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We consider inflationary models with the inflaton coupled to the Gauss-Bonnet term assuming a special relation $\delta_1=2\lambda\epsilon_1$ between the two slow-roll parameters $\delta_1$ and $\epsilon_1$. For the slow-roll inflation, the…

General Relativity and Quantum Cosmology · Physics 2018-10-19 Zhu Yi , Yungui Gong , Mudassar Sabir

We investigate a single field model in the context of the constant-roll inflation in which inflaton moves down to the minimum point of the potential with a constant rate of rolling. We use a quintessential inflationary model obtained by a…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-23 Mehdi Shokri , Jafar Sadeghi , Saeed Noori Gashti

A field kinetic coupling with the Einstein tensor leads to a gravitationally enhanced friction during inflation, by which even steep potentials with theoretically natural model parameters can drive cosmic acceleration. In the presence of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Shinji Tsujikawa

We provide a refined and much more simplified Einstein-Gauss-Bonnet inflationary theoretical framework, which is compatible with the GW170817 observational constraints on the gravitational wave speed. As in previous works, the constraint…

General Relativity and Quantum Cosmology · Physics 2021-09-22 V. K. Oikonomou

In this work we construct a bottom-up reconstruction technique for Loop Quantum Cosmology scalar-tensor theories, from the observational indices. Particularly, the reconstruction technique is based on fixing the functional form of the…

General Relativity and Quantum Cosmology · Physics 2018-05-02 Jaume de Haro , S. D. Odintsov , V. K. Oikonomou

In this article we present an alternative formalism for the inflationary phenomenology of rescaled Einstein-Gauss-Bonnet models which are in agreement with the GW170817 event. By constraining the propagation velocity of primordial tensor…

General Relativity and Quantum Cosmology · Physics 2023-08-01 S. D. Odintsov , V. K. Oikonomou , F. P. Fronimos

We show how short inflation naturally arises in a non-minimal gravity theory with a scalar field without any potential terms. This field drives inflation solely by its derivatives, which couple to the matter only through the combination…

High Energy Physics - Phenomenology · Physics 2010-04-05 Nemanja Kaloper

We study models of inflation where the inflaton corresponds to a flat direction in field space and its mass term is generated by gravity mediated soft supersymmetry breaking at high scale. Assuming the inflaton to have non negligible…

High Energy Physics - Phenomenology · Physics 2007-05-23 Laura Covi

We perform a precision investigation of smooth quintessential inflation in which a single canonical scalar field unifies the two known phases of cosmic acceleration. Using a CMB-normalized runaway exponential potential, we obtain sharply…

General Relativity and Quantum Cosmology · Physics 2025-11-26 Sayantan Choudhury , Swapnil Kumar Singh , Satish Kumar Sahoo

We re-examine large scalar fields within effective field theory, in particular focussing on the issues raised by their use in inflationary models (as suggested by BICEP2 to obtain primordial tensor modes). We argue that when the large-field…

High Energy Physics - Theory · Physics 2015-03-18 C. P. Burgess , M. Cicoli , F. Quevedo , M. Williams

In the context of scalar-tensor theories of gravity we compute the third-order corrected spectral indices in the slow-roll approximation. The calculation is carried out by employing the Green's function method for scalar and tensor…

General Relativity and Quantum Cosmology · Physics 2017-09-27 Alexandros Karam , Thomas Pappas , Kyriakos Tamvakis

We study a supergravity model of inflation essentially depending on one parameter which can be identified with the slope of the potential at the origin. In this type of models the inflaton rolls at high energy from negative values and a…

Astrophysics · Physics 2009-11-10 G. German , A. de la Macorra

We explore a possibility that an inflaton, which drives the cosmological inflation in the early Universe, can be detected by the recently approved FASER at the High-Luminosity LHC (HL-LHC). We consider nonminimal quartic inflation scenario…

High Energy Physics - Phenomenology · Physics 2021-04-07 Nobuchika Okada , Digesh Raut

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 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

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

For a narrow band of values of the top quark and Higgs boson masses, the Standard Model Higgs potential develops a false minimum at energies of about $10^{16}$ GeV, where primordial Inflation could have started in a cold metastable state. A…

High Energy Physics - Phenomenology · Physics 2013-05-30 Isabella Masina , Alessio Notari

Inflation occurring at energy densities less than (10$^{14}$ GeV)$^4$ produces tensor perturbations too small to be measured by cosmological surveys. However, we show that it is possible to probe low scale inflation by measuring the mass of…

High Energy Physics - Phenomenology · Physics 2016-12-14 Joseph Bramante , Jessica Cook , Antonio Delgado , Adam Martin

Inflation with plateau potentials give the best fit to the CMB observables as they predict tensor to scalar ratio stringently bounded by the observations from Planck and BICEP2/Keck. In supergravity models it is possible to obtain plateau…

High Energy Physics - Phenomenology · Physics 2016-11-09 Girish Kumar Chakravarty , Ujjal Kumar Dey , Gaetano Lambiase , Subhendra Mohanty

Quintessential inflation refers to an attempt to unify inflation and late-time cosmic acceleration using a single scalar field. In this letter we consider two different classes of quintessential inflation, one of which is based upon a…

General Relativity and Quantum Cosmology · Physics 2014-09-01 Md. Wali Hossain , R. Myrzakulov , M. Sami , Emmanuel N. Saridakis