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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

We develop a method to reconstruct the primordial power spectrum, P(k), using both temperature and polarisation data from the joint analysis of a number of Cosmic Microwave Background (CMB) observations. The method is an extension of the…

Cosmology and Nongalactic Astrophysics · Physics 2009-07-22 Gavin Nicholson , Carlo R. Contaldi

Several results on constrained spline smoothing are obtained. In particular, we establish a general result, showing how one can constructively smooth any monotone or convex piecewise polynomial function (ppf) (or any $q$-monotone ppf,…

Numerical Analysis · Mathematics 2014-04-01 K. Kopotun , D. Leviatan , A. Prymak

We present a Bayesian analysis of large-scale structure and cosmic microwave background data to constrain the form of the primordial power spectrum. We have extended the usual presumption of a scale invariant spectrum to include: (i) a…

Astrophysics · Physics 2009-11-11 M. Bridges , A. N. Lasenby , M. P. Hobson

The preferred shape for the primordial spectrum of curvature perturbations is determined by performing a Bayesian model selection analysis of cosmological observations. We first reconstruct the spectrum modelled as piecewise linear in \log…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-27 J. Alberto Vazquez , M. Bridges , M. P. Hobson , A. N. Lasenby

With the recently published Cosmic Microwave Background data from Planck we address the optimized binning of the primordial power spectrum. As an important modification to the usual binning of the primordial spectrum, along with the…

Cosmology and Nongalactic Astrophysics · Physics 2014-01-06 Dhiraj Kumar Hazra , Arman Shafieloo , George F. Smoot

We investigate the question of how tightly we can constrain the cosmological parameters by using the ``cosmic inversion'' method in which we directly reconstruct the power spectrum of primordial curvature perturbations, $P(k)$, from the…

Astrophysics · Physics 2009-10-09 Noriyuki Kogo , Misao Sasaki , Jun'ichi Yokoyama

The form of the primordial power spectrum (PPS) of cosmological scalar (matter density) perturbations is not yet constrained satisfactorily in spite of the tremendous amount of information from the Cosmic Microwave Background (CMB) data.…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-21 Benjamin L'Huillier , Arman Shafieloo , Dhiraj Kumar Hazra , George F. Smoot , Alexei A. Starobinsky

We use Bayesian inference and nested sampling to develop a non-parametric method to reconstruct the primordial power spectrum $P_{\mathcal{R}}(k)$ from Large Scale Structure (LSS) data. The performance of the method is studied by applying…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-16 G. Martínez-Somonte , A. Marcos-Caballero , E. Martínez-González , G. Cañas-Herrera

The formation of primordial black holes or other dark matter relics from amplified density fluctuations in the early universe may also generate scalar-induced gravitational waves (GW), carrying vital information about the primordial power…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-25 Aya Ghaleb , Ameek Malhotra , Gianmassimo Tasinato , Ivonne Zavala

Sudden violations of the slow-roll regime during inflation, a natural prediction of many UV-complete inflationary models, give rise to sharp features in the primordial power spectrum. At large scales, these features provide a unique window…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-05 Clément Stahl , Denis Werth , Vivian Poulin

Reconstructions of the primordial power spectrum (PPS) of curvature perturbations from cosmic microwave background anisotropies and large-scale structure data suggest that the usually assumed power-law PPS has localised features (up to…

Cosmology and Nongalactic Astrophysics · Physics 2019-10-16 Amel Durakovic , Paul Hunt , Subodh P. Patil , Subir Sarkar

We introduce a new method for reconstructing the primordial power spectrum, $P(k)$, directly from observations of the Cosmic Microwave Background (CMB). We employ Singular Value Decomposition (SVD) to invert the radiation perturbation…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Gavin Nicholson , Carlo R. Contaldi , Paniez Paykari

The basic cosmological parameters and the primordial power spectrum together completely specify predictions for the cosmic microwave background radiation anisotropy and large scale structure. Here we show how we can strongly constrain both…

Astrophysics · Physics 2010-11-30 Yun Wang , David N. Spergel , Michael A. Strauss

The classical square well potential is smoothed with a finite range smoothing function in order to get a new simple strictly finite range form for the phenomenological nuclear potential. The smoothed square well form becomes exactly zero…

Nuclear Theory · Physics 2017-08-02 Péter Salamon , Tamás Vertse

Primordial power spectra with low power at long wavelengths can alleviate lensing anomaly. However the extent to which data favours such a primordial spectra is not clear. In this work, we investigate power suppression and related…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-03 Roshna K , V. Sreenath

The primordial curvature fluctuation spectrum is reconstructed by the maximum likelihood reconstruction method using the five-year Wilkinson Microwave Anisotropy Probe data of the cosmic microwave background temperature anisotropy. We apply…

Astrophysics · Physics 2009-02-19 Ryo Nagata , Jun'ichi Yokoyama

The shape of the primordial matter power spectrum Plin(k) encodes critical information on cosmological parameters. At large scales, the observable galaxy power spectrum Pobs(k) is expected to follow the shape of Plin(k), but on smaller…

Astrophysics · Physics 2011-02-11 Jaiyul Yoo , David H. Weinberg , Jeremy L. Tinker , Zheng Zheng , Michael S. Warren

We present cosmological dark matter (DM)--only zoom-in simulations of a Milky Way analog originating from enhanced linear matter power spectra $P(k)$ relative to the standard cold, collisionless DM (CDM) cosmology. We consider a Gaussian…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-23 Ethan O. Nadler , Vera Gluscevic , Andrew Benson

We investigate a set of cosmological models for which the primordial power spectrum has a large-scale power deficit. The standard power-law spectrum is subject to long-wavelength modifications described by some new parameters, resulting in…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-13 Sandro D. P. Vitenti , Patrick Peter , Antony Valentini