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We investigate the impact of inhomogeneous inflaton perturbations on primordial magnetic fields within the framework of generalized inflationary magnetogenesis models. Extending the Ratra model to general spacetime backgrounds, we analyze…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-28 Yu Li , Shuang Liu , Hang Wang , Yao-Chuan Wang

We provide some comments about the constraints on the inflationary models inferred from the two Swampland criteria which have been recently proposed. In particular we argue that, in the absence of any knowledge about the origin of the…

High Energy Physics - Theory · Physics 2018-11-14 Alex Kehagias , Antonio Riotto

We study the dynamics of axion-like fields in F-theory and suggest that they can serve as inflatons in models of natural inflation. The axions arise from harmonic three-forms on the F-theory compactification space and parameterize a complex…

High Energy Physics - Theory · Physics 2021-12-21 Thomas W. Grimm

We show how observations of the perturbation spectra produced during inflation may be used to constrain the parameters of general scalar-tensor theories of gravity, which include both an inflaton and dilaton field. An interesting feature of…

General Relativity and Quantum Cosmology · Physics 2016-08-24 Juan Garcia-Bellido , David Wands

We describe models of single-field inflation with small and sharp step features in the potential (and sound speed) of the inflaton field, in the context of the Effective Field Theory of Inflation. This approach allows us to study the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Nicola Bartolo , Dario Cannone , Sabino Matarrese

Using the constant-roll approach, DBI inflationary scenario will be studied and it is sought to compare the result with observational data. By considering the cosmological perturbations of the model, it is realized that some extra terms…

General Relativity and Quantum Cosmology · Physics 2020-05-12 Abolhassan Mohammadi , Tayeb Golanbari , Khaled Saaidi

Attention has been recently drawn towards models in which inflation and quintessence schemes are unified. In such `quintessential inflation' models, a unique scalar field is required to play both the role of the inflaton and of the…

High Energy Physics - Phenomenology · Physics 2016-09-06 Marco Peloso , Francesca Rosati

We examine the dynamics of inflation driven by multiple, interacting scalar fields and derive a multi field version of the Hubble slow roll expansion. We show that the properties of this expansion naturally generalize those of the single…

Astrophysics · Physics 2013-05-29 Richard Easther , John T Giblin

We consider the consistency condition for ``strong'' sustained rapid turn inflation with third order slow roll (SRRT) in two-field cosmological models with oriented scalar manifold as a geometric PDE which constrains the metric and…

High Energy Physics - Theory · Physics 2024-08-15 E. M. Babalic , C. I. Lazaroiu , V. O. Slupic

On the example of a real scalar field, an approach to quantization of non-linear fields and construction of the perturbation theory with account of spontaneous symmetry breaking is proposed. The method is based on using as the main…

General Physics · Physics 2015-07-10 Y. M. Poluektov

We study observational constraints on the assisted k-inflation models in which multiple scalar fields join an attractor characterized by an effective single field $\phi$. This effective single-field system is described by the Lagrangian…

Cosmology and Nongalactic Astrophysics · Physics 2011-05-26 Junko Ohashi , Shinji Tsujikawa

Inflationary models predict a definite, model independent, angular dependence for the three-point correlation function of $\Delta T/T$ at large angles (greater than $\sim 1^\circ$) which we calculate. The overall amplitude is model…

Astrophysics · Physics 2009-10-22 Toby Falk , Raghavan Rangarajan , Mark Srednicki

We explore the dynamics and observational predictions of the Warm Little Inflaton scenario, presently the simplest realization of warm inflation within a concrete quantum field theory construction. We consider three distinct types of scalar…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-10 Mar Bastero-Gil , Arjun Berera , Rafael Hernandez-Jimenez , Joao G. Rosa

Nongaussian statistics are a powerful discriminant between inflationary models, particularly those with noncanonical kinetic terms. Focusing on theories where the Lagrangian is an arbitrary Lorentz-invariant function of a scalar field and…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-19 Clare Burrage , Raquel H. Ribeiro , David Seery

We study the possibility that inflation is driven by a scalar field together with a vector field minimally coupled to gravity. By assuming an effective potential that incorporates both fields into the action, we explore two distinct…

General Relativity and Quantum Cosmology · Physics 2024-12-09 Manuel Gonzalez-Espinoza , Ramon Herrera

We discuss the spectrum of scalar density perturbations from warm inflation when the friction coefficient $\Gamma$ in the inflaton equation is dependent on the inflaton field. The spectral index of scalar fluctuations depends on a new…

Astrophysics · Physics 2009-11-10 Lisa M. H. Hall , Ian G. Moss , Arjun Berera

We study the linear perturbations of multi-field inflationary models governed by a Lagrangian which is a general function of the scalar fields and of a global kinetic term combining their spacetime gradients with an arbitrary field space…

High Energy Physics - Theory · Physics 2008-11-26 David Langlois , Sébastien Renaux-Petel

It has been argued that oscillatory features from spectator fields in the primordial power spectrum could be a probe of alternatives to inflation. In this work, we soften this claim by showing that the frequency and amplitude dependence of…

Cosmology and Nongalactic Astrophysics · Physics 2019-01-29 Guillem Domènech , Javier Rubio , Julius Wons

We discuss the coupled Einstein-Klein-Gordon equations for a complex scalar field with and without a quartic self-interaction in a zero curvature Friedman-Lema\^{\i}tre Universe. The complex scalar field, as well as the metric, is…

General Relativity and Quantum Cosmology · Physics 2011-04-15 D. Scialom

Starting from the problem of two fixed centres we find a simple derivation of its third integral in terms of the scalar product of the angular momenta about the two fixed centres. This is then generalised to find the general form of the…

Astrophysics · Physics 2009-11-07 Donald Lynden-Bell
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