Related papers: Tachyonic Resonance Preheating in Expanding Univer…
In this work, we investigate the preheating mechanism in a disformally-coupled inflationary model where the scalar field $\phi$ (which is the inflaton field) naturally coupled to another matter field $\chi$ induced by the disformal…
We consider tachyonic warm-inflationary models in the context of intermediate inflation. We derive the characteristics of this model in slow-roll approximation and develop our model in two cases, 1- For a constant dissipative parameter…
In the canonical tachyonic resonance preheating scenario, only an order one fraction of energy density in the inflaton is transferred to radiation, due to backreaction effects. One possible way to improve the energy transfer efficiency is…
In inflationary cosmology, the particles constituting the Universe are created after inflation due to their interaction with moving inflaton field(s) in the process of preheating. In the fermionic sector, the leading channel is out-of…
Inflation in the early Universe can be followed by a brief period of preheating, resulting in rapid and non-equilibrium particle production through the dynamics of parametric resonance. However, the parametric resonance effect is very…
Particle production in the background of an external classical oscillating field is a key process describing the stage of preheating after inflation. For sufficiently strong couplings between the inflaton and matter fields, this process is…
In inflationary cosmology, the particles constituting the Universe are created after inflation in the process of reheating due to their interaction with the oscillating inflaton field. In the bosonic sector, the leading channel of particle…
The gravitational wave equations form a parametric resonance system during oscillatory reheating after inflation, when cast in terms of the electric and magnetic parts of the Weyl tensor. This is in direct analogy with preheating. For…
We review results of a numerical study of resonant inflaton decay in a wide range of realistic models and parameters. Wide enough parametric resonance can withstand the expansion of the Universe, though account for the expansion is very…
We show that the primordial curvature perturbations may originate not from the quantum fluctuations of inflaton during inflation but from isocurvature perturbations which are amplified during preheating after inflation. We consider a simple…
We investigate the problem of perturbative reheating and its effects on the evolution of the curvature perturbations in tachyonic inflationary models. We derive the equations governing the evolution of the scalar perturbations for a system…
We study the post-inflationary energy transfer from the inflaton ($\phi$) into a scalar field ($\chi$) non-minimally coupled to gravity through $\xi R|\chi|^2$, considering models with inflaton potential $V_{\rm inf} \propto |\phi|^{\,p}$…
Non-perturbative production of fermions after chaotic inflation has been the object of several studies in the very recent past. However, the results in the most interesting case of production of massive fermions in an expanding Universe…
We study chaotic dynamics in preheating after inflation in which an inflaton $\phi$ is coupled to another scalar field $\chi$ through an interaction $(1/2)g^2\phi^2\chi^2$. We first estimate the size of the quasi-homogeneous field $\chi$ at…
We investigate the production of gravitational waves (GWs) during preheating with monomial/polynomial inflationary potentials, considering a trilinear coupling $\phi\chi^2$ between a daughter field $\chi$ and the inflaton $\phi$. For…
In the present work, we study warm tachyon inflation model in the context of "logamediate inflation" where the cosmological scale factor expands as $a=a_0\exp(A[\ln t]^{\lambda})$. The characteristics of this model in slow-roll…
We study non-Gaussianity in two distinct models of preheating: instant and tachyonic. In instant preheating non-Gaussianity is sourced by the local terms generated through the coupled perturbations of the two scalar fields. We find that the…
We investigate a resonant particle production of a scalar field $\chi$ coupled non-minimally to a spacetime curvature $R$ ($\xi R \chi^2$) as well as to an inflaton field $\phi$ ($g^2\phi^2\chi^2$). In the case of $g < 3 \times 10^{-4}$,…
We study numerically the decay of massive and massless inflatons into massive excitations, via a $\phi^2 X^2$ coupling, in the expanding Universe. We find that a wide enough resonance can survive the Universe expansion, though account for…
We characterize the post-inflationary evolution of the equation of state of the universe from the end of inflation until the onset of radiation domination, when the inflaton is coupled to a daughter field through a trilinear interaction. We…