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Related papers: Non-Gaussianities in Multi-field Inflation

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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

The generic prediction for the perturbations generated during slow--roll, single--field inflation, as they appear in the cosmic microwave background (CMB), is a flat, close--to--Gaussian spectrum. We calculate the general solution for a…

Astrophysics · Physics 2007-05-23 S. Gupta

We perform a general study of primordial scalar non-Gaussianities in single field inflationary models in Einstein gravity. We consider models where the inflaton Lagrangian is an arbitrary function of the scalar field and its first…

High Energy Physics - Theory · Physics 2009-11-11 Xingang Chen , Min-xin Huang , Shamit Kachru , Gary Shiu

In the present paper, certain inflation models are shown to have large non-Gaussianity in special cases. Namely, finite length inflation models with an effective higher derivative interaction, in which slow-roll inflation is adopted as…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-26 Shiro Hirai , Tomoyuki Takami

We consider the non-Gaussianity of the nonlinear density perturbations in a single-field inflationary model when a scalar field couples nonminimally with gravity. Gravity theories with a nonminimal coupling can be transformed into the…

Astrophysics · Physics 2007-05-23 Seoktae Koh

We consider a model of two-field inflation, containing an ordinary scalar field and a DBI field. We work beyond the slow-roll approximation, but we assume a separable Hubble parameter. We then derive the form of potential in this framework…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-25 Kourosh Nozari , Kosar Asadi

Motivated by the possibility of inflation in the cosmic landscape, which may be approximated by a complicated potential, we study the density perturbations in multi-field inflation with a random potential. The random potential causes the…

High Energy Physics - Theory · Physics 2009-04-24 S. -H. Henry Tye , Jiajun Xu , Yang Zhang

Canonical models of single-field, slow-roll inflation do not lead to appreciable non-Gaussianity, unless derivative interactions of the inflaton become uncontrollably large. We propose a novel slow-roll scenario where scalar perturbations…

High Energy Physics - Theory · Physics 2016-05-25 David Pirtskhalava , Luca Santoni , Enrico Trincherini , Filippo Vernizzi

In the context of Type IIB LARGE volume orientifold setup equipped with poly-instanton corrections, the standard single-field poly-instanton inflation driven by a 'Wilson' divisor volume modulus is generalized by the inclusion of respective…

High Energy Physics - Theory · Physics 2013-03-28 Xin Gao , Pramod Shukla

We analyze the non-Gaussianity for primordial curvature perturbations generated in multi-scalar slow-roll inflation model including the model with non-separable potential by making use of $\delta N$ formalism. Many authors have investigated…

Astrophysics · Physics 2009-06-23 Shuichiro Yokoyama , Teruaki Suyama , Takahiro Tanaka

Single field inflationary models predict nearly Gaussian initial conditions and hence a detection of non-Gaussianity would be a signature of the more complex inflationary scenarios. In this paper we study the effect on the cosmic microwave…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-02 Dmitriy Tseliakhovich , Christopher Hirata , Anze Slosar

We evaluate the dimensionless non-Gaussianity parameter $h_{_{\rm NL}}$, that characterizes the amplitude of the tensor bispectrum, numerically for a class of two field inflationary models such as double inflation, hybrid inflation and…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-26 Rathul Nath Raveendran , L. Sriramkumar

We present the model-independent studies of non attractor inflation in the context of effective field theory (EFT) of inflation. Within the EFT approach two independent branches of non-attractor inflation solutions are discovered in which a…

High Energy Physics - Theory · Physics 2015-08-06 Mohammad Akhshik , Hassan Firouzjahi , Sadra Jazayeri

We construct models of inflation with many randomly interacting fields and use these to study the generation of cosmological observables. We model the potentials as multi-dimensional Gaussian random fields (GRFs) and identify powerful…

Cosmology and Nongalactic Astrophysics · Physics 2018-02-28 Theodor Bjorkmo , M. C. David Marsh

We compute the super-Hubble evolution of non-Gaussianity of primordial curvature perturbations in two-field inflation models by employing two formalisms: delta N and covariant formalisms. Although two formalisms treat the evolution of…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 Yuki Watanabe

We compute the 3-point correlation function for a general model of inflation driven by a single, minimally coupled scalar field. Our approach is based on the numerical evaluation of both the perturbation equations and the integrals which…

Astrophysics · Physics 2010-10-27 Xingang Chen , Richard Easther , Eugene A. Lim

Theories beyond the standard model such as string theory motivate low energy effective field theories with several scalar fields which are not only coupled through a potential but also through their kinetic terms. For such theories we…

Astrophysics · Physics 2010-10-27 Ki-Young Choi , Lisa M. H. Hall , Carsten van de Bruck

This paper presents and investigates non-Gaussian perturbations for the warm k-inflation model that is driven by pure kinetic energy. The two complementary components of the overall non-Gaussianity are the three-point and four-point…

General Relativity and Quantum Cosmology · Physics 2025-11-21 Xiao-Min Zhang , Run-Qing Zhao , Yun-Cai Feng , Peng-Cheng Chu , Zhi-Peng Peng , Xi-Bin Li

The effects of a scalar field, known as the "assistant field," which nonminimally couples to gravity, on single-field inflationary models are studied. The analysis provides analytical expressions for inflationary observables such as the…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-31 Sang Chul Hyun , Jinsu Kim , Tatsuki Kodama , Seong Chan Park , Tomo Takahashi

The methods of effective field theory are used to study generic theories of inflation with a single inflaton field and to perform a general analysis of the associated non-Gaussianities. We investigate the amplitudes and shapes of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Nicola Bartolo , Matteo Fasiello , Sabino Matarrese , Antonio Riotto