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While detection of the "local form" bispectrum of primordial perturbations would rule out all single-field inflation models, multi-field models would still be allowed. We show that multi-field models described by the $\delta N$ formalism…

General Relativity and Quantum Cosmology · Physics 2011-07-28 Naonori S. Sugiyama , Eiichiro Komatsu , Toshifumi Futamase

We calculate the contribution of the fluctuations with the thermal origin to the inflationary nonGaussianity. We find that even a small component of radiation can lead to a large nonGaussianity. We show that this thermal nonGaussianity…

High Energy Physics - Theory · Physics 2009-12-15 Bin Chen , Yi Wang , Wei Xue

We study the level of primordial non-Gaussianity in slow-roll two-field inflation. Using an analytic formula for the nonlinear parameter f_nl in the case of a sum or product separable potential, we find that it is possible to generate…

Astrophysics · Physics 2011-07-13 Christian T. Byrnes , Ki-Young Choi , Lisa M. H. Hall

We calculate the conditions required to produce a large local trispectrum during two-field slow-roll inflation. This is done by extending and simplifying the 'heatmap' approach developed by Byrnes et al. The conditions required to generate…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-10 Joseph Elliston , Laila Alabidi , Ian Huston , David J. Mulryne , Reza Tavakol

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

The single-field consistency conditions and the local ansatz have played separate but important roles in characterizing the non-Gaussian signatures of single- and multifield inflation respectively. We explore the precise relationship…

High Energy Physics - Theory · Physics 2017-03-08 Roland de Putter , Olivier Doré , Daniel Green , Joel Meyers

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

In our previous work the nonlinearity parameter f_NL, which characterizes nongaussianity in the cosmic microwave background, was estimated for a class of inflationary models based on nonlocal field theory. These models include p-adic…

High Energy Physics - Theory · Physics 2009-08-25 Neil Barnaby , James M. Cline

We forecast the constraints on single-field inflation from the bispectrum of future high-redshift surveys such as MegaMapper. Considering non-local primordial non-Gaussianity (NLPNG), we find that current methods will yield constraints of…

Cosmology and Nongalactic Astrophysics · Physics 2023-09-06 Giovanni Cabass , Mikhail M. Ivanov , Oliver H. E. Philcox , Marko Simonovic , Matias Zaldarriaga

We briefly summarize and update a class of inflationary models from the early eighties based on a quartic (Coleman-Weinberg) potential for a gauge singlet scalar (inflaton) field. For vacuum energy scales comparable to the grand unification…

Astrophysics · Physics 2011-05-12 Q. Shafi , V. N. Senoguz

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

Many alternatives to canonical slow-roll inflation have been proposed over the years, one of the main motivations being to have a model, capable of generating observable values of non-Gaussianity. In this work, we (re-)explore the physical…

High Energy Physics - Theory · Physics 2016-07-06 David Pirtskhalava , Luca Santoni , Enrico Trincherini

Warm inflation is extended from the canonical field to the noncanonical field with a general Lagrangian density having coupling form of kinetic and potential terms. We develop the motion equation of the noncanonical inflaton field, and…

General Relativity and Quantum Cosmology · Physics 2019-01-02 Kai Li , Xiao-Min Zhang , Hong-Yang Ma , Jian-Yang Zhu

We show that theories of inflation with multiple, rapidly turning fields can generate large amounts of non-Gaussianity. We consider a general theory with two fields, an arbitrary field-space metric, and a potential that supports sustained,…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-21 Oksana Iarygina , M. C. David Marsh , Gustavo Salinas

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 effect of self-interactions of heavy scalar fields during inflation on the primordial non-Gaussianity is studied. We take a specific constant-turn quasi-single field inflation as an example. We derive an effective theory with emphasis…

High Energy Physics - Theory · Physics 2015-06-16 Jinn-Ouk Gong , Shi Pi , Misao Sasaki

The general kind noncanonical warm inflation is introduced and its total non-Gaussianity of perturbation on uniform energy density hypersurfaces is studied. The total non-Gaussianity contains two complementary parts: the three- and the…

General Relativity and Quantum Cosmology · Physics 2019-12-19 Xiao-Min Zhang , Kai Li , Hong-Yang Ma , Qian Liu , Jian-Yang Zhu

We explore the noncommutative effect on single field inflation and compare with WMAP five-year data. First, we calculate the noncommutative effect from the potential and dynamical terms, and construct the general form of modified power…

Astrophysics · Physics 2009-06-18 Hong-Guang Zhang , Jie Ren , Xin-He Meng

Current observations indicate that an inverse exponential form of the inflaton potential provides an excellent description of single-field inflation. This potential fits the SPA$+$BK$+$DESI data sets well with in the $1\sigma$ bound in the…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-03 Md. Wali Hossain

We consider a two component hybrid inflation model, in which two fields drive inflation. Our results show that this model generates an observable non-gaussian contribution to the curvature spectrum, within the limits allowed by the recent…

Astrophysics · Physics 2009-11-11 Laila Alabidi