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Related papers: Bispectra from two-field inflation using the long-…

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We compute the covariant three-point function near horizon-crossing for a system of slowly-rolling scalar fields during an inflationary epoch, allowing for an arbitrary field-space metric. We show explicitly how to compute its subsequent…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-10 Joseph Elliston , David Seery , Reza Tavakol

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

We derive analytical expressions for the power spectra at the end of inflation in theories with two inflaton fields and non-canonical kinetic terms. We find that going beyond the slow-roll approximation is necessary and that the nature of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Carsten van de Bruck , Mathew Robinson

We develop the path integral formalism for studying cosmological perturbations in multi-field inflation, which is particularly well suited to study quantum theories with gauge symmetries such as diffeomorphism invariance. We formulate the…

High Energy Physics - Theory · Physics 2016-08-24 Jinn-Ouk Gong , Min-Seok Seo , Gary Shiu

We investigate primordial non-Gaussianity in the Inflation without an Inflaton (IWI) framework, where scalar perturbations are generated at second order by primordial gravitational waves in Einstein gravity on an exact de Sitter (dS)…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-17 Mariam Abdelaziz , Marisol Traforetti , Daniele Bertacca , Raul Jimenez , Sabino Matarrese , Angelo Ricciardone

In this paper we investigate the inflationary phenomenology of an Einstein-Gauss-Bonnet theory compatible with the GW170817 event, by imposing the constant-roll evolution on the scalar field. We develop the constant-roll GW170817-compatible…

General Relativity and Quantum Cosmology · Physics 2020-09-15 S. D. Odintsov , V. K. Oikonomou , F. P. Fronimos , S. A. Venikoudis

We discuss the effect of superimposing multiple sources of resonant non-Gaussianity, which arise for instance in models of axion inflation. The resulting sum of oscillating shape contributions can be used to "Fourier synthesize" different…

High Energy Physics - Theory · Physics 2013-06-18 Rhiannon Gwyn , Markus Rummel , Alexander Westphal

The beta function formalism is being used to study the constant-roll inflation in the k-essence model. Assuming the second slow-roll parameter as a constant leads to a first-order differential equation for $\beta$-function which is much…

General Relativity and Quantum Cosmology · Physics 2020-05-12 Abolhassan Mohammadi , Tayeb Golanbari , Khaled Saaidi

We investigate the non-Gaussianity of primordial curvature perturbation in the modulated reheating scenario where the primordial perturbation is generated due to the spacial fluctuation of the inflaton decay rate to radiation. We use the…

Astrophysics · Physics 2008-11-26 Teruaki Suyama , Masahide Yamaguchi

Non-Gaussianity in the distribution of inflationary perturbations, measurable in statistics of the cosmic microwave background (CMB) and large scale structure fluctuations, can be used to probe non-trivial initial quantum states for these…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Joyce Byun , Nishant Agarwal , Rachel Bean , Richard Holman

We revisit the squeezed-limit non-Gaussianity in the single-field non-attractor inflation models from the viewpoint of the cosmological soft theorem. In the single-field attractor models, inflaton's trajectories with different initial…

High Energy Physics - Theory · Physics 2023-12-06 Teruaki Suyama , Yuichiro Tada , Masahide Yamaguchi

A method is presented for the unbiased numerical computation of two-particle response functions of correlated electron materials via a solution of the dynamical mean-field equations in the presence of a perturbing field. The power of the…

Strongly Correlated Electrons · Physics 2012-12-21 Nan Lin , Emanuel Gull , Andrew J. Millis

Motivated by the recent `Higgs-inflation' scenario based on a single inflaton field, we consider more generic two-field inflation with non-minimal coupling term. The generic analytic expressions are derived for cosmological observables with…

High Energy Physics - Phenomenology · Physics 2015-03-13 Jinsu Kim , Yoonbai Kim , Seong Chan Park

In previous work, two of us have proposed a model of inflationary magnetogenesis based on a rolling auxiliary field able both to account for the magnetic fields inferred by the (non) observation of gamma-rays from blazars, and to start the…

Cosmology and Nongalactic Astrophysics · Physics 2018-06-13 Chiara Caprini , Maria Chiara Guzzetti , Lorenzo Sorbo

We study the bispectrum of the primordial curvature perturbation on uniform-density hypersurfaces generated by a kind of the noncanonical warm inflation, wherein the inflation is provided by a noncanonical scalar inflaton field that is…

General Relativity and Quantum Cosmology · Physics 2015-04-09 Xiao-Min Zhang , Jian-Yang Zhu

Non-linear interactions during inflation generate non-Gaussianities in the distribution of primordial curvature. In many theories, the physics is scale-invariant, such that the induced three-point function depends solely on a dimensionless…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-27 Oliver H. E. Philcox

We study slow-roll inflation with a Gauss-Bonnet term that is coupled to an inflaton field nonminimally. We investigate the inflationary solutions for a specific type of the nonminimal coupling to the Gauss-Bonnet term and inflaton…

General Relativity and Quantum Cosmology · Physics 2014-10-08 Seoktae Koh , Bum-Hoon Lee , Wonwoo Lee , Gansukh Tumurtushaa

In this letter, we demonstrate how to use the generalized $\delta N$ formalism, which enables us to compute the evolution of all the large scale fluctuations, including gravitational waves, solely by solving the evolution of the background…

General Relativity and Quantum Cosmology · Physics 2024-08-27 Takahiro Tanaka , Yuko Urakawa

We perform a general study of the primordial scalar non-Gaussianities in multi-field inflationary models in Einstein gravity. We consider models governed by a Lagrangian which is a general function of the scalar fields and their first…

Astrophysics · Physics 2009-06-23 Xian Gao

The no-boundary wave function of quantum gravity usually assigns only very small probability to long periods of inflation. This was a reason to doubt about the no-boundary wave function to explain the observational universe. We study the…

General Relativity and Quantum Cosmology · Physics 2013-10-09 Dong-il Hwang , Soo A Kim , Bum-Hoon Lee , Hanno Sahlmann , Dong-han Yeom
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