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We obtain cosmological constraints on models of inflation which exhibit rapid roll solutions. Rapid roll attractors exist for potentials with large mass terms and are thus of interest for inflationary model building within string theory. We…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-15 Takeshi Kobayashi , Shinji Mukohyama , Brian A. Powell

We revisit a two-component inflaton model with a turning trajectory in the field space, where the field slowly rolls down along the trajectory. We consider the case when the effective mass in the direction perpendicular to the trajectory,…

High Energy Physics - Theory · Physics 2012-11-09 Shi Pi , Misao Sasaki

The computation of the primordial power spectrum in multi-field inflation models requires us to correctly account for all relevant interactions between adiabatic and non-adiabatic modes around and after horizon crossing. One specific…

High Energy Physics - Phenomenology · Physics 2015-03-17 Ana Achúcarro , Jinn-Ouk Gong , Sjoerd Hardeman , Gonzalo A. Palma , Subodh P. Patil

The delta N formula that relates the final curvature perturbation on comoving slices to the inflaton perturbation on flat slices after horizon crossing is a powerful and intuitive tool to compute the curvature perturbation spectrum from…

Astrophysics · Physics 2009-10-09 Hyun-Chul Lee , Misao Sasaki , Ewan D. Stewart , Takahiro Tanaka , Shuichiro Yokoyama

We assess the potential of a future large-volume photometric redshift survey to constrain observational inflationary parameters using three large-scale structure observables: the angular shear and galaxy power spectra, and the cluster mass…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-12 Tobias Basse , Jan Hamann , Steen Hannestad , Yvonne Y. Y. Wong

Precise cosmological data from WMAP and forthcoming CMB experiments motivate the study of the quantum corrections to the slowroll inflationary parameters.We find the quantum (loop) corrections to the equations of motion of the classical…

Astrophysics · Physics 2009-11-10 D. Boyanovsky , H. J. de Vega , N. G. Sanchez

A step feature in the inflaton potential can model a transient breakdown of slow-roll inflation. Here we generalize the step feature to include space-dependence, allowing it also to model a breakdown of homogeneity and isotropy. The…

Astrophysics · Physics 2010-04-15 Rose Lerner , John McDonald

Formulae are derived for the spectra of scalar curvature perturbations and gravitational waves produced during inflation, special cases of which include power law inflation, natural inflation in the small angle approximation and inflation…

General Relativity and Quantum Cosmology · Physics 2008-11-26 E. D. Stewart , D. H. Lyth

In this paper we analyze scalar gravitational perturbations on a Robertson-Walker background in the presence of multiple scalar fields that take values on a (geometrically non-trivial) field manifold during slow-roll inflation. For this…

High Energy Physics - Phenomenology · Physics 2007-05-23 S. Groot Nibbelink , B. J. W. van Tent

We investigate radiative corrections to the inflaton potential from heavy fields undergoing a fast-roll phase transition. We find that a logarithmic one-loop correction to the inflaton potential involving this field can induce a temporary…

High Energy Physics - Theory · Physics 2015-06-16 Rajeev Kumar Jain , McCullen Sandora , Martin S. Sloth

In the framework of gravitational models obtained from the Geometric Inflation's proposal, where an infinite tower of curvature scalars are included into the action, we compute the slow-roll parameters by the Hubble slow-roll approach. We…

General Relativity and Quantum Cosmology · Physics 2020-09-02 Gustavo Arciniega , Luisa Jaime , Gabriella Piccinelli

We study models of inflation where the inflaton corresponds to a flat direction in field space and its mass term is generated by gravity mediated soft supersymmetry breaking at high scale. Assuming the inflaton to have non negligible…

High Energy Physics - Phenomenology · Physics 2007-05-23 Laura Covi

Inflation is often described through the dynamics of a scalar field, slow-rolling in a suitable potential. Ultimately, this inflaton must be identified as the expectation value of a quantum field, evolving in a quantum effective potential.…

High Energy Physics - Phenomenology · Physics 2021-05-11 Jens O. Andersen , Magdalena Eriksson , Anders Tranberg

We propose new slow-roll approximations for inflationary models with the Gauss-Bonnet term. We find more accurate expressions of the standard slow-roll parameters as functions of the scalar field. To check the accuracy of approximations…

General Relativity and Quantum Cosmology · Physics 2024-09-24 Ekaterina O. Pozdeeva , Maria A. Skugoreva , Alexey V. Toporensky , Sergey Yu. Vernov

The ultra-slow-roll (USR) inflationary models predict large-amplitude scalar perturbations at small scales which can lead to the primordial black hole production and scalar-induced gravitational waves. In general scalar perturbations in the…

Cosmology and Nongalactic Astrophysics · Physics 2020-04-29 Jing Liu , Zong-Kuan Guo , Rong-Gen Cai

We compute one-loop corrections to the power spectrum of the curvature perturbation in single-field slow-roll inflation arising from gravitons and inflaton interactions. The quantum corrections due to gravitons to the power spectrum of the…

Astrophysics · Physics 2011-07-13 Emanuela Dimastrogiovanni , Nicola Bartolo

We consider inflation using a class of non-canonical Lagrangians for which the modification to the kinetic term depends on the field, but not its derivatives. We generalize the standard Hubble slow roll expansion to the non-canonical case…

Astrophysics · Physics 2010-10-27 Gabriela Barenboim , William H. Kinney

In constant-roll inflation, the scalar field that drives the accelerated expansion of the Universe is rolling down its potential at a constant rate. Within this framework, we highlight the relations between the Hubble slow-roll parameters…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-08 Alexandros Karam , Luca Marzola , Thomas Pappas , Antonio Racioppi , Kyriakos Tamvakis

Usual inflation is realized with a slow rolling scalar field minimally coupled to gravity. In contrast, we consider dynamics of a scalar with a flat effective potential, conformally coupled to gravity. Surprisingly, it contains an attractor…

High Energy Physics - Theory · Physics 2008-11-26 Lev Kofman , Shinji Mukohyama

We study the slow-roll inflation models, where the inflaton slow-rolls along a trajectory whose orthogonal directions are lifted by potentials with masses of order the Hubble parameter. In these models large non-Gaussianities can be…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-06 Xingang Chen , Yi Wang