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Generically,the classical evolution of the inflaton has a brief fast roll stage that precedes the slow roll regime. The fast roll stage leads to a purely attractive potential for the curvature and tensor perturbations (this potential is…

Astrophysics · Physics 2008-12-18 C. Destri , H. J. de Vega , N. G. Sanchez

It is well known that damped superimposed oscillations at large scales in the primordial power spectrum can be generated in both single field and two field models. In single field inflationary models, these features typically arise due to…

Cosmology and Nongalactic Astrophysics · Physics 2023-10-27 Anvy Moly Tom , Rathul Nath Raveendran

We consider the pertubative consistency of inflationary models with features with effective field theory methods. By estimating the size of one-loop contributions to the three-point function, we find the energy scale where their…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-02 Dario Cannone , Nicola Bartolo , Sabino Matarrese

We study the WKB approximation beyond leading order for cosmological perturbations during inflation. To first order in the slow-roll parameters, we show that an improved WKB approximation leads to analytical results agreeing to within 0.1%…

General Relativity and Quantum Cosmology · Physics 2008-11-26 R. Casadio , F. Finelli , M. Luzzi , G. Venturi

We compute the universal generic corrections to the power spectrum in slow-roll inflation due to unknown high-energy physics. We arrive at this result via a careful integrating out of massive fields in the "in-in" formalism yielding a…

High Energy Physics - Theory · Physics 2015-03-19 Mark G. Jackson , Koenraad Schalm

We study slow-roll inflation model controlled by the modular flavor symmetry. In the model, the modulus field plays a role of inflaton and the introduction of the stabilizer field coupled to a modular form in the superpotential produces the…

High Energy Physics - Phenomenology · Physics 2023-07-26 Yoshihiko Abe , Tetsutaro Higaki , Fumiya Kaneko , Tatsuo Kobayashi , Hajime Otsuka

The slow-roll approximation is an analytical approach to study dynamical properties of the inflationary universe. In this article, systematic construction of the slow-roll expansion for effective loop quantum cosmology is presented. The…

General Relativity and Quantum Cosmology · Physics 2017-02-01 Joanna Luc , Jakub Mielczarek

The meaning of the inflationary slow-roll approximation is formalised. Comparisons are made between an approach based on the Hamilton-Jacobi equations, governing the evolution of the Hubble parameter, and the usual scenario based on the…

Astrophysics · Physics 2009-10-22 Andrew R. Liddle , Paul Parsons , John D. Barrow

The Taylor expansion method has been used to investigate the scale dependence of the power spectrum of the curvature perturbation. In the present study, an alternative numerical method is used to clarify the $k$ dependence. Although there…

Cosmology and Nongalactic Astrophysics · Physics 2009-08-06 Shiro Hirai , Tomoyuki Takami

We calculate the scalar gravitational and matter perturbations in the context of slow-roll inflation with multiple scalar fields, that take values on a (curved) manifold, to first order in slow roll. For that purpose a basis for these…

High Energy Physics - Phenomenology · Physics 2011-10-11 S. Groot Nibbelink , B. J. W. van Tent

We construct a model of inflation based on a low-energy effective theory of spontaneously broken global scale invariance. This provides a shift symmetry that protects the inflaton potential from quantum corrections. Since the underlying…

High Energy Physics - Theory · Physics 2014-10-22 Csaba Csaki , Nemanja Kaloper , Javi Serra , John Terning

We provide a precise and quantitative holographic description of a class of inflationary slow-roll models. The dual QFT is a deformation of a three-dimensional CFT by a nearly marginal operator, which, in the models we consider, generates…

High Energy Physics - Theory · Physics 2013-08-28 Adam Bzowski , Paul McFadden , Kostas Skenderis

We extend the work of Contaldi et al. and derive analytical approximations for primordial power spectra arising from models of inflation which include primordial spatial curvature. These analytical templates are independent of any specific…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-25 Ayngaran Thavanesan , Denis Werth , Will Handley

We explore some issues in slow roll inflation in situations where field excursions are small compared to $M_p$. We argue that for small field inflation, minimizing fine tuning requires low energy supersymmetry and a tightly constrained…

High Energy Physics - Phenomenology · Physics 2015-05-30 Michael Dine , Lawrence Pack

The simplest inflationary models present us with few observable parameters to discriminate between them. A detection of features in the spectra of primordial density perturbations could provide valuable insights and lead to stringent tests…

Cosmology and Nongalactic Astrophysics · Physics 2015-01-14 J. R. Fergusson , H. F. Gruetjen , E. P. S. Shellard , M. Liguori

We study the two-field warm inflation models with a double quadratic potential and a linear temperature dependent dissipative coefficient. We derived the evolution equation of all kinds of perturbations without assuming slow-roll…

General Relativity and Quantum Cosmology · Physics 2019-05-23 Yang-yang Wang , Xiao-Min Zhang , Jian-Yang Zhu

The slow-roll approximation is the usual starting point to study the constraints imposed on the inflaton potential parameters by the observational data. We show that, for a potential exhibiting at least two extrema and giving rise to a…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Tiago Charters , Jose P. Mimoso , Ana Nunes

We consider an inflationary scenario where the rate of inflaton roll defined by $\ddot\phi/H\dot \phi$ remains constant. The rate of roll is small for slow-roll inflation, while a generic rate of roll leads to the interesting case of…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-09 Hayato Motohashi , Alexei A. Starobinsky , Jun'ichi Yokoyama

We investigate all single-field, slow-roll inflationary models whose slow-roll parameters scale as 1/N in the limit of a large number of e-folds N. We proof that all such models belong to two universality classes, characterised by a single…

High Energy Physics - Theory · Physics 2015-06-17 Diederik Roest

We consider low scale slow roll inflation driven by the gauge invariant flat directions {\bf udd} and {\bf LLe} of the Minimally Supersymmetric Standard Model at the vicinity of a saddle point of the scalar potential. We study the stability…

High Energy Physics - Phenomenology · Physics 2010-10-27 Rouzbeh Allahverdi , Kari Enqvist , Juan Garcia-Bellido , Asko Jokinen , Anupam Mazumdar