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Related papers: Formalising the Slow-Roll Approximation in Inflati…

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In this work, we investigate the Higgs-Starobinsky (HS) model in the context of warm inflation scenario. The dissipative parameter as a linear form of temperature of warm inflation is considered with strong and weak regimes. We study the HS…

General Relativity and Quantum Cosmology · Physics 2022-02-10 Daris Samart , Patinya Ma-adlerd , Phongpichit Channuie

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

We investigated the evolution of the primordial density perturbations produced by inflation with thermal dissipation. A full relativistic analysis on the evolution of initial perturbations from the warm inflation era to a…

Astrophysics · Physics 2009-10-31 W. L. Lee , L. Z. Fang

Combining the stochastic and $\delta N$ formalisms, we derive non perturbative analytical expressions for all correlation functions of scalar perturbations in single-field, slow-roll inflation. The standard, classical formulas are recovered…

High Energy Physics - Theory · Physics 2016-12-01 Vincent Vennin , Alexei A. Starobinsky

We present a systematic method for evaluation of perturbation observables in non-canonical single-field inflation models within the slow-roll approximation, which allied with field redefinitions enables predictions to be established for a…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Sheng Li , Andrew R Liddle

We display some simple cosmological solutions of gravity theories with quadratic Ricci curvature terms added to the Einstein-Hilbert lagrangian which exhibit anisotropic inflation. The Hubble expansion rates are constant and unequal in…

General Relativity and Quantum Cosmology · Physics 2010-04-21 J. D. Barrow , S. Hervik

We consider a type of k-inflation under the Hamilton-Jacobi approach. We calculate various observables such as the scalar power spectrum, the tensor-to-scalar ratio, the scalar spectra index for the case where the Hubble parameter is a…

General Relativity and Quantum Cosmology · Physics 2024-06-27 Rong-Jia Yang , Ming Liu

We propose a novel mechanism for realizing slow-roll inflation that is fully consistent with observational data, based on conformal transformations acting exclusively on a complex scalar field -- without coupling to the gravitational…

High Energy Physics - Theory · Physics 2026-05-12 Kenji Ebata , So Katagiri , Yoshiki Matsuoka , Takaaki Sehara , Akio Sugamoto

We review aspects of the Hartle-Hawking no boundary geometry in the context of slow roll inflation. We give an analytic approximation to the geometry and we explain the rationale for the proposal. We also explain why it gives a prediction…

High Energy Physics - Theory · Physics 2024-10-04 Juan Maldacena

We develop a potential-independent cosmographic framework, in which cosmographic parameters are promoted to dynamical variables within a closed autonomous system. Although the cosmographic hierarchy is formally infinite, we achieve closure…

General Relativity and Quantum Cosmology · Physics 2026-05-13 Seturumane Tema , S. Shajidul Haque , Saurya Das , Peter Dunsby

We show that models of `just enough' inflation, where the slow-roll evolution lasted only $50-60$ e-foldings, feature modifications of the CMB power spectrum at large angular scales. We perform a systematic and model-independent analysis of…

High Energy Physics - Theory · Physics 2015-06-22 Michele Cicoli , Sean Downes , Bhaskar Dutta , Francisco G. Pedro , Alexander Westphal

Motivated by trans-Planckian issues in inflation, we determine the Hilbert space and amplitudes of quantum perturbations in the general low-energy effective theory of (multi-)field inflation without relying on the sub-horizon limit. The…

High Energy Physics - Theory · Physics 2026-05-29 Andrea Ambrosi de Magistris , Alberto Salvio

We investigate the accuracy of slow-roll inflation in light of current observational constraints, which do not allow for a large deviation from scale invariance. We investigate the applicability of the first and second order slow-roll…

Astrophysics · Physics 2007-05-23 Alexey Makarov

In negatively curved field spaces, inflation can be realised even in steep potentials. Hyperinflation invokes the `centrifugal force' of a field orbiting the hyperbolic plane to sustain inflation. We generalise hyperinflation by showing…

High Energy Physics - Theory · Physics 2019-05-22 Theodor Bjorkmo , M. C. David Marsh

We are on the verge of the first precision testing of the inflationary cosmology as a model for the origin of structure in the Universe. I review the key predictions of inflation which can be used as observational tests, in the sense of…

Astrophysics · Physics 2007-05-23 Andrew R Liddle

We consider Einstein-Gauss-Bonnet (EGB) inflationary models using the effective potential approach. We present evolution equations in the slow-roll regime using the effective potential and the tensor-to-scalar ratio. The choice of the…

General Relativity and Quantum Cosmology · Physics 2021-06-30 Ekaterina O. Pozdeeva

We consider slow-roll inflation for a single scalar field with an arbitrary potential and an arbitrary nonminimal coupling to the Gauss-Bonnet term. By introducing a combined hierarchy of Hubble and Gauss-Bonnet flow functions, we…

High Energy Physics - Theory · Physics 2014-11-20 Zong-Kuan Guo , Dominik J. Schwarz

We often find in the literature solutions to the Friedmann and fluid equations for simple cosmological models during the matter, radiation or cosmological constant dominated epochs. However no solutions appear for the inflationary era…

General Relativity and Quantum Cosmology · Physics 2020-07-30 Gabriel German

Seemingly unrelated models of inflation that originate from different physical setups yield, in some cases, identical predictions for the currently constrained inflationary observables. In order to classify the available models, we propose…

High Energy Physics - Phenomenology · Physics 2017-04-19 Laur Järv , Kristjan Kannike , Luca Marzola , Antonio Racioppi , Martti Raidal , Mihkel Rünkla , Margus Saal , Hardi Veermäe

We derive analytical expressions for the power spectra at the end of inflation in theories with two inflaton fields and non-canonical kinetic terms. We find that going beyond the slow-roll approximation is necessary and that the nature of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Carsten van de Bruck , Mathew Robinson