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In models like axion monodromy, temporal features during inflation which are not associated with its ending can produce scalar, and to a lesser extent, tensor power spectra where deviations from scale-free power law spectra can be as large…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-31 Hayato Motohashi , Wayne Hu

We extend the WKB method for the computation of cosmological perturbations during inflation beyond leading order and provide the power spectra of scalar and tensor perturbations to second order in the slow-roll parameters. Our method does…

General Relativity and Quantum Cosmology · Physics 2009-11-11 R. Casadio , F. Finelli , M. Luzzi , G. Venturi

In this paper we perform a global analysis of the constraints on the inflationary parameters in the presence of dynamical dark energy models from the current observations, including the three-year Wilkinson Microwave Anisotropy Probe…

Astrophysics · Physics 2008-11-26 Jun-Qing Xia , Xinmin Zhang

Suppression of the scalar power spectrum on large scales is one way to reconcile the tension between Planck and BICEP2 data. This suppression can occur by introducing a phase transition from the fast-roll phase to the slow-roll phase in a…

General Relativity and Quantum Cosmology · Physics 2015-03-25 Seyen Kouwn , O-Kab Kwon , Phillial Oh

Amongst the multitude of inflationary models currently available, models that lead to features in the primordial scalar spectrum are drawing increasing attention, since certain features have been found to provide a better fit to the CMB…

Cosmology and Nongalactic Astrophysics · Physics 2013-04-30 Moumita Aich , Dhiraj Kumar Hazra , L. Sriramkumar , Tarun Souradeep

Last year we argued that if slow-roll inflation followed the decay of a false vacuum in a large landscape, the steepening of the scalar potential between the inflationary plateau and the barrier generically leads to a potentially observable…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Raphael Bousso , Daniel Harlow , Leonardo Senatore

Using a principal component (PC) basis that accommodates order unity features in the slow roll parameters as fine as 1/10 of a decade across more than 2 decades of the inflationary expansion, we test slow roll and single field inflation…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-29 Cora Dvorkin , Wayne Hu

We point out that the inclusion of a string component contributing around 5% to the CMB power spectrum amplitude on large scales can increase the preferred value of the spectral index n_s of density fluctuations measured by CMB experiments.…

Astrophysics · Physics 2009-11-11 Richard A. Battye , Bjorn Garbrecht , Adam Moss

The spectrum of primordial fluctuations from inflation can be obtained using a mathematically controlled, and systematically extendable, uniform approximation. Closed-form expressions for power spectra and spectral indices may be found…

Measurements of CMB temperature fluctuations by the Wilkinson Microwave Anisotropy Probe (WMAP) indicate that the fluctuation amplitude in one half of the sky differs from the amplitude in the other half. We show that such an asymmetry…

Astrophysics · Physics 2008-12-30 Adrienne L. Erickcek , Marc Kamionkowski , Sean M. Carroll

We study the back-reaction of moduli fields on the inflaton potential in generic models of F-term inflation. We derive the moduli corrections as a power series in the ratio of Hubble scale and modulus mass. The general result is illustrated…

High Energy Physics - Theory · Physics 2015-06-19 Wilfried Buchmuller , Clemens Wieck , Martin Wolfgang Winkler

We present a semi--analytic exploration of some low--$\ell$ angular power spectra inspired by "Brane Supersymmetry Breaking". This mechanism splits Bose and Fermi excitations in String Theory, leaving behind an exponential potential that is…

High Energy Physics - Theory · Physics 2015-08-26 N. Kitazawa , A. Sagnotti

We constrain cosmological models where the primordial perturbations have both an adiabatic and a (possibly correlated) cold dark matter (CDM) or baryon isocurvature component. We use both a phenomenological approach, where the primordial…

Cosmology and Nongalactic Astrophysics · Physics 2012-07-09 Jussi Valiviita , Matti Savelainen , Marianne Talvitie , Hannu Kurki-Suonio , Stanislav Rusak

[Abridged] A variety of model-dependent as well as model-independent approaches suggest that certain localized features in the primordial scalar power spectrum can lead to a significantly better fit to the observed anisotropies in the…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-16 Alipriyo Hoory , Dhiraj Kumar Hazra , L. Sriramkumar

Slow-roll inflationary scenario is considered in non-canonical scalar field model supposing a power-law function for kinetic term, and using two formalisms. In the first approach, the potential is considered as a power-law function, that is…

General Relativity and Quantum Cosmology · Physics 2017-08-15 Kh. Saaidi , A. Mohammadi , T. Golanbari

We provide the latest constraints on the power spectra of both scalar and tensor perturbations from the CMB data (including \textit{Planck}~2015, BICEP2 \& \textit{Keck Array} experiments) and the new BAO scales from SDSS-III BOSS…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-20 Qing-Guo Huang , Ke Wang , Sai Wang

Using the constant-roll approach, DBI inflationary scenario will be studied and it is sought to compare the result with observational data. By considering the cosmological perturbations of the model, it is realized that some extra terms…

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

We discuss ability of the harmonic pattern of peaks in the CMB angular power spectrum to test inflation. By studying robust features of alternate models, which must all be isocurvature in nature, we reveal signatures unique to inflation.…

Astrophysics · Physics 2007-05-23 Martin White , Wayne Hu

We are interested on studing various inflationary spectrum perturbation parameters in the context of the Randall-Sandrum type 2 Braneworld model. We consider in particular three types of potentials. We apply the slow-roll approximation in…

High Energy Physics - Theory · Physics 2015-06-03 R. Zarrouki , Z. Sakhi , M. Bennai

We revisit the Cosmic Microwave Background (CMB) constraints on the spatial curvature of the Universe, assessing how they change when the curvature parameter and the primordial inflationary scalar spectrum are treated consistently within…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-01 Enrico Specogna , Tatevik Vardanyan , William Giarè , Eleonora Di Valentino