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The generic prediction for the perturbations generated during slow--roll, single--field inflation, as they appear in the cosmic microwave background (CMB), is a flat, close--to--Gaussian spectrum. We calculate the general solution for a…

Astrophysics · Physics 2007-05-23 S. Gupta

We obtain the non-equilibrium effective action of an inflaton like scalar field --the system-- by tracing over sub Hubble degrees of freedom of "environmental" light scalar fields. The effective action is stochastic leading to effective…

Cosmology and Nongalactic Astrophysics · Physics 2016-02-04 D. Boyanovsky

We discuss a new mechanism to enhance the spectrum of primordial tensor fluctuations in single field inflationary scenarios. The enhancement relies on a transitory non-attractor inflationary phase, which amplifies the would-be decaying…

General Relativity and Quantum Cosmology · Physics 2019-02-22 Maria Mylova , Ogan Özsoy , Susha Parameswaran , Gianmassimo Tasinato , Ivonne Zavala

We consider the pertubative consistency of inflationary models with features with effective field theory methods. By estimating the size of one-loop contributions to the three-point function, we find the energy scale where their…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-02 Dario Cannone , Nicola Bartolo , Sabino Matarrese

We investigate the reconstruction of standard and generalized Rastall gravity inflationary models, using the scalar spectral index and the Rastall parameter expressed as functions of the number of $e-$folds $N$. Within a general formalism,…

General Relativity and Quantum Cosmology · Physics 2025-12-09 Ramon Herrera , Carlos Rios

For the original hybrid inflation model, we calculate the power spectrum of curvature perturbations generated during the waterfall, taking into account the contribution of entropic modes. We study the regime where the potential is very…

General Relativity and Quantum Cosmology · Physics 2016-02-04 R. Kabir , A. Mukherjee

Chaotic inflation based on a simple monomial scalar potential, V(phi) ~ phi^p, is an attractive large-field model of inflation capable of generating a sizable tensor-to-scalar ratio r. Therefore, assuming that future CMB observations will…

High Energy Physics - Phenomenology · Physics 2014-12-24 Keisuke Harigaya , Masahiro Ibe , Kai Schmitz , Tsutomu T. Yanagida

We elucidate the counting of the relevant small parameters in inflationary perturbation theory. Doing this allows for an explicit delineation of the domain of validity of the semi-classical approximation to gravity used in the calculation…

High Energy Physics - Theory · Physics 2018-02-21 Peter Adshead , C. P. Burgess , R. Holman , Sarah Shandera

If the inflaton decays into several components during reheating, and if the corresponding decay rates are functions of spacetime-dependent quantities, it is possible to generate entropy perturbations after a stage of single-field inflation.…

Astrophysics · Physics 2007-05-23 C. Armendariz-Picon

Inflation gives rise to a nearly scale-invariant spectrum of tensor perturbations (gravitational waves), their contribution to the Cosmic Background Radiation (CBR) anisotropy depends upon the present cosmological parameters as well as…

Astrophysics · Physics 2014-10-13 Michael S. Turner , Yun Wang

The discovery of many novel realizations of the inflationary universe paradigm has led to a degeneracy problem: many different inflationary Lagrangians generate the same perturbation spectra. Resolving this problem requires the future…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-18 Damien A. Easson , Brian A. Powell

The power spectra of the scalar and tensor perturbations in the noncommutative k-inflation model are calculated in this paper. In this model, all the modes created when the stringy space-time uncertainty relation is satisfied are generated…

Cosmology and Nongalactic Astrophysics · Physics 2015-02-11 Chao-Jun Feng , Xin-Zhou Li , Dao-Jun Liu

It is well known that damped superimposed oscillations at large scales in the primordial power spectrum can be generated in both single field and two field models. In single field inflationary models, these features typically arise due to…

Cosmology and Nongalactic Astrophysics · Physics 2023-10-27 Anvy Moly Tom , Rathul Nath Raveendran

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 perform the analysis of the trispectrum of curvature perturbations generated by the interactions characterizing a general theory of single-field inflation obtained by effective field theory methods. We find that curvature-generated…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-27 Nicola Bartolo , Matteo Fasiello , Sabino Matarrese , Antonio Riotto

We investigate the warm inflationary scenario within the context of the linear version of f (Q, T ) gravity, coupled with both the inflaton scalar field and the radiation field, under the conditions of the strong dissipation regime. First,…

General Relativity and Quantum Cosmology · Physics 2024-08-14 Maryam Shiravand , Mehrdad Farhoudi , Parviz Goodarzi

We derive power spectra of the scalar- and tensor-type structures generated in an inflation model based on a massive non-minimally coupled scalar field with the strong coupling assumption. We make analyses in both the original-frame and the…

Astrophysics · Physics 2009-12-30 J. Hwang , H. Noh

We present a comprehensive analysis of inflationary models in light of projected sensitivities from forthcoming CMB and gravitational wave experiments, incorporating data from recent ACT DR6, DESI DR2, CMB-S4, LiteBIRD, and SPHEREx.…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-17 Sayantan Choudhury , Gulnur Bauyrzhan , Swapnil Kumar Singh , Koblandy Yerzhanov

The methods of effective field theory are used to study generic theories of inflation with a single inflaton field and to perform a general analysis of the associated non-Gaussianities. We investigate the amplitudes and shapes of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Nicola Bartolo , Matteo Fasiello , Sabino Matarrese , Antonio Riotto

In this work, we analyze a power-law inflationary potential enhanced with a step that can introduce features in the primordial power spectrum. We focus on the computation of the Spectral Distortions (SD) induced by these features obtained…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-27 Jorge Mastache , Wilson Barrera , Raúl Henríquez-Ortiz