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Related papers: Initial conditions for inflation

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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 make a case for setting initial conditions for inflation at the Planck epoch in the kinetically dominated regime. For inflationary potentials with a plateau or a hill, i.e. potentials that are bounded from above within a certain region…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-10 L. T. Hergt , W. J. Handley , M. P. Hobson , A. N. Lasenby

We investigate a nonsingular initial state of the Universe which leads to inflation naturally. The model is described by a scalar field with a quadratic potential in Eddington-inspired Born-Infeld gravity. The curvature of this initial…

General Relativity and Quantum Cosmology · Physics 2013-08-26 Inyong Cho , Hyeong-Chan Kim , Taeyoon Moon

We examine the class of initial conditions which give rise to inflation. Our analysis is carried out for several popular models including: Higgs inflation, Starobinsky inflation, chaotic inflation, axion monodromy inflation and…

General Relativity and Quantum Cosmology · Physics 2018-11-07 Swagat S. Mishra , Varun Sahni , Alexey V. Toporensky

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 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 effects of the non-attractor initial conditions for the canonical single-field inflation. The non-attractor stage can last only several $e$-folding numbers, and should be followed by hilltop inflation. This two-stage evolution…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-13 Yi-Fu Cai , Jinn-Ouk Gong , Dong-Gang Wang , Ziwei Wang

Inflationary $\alpha$-attractor models in supergravity, which provide excellent fits to the latest observational data, are based on the Poincare disk hyperbolic geometry. We refine these models by constructing Kahler potentials with…

High Energy Physics - Theory · Physics 2015-09-23 John Joseph M. Carrasco , Renata Kallosh , Andrei Linde

We investigate a compelling model of quintessential inflation in the context of $\alpha$-attractors, which naturally result in a scalar potential featuring two flat regions, the inflationary plateau and the quintessential tail. The…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-28 Konstantinos Dimopoulos , Leonora Donaldson Wood , Charlotte Owen

In the context of inflationary models with a pre-inflationary stage, in which the Einstein equations are obeyed, the weak energy condition is satisfied, and spacetime topology is trivial, we argue that homogeneity on super-Hubble scales…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Tanmay Vachaspati , Mark Trodden

We offer a geometric interpretation of attractor theories with singular kinetic terms as a union of multiple canonical models. We demonstrate that different domains (separated by poles) can drastically differ in their phenomenology. We…

High Energy Physics - Theory · Physics 2019-09-25 Sotirios Karamitsos

I review the present status of the problem of initial conditions for inflation and describe several ways to solve this problem for many popular inflationary models, including the recent generation of the models with plateau potentials…

High Energy Physics - Theory · Physics 2025-11-13 Andrei Linde

Studies of the initial conditions for inflation have conflicting predictions from exponential suppression to inevitability. At the level of phase space, this conflict arises from the competing intuitions of CPT invariance and…

High Energy Physics - Theory · Physics 2012-11-20 Sean Downes , Bhaskar Dutta , Kuver Sinha

Using numerical solutions of the full Einstein field equations coupled to a scalar inflaton field in 3+1 dimensions, we study the conditions under which a universe that is initially expanding, highly inhomogeneous and dominated by gradient…

High Energy Physics - Theory · Physics 2016-09-07 William E. East , Matthew Kleban , Andrei Linde , Leonardo Senatore

In this paper we investigate the induced inflation with two flat regions: one Starobinsky-like plateau in big field regime and one shorter plateau around the saddle point of the Einstein frame potential. This multi-phase inflationary…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-11 Michal Artymowski , Zygmunt Lalak , Marek Lewicki

We construct a two-stage inflationary model which can accommodate early inflation at a scale $\Lambda_1$ as well as a second stage of inflation at $\Lambda_2$ with a single scalar field $\phi$. We use a symmetric potential, valid in a…

Astrophysics · Physics 2008-11-26 G. German , A. de la Macorra

Minimal chaotic models of D-term inflation predicts too large primordial tensor perturbations. Although it can be made consistent with observations utilizing higher order terms in the K\"ahler potential, expansion is not controlled in the…

High Energy Physics - Theory · Physics 2016-05-13 Kazunori Nakayama , Ken'ichi Saikawa , Takahiro Terada , Masahide Yamaguchi

We show that the initial field values required to produce inflation in the two fields original hybrid model, and its supergravity F-term extension, do not suffer from any fine-tuning problem, even when the fields are restricted to be…

Cosmology and Nongalactic Astrophysics · Physics 2010-01-07 Sebastien Clesse , Christophe Ringeval , Jonathan Rocher

The evolution of a scalar field is explored taking into account the presence of a background fluid in a positively curved Universe in the framework of loop quantum cosmology. Though the mechanism that provides the initial conditions for…

Astrophysics · Physics 2009-11-13 N. J. Nunes

We propose an intuitive framework for studying the problem of initial conditions in slow-roll inflation. In particular, we consider a universe at high, but sub-Planckian energy density and analyze the circumstances under which it is…

High Energy Physics - Theory · Physics 2015-09-30 Lasha Berezhiani , Mark Trodden
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