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Related papers: Troubles for observing the inflaton potential

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We derive the power spectrum $\mathcal P(k)$ of the density perturbations produced during inflation up to second-order corrections in the standard slow-roll approximation for an inflaton with more than one degree of freedom. We also present…

Astrophysics · Physics 2008-11-26 Jin-Ook Gong , Ewan D. Stewart

The inflationary paradigm enjoys a very wide acceptance in the cosmological community, due in large part to the fact that it is said to "naturally account" for a nearly scale independent power primordial spectrum of fluctuations which is in…

General Relativity and Quantum Cosmology · Physics 2011-03-28 Gabriel Leon , Daniel Sudarsky

The evolution of gauge invariant second-order scalar perturbations in a general single field inflationary scenario are presented. Different second order gauge invariant expressions for the curvature are considered. We evaluate…

General Relativity and Quantum Cosmology · Physics 2008-11-26 F. Finelli , G. Marozzi , G. P. Vacca , G. Venturi

For the constant-roll tachyon inflation, we derive the analytical expressions for the scalar and tensor power spectra, the scalar and tensor spectral tilts and the tensor to scalar ratio up to the first order by using the method of Bessel…

General Relativity and Quantum Cosmology · Physics 2018-05-03 Qing Gao , Yungui Gong , Qin Fei

We develop a variant of the generalized slow roll approach for calculating the curvature power spectrum that is well-suited for order unity deviations in power caused by sharp features in the inflaton potential. As an example, we show that…

Cosmology and Nongalactic Astrophysics · Physics 2010-07-07 Cora Dvorkin , Wayne Hu

The slow rolling inflation is dual to the random walk of conformal zero-mode. The 2 dimensional Fokker-Planck theory predicts the slow roll parameters of 4d inflation theory. The O(N) enhancements of the two point functions, N is the…

High Energy Physics - Theory · Physics 2023-05-02 Yoshihisa Kitazawa

We study inflation in a model with constant second slow-roll parameter $\eta$. In this case, the Hubble expansion rate equation has analytical solutions describing four possible, nontrivial inflation scenarios. The evolution of the inflaton…

General Relativity and Quantum Cosmology · Physics 2024-07-03 Marko Stojanovic , Neven Bilic , Dragoljub D. Dimitrijevic , Goran S. Djordjevic , Milan Milosevic

We continue to investigate properties of the strongly coupled inflaton in a setup introduced in arXiv:0807.3191 through the AdS/CFT correspondence. These properties are qualitatively different from those in conventional inflationary models.…

High Energy Physics - Theory · Physics 2011-06-15 Xingang Chen

We review the relation between the inflationary potential and the spectra of density (scalar) perturbations and gravitational waves (tensor perturbations) produced, with particular emphasis on the possibility of reconstructing the inflaton…

In this note we point out that, contrary to the standard point of view, slow roll inflation is due to high gravitational friction. We show that the requirement of slow roll coincides with the requirement of a flat scalar field potential in…

Cosmology and Nongalactic Astrophysics · Physics 2011-12-07 Cristiano Germani

We derive the spectral indices and their runnings of single inflation models by a new approach. We perform a dilatation transformation to the linear cosmological perturbations and derive a current (non-)conservation law. Using it, we…

High Energy Physics - Theory · Physics 2019-08-29 Pisin Chen , Jiro Matsumoto , Rio Saitou

We explore the inflationary phase of a scalar field with a kinetic term non-minimally coupled to gravity. We find that one of the slow-roll conditions is naturally consequence of the equation of motion of the scalar field. Thus, slow-roll…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-16 Amir Ghalee

We quantify the slow-roll corrections to primordial density perturbations arising from inflation driven by a four-dimensional scalar field with a monomial potential in a five-dimensional non-compact bulk spacetime. Although the difference…

Astrophysics · Physics 2008-11-26 Kazuya Koyama , Andrew Mennim , David Wands

The viability of slow-roll approximation is examined by considering the structure of phase spaces in scalar-tensor theories of gravitation and the analysis is exemplified with a nonminimally coupled scalar field to the spacetime curvature.…

General Relativity and Quantum Cosmology · Physics 2020-07-22 Kemal Akın , A. Savaş Arapoğlu , A. Emrah Yükselci

I generalize the inflationary flow equations of Hoffman and Turner to arbitrary order in slow roll. This makes it possible to study the predictions of slow roll inflation in the full observable parameter space of tensor/scalar ratio $r$,…

Astrophysics · Physics 2009-11-07 William H. Kinney

In single-field inflation, violation of the slow-roll approximation can lead to growth of curvature perturbation outside the horizon. This violation is characterized by a period with a large negative value of the second slow-roll parameter.…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-11 Jason Kristiano , Jun'ichi Yokoyama

Slow-roll inflation can be studied as an effective field theory. The form of the inflaton potential consistent with the data is V(phi) = N M^4 w(phi/[sqrt{N} M_{Pl}]) where phi is the inflaton field, M is the inflation energy scale, and N ~…

Astrophysics · Physics 2007-05-23 D. Boyanovsky , H. J. de Vega , N. G. Sanchez

If a coupling between the inflaton and the Gauss-Bonnet term is introduced, many models of inflation that were ruled out by the most recent Planck data can be made viable again. The predictions for the scalar spectral index and…

General Relativity and Quantum Cosmology · Physics 2025-04-22 Kamil Mudrunka , Kazunori Nakayama

One method to reconstruct the scalar field potential of inflation is a perturbative approach, where the values of the potential and its derivatives are calculated as an expansion in departures from the slow-roll approximation. They can then…

Astrophysics · Physics 2013-11-13 Edmund Copeland , Edward W. Kolb , Andrew R. Liddle , James E. Lidsey

Slow-roll inflation is studied as an effective field theory.We find as consistent form of the inflaton potential V(phi)=N M^4 w(phi/[sqrt{N}M_P]) where phi is the inflaton field, M the inflation energy scale, M_P the Planck mass, and N~50…

Astrophysics · Physics 2009-11-13 D. Boyanovsky , H. J. de Vega , N. G. Sanchez