scholarly journals EARLY UNIVERSE SOURCES FOR CMB NON-GAUSSIANITY

2002 ◽  
Vol 17 (29) ◽  
pp. 4273-4280
Author(s):  
ALEJANDRO GANGUI
Keyword(s):  
Power Spectrum ◽  
Cosmic Microwave Background ◽  
Early Universe ◽  
Microwave Background ◽  
Scale Invariant ◽  
Invariant Model ◽  
Primordial Power Spectrum ◽  
Initial States ◽  
Non Gaussian ◽  
Inflationary Models

In the framework of inflationary models with non-vacuum initial states for cosmological perturbations, we study non-Gaussian signatures on the cosmic microwave background (CMB) radiation produced by a broken-scale-invariant model which incorporates a feature at a privileged scale in the primordial power spectrum.

scholarly journals Cosmic Strings and Their Induced Non-Gaussianities in the Cosmic Microwave Background

2010 ◽  
Vol 2010 ◽  
pp. 1-28 ◽  
Author(s):  
Christophe Ringeval
Keyword(s):  
Power Spectrum ◽  
Cosmic Microwave Background ◽  
Early Universe ◽  
Cosmic Strings ◽  
Point Function ◽  
Microwave Background ◽  
Angular Power Spectrum ◽  
Gravitational Perturbations ◽  
The One ◽  
Non Gaussian

Motivated by the fact that cosmological perturbations of inflationary quantum origin were born Gaussian, the search for non-Gaussianities in the cosmic microwave background (CMB) anisotropies is considered as the privileged probe of nonlinear physics in the early universe. Cosmic strings are active sources of gravitational perturbations and incessantly produce non-Gaussian distortions in the CMB. Even if, on the currently observed angular scales, they can only contribute a small fraction of the CMB angular power spectrum, cosmic strings could actually be the main source of its non-Gaussianities. In this paper, after having reviewed the basic cosmological properties of a string network, we present the signatures Nambu-Goto cosmic strings would induce in various observables ranging from the one-point function of the temperature anisotropies to the bispectrum and trispectrum. It is shown that string imprints are significantly different than those expected from the primordial type of non-Gaussianity and could therefore be easily distinguished.

scholarly journals PRISM: Sparse recovery of the primordial spectrum from WMAP9 and Planck datasets

2014 ◽  
Vol 10 (S306) ◽  
pp. 60-63
Author(s):  
P. Paykari ◽  
F. Lanusse ◽  
J.-L. Starck ◽  
F. Sureau ◽  
J. Bobin
Keyword(s):  
Inverse Problem ◽  
Power Spectrum ◽  
Structure Formation ◽  
Simulated Data ◽  
Inversion Method ◽  
Formation Mechanisms ◽  
Parametric Approach ◽  
Microwave Background ◽  
Scale Invariant ◽  
Primordial Power Spectrum

AbstractThe primordial power spectrum is an indirect probe of inflation or other structure-formation mechanisms. We introduce a new method, named PRISM, to estimate this spectrum from the empirical cosmic microwave background (CMB) power spectrum. This is a sparsity-based inversion method, which leverages a sparsity prior on features in the primordial spectrum in a wavelet dictionary to regularise the inverse problem. This non-parametric approach is able to reconstruct the global shape as well as localised features of the primordial spectrum accurately and proves to be robust for detecting deviations from the currently favoured scale-invariant spectrum. We investigate the strength of this method on a set of WMAP nine-year simulated data for three types of primordial spectra and then process the WMAP nine-year data as well as the Planck PR1 data. We find no significant departures from a near scale-invariant spectrum.

EFFECTS OF PRIMORDIAL MAGNETIC FIELD ON EARLY UNIVERSE

2008 ◽  
Vol 23 (17n20) ◽  
pp. 1695-1706 ◽  
Author(s):  
DAI G. YAMAZAKI ◽  
KIYOTOMO ICHIKI ◽  
KAJINO TOSHITAKA ◽  
GRANT J. MATHEWS
Keyword(s):  
Magnetic Field ◽  
Power Spectrum ◽  
Cosmic Microwave Background ◽  
Early Universe ◽  
Large Scale ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Microwave Background ◽  
Primordial Magnetic Field

The existence of a primordial magnetic field (PMF) would affect both the temperature and polarization anisotropies of the cosmic microwave background (CMB) and the formation of the large scale structure(LSS). It also provides a plausible explanation for the disparity between observations and theoretical fits to the CMB power spectrum and the LSS. Here we report on calculations of not only the numerical power spectrum of the PMF, but also the correlations between the PMF power spectrum and the primary curvature perturbations.

scholarly journals HIGGS BOSON IN RG RUNNING INFLATIONARY COSMOLOGY

2012 ◽  
Vol 21 (14) ◽  
pp. 1250094 ◽  
Author(s):  
YI-FU CAI ◽  
DAMIEN A. EASSON
Keyword(s):  
Higgs Boson ◽  
Power Spectrum ◽  
Higgs Mass ◽  
Hadron Collider ◽  
Higgs Sector ◽  
Inflationary Cosmology ◽  
Microwave Background ◽  
Scale Invariant ◽  
Primordial Power Spectrum ◽  
The Standard Model

An intriguing hypothesis is that gravity may be nonperturbatively renormalizable via the notion of asymptotic safety (AS). We show that the Higgs sector of the standard model (SM) minimally coupled to asymptotically safe gravity can generate the observed near scale-invariant spectrum of the Cosmic Microwave Background through the curvaton mechanism. The resulting primordial power spectrum places an upper bound (CMB) on the Higgs mass, which for finely tuned values of the curvaton parameters, is compatible with the recently released Large Hadron Collider (LHC) data.

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