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We explore the superhorizon generation of large fnl of the local form in two field inflation. We calculate the two- and three-point observables in a general class of potentials which allow for an analytic treatment using the delta N…

Cosmology and Nongalactic Astrophysics · Physics 2011-06-17 Joel Meyers , Navin Sivanandam

Generation of large-scale magnetic fields in inflationary cosmology is studied in teleparallelism, where instead of the scalar curvature in general relativity, the torsion scalar describes the gravity theory. In particular, we investigate a…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-26 Kazuharu Bamba , Chao-Qiang Geng , Ling-Wei Luo

We introduce a self-consistent stochastic coarse-graining method, which includes both metric and scalar field fluctuations, to investigate the back reaction of long wavelength perturbations in single-scalar driven inflation, up to the…

General Relativity and Quantum Cosmology · Physics 2009-08-29 Ghazal Geshnizjani , Niayesh Afshordi

Inflation offers a simple model for very early evolution of our Universe and the origin of primordial perturbations on large scales. Over the last 25 years we have become familiar with the predictions of single-field models, but inflation…

Astrophysics · Physics 2008-11-26 David Wands

A class of solutions for phantom field corresponding to a generalized k-essence lagrangian has been presented, employing a simple method which provides the scope to explore many such. All the solutions having dynamical state parameter are…

Astrophysics · Physics 2008-11-26 Abhik Kumar Sanyal

We analyze the weak (2 sigma) evidence for a running spectral index seen in the three-year WMAP dataset and its implications for single field, slow roll inflation. We assume that the running is comparable to the central value found from the…

Astrophysics · Physics 2011-05-12 Richard Easther , Hiranya Peiris

We investigate slow-roll inflation in a multi-field random Gaussian landscape. The landscape is assumed to be small-field, with a correlation length much smaller than the Planck scale. Inflation then typically occurs in small patches of the…

High Energy Physics - Theory · Physics 2018-02-13 Ali Masoumi , Alexander Vilenkin , Masaki Yamada

We construct a chaotic inflation model in which the Higgs fields play the role of the inflaton in the standard model as well as in the singlet extension of the supersymmetric standard model. The key idea is to allow a non-canonical kinetic…

High Energy Physics - Phenomenology · Physics 2011-02-15 Kazunori Nakayama , Fuminobu Takahashi

Non-local primordial non-Gaussianity (NLPNG) is a smoking gun of interactions in single-field inflationary models, and can be written as a combination of the equilateral and orthogonal templates. We present the first constraints on these…

Cosmology and Nongalactic Astrophysics · Physics 2022-07-20 Giovanni Cabass , Mikhail M. Ivanov , Oliver H. E. Philcox , Marko Simonović , Matias Zaldarriaga

Recently we studied inflation models in which the inflaton potential is characterized by an underlying approximate global symmetry. In the first work we pointed out that in such a model curvature perturbations are generated after the end of…

Astrophysics · Physics 2008-11-26 Edward W. Kolb , Antonio Riotto , Alberto Vallinotto

Long standing themes in inflation include the issue of large field vs. small field inflation as well as the question what fraction of phase space leads to sufficient inflation, and furthermore is compatible with the experimental data. In…

High Energy Physics - Theory · Physics 2022-04-13 Rolf Schimmrigk

In this paper we derive a generic expression, which is valid for scales larger than Hubble radius and contains only the local terms, for the second order curvature perturbations for more than one field, provided the expansion is sourced by…

Astrophysics · Physics 2009-11-13 Asko Jokinen , Anupam Mazumdar

We present a simple effective field theory formulation of a general family of single field flux monodromy models for which strong coupling effects at large field values can flatten the potential and activate operators with higher powers of…

High Energy Physics - Theory · Physics 2018-09-12 Guido D'Amico , Nemanja Kaloper , Albion Lawrence

We derive semi-analytic formulae for the local bispectrum and trispectrum in general two-field inflation and provide a simple geometric recipe for building observationally allowed models with observable non-Gaussianity. We use the \delta N…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Courtney M. Peterson , Max Tegmark

We study the dynamics of inflation in a generalized scalar-torsion gravity scenario by assuming a canonical scalar field non-minimally coupled to torsion with a Galileon-type self-interaction. After obtaining the field equations for a flat…

General Relativity and Quantum Cosmology · Physics 2019-08-26 Manuel Gonzalez-Espinoza , Giovanni Otalora , Nelson Videla , Joel Saavedra

Non-abelian gauge field inflation is studied in the context of warm inflation scenario. We introduce this scenario as a mechanism that gives an end for gauge-flation model. Slow-roll parameters and perturbation parameters are presented for…

General Relativity and Quantum Cosmology · Physics 2015-06-17 M. R. Setare , V. Kamali

We review 51 models of single-field inflation, paying special attention to the possibility that self-resonance of the unstable inflaton perturbations leads to reheating. We compute Floquet exponents for the models that are consistent with…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-01 Krzysztof Turzyński , Michał Wieczorek

We consider models in which the (transverse) photon mass is non-zero during inflation and drops to zero non-adiabatically at the end of inflation. Through this process, vacuum fluctuations of the photon field are converted into physical,…

Chromo-natural inflation is a novel model of inflation which relies on the existence of non-abelian gauge fields interacting with an axion. In its simplest realization, an SU(2) gauge field is assumed to begin inflation in a rotationally…

High Energy Physics - Theory · Physics 2015-06-12 Emanuela Dimastrogiovanni , Matteo Fasiello , Andrew J. Tolley

We study the linear perturbation of the recently proposed model of inflation where a uniform gauge-kinetic coupling of the inflaton to multiple vector fields breaks the cosmic no-hair conjecture while maintaining the isotropy. We derive the…

Cosmology and Nongalactic Astrophysics · Physics 2012-10-09 Kei Yamamoto