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We develop analytic and numerical techniques for studying the statistics of slow-roll inflation in random Gaussian landscapes. As an illustration of these techniques, we analyze small-field inflation in a one-dimensional landscape. We…

High Energy Physics - Theory · Physics 2017-06-14 Ali Masoumi , Alexander Vilenkin , Masaki Yamada

Motivated by the prospect of testing inflation from precision cosmic microwave background observations, we present analytic results for scalar and tensor perturbations in single-field inflation models based on the application of uniform…

Astrophysics · Physics 2009-11-07 Salman Habib , Katrin Heitmann , Gerard Jungman , Carmen Molina-Paris

The distinctive features of single field inflationary models with non-minimal kinetic terms, like Dirac-Born-Infeld and k-inflation, can be captured by more familiar multiple field inflationary systems of the type that typically arise in…

High Energy Physics - Theory · Physics 2014-11-20 Andrew J. Tolley , Mark Wyman

We present a simple way to calculate non-Gaussianity in inflation using fully non-linear equations on long wavelengths with stochastic sources to take into account the short-wavelength quantum fluctuations. Our formalism includes both…

Astrophysics · Physics 2009-11-10 G. I. Rigopoulos , E. P. S. Shellard , B. J. W. van Tent

We obtain cosmological constraints on models of inflation which exhibit rapid roll solutions. Rapid roll attractors exist for potentials with large mass terms and are thus of interest for inflationary model building within string theory. We…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-15 Takeshi Kobayashi , Shinji Mukohyama , Brian A. Powell

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

Primordial Gravitational Waves, i.e. a background of metric perturbations sourced by the quantum inflationary fluctuations, if measured, could both provide a substantial evidence for primordial inflation and shed light on physics at…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-28 William Giarè , Fabrizio Renzi

Inflationary models with a scalar field nonminimally coupled both with the Ricci scalar and with the Gauss-Bonnet term are studied. We propose the way of generalization of inflationary scenarios with the Gauss-Bonnet term and a scalar field…

General Relativity and Quantum Cosmology · Physics 2021-07-21 Ekaterina O. Pozdeeva , Sergey Yu. Vernov

We study multifield contributions to the scalar power spectrum in an ensemble of six-field inflationary models obtained in string theory. We identify examples in which inflation occurs by chance, near an approximate inflection point, and we…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Liam McAllister , Sébastien Renaux-Petel , Gang Xu

Using the "$\delta N$-formalism", We obtain the expression of the non-Gaussianity of multiple-field inflationary models with the nontrivial field-space metric. Further, we rewritten the result by using the slow-rolling approximation.

Astrophysics · Physics 2009-11-11 C. Y. Sun , D. H. Zhang

We compute the bispectrum of primordial density perturbations in CMB to second order in the slow-roll parameters of single field inflation. We correct previous results and found that next-to-leading order corrections can be of the same…

High Energy Physics - Theory · Physics 2026-03-31 Ignatios Antoniadis , Auttakit Chatrabhuti , Jules Cunat , Hiroshi Isono

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

We introduce a frame-covariant formalism for inflation of scalar-curvature theories by adopting a differential geometric approach which treats the scalar fields as coordinates living on a field-space manifold. This ensures that our…

High Energy Physics - Phenomenology · Physics 2018-01-09 Sotirios Karamitsos , Apostolos Pilaftsis

We study the generation of primordial perturbations in a (single-field) slow-roll inflationary universe. In momentum space, these (Gaussian) perturbations are characterized by a zero mean and a non-zero variance $\Delta^2(k, t)$. However,…

High Energy Physics - Theory · Physics 2010-04-06 Ivan Agullo , Jose Navarro-Salas , Gonzalo J. Olmo , Leonard Parker

We study small field models of inflation, which, against previous expectations, yield significant Gravitational Wave (GW) signal while reproducing other measured observable quantities in the Cosmic Microwave Background (CMB). We numerically…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-01 Ira Wolfson

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 models which generate a large non-Gaussianity of the local form. We first briefly consider three models which generate the non-Gaussianity either at or after the end of inflation; the curvaton scenario, modulated (p)reheating and…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-13 Christian T. Byrnes , Ki-Young Choi

It is shown that a large class of higher-order (i.e. non-quadratic) scalar kinetic terms can, without the help of potential terms, drive an inflationary evolution starting from rather generic initial conditions. In many models, this…

High Energy Physics - Theory · Physics 2008-11-26 C. Armendariz-Picon , T. Damour , V. Mukhanov

Using the recently developed effective field theory of inflation, we argue that the size and the shape of the non-Gaussianities generated by single-field inflation are generically well described by two parameters: f_NL^equil, which…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-04 Leonardo Senatore , Kendrick M. Smith , Matias Zaldarriaga

We study a multi-field inflationary theory with separable Lagrangian, which has different speed of sound for each field. We find that the fields always coupled at perturbative level through gravitational interaction. We show that if the…

High Energy Physics - Theory · Physics 2015-05-28 Shi Pi , Du Wang