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We calculate the scalar-induced one-loop correction to the power spectrum of tensor perturbations produced during single-field slow-roll inflation. We find that the correction is given by the square of the product of the slow-roll parameter…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-06 Jiwon Kong , Jieun Jeon , Jinn-Ouk Gong

Inflationary observables, like the power spectrum, computed at one- and higher-order loop level seem to be plagued by large infra-red corrections. In this short note, we point out that these large infra-red corrections appear only in…

Astrophysics · Physics 2009-06-23 N. Bartolo , S. Matarrese , M. Pietroni , A. Riotto , D. Seery

Recently, it has been claimed that inflationary models with an inflection point in the scalar potential can produce a large resonance in the power spectrum of curvature perturbation. In this paper however we show that the previous analyses…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-06 Cristiano Germani , Tomislav Prokopec

The latest results from PLANCK impose strong constraints on features in the spectrum of the curvature perturbations from inflation. We analyse the possibility of particle production induced by sharp turns of the trajectory in field space in…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Maciej Konieczka , Raquel H. Ribeiro , Krzysztof Turzynski

We investigate how the uncertainty of noncommutative spacetime affects on inflation. For this purpose, the noncommutative parameter $\mu_0$ is taken to be a zeroth order slow-roll parameter. We calculate the noncommutative power spectrum up…

High Energy Physics - Theory · Physics 2009-11-10 Hungsoo Kim , Gil Sang Lee , Hyung Won Lee , Yun Soo Myung

Inflationary predictions based on the linear theory of cosmological perturbations are related to the two point function of a (second quantized) real scalar free field during the accelerated stage. Such a two point function is finite, in…

High Energy Physics - Theory · Physics 2008-11-26 F. Finelli , G. Marozzi , G. P. Vacca , G. Venturi

We explore the correlations between correlation functions of the primordial curvature perturbation produced during inflation. We find that for general single field inflation, other than the source terms which depend on the model details,…

Cosmology and Nongalactic Astrophysics · Physics 2014-04-02 Jinn-Ouk Gong , Koenraad Schalm , Gary Shiu

One-loop correction to the power spectrum in generic single-field inflation is calculated by using standard perturbation theory. Because of the enhancement inversely proportional to the observed red tilt of the spectral index of curvature…

High Energy Physics - Theory · Physics 2022-02-11 Jason Kristiano , Jun'ichi Yokoyama

Inflection point inflation generically includes a deviation from slow-roll when the inflaton approaches the inflection point. Such deviations are shown to be generated by transitions between singular trajectories. The effects on the power…

High Energy Physics - Theory · Physics 2013-07-22 Sean Downes , Bhaskar Dutta

We derive the power spectrum $\mathcal P(k)$ of the density perturbations produced during inflation up to second-order corrections in the standard slow-roll approximation for an inflaton with more than one degree of freedom. We also present…

Astrophysics · Physics 2008-11-26 Jin-Ook Gong , Ewan D. Stewart

We calculate the power spectra of primordial curvature and isocurvature perturbations from a general two field inflation model at next-to-leading order correction in a slow-roll expansion. In particular we calculate the spectral indices to…

Astrophysics · Physics 2009-11-11 Christian T. Byrnes , David Wands

We investigate the evolution of the non-linear long wavelength fluctuations during preheating after inflation. By using the separate universe approach, the temporal evolution of the power spectrum of the scalar fields and the curvature…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Yasusada Nambu , Yohei Araki

Power suppression of the cosmic microwave background on the largest observable scales could provide valuable clues about the particle physics underlying inflation. Here we consider the prospect of power suppression in the context of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-01 Jose J. Blanco-Pillado , Mafalda Dias , Jonathan Frazer , Kepa Sousa

Because of the non-linearity of the Einstein equations, the cosmological fluctuations which are generated during inflation on a wide range of wavelengths do not evolve independently. In particular, to second order in perturbation theory,…

Astrophysics · Physics 2009-11-11 Patrick Martineau , Robert Brandenberger

We investigate two-field inflationary models in which scalar cosmological pertubations are generated via a spectator field nonminimally coupled to gravity, with the particular emphasis on curvaton scenarios. The principal advantage of these…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-17 Lei-Hua Liu , Tomislav Prokopec

In this paper we break the scale invariance of the primordial power spectrum of curvature perturbations of inflation. Introducing a singular behaviour due to spontaneous symmetry breaking in the inflaton potential, we obtain fully analytic…

Astrophysics · Physics 2009-11-11 Jinn-Ouk Gong

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

Several models of inflation employing a triplet of SU(2) vectors with spatially orthogonal vacuum expectation values (VEVs) have been recently proposed. One (tensor) combination $t$ of the vector modes is amplified in some momentum range…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-03 Alexandros Papageorgiou , Marco Peloso , Caner Unal

Inflationary cosmology provides a natural mechanism for the generation of primordial perturbations which seed the formation of observed cosmic structure and lead to specific signals of anisotropy in the cosmic microwave background…

Astrophysics · Physics 2011-07-19 Salman Habib , Andreas Heinen , Katrin Heitmann , Gerard Jungman

The linear and quadratic perturbations for a scalar-tensor model with non-minimal coupling to curvature, coupling to the Gauss-Bonnet invariant and non-minimal kinetic coupling to the Einstein tensor are developed. The quadratic action for…

General Relativity and Quantum Cosmology · Physics 2019-09-24 L. N. Granda , D. F. Jimenez