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We study chaotic and runaway potential inflationary models in the curvaton scenario. In particular, we address the issue of large tensor-to-scalar ratio and red-tilted spectrum in chaotic models and reheating in runaway model in the light…

General Relativity and Quantum Cosmology · Physics 2020-08-27 Mohit Kumar Sharma , Kairat Myrzakulov , Mudhahir Al Ajmi

We study the effect of finite temperatures and Fermion density on the effective pseudo-scalar-photon vertex induced by the triangle diagram. The manifestly covariant calculations show that when the pseudo-scalar mass is much less than the…

High Energy Physics - Phenomenology · Physics 2007-05-23 Sourendu Gupta , S. N. Nayak

We analyse the primordial density perturbation when it is generated by a `curvaton' field different from the inflaton. In some cases this perturbation may have large isocurvature components, fully correlated or anti-correlated with the…

Astrophysics · Physics 2009-07-09 David H. Lyth , Carlo Ungarelli , David Wands

We investigate the impact of finite temperature effects on axions in the context of cosmology. The temperature dependence of the decay constant is modeled analogous to pions. For the two interesting cases considered here, we find that the…

High Energy Physics - Phenomenology · Physics 2007-05-23 Namit Mahajan , Sukanta Panda

There might be a light scalar field during inflation which is not responsible for the accelerating inflationary expansion. Then, its quantum fluctuation is stretched during inflation. This scalar field could be a curvaton, if it decays at a…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Ki-Young Choi , Osamu Seto

We consider a curvaton scenario in which the late-time domination and the generation of the curvature perturbation is achieved by a non-oscillatory (NO) curvaton potential. Instead of considering the conventional curvaton oscillation, we…

High Energy Physics - Phenomenology · Physics 2008-11-26 Tomohiro Matsuda

We present a formalism for studying the influence of dispersive and absorbing dielectric bodies on a radiating atom in the framework of quantization of the phenomenological Maxwell equations for given complex permittivities of the bodies.…

Quantum Physics · Physics 2007-05-23 Stefan Scheel , Ludwig Knoell , Dirk-Gunnar Welsch

We calculate curvature perturbations in the scenario in which the curvaton field decays into another scalar field via parametric resonance. As a result of a nonlinear stage at the end of the resonance, standard perturbative calculation…

Cosmology and Nongalactic Astrophysics · Physics 2010-06-15 Alex Chambers , Sami Nurmi , Arttu Rajantie

We investigate how the background evolution affects the curvature perturbations generated by the curvaton, assuming a curvaton potential that may deviate slightly from the quadratic one, and parameterizing the background fluid density as…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Kari Enqvist , Tomo Takahashi

We study a model where two scalar fields, that are subdominant during inflation, decay into radiation some time after inflation has ended but before primordial nucleosynthesis. Perturbations of these two curvaton fields can be responsible…

Astrophysics · Physics 2008-06-05 Jussi Valiviita , Hooshyar Assadullahi , David Wands

We build a realistic model of curvaton cosmology, in which the energy content is described by radiation, WIMP dark matter and a curvaton component. We calculate the curvature and isocurvature perturbations, allowing for arbitrary initial…

Astrophysics · Physics 2008-11-26 Martin Lemoine , Jerome Martin

We study a ghost-free model of massive vector curvaton proposed in the literature, where the quick decrease of the vector background expectation value is avoided by a suitable choice of kinetic and mass functions. The curvaton perturbations…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 Ryo Namba

In this paper, we will use $\delta \mathcal{N}$-formalism to calculate the primordial curvature perturbation for the curvaton model with a Lagrange multiplier field. We calculate the non-linearity parameters $f_{NL}$ and $g_{NL}$ in the…

Cosmology and Nongalactic Astrophysics · Physics 2012-09-27 Chao-Jun Feng , Xin-Zhou Li

The effects of thermal diffuse scattering on the transmission and eventual diffraction of highly accelerated electrons are investigated with a method that incorporates the frozen phonon approximation to the exact numerical solution of the…

Computational Physics · Physics 2018-01-22 S. Rudinsky , A. S. Sanz , R. Gauvin

Recent analyses of the statistical distribution of the temperature anisotropies in the CMB do not rule out the possibility that there is a large non-gaussian contribution to the primordial power spectrum. This fact motivates the re-analysis…

Astrophysics · Physics 2008-11-26 Maria Beltrán

In this paper we provide a detailed numerical study of the influence of thermal effects on the original picture of AD baryogenesis. These effects are found to modify the results greatly in some cases. We estimate the baryon/entropy ratio…

High Energy Physics - Phenomenology · Physics 2015-06-25 Alexey Anisimov

In this article we investigate dependency of the adiabatic and entropy spectral indices of the cosmological perturbations on the geometry and topology of the background universe. Our discussion includes the post-inflationary universe i.e.…

General Relativity and Quantum Cosmology · Physics 2019-03-11 Ali A. Asgari , Amir H. Abbassi , Jafar Khodagholizadeh

We analyze the simplest possible realization of the curvaton scenario, where a nearly scale-invariant spectrum of adiabatic perturbations is generated by conversion of an isocurvature perturbation generated during inflation, rather than the…

Astrophysics · Physics 2009-11-07 N Bartolo , Andrew R Liddle

We consider an inflationary curvaton scenario, where the curvaton decays into two non-interacting relativistic fluids and later during the cosmological evolution one of them becomes non-relativistic, forming dark matter component of the…

Cosmology and Nongalactic Astrophysics · Physics 2010-05-12 Jani Sainio , Iiro Vilja

The time dependence of the temperature during the reheating process is studied. We consider the thermal feedback effects of the produced particles on the effective dissipation rate of the inflaton field, which can lead to enhanced…

High Energy Physics - Phenomenology · Physics 2021-09-28 Lei Ming