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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

The effective field theory (EFT) of cosmological perturbations is a useful framework to deal with the low-energy degrees of freedom present for inflation and dark energy. We review the EFT for modified gravitational theories by starting…

General Relativity and Quantum Cosmology · Physics 2014-11-13 Shinji Tsujikawa

There are many inflationary models in which inflaton field does not satisfy the slow-roll condition. However, in such models, it is always difficult to generate the curvature perturbation during inflation. Thus, to generate the curvature…

High Energy Physics - Phenomenology · Physics 2009-11-11 Tomohiro Matsuda

We investigate the one loop effective potential of inflation in a standard model of chaotic inflation. The leading one loop corrections to the effective inflaton potential are evaluated in the quasi de Sitter background, and we estimate the…

Astrophysics · Physics 2009-11-11 Martin S. Sloth

We consider a quasi-single field inflation model in which the inflaton interacts with a massive scalar field called the isocurvaton. Due to the breaking of time translational invariance by the inflaton background, these interactions induce…

High Energy Physics - Phenomenology · Physics 2018-06-27 Haipeng An , Michael McAneny , Alexander K. Ridgway , Mark B. Wise

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

Scattering amplitudes at weak coupling are highly constrained by Lorentz invariance, locality and unitarity, and depend on model details only through coupling constants and particle content. In this paper, we develop an understanding of…

High Energy Physics - Theory · Physics 2019-11-01 Nima Arkani-Hamed , Daniel Baumann , Hayden Lee , Guilherme L. Pimentel

Strongly non-geodesic, or rapidly turning trajectories in multifield inflation have attracted much interest recently from both theoretical and phenomenological perspectives. Most models with large turning rates in the literature are…

High Energy Physics - Theory · Physics 2022-03-09 Vikas Aragam , Roberta Chiovoloni , Sonia Paban , Robert Rosati , Ivonne Zavala

We study next-to-leading corrections to the effective action of the curvature perturbation obtained by integrating out the coupled heavy isocurvature perturbation. These corrections result from including higher order derivative operators,…

High Energy Physics - Theory · Physics 2015-03-12 Jinn-Ouk Gong , Min-Seok Seo , Spyros Sypsas

We investigate the dynamics of super-inflation in two versions of Loop Quantum Cosmology, one in which the Friedmann equation is modified by the presence of inverse volume corrections, and one in which quadratic corrections are important.…

General Relativity and Quantum Cosmology · Physics 2008-11-26 E. J. Copeland , D. J. Mulryne , N. J. Nunes , M. Shaeri

We analyze the signatures of inflationary models that are coupled to strongly interacting field theories, a basic class of multifield models also motivated by their role in providing dynamically small scales. Near the squeezed limit of the…

High Energy Physics - Theory · Physics 2015-06-12 Daniel Green , Matthew Lewandowski , Leonardo Senatore , Eva Silverstein , Matias Zaldarriaga

We investigate the accuracy of the slow-roll approximation for calculating perturbation spectra generated during inflation. The Hamilton-Jacobi formalism is used to evolve inflationary models with different histories. Models are identified…

Astrophysics · Physics 2010-10-27 Sirichai Chongchitnan , George Efstathiou

It has been shown that hybrid inflation may end with the formation of non-topological solitons of inflaton field. As a first step towards a fully realistic picture of the post-inflation era and reheating in supersymmetric hybrid inflation…

High Energy Physics - Phenomenology · Physics 2009-11-10 Matt Broadhead , John McDonald

The one-loop corrections (1LC) to the power spectrum of scalar perturbations arising from cubic interactions in the single-field E-type $\alpha$-attractor models of inflation and primordial black hole (PBH) production are numerically…

General Relativity and Quantum Cosmology · Physics 2025-05-19 Daniel Frolovsky , Sergei V. Ketov

Inflationary predictions based on the linear theory of cosmological perturbations are related to the two point function of a (second quantized) real scalar free field during the accelerated stage. Such a two point function is finite, in…

High Energy Physics - Theory · Physics 2008-11-26 F. Finelli , G. Marozzi , G. P. Vacca , G. Venturi

We elucidate the counting of the relevant small parameters in inflationary perturbation theory. Doing this allows for an explicit delineation of the domain of validity of the semi-classical approximation to gravity used in the calculation…

High Energy Physics - Theory · Physics 2018-02-21 Peter Adshead , C. P. Burgess , R. Holman , Sarah Shandera

The quantum-to-classical transition of inflationary perturbations remains an unresolved fundamental problem, and quantum decoherence is one of the promising solutions. By considering quantum perturbations during inflation as an open quantum…

General Relativity and Quantum Cosmology · Physics 2025-07-01 Zhongkai Wang , Yungui Gong

The application of Effective Field Theory (EFT) methods to inflation has taken a central role in our current understanding of the very early universe. The EFT perspective has been particularly useful in analyzing the self-interactions…

High Energy Physics - Theory · Physics 2013-04-05 Rhiannon Gwyn , Gonzalo A. Palma , Mairi Sakellariadou , Spyros Sypsas

We investigate the cosmological perturbations in generalized gravity, where the Ricci scalar and a scalar field are non-minimally coupled via an arbitrary function. In the Friedmann-Lemaitre-Robertson-Walker background, by studying the…

High Energy Physics - Theory · Physics 2009-07-30 Xiangdong Ji , Tower Wang

The nonattractor evolution in ultra-slow-roll (USR) inflation results in the amplification of superhorizon curvature perturbations and then induces a strong and detectable stochastic gravitational wave background. In this letter, we search…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-08 Bo Mu , Gong Cheng , Jing Liu , Zong-Kuan Guo