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We study the primordial density perturbations and non-Gaussianities generated from the combined effects of an inhomogeneous end of inflation and curvaton decay in hybrid inflation. This dual role is played by a single isocurvature field…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Hooshyar Assadullahi , Hassan Firouzjahi , Mohammad Hossein Namjoo , David Wands

In this paper we study the non-Gaussian features of the primordial fluctuations in loop quantum cosmology with the inverse volume corrections. The detailed analysis is performed in the single field slow-roll inflationary models. However,…

General Relativity and Quantum Cosmology · Physics 2012-09-25 Li-Fang Li , Rong-Gen Cai , Zong-Kuan Guo , Bin Hu

We consider the UV-protected inflation, where the inflaton potential is obtained by quantum (one-loop) breaking of a global symmetry into a discrete symmetry. In this model, all coupling scales are sub-Planckian. This is achieved by…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-09 Cristiano Germani , Yuki Watanabe

We present a method for the study of second-order superhorizon perturbations in multi field inflationary models with non trivial kinetic terms. We utilise a change of coordinates in field space to separate isocurvature and adiabatic…

Astrophysics · Physics 2008-11-26 Gerasimos Rigopoulos

We study the impact of (generalized) cuscuton models on standard single scalar field inflation. Generalized cuscuton models are characterized by spatial covariant gravity where a scalar degree of freedom is made non dynamical, and there are…

General Relativity and Quantum Cosmology · Physics 2022-05-10 Nicola Bartolo , Alexander Ganz , Sabino Matarrese

We study the non-Gaussianity and secondary Gravitational Waves (GWs) in the process of the Primordial Black Holes (PBHs) production from inflation. In our work, we focus on the $\alpha$-attractor inflation model in which a tiny bump in the…

General Relativity and Quantum Cosmology · Physics 2022-08-31 Kazem Rezazadeh , Zeinab Teimoori , Saeid Karimi , Kayoomars Karami

We consider inflation as an effective field theory and study the effects of the addition to the Lagrangian of irrelevant operators with higher powers of first derivatives on its dynamics and observables. We find that significant deviations…

High Energy Physics - Theory · Physics 2017-08-11 Francisco G. Pedro

We explore extensions of hybrid inflationary models in the context of supersymmetric D-term inflation. We point out that a large variety of inflationary scenarios can be encountered when the field content is extended. It is not only…

High Energy Physics - Phenomenology · Physics 2008-11-26 Francis Bernardeau , Tristan Brunier

Most of the inflationary models that are in agreement with the Planck data rely on the presence of non-renormalizable operators. If the connection to low energy particle physics is made, the renormalization group (RG) introduces a…

High Energy Physics - Phenomenology · Physics 2020-10-28 Jacopo Fumagalli , Marieke Postma , Melvin van den Bout

The strongest non-Gaussianity in single-scalar potential models of inflation is associated with features in the power spectrum. We stress the importance of accurately modelling the expected signal in order for the standard estimator to…

General Relativity and Quantum Cosmology · Physics 2019-09-25 S. Basu , D. J. Brooker , N. C. Tsamis , R. P. Woodard

We study the non-Gaussianities generated by light axions, or compact scalar fields, during inflation. To correctly calculate their impact on primordial statistics, we will argue that it is necessary to account for the periodicity, or gauge…

High Energy Physics - Theory · Physics 2025-10-28 Priyesh Chakraborty

We use the long-wavelength formalism to compute the bispectral non-Gaussianity produced in two-field inflation. We find an exact result that is used as the basis of numerical studies, and an explicit analytical slow-roll expression for…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Eleftheria Tzavara , Bartjan van Tent

We conduct a thorough study of the comoving curvature perturbation $\mathcal{R}$ in single-field inflation with two stages, represented by a piecewise quadratic potential, where both the first and second derivatives are allowed to be…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-23 Xinpeng Wang , Xiao-Han Ma , Misao Sasaki

We study the impact of higher dimension operators in the inflaton Lagrangian on the non-gaussianity of the scalar spectrum. These terms can strongly enhance the effect without spoiling slow-roll, though it is difficult to exceed f_NL ~ 1,…

Astrophysics · Physics 2011-05-05 Paolo Creminelli

We interpret cosmological evolution holographically as a renormalisation group flow in a dual Euclidean field theory, as suggested by the conjectured dS/CFT correspondence. Inflation is described by perturbing around the infra-red fixed…

High Energy Physics - Theory · Physics 2009-11-07 Finn Larsen , Jan Pieter van der Schaar , Robert G. Leigh

We carry out a numerical calculation of the bispectrum in generalised trajectories of canonical, single--field inflation. The trajectories are generated in the Hamilton-Jacobi (HJ) formalism based on Hubble Slow Roll (HSR) parameters. The…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Jonathan S. Horner , Carlo R. Contaldi

In this work we generalize a previously developed semiclassical approach to inflation, devoted to the analysis of the effective dynamics of coarse-grained fields, which are essential to the stochastic approach to inflation. We consider…

General Relativity and Quantum Cosmology · Physics 2011-07-19 H. Casini , R. Montemayor , P. Sisterna

We show that a perturbed inflationary spacetime, driven by a canonical single scalar field, is invariant under a special class of coordinate transformations together with a field reparametrization of the curvature perturbation in co-moving…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-15 Rafael Bravo , Sander Mooij , Gonzalo A. Palma , Bastián Pradenas

We study the analytic properties of tree-level wavefunction coefficients in quasi-de Sitter space. We focus on theories which spontaneously break dS boost symmetries and can produce significant non-Gaussianities. The corresponding…

High Energy Physics - Theory · Physics 2021-12-15 David Meltzer

We calculate one-loop correction to the two-point functions of curvature perturbation in single-field inflation generated by cubic self-interaction. Incorporating the observed red-tilted spectrum of curvature perturbation, the relevant…

High Energy Physics - Theory · Physics 2022-07-05 Jason Kristiano , Jun'ichi Yokoyama
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