scholarly journals Polarized CMB: Reionization and Primordial Tensor Modes

2005 ◽  
Vol 216 ◽  
pp. 51-58
Author(s):  
Asantha Cooray
Keyword(s):  
Gravitational Waves ◽  
Optical Depth ◽  
Electron Scattering ◽  
Wave Polarization ◽  
Microwave Background ◽  
Grand Unified Theories ◽  
Experimental Parameters ◽  
Unified Theories ◽  
Cmb Polarization ◽  
Density Perturbations

We discuss upcoming opportunities with cosmic microwave background (CMB) observations during the post-WMAP era. The curl-modes of CMB polarization probe inflationary gravitational waves (IGWs). While a significant source of confusion is expected from cosmic shear conversion of polarization related to density perturbations, higher resolution observations of CMB anisotropies can be used for a lensing reconstruction and to separate gravitational-wave polarization signature from that of lensing. Separations based on current lensing reconstruction techniques allow the possibility to probe inflationary energy scales below 1015 GeV in a range that includes grand unified theories. The observational detection of primordial curl-modes is aided by rescattering at late times during the reionized epoch with optical depth to electron scattering at the level of 0.1 and above. An improved measurement of this optical depth is useful to optimize experimental parameters of a post-WMAP mission attempting to target the IGW background.

scholarly journals ON THE CONTRIBUTION OF DENSITY PERTURBATIONS AND GRAVITATIONAL WAVES TO THE LOWER ORDER MULTIPOLES OF THE COSMIC MICROWAVE BACKGROUND RADIATION

2002 ◽  
Vol 11 (02) ◽  
pp. 259-297 ◽  
Author(s):  
A. DIMITROPOULOS ◽  
L. P. GRISHCHUK
Keyword(s):  
Dipole Moment ◽  
Gravitational Waves ◽  
Lower Order ◽  
Background Radiation ◽  
Infrared Divergence ◽  
Red Shift ◽  
Horizontal Line ◽  
Microwave Background ◽  
Microwave Background Radiation ◽  
Density Perturbations

The important studies of Peebles, and Bond and Efstathiou have led to the formula Cℓ= const. /[ℓ(ℓ+1)] aimed at describing the lower order multipoles of the CMBR temperature variations caused by density perturbations with the flat spectrum. Clearly, this formula requires amendments, as it predicts an infinitely large monopole C0, and a dipole moment C1 only 6/2 times larger than the quadrupole C2, both predictions in conflict with observations. We restore the terms omitted in the course of the derivation of this formula, and arrive at a new expression. According to the corrected formula, the monopole moment is finite and small, while the dipole moment is sensitive to short-wavelength perturbations, and numerically much larger than the quadrupole, as one would expect on physical grounds. At the same time, the function ℓ(ℓ+1)Cℓ deviates from a horizontal line and grows with ℓ, for ℓ≥2. We show that the inclusion of the modulating (transfer) function terminates the growth and forms the first peak, recently observed. We fit the theoretical curves to the position and height of the first peak, as well as to the observed dipole, varying three parameters: red-shift at decoupling, red-shift at matter-radiation equality, and slope of the primordial spectrum. It appears that there is always a deficit, as compared with the COBE observations, at small multipoles, ℓ~10. We demonstrate that a reasonable and theoretically expected amount of gravitational waves bridges this gap at small multipoles, leaving the other fits as good as before. We show that the observationally acceptable models permit somewhat "blue" primordial spectra. This allows one to avoid the infrared divergence of cosmological perturbations, which is otherwise present.

THE POLARIZATION OF THE COSMIC MICROWAVE BACKGROUND DUE TO PRIMORDIAL GRAVITATIONAL WAVES

2006 ◽  
Vol 21 (12) ◽  
pp. 2459-2479 ◽  
Author(s):  
BRIAN G. KEATING ◽  
ALEXANDER G. POLNAREV ◽  
NATHAN J. MILLER ◽  
DEEPAK BASKARAN
Keyword(s):  
Cosmic Microwave Background ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
Microwave Background ◽  
Primordial Gravitational Waves ◽  
Cmb Polarization ◽  
Cosmological Inflation ◽  
Gravitational Wave Background ◽  
Review Current ◽  
Rule Out

