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Related papers: Localized Steps toward ACT-Favored Inflation

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We show that multi-field inflationary models with negligible turning in field space during inflation can lead to an effective sourcing of adiabatic from entropic perturbations {\it after} the end of inflation. We illustrate this general…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-08 Rodrigo Gonzalez Quaglia , Martino Michelotti , Diederik Roest , John Joseph Carrasco , Renata Kallosh , Andrei Linde

We revisit the Cosmic Microwave Background (CMB) constraints on the spatial curvature of the Universe, assessing how they change when the curvature parameter and the primordial inflationary scalar spectrum are treated consistently within…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-01 Enrico Specogna , Tatevik Vardanyan , William Giarè , Eleonora Di Valentino

We reconsider the fine-tuning problem of scalar-driven inflation arising from the need to couple the inflaton to ordinary matter in order to make reheating efficient. Quantum fluctuations of this matter induce Coleman-Weinberg corrections…

General Relativity and Quantum Cosmology · Physics 2019-11-13 S. P. Miao , S. Park , R. P. Woodard

There are many single field inflationary models that are consistent with the recent Planck 2018 measurements of the spectral index $n_s$ and tensor-to-scalar ratio $r$. Despite good agreement with observational data some of these models…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-18 Josh Hoffmann , David Sloan

We study inflationary constraints from reheating on two classes of single-field inflationary models: a generalized $\alpha$-attractor with potential $V(\phi) = V_0 \!\left(1 - \sech^p\!\left[\phi/(\sqrt{6\alpha}\,M_{Pl})\right]\right)$ and…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-26 Gabriel German , Juan Carlos Hidalgo

We study a class of minimally coupled scalar field theories which leads to analytic solutions for the Hubble rate and the scalar field, where the scalar field obeys a generalized tracking law $\dot{\phi}^2\sim H^{-m}$. The inflationary…

General Relativity and Quantum Cosmology · Physics 2026-03-17 V. K. Oikonomou

We study single-field inflationary models with steep step-like features in the potential that lead to the temporary violation of the slow-roll conditions during the evolution of the inflaton. These features enhance the power spectrum of the…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-18 I. Dalianis , G. P. Kodaxis , I. D. Stamou , N. Tetradis , A. Tsigkas-Kouvelis

We investigate the possibility of obtaining inflationary solutions of the slow roll type from a low energy Lagrangian coming from superstrings. The advantage of such an approach is that in these theories the scalar potential has only one…

High Energy Physics - Phenomenology · Physics 2009-10-28 A. De la Macorra , S. Lola

We propose a new inflation scenario in flux compactification, where a zero mode scalar field of extra components of the higher dimensional gauge field is identified with an inflaton. The scalar field is a pseudo Nambu-Goldstone boson of…

High Energy Physics - Theory · Physics 2021-10-04 Takuya Hirose , Nobuhito Maru

Recent analyses combining Atacama Cosmology Telescope (ACT) data with other cosmological datasets report a higher scalar spectral index $n_s$, creating tension with a wide range of inflationary models. Since a Gauss-Bonnet term with a…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-03 Yigan Zhu , Qing Gao , Yungui Gong , Zhu Yi

We present a comprehensive study of warm hybrid inflation within the framework of $\alpha$-attractor models, where an axionic inflaton is coupled to a waterfall field in the presence of thermal dissipation. The model is analyzed for both…

High Energy Physics - Phenomenology · Physics 2026-01-16 Waqas Ahmed , Waqar Ahmad , Ahsan Illahi , M. Junaid

Power spectra always play an important role in the theory of inflation. In particular, the ability to reproduce the galaxy matter power spectrum and the CMB temperature angular power spectrum coefficients to high accuracy is often…

General Relativity and Quantum Cosmology · Physics 2019-11-01 Herbert W. Hamber , Lu Heng Sunny Yu

Multi-field inflation can be inherently non-predictive, with the exception of models with strong attractors. In this work, we focus on models with multiple scalar fields that are non-minimally coupled to the space-time Ricci curvature…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-18 Perseas Christodoulidis , Robert Rosati , Evangelos I. Sfakianakis

We investigate models of `intermediate' inflation, where the scale factor $a(t)$ grows as $a(t) = \exp (A t^f)$, $0 < f < 1$, $A$ constant. These solutions arise as exact analytic solutions for a given class of potentials for the inflaton…

Astrophysics · Physics 2009-12-30 John D Barrow , Andrew R Liddle

There are hidden observables for inflation, such as features localized in position space, which do not manifest themselves when only one inflation trajectory is considered. To address this issue, we investigate inflation dynamics in a…

High Energy Physics - Theory · Physics 2012-10-02 Francis Duplessis , Yi Wang , Robert Brandenberger

In this article we confront both large-field and small-field sectors of mutated hilltop inflation model with the recent observational results. We begin with confrontation of predictions from mutated hilltop inflation with the joint analysis…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-17 Barun Kumar Pal

Inflation is part of the Standard Model of the Universe supported by CMB and large scale structure LSS datasets. This review presents new developments of inflation in three main chapters. (I): The effective theory of inflation a la…

Cosmology and Nongalactic Astrophysics · Physics 2011-07-13 D. Boyanovsky , C. Destri , H. J. de Vega , N. G. Sanchez

Inflationary $\alpha$-attractor models can be naturally implemented in supergravity with hyperbolic geometry. They have stable predictions for observables, such as $n_s=1-{2/ N_e} $, assuming that the potential in terms of the original…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-20 Renata Kallosh , Andrei Linde

A new shifted hybrid inflationary scenario is introduced which, in contrast to the older one, relies only on renormalizable superpotential terms. This scenario is automatically realized in a concrete extension of the "minimal"…

High Energy Physics - Phenomenology · Physics 2009-11-07 R. Jeannerot , S. Khalil , G. Lazarides

We revisit large field inflation models with modulations in light of the recent discovery of the primordial B-mode polarization by the BICEP2 experiment, which, when combined with the Planck + WP + highL data, gives a strong hint for…

Cosmology and Nongalactic Astrophysics · Physics 2014-06-27 Michael Czerny , Takeshi Kobayashi , Fuminobu Takahashi
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