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The next generation of cosmic microwave background, gravitational wave, and large scale structure, experiments will provide an unprecedented opportunity to probe the primordial power spectrum on small scales. An exciting possibility for…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-02 Keisuke Inomata , Evan McDonough , Wayne Hu

We study an inflationary scenario where thermal inflation is followed by fast-roll inflation. This is a rather generic possibility based on the effective potentials of spontaneous symmetry breaking in the context of particle physics models.…

High Energy Physics - Phenomenology · Physics 2008-11-26 Jinn-Ouk Gong

Motivated by the idea that inflation occurs at the GUT symmetry breaking scale, in this paper we construct a new class of large field inflaton potentials where the inflaton starts with a power law potential; after initial period of relative…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-24 Dhiraj Kumar Hazra , Arman Shafieloo , George F. Smoot , Alexei A. Starobinsky

We extend a previous analysis concerning cosmological fluids with generalized equations of state in order to study inflationary scenarios. In the framework of the slow-roll approximation we find the expressions for the perturbation…

Astrophysics · Physics 2009-10-28 G. Mangano , G. Miele , C. Stornaiolo

We investigate the reconstruction of standard and generalized Rastall gravity inflationary models, using the scalar spectral index and the Rastall parameter expressed as functions of the number of $e-$folds $N$. Within a general formalism,…

General Relativity and Quantum Cosmology · Physics 2025-12-09 Ramon Herrera , Carlos Rios

We show that the generalized slow-roll approach for calculating the power spectrum where the inflationary slow roll parameters are neither small nor slowly varying can be readily extended to models with non-canonical kinetic terms in the…

Cosmology and Nongalactic Astrophysics · Physics 2011-08-09 Wayne Hu

Recently, there has been some interest for building supersymmetric models of double inflation. These models, realistic from a particle physics point of view, predict a broken-scale-invariant power spectrum of primordial cosmological…

High Energy Physics - Phenomenology · Physics 2014-11-17 Julien Lesgourgues

We give final shape to a recent formalism for deriving the functional forms of the primordial power spectra of single-scalar potential models and theories which are related to them by conformal transformation. An excellent analytic…

General Relativity and Quantum Cosmology · Physics 2017-11-29 D. J. Brooker , N. C. Tsamis , R. P. Woodard

In the ``natural inflation'' model, the inflaton potential is periodic. We show that Planck scale physics may induce corrections to the inflaton potential, which is also periodic with a greater frequency. Such high frequency corrections…

Astrophysics · Physics 2008-11-26 Xiulian Wang , Bo Feng , Mingzhe Li , Xue-Lei Chen , Xinmin Zhang

We study inflation in a random multifield potential, using techniques developed by Marsh et al. The potential is a function of a large number of fields, and we choose parameters so that inflation only occurs in regions where the potential…

High Energy Physics - Theory · Physics 2016-08-02 Ben Freivogel , Roberto Gobbetti , Enrico Pajer , I-Sheng Yang

The superpotential method is a reconstruction technique which has proven useful to build exact cosmological solutions. We here employ the superpotential method in order to reconstruct the features necessary for the inflaton potential to…

General Relativity and Quantum Cosmology · Physics 2025-01-22 Alexander Y. Kamenshchik , Ekaterina O. Pozdeeva , Augustin Tribolet , Alessandro Tronconi , Giovanni Venturi , Sergey Yu. Vernov

Through a principal component analysis, we study how accurately CMB observables can constrain inflaton potentials in a model independent manner. We apply the general slow-roll approximation in our analysis where we allow, in contrast to the…

Astrophysics · Physics 2008-11-26 Kenji Kadota , Scott Dodelson , Wayne Hu , Ewan D. Stewart

Motivated by the possibility of inflation in the cosmic landscape, which may be approximated by a complicated potential, we study the density perturbations in multi-field inflation with a random potential. The random potential causes the…

High Energy Physics - Theory · Physics 2009-04-24 S. -H. Henry Tye , Jiajun Xu , Yang Zhang

We propose a large class of supergravity models in terms of a single chiral matter superfield, leading to (almost) arbitrary single-field inflationary scalar potentials similar to the F-term in rigid supersymmetry. Those scalar potentials…

High Energy Physics - Theory · Physics 2015-02-25 Sergei V. Ketov , Takahiro Terada

We show how observations of the density perturbation (scalar) spectrum and the gravitational wave (tensor) spectrum allow a reconstruction of the potential responsible for cosmological inflation. A complete functional reconstruction or a…

High Energy Physics - Phenomenology · Physics 2009-10-22 Edmund J. Copeland , Edward W. Kolb , Andrew R. Liddle , James E. Lidsey

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

Starting from parametrization of scalar perturbations generated during inflation in terms of $e$--fold $N$ and using an approach recently developed by Starobinsky, dubbed "direct smooth reconstruction", we show that, in the slow--roll…

General Relativity and Quantum Cosmology · Physics 2024-01-26 Gianluca Giacomozzi , Sergio Zerbini

We study multifield contributions to the scalar power spectrum in an ensemble of six-field inflationary models obtained in string theory. We identify examples in which inflation occurs by chance, near an approximate inflection point, and we…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Liam McAllister , Sébastien Renaux-Petel , Gang Xu

We describe models of single-field inflation with small and sharp step features in the potential (and sound speed) of the inflaton field, in the context of the Effective Field Theory of Inflation. This approach allows us to study the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Nicola Bartolo , Dario Cannone , Sabino Matarrese

In this work, we investigate the post-inflationary dynamics of a simple single-field model with a renormalizable inflaton potential featuring a near-inflection point at a field value $\phi_0$. Due to the concave shape of the scalar…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-24 Manuel Drees , Chenhuan Wang