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We consider the expected level of primordial non-Gaussianities in models in which density perturbations are produced by spatial fluctuations in the decay rate of the inflaton. We consider both the non-Gaussianities resulting from the…

Astrophysics · Physics 2008-11-26 Matias Zaldarriaga

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

We use the long-wavelength formalism to investigate the level of bispectral non-Gaussianity produced in two-field inflation models with standard kinetic terms. Even though the Planck satellite has so far not detected any primordial…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-17 Gabriel Jung , Bartjan van Tent

A model of multi-component hybrid inflation, dubbed multi-brid inflation, in which various observable quantities including the non-Gaussianity parameter f_{NL} can be analytically calculated was proposed recently. In particular, for a…

Astrophysics · Physics 2009-10-09 Atsushi Naruko , Misao Sasaki

We study perturbations in the multi-field axion Nflation model, taking account of the full cosine potential. We find significant differences with previous analyses which made a quadratic approximation to the potential. The tensor-to-scalar…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Soo A Kim , Andrew R Liddle , David Seery

Tensor non-Gaussianity represents an important future probe of the physics of inflation. Inspired by recent works, we elaborate further on the possibility of significant primordial tensor non-Gaussianities sourced by extra fields during…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-20 Emanuela Dimastrogiovanni , Matteo Fasiello , Gianmassimo Tasinato , David Wands

We discuss phenomenological aspects of no-scale supergravity inflationary models motivated by compactified string models, in which the inflaton may be identified either as a K\"ahler modulus or an untwisted matter field, focusing on models…

High Energy Physics - Phenomenology · Physics 2015-10-07 John Ellis , Marcos A. G. Garcia , Dimitri V. Nanopoulos , Keith A. Olive

Non-perturbative corrections and modular properties of four-dimensional type IIB Calabi-Yau orientifolds are discussed. It is shown that certain non-perturbative alpha' corrections survive in the large volume limit of the orientifold and…

High Energy Physics - Theory · Physics 2009-04-30 Thomas W. Grimm

We study the non-Gaussianity generated during multiple-field inflation. We provide an exact expression for the bispectrum parameter f_NL which is valid beyond the slow-roll regime, valid for certain classes of inflationary models. We then…

Cosmology and Nongalactic Astrophysics · Physics 2011-11-04 Christian T. Byrnes , Gianmassimo Tasinato

We study cosmological properties of type IIA compactifications on orientifolds of SU(3)-structure manifolds with non-vanishing geometric flux. These compactifications give rise to effective 4D N=1 supergravity theories that do not fall…

High Energy Physics - Theory · Physics 2009-04-17 Claudio Caviezel , Paul Koerber , Simon Kors , Dieter Lust , Timm Wrase , Marco Zagermann

Slow-roll inflation is studied as an effective field theory.We find as consistent form of the inflaton potential V(phi)=N M^4 w(phi/[sqrt{N}M_P]) where phi is the inflaton field, M the inflation energy scale, M_P the Planck mass, and N~50…

Astrophysics · Physics 2009-11-13 D. Boyanovsky , H. J. de Vega , N. G. Sanchez

The subject of this paper is the investigation of inflationary non-Gaussianities of the local type with extreme value statistics of the weak lensing convergence kappa. Specifically, we describe the influence of inflationary…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-08 Federica Capranico , Angelos Fotios Kalovidouris , Bjoern Malte Schaefer

We study cosmological inflation within a recently proposed framework of perturbative moduli stabilisation in type IIB/F theory compactifications on Calabi-Yau threefolds. The stabilisation mechanism utilises three stacks of magnetised…

High Energy Physics - Theory · Physics 2019-04-05 Ignatios Antoniadis , Yifan Chen , George K. Leontaris

We review progress made over the past couple of years in the field of Swiss Cheese Phenomenology involving a mobile space-time filling D3-brane and stack(s) of fluxed D7-branes wrapping the "big" (as opposed to the "small") divisor in (the…

High Energy Physics - Theory · Physics 2011-02-11 Aalok Misra

We present here the effective theory of inflation `a la Ginsburg-Landau in which the inflaton potential is a polynomial. The slow-roll expansion becomes a systematic 1/N expansion where N ~ 60. The spectral index and the ratio of…

Cosmology and Nongalactic Astrophysics · Physics 2010-06-24 H. J. de Vega

By introducing the small noise expansion techniques, we show that the fully nonlinear (non-Markovian) stochastic inflationary system, may be re-cast in terms of an infinite set of Wiener processes (stochastic equations with white noises).…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-02 Diego Cruces , Cristiano Germani , Amin Nassiri-Rad , Masahide Yamaguchi

We take a pragmatic, model independent approach to single field slow-roll canonical inflation by imposing conditions, not on the potential, but on the slow-roll parameter $\epsilon(\phi)$ and its derivatives $\epsilon^{\prime }(\phi)$ and…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-17 Gabriel German , Alfredo Herrera-Aguilar , Juan Carlos Hidalgo , Roberto A. Sussman

A $\delta N$ formalism is used to study the non-Gaussianity of the primordial curvature perturbation on an uniform density hypersurfaces generated by the warm inflation for the first time. After introducing the framework of the warm…

General Relativity and Quantum Cosmology · Physics 2016-04-01 Xiao-Min Zhang , Hong-Yang Ma , Peng-Cheng Chu , Jun-Ting Liu , Jian-Yang Zhu

Moduli stabilisation in superstring compactifications on Calabi-Yau orientifolds remains a key challenge in the search for realistic string vacua. In particular, odd moduli arising from the reduction of 2-forms $(B_2,C_2)$ in type IIB are…

High Energy Physics - Theory · Physics 2022-04-29 Michele Cicoli , Andreas Schachner , Pramod Shukla

We compute the amplitude of the non-Gaussianities in inflationary models with multiple, uncoupled scalar fields. This calculation thus applies to all models of assisted inflation, including N-flation, where inflation is driven by multiple…

Astrophysics · Physics 2010-10-27 Thorsten Battefeld , Richard Easther