large scales in the inflationary scenario. The formula for its magnitude is reviewed from first principles and applied to the original model of extended inflation. Our estimate is an…
The two approaches to compute perturbations in warm inflation are examined. It is shown that both approaches lead to different expressions for the amplitude of the primordial spectrum, with a difference between them of $\Upsilon/(4H)$ at…
We re-examine the constraints on the density perturbation spectrum, including its spectral index $n$, from the production of primordial black holes. The standard cosmology, where the Universe is radiation dominated from the end of inflation…
We explore constraints on the spectral index $n$ of density fluctuations and the neutrino energy density fraction $\Omega_{HDM}$, employing data from a variety of large scale observations. The best fits occur for $n\approx 1$ and…
We suggest here a mechanism for the seeding of the primordial density fluctuations. We point out that a process like reheating at the end of inflation will inevitably generate perturbations, even on superhorizon scales, by the local…
After cosmic inflation and before the transition to radiation domination, the cosmic energy density may have been dominated during an extended period by an oscillating massive scalar condensate. We show that during this period, sub-Hubble…
We discuss the spectrum of scalar density perturbations from warm inflation when the friction coefficient $\Gamma$ in the inflaton equation is dependent on the inflaton field. The spectral index of scalar fluctuations depends on a new…
The primordial matter power spectrum quantifies fluctuations in the distribution of dark matter immediately following inflation. Over cosmic time, over-dense regions of the primordial density field grow and collapse into dark matter halos,…
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…
We compute the spectrum of cosmological perturbations in a scenario in which inflation is driven by radiation in a non-commutative space-time. In this scenario, the non-commutativity of space and time leads to a modified dispersion relation…
We compute the power spectrum of super-horizon curvature perturbations generated during a late period of thermal inflation, taking into account fluctuation-dissipation effects resulting from the scalar flaton field's interactions with the…
We study an inflationary scenario where thermal inflation is followed by fast-roll inflation. This is a rather generic possibility based on the effective potentials of spontaneous symmetry breaking in the context of particle physics models.…
We study the amplitude and spectral tilt of density perturbations in the simplest hybrid inflation models. We give an exact expression for the amplitude of quantum fluctuations on all scales in the limit where we can neglect the…
We investigate the primordial scalar perturbations in the thermal dissipative inflation where the radiation component (thermal bath) persists and the density fluctuations are thermally originated. The perturbation generated in this model is…
Within the context of supersymmetric hybrid inflation, we study a multiple-stage inflationary scenario that can generate a primordial spectrum of adiabatic density perturbations with a break at $k_b \simeq 0.05 h Mpc^{-1}$. The presence of…
We study the phenomenological constraints on a recently proposed model of open inflation in the context of induced gravity. The main interest of this model is the relatively small number of parameters, which may be constrained by many…
The solution to large-scale power deficit in the cosmic microwave background fluctuations may be relevant with the physics in the preinflationry period, and significantly depends on whether the initial conditions are set as Bunch-Davies…