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We propose a new class of natural inflation models based on a hidden scale invariance. In a very generic Wilsonian effective field theory with an arbitrary number of scalar fields, which exhibits scale invariance via the dilaton, the…

General Relativity and Quantum Cosmology · Physics 2016-04-20 Neil D. Barrie , Archil Kobakhidze , Shelley Liang

We consider single-field inflation in light of string-motivated "swampland" conjectures suggesting that effective scalar field theories with a consistent UV completion must have field excursion $\Delta \phi \lesssim M_{\rm Pl}$, in…

Cosmology and Nongalactic Astrophysics · Physics 2019-05-14 William H. Kinney , Sunny Vagnozzi , Luca Visinelli

We investigate the cosmological inflation in a class of supergravity models that are generalizations of non-supersymmetric $R^2$ models. Although such models have been extensively studied recently, especially after the launch of the PLANCK…

High Energy Physics - Theory · Physics 2015-06-23 G. A. Diamandis , B. C. Georgalas , K. Kaskavelis , P. Kouroumalou , A. B. Lahanas , G. Pavlopoulos

In this paper, we apply reconstruction techniques to recover the potential parameters for a particular class of single-field models, the $\alpha$-attractor (supergravity) models of inflation. This also allows to derive the inflaton vacuum…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-28 A. Di Marco , P. Cabella , N. Vittorio

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

We investigate to which extent and under which circumstances false vacuum energy ($V_0$) dominated slow-roll inflation is compatible with a large tensor-to-scalar ratio $r = O(0.1)$, as indicated by the recent BICEP2 measurement. With $V_0$…

High Energy Physics - Phenomenology · Physics 2014-10-23 Stefan Antusch , Francesco Cefala , David Nolde , Stefano Orani

Recent measurements from the Atacama Cosmology Telescope (ACT), combined with Planck and DESI data, suggest a scalar spectral index $n_s$ higher than the Planck 2018 baseline, thereby placing conventional attractor-type inflationary models…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-18 Jureeporn Yuennan , Peeravit Koad , Farruh Atamurotov , Phongpichit Channuie

Simple monomial inflationary scenarios have been ruled out by recent observations. In this work we revisit the next simplest scenario, a single--field model where the scalar potential is a polynomial of degree four which features a concave…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-14 Manuel Drees , Yong Xu

We show that embedding Natural Inflation in a more general scalar-tensor theory, with non-minimal couplings to the Ricci scalar and the kinetic term, alleviates the current tension of Natural Inflation with observational data. The coupling…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-15 Guillem Simeon

During inflation, there is a preferred reference frame in which the expansion of the background spacetime is spatially isotropic. In contrast to Minkowski spacetime, observables can depend on the velocity of the system with respect to this…

General Relativity and Quantum Cosmology · Physics 2021-02-16 Tanguy Grall , Scott Melville

We consider slow-roll inflation in the context of a modified Brans-Dicke dilaton gravity. From a two self-interacting potentials $V(\phi)$, we reproduce a Starobinsky-like potential and, commonly in syperstring models, an exponential tail…

General Relativity and Quantum Cosmology · Physics 2024-11-11 Abraão J. S. Capistrano , Gilberto M. Kremer

The measurement of the tensor-to-scalar ratio $r$ shows a very powerful constraint to theoretical inflation models through the detection of B-mode. In this paper, we propose a single inflation model with infinity pows series potential…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-11 Chao-Jun Feng , Xin-Zhou Li

We study a simple extension of Linde's hybrid inflation model, with the inflaton mass term replaced by the most general renormalizable potential for $\phi$. The unprocessed power spectrum of density perturbations can have two minima and one…

Astrophysics · Physics 2009-10-22 Yun Wang

We propose an inflationary scenario, M-flation, in which inflation is driven by three $N\times N$ hermitian matrices $\Phi_i, i=1,2,3$. The inflation potential of our model, which is strongly motivated from string theory, is constructed…

High Energy Physics - Theory · Physics 2010-10-13 Amjad Ashoorioon , Hassan Firouzjahi , M. M. Sheikh-Jabbari

Nonminimally coupled inflation models based on a nonminimal coupling $\xi \phi^{2} R$ and a $\phi^{4}$ potential are in excellent agreement with the scalar spectral index observed by Planck. Here we consider the modification of these models…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-28 Jinsu Kim , John McDonald

We reconstruct the potential of minimally coupling inflation model which produces small value of the tensor-scalar ratio. In these inflation models, tensor-scalar ratio is proportional to 1/N^2 scalar spectral index is in good agreement…

General Relativity and Quantum Cosmology · Physics 2019-04-10 Jun Chen

Here, the quartic inflationary potential $V(\phi)=\frac{\lambda}{4}\phi^4$ within a non-canonical framework characterized by a power-law Lagrangian is investigated. We demonstrate that the predictions of this model align with the Planck…

General Relativity and Quantum Cosmology · Physics 2025-05-12 Iraj Safaei , Kayoomars Karami

A simple realization of inflation consists of adding the following operators to the Einstein-Hilbert action: (partial phi)^2, lambda phi^4, and xi phi^2 R, with xi a large non-minimal coupling. Recently there has been much discussion as to…

High Energy Physics - Phenomenology · Physics 2010-12-01 Mark P. Hertzberg

We perform a Bayesian analysis for small field models of inflation, using the most recent datasets produced by Planck`18, ACTPol, and BICEP3. We employ Artificial Neural Networks (ANN) to perform analyses with model coefficients, instead of…

Cosmology and Nongalactic Astrophysics · Physics 2022-07-08 Ira Wolfson , Utkarsh Kumar , Ido Ben-Dayan , Ram Brustein

In this paper, we analyze the early-time inflation in a scalar-tensor theory of gravity where the scalar field is minimally coupled with the Gauss-Bonnet four dimensional topological invariant. The theory belongs to a class of Horndeski…

General Relativity and Quantum Cosmology · Physics 2017-12-11 Lorenzo Sebastiani , Shynaray Myrzakul , Ratbay Myrzakulov