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For the inflaton perturbations it is shown that the evolution of the difference between the spectral indices can be translated into information on the scale dependence of the tensor to scalar amplitudes ratio, $r$, and how the scalar field…

Astrophysics · Physics 2009-11-07 C. A. Terrero-Escalante

We study the inflation and the cosmological perturbations generated during the inflation in a local scale invariant model. The local scale invariant model introduces a vector field $S_{\mu}$ in this theory. In this paper, for simplicity, we…

General Physics · Physics 2018-09-24 Naveen K. Singh , Sukanta Panda

Expanding on [1], we analyze in detail the single field chaotic inflationary models plus a cosine modulation term, augmented by a light scalar field with inflaton dependent oscillatory mass term. We work out in detail the Feynman diagrams…

High Energy Physics - Theory · Physics 2020-07-01 A. A. Abolhasani , M. M. Sheikh-Jabbari

We compute the connected four-point correlation function of the primordial curvature perturbation generated during inflation with standard kinetic terms, where the correlation is established via exchange of a graviton between two pairs of…

Astrophysics · Physics 2010-04-21 David Seery , Martin S. Sloth , Filippo Vernizzi

We show that the anisotropies in the spectrum of gravitational waves induced by scalar modes after the end of inflation in canonical, single-field models are completely determined by the tilt of the scalar and tensor power spectra. The…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-14 Julián Rey

We derive the spectral indices and their runnings of single inflation models by a new approach. We perform a dilatation transformation to the linear cosmological perturbations and derive a current (non-)conservation law. Using it, we…

High Energy Physics - Theory · Physics 2019-08-29 Pisin Chen , Jiro Matsumoto , Rio Saitou

We present a numerical integration of the cosmological scalar perturbation equations in warm inflation. The initial conditions are provided by a discussion of the thermal fluctuations of an inflaton field and thermal radiation using a…

Astrophysics · Physics 2009-11-07 Lisa M. H. Hall , Ian G. Moss , Arjun Berera

A perturbative strategy for inflation described by two-inflaton fields is developed using a mathematical analogy with the renormalization-group. Two small quantities, $\alpha$ and $\lambda$, corresponding to standard slow-roll parameters…

High Energy Physics - Theory · Physics 2025-06-10 Bohdan Grzadkowski , Marco Piva

We calculate the power spectrum of curvature perturbations when the inflaton field is rolling over the top of a local maximum of a potential. We show that the evolution of the field can be decomposed into a late-time attractor, which is…

Astrophysics · Physics 2008-11-26 Konstantinos Tzirakis , William H. Kinney

We examine the quantum loop effects on the single-field inflationary models in a spatially flat Friedmann-Robertson-Walker (FRW) cosmological space-time with a general self-interacting scalar field potential, which is modeled in terms of…

General Relativity and Quantum Cosmology · Physics 2020-02-05 Wei-Can Syu , Da-Shin Lee , Kin-Wang Ng

We study next-to-leading corrections to the effective action of the curvature perturbation obtained by integrating out the coupled heavy isocurvature perturbation. These corrections result from including higher order derivative operators,…

High Energy Physics - Theory · Physics 2015-03-12 Jinn-Ouk Gong , Min-Seok Seo , Spyros Sypsas

In this paper we compute 1-loop corrections to the bispectrum in the decoupling limit of the Effective Field Theory of Inflation (EFToI). We regulate the divergences by employing dimensional regularization and work in $d=3+\delta$…

High Energy Physics - Theory · Physics 2024-10-11 Supritha Bhowmick , Diptimoy Ghosh , Farman Ullah

In this paper we use two methods to constrain the the canonical single-field slow-roll inflation model. The first method exploits the analytic slow-roll-parameter dependence of primordial perturbations, and the second consists of a…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-17 Jun Li , Guang-Hai Guo

We consider the backreaction of the long wavelength tensor modes produced during a slow-roll inflationary regime driven by a single scalar field in a spatially flat Friedmann-Lema\^{\i}tre-Robertson-Walker background geometry. We…

General Relativity and Quantum Cosmology · Physics 2014-08-27 G. Marozzi , G. P. Vacca

We elucidate the counting of the relevant small parameters in inflationary perturbation theory. Doing this allows for an explicit delineation of the domain of validity of the semi-classical approximation to gravity used in the calculation…

High Energy Physics - Theory · Physics 2018-02-21 Peter Adshead , C. P. Burgess , R. Holman , Sarah Shandera

Primordial inflation results in the production of a vast ensemble of highly infrared, massless, minimally coupled scalars. We use a recent fully renormalized computation of the one loop contribution to the graviton self-energy from these…

General Relativity and Quantum Cosmology · Physics 2012-01-04 Sohyun Park , R. P. Woodard

We study linear scalar perturbations in single-field models of inflation featuring a non-attractor phase. These models lead to a peak in the curvature power spectrum that may result in the formation of primordial black holes. We develop a…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-26 Vadim Briaud , Alexandros Karam , Niko Koivunen , Eemeli Tomberg , Hardi Veermäe , Vincent Vennin

We invert the second order, single field, general slow-roll formula for the power spectrum, to obtain a second order formula for inflationary parameters in terms of the primordial power spectrum.

Astrophysics · Physics 2009-11-13 Minu Joy , Ewan D. Stewart

The scenario of the slow-roll inflation is studied in the frame of the scalar-tensor theory of gravity where the scalar field has a non-minimal coupling to the geometric part. After deriving the main dynamical and perturbation equations,…

General Relativity and Quantum Cosmology · Physics 2020-12-01 Abolhassan Mohammadi , Tayeb Golanbari , Jamil Enayati , Shahram Jalalzadeh , Khaled Saaidi

The Taylor expansion method has been used to investigate the scale dependence of the power spectrum of the curvature perturbation. In the present study, an alternative numerical method is used to clarify the $k$ dependence. Although there…

Cosmology and Nongalactic Astrophysics · Physics 2009-08-06 Shiro Hirai , Tomoyuki Takami