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The first year WMAP measurement of the CMB temperature anisotropy is intriguingly consistent with a larger running of the inflationary scalar spectral index than would be expected for single-field inflation. We revisit the issue of a large…

Astrophysics · Physics 2009-11-11 James M. Cline , Loison Hoi

The simplest inflationary models predict the primordial power spectrum (PPS) of curvature perturbations to be nearly scale-invariant. However, various other models of inflation predict deviations from this behaviour, motivating a…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-03 Subarna Chaki , Andrina Nicola , Alessio Spurio Mancini , Davide Piras , Robert Reischke

Using modified Richardson-Lucy algorithm we reconstruct the primordial power spectrum (PPS) from Planck Cosmic Microwave Background (CMB) temperature anisotropy data. In our analysis we use different combinations of angular power spectra…

Cosmology and Nongalactic Astrophysics · Physics 2014-12-19 Dhiraj Kumar Hazra , Arman Shafieloo , Tarun Souradeep

In this paper, inflationary cosmology is reviewed, paying particular attention to its observational signatures associated with large-scale density perturbations generated from quantum fluctuations. In the most general scalar-tensor theories…

Cosmology and Nongalactic Astrophysics · Physics 2014-06-13 Shinji Tsujikawa

The first year of observations by the Planck satellite mission shows that the cosmic microwave background (CMB) fluctuations are consistent with gaussian statistics in the primordial perturbations, a key prediction of the simplest models of…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-19 Ana Achucarro , Vicente Atal , Pablo Ortiz , Jesus Torrado

Single field inflationary models that seek to greatly enhance small scale power in order to form primordial black holes predict both a squeezed bispectrum that is enhanced by this small scale power and a potentially detectable enhancement…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-08 David Zegeye , Keisuke Inomata , Wayne Hu

The inflationary cosmology paradigm is very successful in explaining the CMB anisotropy to the percent level. Besides the dependence on the inflationary model, the power spectra, spectral tilt and non-Gaussianity of the CMB temperature…

High Energy Physics - Theory · Physics 2014-02-18 Amjad Ashoorioon , Konstantinos Dimopoulos , M. M. Sheikh-Jabbari , Gary Shiu

All single-field inflationary models invoke varying degrees of tuning in order to account for cosmological observations. Mechanisms that generate primordial black holes (PBHs) from enhancement of primordial power at small scales posit…

Cosmology and Nongalactic Astrophysics · Physics 2023-08-17 Philippa S. Cole , Andrew D. Gow , Christian T. Byrnes , Subodh P. Patil

Measuring the deviation from scale invariance of the primordial power spectrum is a critical test of inflation. In this paper we reconstruct the shape of the primordial power spectrum of curvature perturbations from the cosmic microwave…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-01 Zong-Kuan Guo , Dominik J. Schwarz , Yuan-Zhong Zhang

Detailed analyses of the WMAP data indicate possible oscillatory features in the primordial curvature perturbation, which moreover appears to be suppressed beyond the present Hubble radius. Such deviations from the usual inflationary…

Astrophysics · Physics 2014-11-18 Paul Hunt , Subir Sarkar

Cosmological inflation predicts that the scalar spectral index "runs" with scale. Constraints on the values of the spectral runnings, $\alpha_s\equiv \textrm{d} n_s/\textrm{d}\ln k$ and $\beta_s\equiv \textrm{d}\alpha_s/\textrm{d}\ln k$,…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-08 Xiaolei Li , Noah Weaverdyck , Saroj Adhikari , Dragan Huterer , Jessica Muir , Hao-Yi Wu

Inflationary models within string theory exhibit unusual scalar field dynamics involving non-minimal kinetic terms and generically referred to as k-inflation. In this situation, the standard slow-roll approach used to determine the behavior…

Cosmology and Nongalactic Astrophysics · Physics 2012-05-08 Christophe Ringeval

Inflationary cosmology has proved to be the most successful at predicting the properties of the anisotropies observed in the cosmic microwave background (CMB). In this essay we show that quantum field renormalization significantly…

General Relativity and Quantum Cosmology · Physics 2014-11-20 Ivan Agullo , Jose Navarro-Salas , Gonzalo J. Olmo , Leonard Parker

Given observations of B-mode polarization power spectrum of the cosmic microwave background (CMB), we can reconstruct power spectra of primordial tensor modes from the early Universe without assuming their functional form such as a…

Cosmology and Nongalactic Astrophysics · Physics 2018-06-20 Takashi Hiramatsu , Eiichiro Komatsu , Masashi Hazumi , Misao Sasaki

Observations of the temperature anisotropies in the Cosmic Microwave Background (CMB) radiation show that the models of inflation with the monomial potentials are inconsistent with the allowed $n_s-r$ bounds. However certain monomial…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-17 Richa Arya , Raghavan Rangarajan

Features in the primordial scalar power spectrum provide a possible roadway to describe the outliers at the low multipoles in the WMAP data. Apart from the CMB angular power spectrum, these features can also alter the matter power spectrum…

Cosmology and Nongalactic Astrophysics · Physics 2013-03-04 Dhiraj Kumar Hazra

[Abridged] As is well known, in order to generate magnetic fields of observed amplitudes during inflation, the conformal invariance of the electromagnetic field has to be broken by coupling it either to the inflaton or to the scalar…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-15 Sagarika Tripathy , Debika Chowdhury , H. V. Ragavendra , Rajeev Kumar Jain , L. Sriramkumar

Cosmological $\alpha$-attractors are a compelling class of inflationary models. They lead to universal predictions for large-scale observables, broadly independent from the functional form of the inflaton potential. In this work we derive…

Cosmology and Nongalactic Astrophysics · Physics 2023-09-21 Laura Iacconi , Matteo Fasiello , Jussi Väliviita , David Wands

If cosmic inflation suffered tiny time-dependent deviations from the slow-roll regime, these would induce the existence of small scale-dependent features imprinted in the primordial spectra, with their shapes and sizes revealing information…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-21 Sander Mooij , Gonzalo A. Palma , Grigoris Panotopoulos , Alex Soto

A possible origin of the anomalous dip and bump in the primordial power spectrum, which are reconstructed from WMAP data corresponding to the multipole $\ell=100\sim 140$ by using the inversion method, is investigated as a consequence of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Kohei Kumazaki , Shuichiro Yokoyama , Naoshi Sugiyama
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