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We constrain several models in Tachyonic Inflation derived from the large-$N$ formalism by considering theoretical aspects as well as the latest observational data. On the theoretical side, we assess the field range of our models by means…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-22 Nandinii Barbosa-Cendejas , Josue De-Santiago , Gabriel German , Juan Carlos Hidalgo , Refugio Rigel Mora-Luna

We study a model for reheating that has been much investigated for parametric resonance, having a quartic interaction of the scalar inflaton with another scalar field. Attention is particularly on the quantum excitations of the inflaton…

High Energy Physics - Phenomenology · Physics 2014-11-17 A. B. Henriques , R. G. Moorhouse

The effect of the initial condition of inflation on the power spectra of scalar and tensor perturbations is estimated assuming a slow-roll inflation model. By defining a more general initial state in inflation particular properties of the…

Astrophysics · Physics 2007-10-15 Shiro Hirai , Tomoyuki Takami

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 study slow-roll inflation with a Gauss-Bonnet term that is coupled to an inflaton field nonminimally. We investigate the inflationary solutions for a specific type of the nonminimal coupling to the Gauss-Bonnet term and inflaton…

General Relativity and Quantum Cosmology · Physics 2014-10-08 Seoktae Koh , Bum-Hoon Lee , Wonwoo Lee , Gansukh Tumurtushaa

We explore a model of inflation where the inflaton mass-squared is generated at a high scale by gravity-mediated soft supersymmetry breaking, and runs at lower scales to the small value required for slow-roll inflation. The running is…

High Energy Physics - Phenomenology · Physics 2009-10-31 Laura Covi , David H. Lyth , Leszek Roszkowski

We show how the inclusion of non-perturbative, {\em dynamical} quantum effects on the evolution of the inflaton can allow for an inflationary phase that is both consistent with cosmological constraints {\em and} avoids the problems…

High Energy Physics - Theory · Physics 2019-05-15 R. Holman , B. Richard

We investigate the possibility that the primordial perturbation has two sources: the inflaton and a spectator field, which is not dynamically important during inflation but which after inflation can contribute to the curvature perturbation.…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Kari Enqvist , Tomo Takahashi

We investigate slow roll inflation and the creation of primordial density fluctuations in the framework of $f(Q,T)$ gravity. Our focus is on constraining the evolution of both the background and perturbations in this theory, specifically…

General Relativity and Quantum Cosmology · Physics 2026-02-09 Parviz Goodarzi

We study constraints on a number of patch inflationary models in noncommutative spacetime using a compilation of recent high-precision observational data. In particular, the four-dimensional General Relativistic (GR) case, the…

Astrophysics · Physics 2007-05-23 Gianluca Calcagni , Shinji Tsujikawa

We consider inflation in a universe with a positive cosmological constant and a nonminimally coupled scalar field, in which the field couples both quadratically and quartically to the Ricci scalar. When considered in the Einstein frame and…

General Relativity and Quantum Cosmology · Physics 2015-08-21 Dražen Glavan , Anja Marunović , Tomislav Prokopec

The primordial curvature perturbation \zeta may be generated by some curvaton field \sigma, which is negligible during inflation and has more or less negligible interactions until it decays. In the current scenario, the curvaton starts to…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Konstantinos Dimopoulos , Kazunori Kohri , David H. Lyth , Tomohiro Matsuda

We study the inflationary perturbations in general (classically) scale-invariant theories. Such scenario is motivated by the hierarchy problem and provides natural inflationary potentials and dark matter candidates. We analyse in detail all…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-04 Alberto Salvio

We explore the observational implications of models of intermediate inflation driven by modified dispersion relations, specifically those representing the phenomenon of dimensional reduction in the ultraviolet limit. These models are…

Cosmology and Nongalactic Astrophysics · Physics 2014-04-23 John D. Barrow , Macarena Lagos , João Magueijo

We revisit inflation with non-canonical scalar fields by applying deformed-steepness exponential potentials. We show that the resulting scenario can lead to inflationary observables, and in particular to scalar spectral index and…

General Relativity and Quantum Cosmology · Physics 2021-08-24 Smaragda Lola , Andreas Lymperis , Emmanuel N. Saridakis

High-energy modifications to general relativity introduce changes to the perturbations generated during inflation, and the latest high-precision cosmological data can be used to place constraints on such modified inflation models. Recently…

Astrophysics · Physics 2009-11-10 Shinji Tsujikawa , M. Sami , Roy Maartens

We study the impact of the use of the power series expression for the primordial tensor spectrum on parameter estimation from future direct detection gravitational wave experiments. The spectrum approximated by the power series expansion…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-19 Sachiko Kuroyanagi , Tomo Takahashi

For the constant-roll tachyon inflation, we derive the analytical expressions for the scalar and tensor power spectra, the scalar and tensor spectral tilts and the tensor to scalar ratio up to the first order by using the method of Bessel…

General Relativity and Quantum Cosmology · Physics 2018-05-03 Qing Gao , Yungui Gong , Qin Fei

When the different wavelengths of the scalar and tensor modes of the geometry are all assigned on the same space-like hypersurface the maximally amplified frequencies of the spectrum remain smaller than the Planck mass only if the duration…

High Energy Physics - Theory · Physics 2020-07-15 Massimo Giovannini

Observations of the cosmic microwave background do not yet determine whether inflation was driven by a slowly-rolling scalar field or involved another physical mechanism. In this paper we discuss the prospects of using the power spectra of…

High Energy Physics - Theory · Physics 2015-12-10 Daniel Baumann , Daniel Green , Rafael A. Porto