We review current observational constraints on the polarization of the Cosmic Microwave Background (CMB), with a particular emphasis on detecting the signature of primordial gravitational waves. We present an analytic solution to the Polanarev approximation for CMB polarization produced by primordial gravitational waves. This simplifies the calculation of the curl, or B-mode power spectrum associated with gravitational waves during the epoch of cosmological inflation. We compare our analytic method to existing numerical methods and also make predictions for the sensitivity of upcoming CMB polarization observations to the inflationary gravitational wave background. We show that upcoming experiments should be able either detect the relic gravitational wave background or completely rule out whole classes of inflationary models.

scholarly journals Confronting SO(10) GUTs with proton decay and gravitational waves

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Stephen F. King ◽  
Silvia Pascoli ◽  
Ye-Ling Zhou ◽  
Jessica Turner
Keyword(s):  
Gravitational Wave ◽  
Gravitational Waves ◽  
Cosmic String ◽  
Cosmic Strings ◽  
Proton Decay ◽  
Null Results ◽  
Grand Unified Theories ◽  
Unified Theories ◽  
Proton Lifetime ◽  
Gut Scale

Abstract Grand Unified Theories (GUT) predict proton decay as well as the formation of cosmic strings which can generate gravitational waves. We determine which non-supersymmetric SO(10) breaking chains provide gauge unification in addition to a gravitational signal from cosmic strings. We calculate the GUT and intermediate scales for these SO(10) breaking chains by solving the renormalisation group equations at the two-loop level. This analysis predicts the GUT scale, hence the proton lifetime, in addition to the scale of cosmic string generation and thus the associated gravitational wave signal. We determine which SO(10) breaking chains survive in the event of the null results of the next generation of gravitational waves and proton decay searches and determine the correlations between proton decay and gravitational waves scales if these observables are measured.

scholarly journals BICEP: a cosmic microwave background polarization telescope at the South Pole

2009 ◽  
Vol 5 (H15) ◽  
pp. 618-619
Author(s):  
Yuki D. Takahashi
Keyword(s):  
Cosmic Microwave Background ◽  
Gravitational Waves ◽  
San Diego ◽  
South Pole ◽  
Polarization Anisotropy ◽  
Atmospheric Conditions ◽  
The South ◽  
Microwave Background ◽  
Cmb Polarization ◽  
Cosmic Microwave Background Polarization

AbstractBicep was a telescope designed to probe the polarization of the cosmic microwave background (CMB) for the signature of gravitational waves produced during the epoch of inflation. The instrument was developed by a team of scientists from Caltech/JPL, UC Berkeley, and UC San Diego. It was installed at the South Pole in November 2005 and the CMB observations were conducted from February to November each year with one winter-over scientist responsible for operating and maintaining the instrument. Taking advantage of the excellent atmospheric conditions at the South Pole, we mapped 2% of the sky at 100 and 150 GHz. We completed 3 years of observations from 2006 to 2008, mapping the CMB polarization anisotropy at degree angular scales with unprecedented sensitivity. In 2010, a next generation instrument, Bicep2, will be installed on the existing telescope mount for an even deeper survey.

PRIMORDIAL GRAVITATIONAL WAVES AND INFLATION: POSSIBILITIES FOR DETECTION

2005 ◽  
Vol 20 (33) ◽  
pp. 2503-2519 ◽  
Author(s):  
ASANTHA COORAY
Keyword(s):  
Gravitational Wave ◽  
Gravitational Waves ◽  
Large Scale ◽  
Rapid Evolution ◽  
Big Bang ◽  
Primordial Gravitational Waves ◽  
Cmb Polarization ◽  
Density Perturbations ◽  
Merger Rate ◽  
The Big Bang

The curl-modes of Cosmic Microwave Background (CMB) polarization probe horizon-scale primordial gravitational waves related to inflation. A significant source of confusion is expected from a lensing conversion of polarization related to density perturbations to the curl mode, during the propagation of photons through the large scale structure. Either high resolution CMB anisotropy observations or 21 cm fluctuations at redshifts 30 and higher can be used to delens polarization data and to separate gravitational-wave polarization signature from that of cosmic-shear related signal. Separations based on proposed lensing reconstruction techniques for reasonable future experiments allow the possibility to probe inflationary energy scales down to 1015 GeV . Beyond CMB polarization, at frequencies between 0.01 Hz to 1 Hz, space-based laser interferometers can also be used to probe the inflationary gravitational wave background. The confusion here is related to the removal of merging neutron star binaries at cosmological distances. Given the low merger rate and the rapid evolution of the gravitational wave frequency across this band, reliable removal techniques can be constructed. We discuss issues related to joint constraints that can be placed on the inflationary models based on CMB polarization information and space-based interferometers such as the Big Bang Observer.

