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Reheating after R^2 inflation proceeds through gravitational particle production of conformally noninvariant fields. We argue that the nonvanishing expectation value of flat directions generic in supersymmetric theories break conformal…

High Energy Physics - Theory · Physics 2013-06-05 Yuki Watanabe , Jun'ichi Yokoyama

Single field inflationary models predict nearly Gaussian initial conditions and hence a detection of non-Gaussianity would be a signature of the more complex inflationary scenarios. In this paper we study the effect on the cosmic microwave…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-02 Dmitriy Tseliakhovich , Christopher Hirata , Anze Slosar

Following inflation, the Universe may pass through an early matter-dominated phase supported by the oscillating inflaton condensate. Initially small fluctuations in the condensate grow gravitationally on subhorizon scales and can collapse…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-03 Benedikt Eggemeier , Jens C. Niemeyer , Karsten Jedamzik , Richard Easther

An inflationary model in the framework of noncommutative space-time may generate a nontrivial running of the scalar spectral index, but usually induces a large tensor-to-scalar ratio simultaneously. With the latest observational data from…

Cosmology and Nongalactic Astrophysics · Physics 2013-07-11 Nan Li , Xin Zhang

We propose a curvaton model in which the initial condition of the curvaton oscillation is determined by its attractor behavior during inflation. Assuming a chaotic inflation model, we find that the initial condition determined by the…

High Energy Physics - Phenomenology · Physics 2013-03-27 Keisuke Harigaya , Masahiro Ibe , Masahiro Kawasaki , Tsutomu T. Yanagida

The possibility that the scale-invariant inflationary spectrum may be modified due to the hidden assumptions about the Planck scale physics -- dubbed as trans-Planckian inflation -- has received considerable attention. To mimic the possible…

High Energy Physics - Theory · Physics 2009-11-11 S. Shankaranarayanan , Musongela Lubo

We investigate whether a recently proposed modulation of the power spectrum of primordial density fluctuations generated through transplankian (maybe stringy) effects during inflation can be observed. We briefly review the mechanism leading…

High Energy Physics - Theory · Physics 2014-11-18 L. Bergstrom , U. H. Danielsson

Recently a mechanism was proposed whereby the primordial density perturbations are generated at the end of inflation. We continue the analysis of the proposed model of this mechanism and calculate the maximum extent to which the density…

Astrophysics · Physics 2009-11-13 Michael P. Salem

We explore the warm inflation scenario theoretical predictions looking at two different dissipative regimes for several representative primordial potentials. As it is well known, the warm inflation is able to decrease the tensor-to-scalar…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-03 Micol Benetti , Rudnei O. Ramos

We propose a novel scenario in which scalar perturbations, that seed the large scale structure of the Universe, are generated without relying on a scalar field (the inflaton). In this framework, inflation is driven by a de Sitter space-time…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-20 Daniele Bertacca , Raul Jimenez , Sabino Matarrese , Angelo Ricciardone

We study non-Gaussianities in the primordial perturbations in single field inflation where there is radiation era prior to inflation. Inflation takes place when the energy density of radiation drops below the value of the potential of a…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-30 Suratna Das , Subhendra Mohanty

Non-commutativity of spacetime at the Planck scale may deform the usual dispersion relations. And these deformed dispersion relations could lead to the accelerating phase without a scalar field. In this paper, we have calculated the…

High Energy Physics - Theory · Physics 2008-11-26 Seoktae Koh

The general kind noncanonical warm inflation is introduced and its total non-Gaussianity of perturbation on uniform energy density hypersurfaces is studied. The total non-Gaussianity contains two complementary parts: the three- and the…

General Relativity and Quantum Cosmology · Physics 2019-12-19 Xiao-Min Zhang , Kai Li , Hong-Yang Ma , Qian Liu , Jian-Yang Zhu

We present the first computation of the cosmological perturbations generated during inflation up to second order in deviations from the homogeneous background solution. Our results, which fully account for the inflaton self-interactions as…

Astrophysics · Physics 2010-04-05 V. Acquaviva , N. Bartolo , S. Matarrese , A. Riotto

We review the main aspects of the warm inflation scenario, focusing on the inflationary dynamics and the predictions related to the primordial spectrum of perturbations, to be compared with the recent cosmological observations. We study in…

High Energy Physics - Phenomenology · Physics 2010-04-21 Mar Bastero-Gil , Arjun Berera

We analyze the dynamics of models of warm inflation with general dissipative effects. We consider phenomenological terms both for the inflaton decay rate and for viscous effects within matter. We provide a classification of the asymptotic…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Jose P. Mimoso , Ana Nunes , Diego Pavon

In the present work we study a warm inflationary model defined by a quasi-exponential inflaton potential and an inflaton decay rate proportional to the Hubble rate. The model is characterized by three free parameters. We compute the power…

General Relativity and Quantum Cosmology · Physics 2018-06-13 Nelson Videla , Grigoris Panotopoulos

We review models which generate a large non-Gaussianity of the local form. We first briefly consider three models which generate the non-Gaussianity either at or after the end of inflation; the curvaton scenario, modulated (p)reheating and…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-13 Christian T. Byrnes , Ki-Young Choi

We investigate the phenomenology of warm inflation and present generic results about the evolution of the inflaton and radiation fields. The general conditions required for warm inflation to take place are derived and discussed. A…

Astrophysics · Physics 2009-10-31 A. N. Taylor , A. Berera

We studied models of inflation with a preferred clock specifying the end of inflation and giving the curvature perturbations, coupled with another non-equivalent clock that at late times defines the same frame and do not contribute to the…

General Relativity and Quantum Cosmology · Physics 2013-10-18 Gustavo Joaquin Turiaci , Matias Zaldarriaga
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