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A perturbative strategy for inflation described by two-inflaton fields is developed using a mathematical analogy with the renormalization-group. Two small quantities, $\alpha$ and $\lambda$, corresponding to standard slow-roll parameters…

High Energy Physics - Theory · Physics 2025-06-10 Bohdan Grzadkowski , Marco Piva

In a previous paper I showed that a classical scalar potential with $V''/V \sim 1$ can be sufficiently flattened by quantum corrections to give rise to slow-roll inflation. In this paper I give a hybrid inflation implementation of that idea…

High Energy Physics - Phenomenology · Physics 2016-08-24 Ewan D. Stewart

We derive general analytic formulae for the power spectrum and spectral index of the curvature perturbation produced during inflation driven by a multi-component inflaton field, up to the second order in the slow-roll approximation. We do…

Astrophysics · Physics 2009-10-28 Takahiro T. Nakamura , Ewan D. Stewart

We reexamine inflation due to a constrained inflaton in the model of a complex scalar. Inflaton evolves along a spiral-like valley of special scalar potential in the scalar field space just like single field inflation. Sub-Planckian…

High Energy Physics - Phenomenology · Physics 2015-12-02 Romy H. S. Budhi , Shoichi Kashiwase , Daijiro Suematsu

Recent observations suggest that the spectral index of the primordial perturbations is very close to unity, as expected in models of slow roll inflation. It is still possible for such models to produce spectra which are scale dependent. We…

Astrophysics · Physics 2009-09-02 Scott Dodelson , Ewan Stewart

We describe a method of obtaining the inflationary potential from observations which does not use the slow-roll approximation. Rather, the microwave anisotropy spectrum is obtained directly from a parametrized potential numerically, with no…

Astrophysics · Physics 2009-12-30 Ian J Grivell , Andrew R Liddle

I show that a classical scalar potential with $ V''/V \sim 1 $ can be sufficiently flattened by quantum corrections to give rise to slow-roll inflation. This provides perhaps the simplest way to generate an inflationary potential without…

High Energy Physics - Phenomenology · Physics 2009-10-28 Ewan D. Stewart

This paper describes a general program for deriving the action of single field inflation models with nonstandard kinetic energy terms using CMBR power spectrum data. This method assumes that an action depends on a set of undetermined…

Astrophysics · Physics 2009-06-23 Christopher S. Gauthier , Ratindranath Akhoury

We consider the spectrum of primordial fluctuations produced by inflationary models where the inflaton potential is the sum of two exponential terms. A wide range of spectra result, with the only constraint being that the scalar spectrum…

Astrophysics · Physics 2009-09-25 Richard Easther

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

In this paper, we present quantitative constraints on the scalar field potential for a general class of inflationary models. (1) We first consider the reconstruction of the inflationary potential for given primordial density fluctuation…

Astrophysics · Physics 2009-10-22 Fred C. Adams , Katherine Freese

Recently, it has been claimed that inflationary models with an inflection point in the scalar potential can produce a large resonance in the power spectrum of curvature perturbation. In this paper however we show that the previous analyses…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-06 Cristiano Germani , Tomislav Prokopec

We present Monte Carlo reconstruction, a new method for ``inverting'' observational data to constrain the form of the scalar field potential responsible for inflation. This stochastic technique is based on the flow equation formalism and…

Astrophysics · Physics 2009-11-07 Richard Easther , William H. Kinney

We calculate analytically the bubble nucleation rate in a model of first order inflation which is able to produce large scale structure. The computation includes the first-order departure from the thin-wall limit, the explicit derivation of…

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 show how backreaction of the inflaton potential energy on heavy scalar fields can flatten the inflationary potential, as the heavy fields adjust to their most energetically favorable configuration. This mechanism operates in previous…

High Energy Physics - Theory · Physics 2015-03-17 Xi Dong , Bart Horn , Eva Silverstein , Alexander Westphal

Current observations indicate that an inverse exponential form of the inflaton potential provides an excellent description of single-field inflation. This potential fits the SPA$+$BK$+$DESI data sets well with in the $1\sigma$ bound in the…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-03 Md. Wali Hossain

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

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

By using the relations between the slow-roll parameters and the power spectrum for the single field slow-roll inflation, we derive the scalar spectral tilt $n_s$ and the tensor to scalar ratio $r$ for the constant slow-roll inflation and…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-06 Qing Gao