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We study the effects of a general type of features of the inflaton potential on the spectrum and bispectrum of primordial curvature perturbations. These features correspond to a discontinuity in the $n$-th order derivative of the potential…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-25 Alexander Gallego Cadavid

Enhancements of primordial curvature fluctuations in single field inflation often involve departures from attractor trajectories in the phase space. We study enhancement/suppression of primordial fluctuations in one of the simplest models…

Cosmology and Nongalactic Astrophysics · Physics 2023-09-25 Guillem Domènech , Gerson Vargas , Teófilo Vargas

Within the $\alpha$-attractors framework we investigate scalar potentials with the same pole as the one featured in the kinetic term. We show that, in field space, this leads to directions without a plateau. Using this, we present a…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-26 Konstantinos Dimopoulos , Michal Artymowski

We study single-field inflationary models with steep step-like features in the potential that lead to the temporary violation of the slow-roll conditions during the evolution of the inflaton. These features enhance the power spectrum of the…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-18 I. Dalianis , G. P. Kodaxis , I. D. Stamou , N. Tetradis , A. Tsigkas-Kouvelis

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 study initial conditions for inflation in scenarios where the inflaton potential has a plateau shape. Such models are those most favored by Planck data and can be obtained in a large number of model classes. As a representative example,…

Cosmology and Nongalactic Astrophysics · Physics 2020-04-29 Tommi Tenkanen , Eemeli Tomberg

We present the model-independent studies of non attractor inflation in the context of effective field theory (EFT) of inflation. Within the EFT approach two independent branches of non-attractor inflation solutions are discovered in which a…

High Energy Physics - Theory · Physics 2015-08-06 Mohammad Akhshik , Hassan Firouzjahi , Sadra Jazayeri

In addition to generating the appropriate perturbation power spectrum, an inflationary scenario must take into account the need for inflation to end subsequently. In the context of single-field inflation models where inflation ends by…

Astrophysics · Physics 2009-11-10 Michaël Malquarti , Samuel M. Leach , Andrew R. Liddle

We study the generation of local non-Gaussianity in models of canonical single field inflation when their backgrounds are either attractor or non-attractor. We show that the invariance of inflation under space-time diffeomorphisms can be…

High Energy Physics - Theory · Physics 2023-04-13 Rafael Bravo , Gonzalo A. Palma

We discuss a new mechanism to enhance the spectrum of primordial tensor fluctuations in single field inflationary scenarios. The enhancement relies on a transitory non-attractor inflationary phase, which amplifies the would-be decaying…

General Relativity and Quantum Cosmology · Physics 2019-02-22 Maria Mylova , Ogan Özsoy , Susha Parameswaran , Gianmassimo Tasinato , Ivonne Zavala

We compute the non-Gaussianities that arise in single field, slow roll inflationary models arising from arbitrary homogeneous initial states, as well as subleading contributions to the power spectrum. Non Bunch-Davies vacuum initial states…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-12 Sina Bahrami , Éanna É. Flanagan

We study a simple extension of quasi-single field inflation in which the inflaton interacts with multiple extra massive scalars known as isocurvatons. Due to the breaking of time translational invariance by the inflaton background, the…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-28 Michael McAneny , Alexander K. Ridgway

Non-attractor inflation is known as the only single field inflationary scenario that can violate non-Gaussianity consistency relation with the Bunch-Davies vacuum state and generate large local non-Gaussianity. However, it is also known…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-08 Yi-Fu Cai , Xingang Chen , Mohammad Hossein Namjoo , Misao Sasaki , Dong-Gang Wang , Ziwei Wang

We show that initial conditions for small-field inflation can be determined quantum mechanically by introducing a suitable flattened region in the scalar potential. The inflaton is then driven towards the slow-roll attractor solution…

High Energy Physics - Theory · Physics 2020-11-18 Ignatios Antoniadis , Auttakit Chatrabhuti , Hiroshi Isono , Spyros Sypsas

We study the problem of initial conditions for slow-roll inflation along a plateau-like scalar potential within the framework of fluctuation-dissipation dynamics. We consider, in particular, that inflation was preceded by a…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-09 Mar Bastero-Gil , Arjun Berera , Robert Brandenberger , Ian G. Moss , Rudnei O. Ramos , Joao G. Rosa

We consider the effect of the Gibbons-Hawking radiation on the inflaton in the situation where it is coupled to a large number of spectator fields. We argue that this will lead to two important effects - a thermal contribution to the…

General Relativity and Quantum Cosmology · Physics 2018-05-03 Malcolm Fairbairn , Tommi Markkanen , David Rodriguez-Roman

We compute the amplitude of the non-Gaussianities in inflationary models with multiple, uncoupled scalar fields. This calculation thus applies to all models of assisted inflation, including N-flation, where inflation is driven by multiple…

Astrophysics · Physics 2010-10-27 Thorsten Battefeld , Richard Easther

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

We study an inflationary scenario with a two-form field to which an inflaton couples non-trivially. First, we show that anisotropic inflation can be realized as an attractor solution and that the two-form hair remains during inflation. A…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-16 Junko Ohashi , Jiro Soda , Shinji Tsujikawa

For the first time, we investigate the non-perturbative dynamics of single field inflation with a departure from slow-roll. Using simulations, we find that oscillatory features in the potential can drastically alter the course of inflation,…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-14 Angelo Caravano , Keisuke Inomata , Sébastien Renaux-Petel
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