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Related papers: Constraining Inflation

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We extend the WKB method for the computation of cosmological perturbations during inflation beyond leading order and provide the power spectra of scalar and tensor perturbations to second order in the slow-roll parameters. Our method does…

General Relativity and Quantum Cosmology · Physics 2009-11-11 R. Casadio , F. Finelli , M. Luzzi , G. Venturi

The meaning of the inflationary slow-roll approximation is formalised. Comparisons are made between an approach based on the Hamilton-Jacobi equations, governing the evolution of the Hubble parameter, and the usual scenario based on the…

Astrophysics · Physics 2009-10-22 Andrew R. Liddle , Paul Parsons , John D. Barrow

The slow-roll inflation paradigm can be systematically generalized within the framework of non-standard entropy formalisms, giving rise to a broad class of inflationary models that deviate from the conventional Bekenstein--Hawking case. We…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-26 H R M Zarandi , Esmaiel Ebrahimi , Yo Toda

We investigate the accuracy of the slow-roll approximation for calculating perturbation spectra generated during inflation. The Hamilton-Jacobi formalism is used to evolve inflationary models with different histories. Models are identified…

Astrophysics · Physics 2010-10-27 Sirichai Chongchitnan , George Efstathiou

Constant-roll inflation was recently introduced by Motohashi, Starobinsky and Yokoyama as a phenomenological way to parametrize deviations from the slow-roll scenarios. In this paper, we investigate the dynamics of both the background and…

Cosmology and Nongalactic Astrophysics · Physics 2019-05-29 Jose T. Galvez Ghersi , Alex Zucca , Andrei V. Frolov

I describe a general approach to characterizing cosmological inflation outside the standard slow-roll approximation, based on the Hamilton-Jacobi formulation of scalar field dynamics. The basic idea is to view the equation of state of the…

High Energy Physics - Phenomenology · Physics 2016-08-24 William H. Kinney

In this paper we perform a global analysis of the constraints on the inflationary parameters in the presence of dynamical dark energy models from the current observations, including the three-year Wilkinson Microwave Anisotropy Probe…

Astrophysics · Physics 2008-11-26 Jun-Qing Xia , Xinmin Zhang

We formalize the Hubble slow-roll formalism for inflationary dynamics in Randall-Sundrum Type II braneworld cosmologies, defining Hubble slow-roll parameters which can be used along with the Hamilton-Jacobi formalism. Focussing on the…

Astrophysics · Physics 2009-11-10 Erandy Ramirez , Andrew R. Liddle

The Hamilton-Jacobi approach is a powerful tool to describe super-Hubble dynamics during cosmological inflation in a non-linear way. A key assumption of this framework is to neglect anisotropic perturbations on large scales. We show that…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-15 Danilo Artigas , Emmanuel Frion , Tays Miranda , Vincent Vennin , David Wands

We develop a method to compute the slow-roll expansion for the Hubble parameter in inflationary models in a flat Friedmann-Lema\^itre-Robertson-Walker spacetime that is applicable to a wide class of potentials including monomial,…

General Relativity and Quantum Cosmology · Physics 2024-10-07 Gabriel Álvarez , Elena Medina

In this paper, an elegant mathematical approach is introduced to solve the equations of warm inflationary model without using extra approximations other than slow-roll. This important inflationary method known as Hamilton-Jacobian…

General Relativity and Quantum Cosmology · Physics 2020-04-08 R. Saleem , M. Zubair

We study the constraints on the inflationary parameter space derived from the 3 year WMAP dataset using ``slow roll reconstruction'', using the SDSS galaxy power spectrum to gain further leverage where appropriate. This approach inserts the…

Astrophysics · Physics 2011-05-12 Hiranya Peiris , Richard Easther

We study the WKB approximation beyond leading order for cosmological perturbations during inflation. To first order in the slow-roll parameters, we show that an improved WKB approximation leads to analytical results agreeing to within 0.1%…

General Relativity and Quantum Cosmology · Physics 2008-11-26 R. Casadio , F. Finelli , M. Luzzi , G. Venturi

We implement Slow Roll Reconstruction -- an optimal solution to the inverse problem for inflationary cosmology -- within ModeCode, a publicly available solver for the inflationary dynamics. We obtain up-to-date constraints on the…

Cosmology and Nongalactic Astrophysics · Physics 2012-07-10 Jorge Noreña , Christian Wagner , Licia Verde , Hiranya V. Peiris , Richard Easther

Slow-roll inflation generically makes several predictions: a flat Universe, primordial adiabatic density perturbations, and a stochastic gravity-wave background. Each inflation model will further predict specific relations between the…

Astrophysics · Physics 2007-05-23 Marc Kamionkowski

In inflation with nonminimal derivative coupling there is not a conformal transformation to the Einstein frame where calculations are straightforward, and thus in order to extract inflationary observables one needs to perform a detailed and…

General Relativity and Quantum Cosmology · Physics 2016-10-14 Haidar Sheikhahmadi , Emmanuel N. Saridakis , Ali Aghamohammadi , Khaled Saaidi

In this paper we use two methods to constrain the the canonical single-field slow-roll inflation model. The first method exploits the analytic slow-roll-parameter dependence of primordial perturbations, and the second consists of a…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-17 Jun Li , Guang-Hai Guo

We not only reconstruct the slow-roll parameters for fit to the running spectral index from WMAP three-year data in the usual slow-roll inflation model and noncommutative inflation model, but also investigate the evolution of these…

Astrophysics · Physics 2008-11-26 Qing-Guo Huang

We propose new versions of the slow-roll approximation for inflationary models with nonminimally coupled scalar fields. We derive more precise expressions for the standard slow-roll parameters as functions of the scalar field. To verify the…

General Relativity and Quantum Cosmology · Physics 2025-05-30 Ekaterina O. Pozdeeva , Maria A. Skugoreva , Alexey V. Toporensky , Sergey Yu. Vernov

Hamilton-Jacobi formalism as a powerful method is being utilized to reconsider warm inflationary scenario, where the scalar field as the main component deriving inflation interacts with other field. Separating the context to strong and weak…

General Relativity and Quantum Cosmology · Physics 2017-08-08 K. Sayar , A. Mohammadi , L. Akhtari , Kh. Saaidi
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