scholarly journals Fluctuations in the Microwave Background Caused by Anisotropy of the Universe and Gravitational Waves

1977 ◽  
Vol 74 ◽  
pp. 335-339
Author(s):  
I. D. Novikov
Keyword(s):  
Gravitational Waves ◽  
Galaxy Formation ◽  
Expanding Universe ◽  
Microwave Background ◽  
Primordial Gravitational Waves ◽  
Order Of Magnitude ◽  
Density Perturbations ◽  
The Universe

The problem described in the title has already been theoretically analysed several times (see for example Dautcourt, 1969 and Novikov, 1974). Recently, however some important new aspects of the problem have been discovered; they are discussed briefly in this report which is based upon the calculations of Doroshkevich, Lukash, Novikov and Polnarev. First consider the influence of primordial gravitational waves on the microwave background. It is natural to assume that in the Universe, in addition to acoustic (or adiabatic) density perturbations which result in galaxy formation and corresponding metric perturbations, there also exist metric perturbations in the form of gravitational waves with wavelengths of the same order of magnitude as the acoustic perturbations. The amplitude of such gravitational waves could in principle be quite arbitrary. Their amplitude can be estimated by comparing the theory of such waves in the expanding Universe with the observed fluctuations in the microwave background which are now available or will be in future.

Possibility of studying the effects of the DM-electron scattering on the cosmic microwave background based on simple assumptions

2020 ◽  
Vol 29 (07) ◽  
pp. 2050049
Author(s):  
Lu chen
Keyword(s):  
Electron Scattering ◽  
Power Spectra ◽  
Coupling Constant ◽  
Microwave Background ◽  
Free Electrons ◽  
Boltzmann Equations ◽  
Important Method ◽  
Basic Assumptions ◽  
Cosmic Evolution ◽  
Cmb Polarization

Investigating the dark matter (DM) properties in the view of cosmic evolution is an important method in searching for DM. In this paper, we derive the modified Boltzmann equations and study how the elastic scattering between the DM particles and the free electrons in our universe influences the CMB and matter power spectra starting from a few basic assumptions. The results indicates that the scattering affects the small scales significantly, especially the CMB polarization power spectra. With this method, the coupling constant between DM and electrons can be constrained with CMB observational data and the results only depend on a few basic assumptions.

Cosmic ray contributions to the WMAP polarization data on the cosmic microwave background

2016 ◽  
Vol 25 (03) ◽  
pp. 1650029
Author(s):  
Tadeusz Wibig ◽  
Arnold W. Wolfendale
Keyword(s):  
Cosmic Microwave Background ◽  
Gravitational Waves ◽  
Gamma Ray ◽  
Polarization Vector ◽  
Cosmic Ray ◽  
Microwave Background ◽  
Polarization Data ◽  
Planck Data ◽  
Cmb Polarization ◽  
Wmap Data

We have updated our analysis of the 9-year WMAP data using the collection of polarization maps looking for the presence of additional evidence for a finite ‘cosmic ray (CR) foreground’ for the cosmic microwave background (CMB). We have given special attention to high Galactic latitudes, where the recent BICEP2 findings were reported although very recent Planck data claims that dust is prevalent, thus nullifying the BICEP2 results. The method of examining the correlation with the observed gamma ray flux proposed in our earlier papers and applied to the polarization data shows that the foreground related to CRs is still observed even at high Galactic latitudes and conclusions about gravitational waves are not yet secure. Theory has it that there is important information about inflationary gravitational waves in the fine structure of the CMB polarization properties (polarization vector and angle) and it is necessary to examine further the conclusions that can be gained from studies of the CMB maps, in view of the disturbing foreground effects.

scholarly journals Gravitational Waves and Proton Decay: Complementary Windows into Grand Unified Theories

2021 ◽  
Vol 126 (2) ◽  
Author(s):  
Stephen F. King ◽  
Silvia Pascoli ◽  
Jessica Turner ◽  
Ye-Ling Zhou
Keyword(s):  
Gravitational Waves ◽  
Proton Decay ◽  
Grand Unified Theories ◽  
Unified Theories

Water, Water, Here and There

2018 ◽  
Author(s):  
Steven E. Vigdor
Keyword(s):  
Quark Mass ◽  
Mass Difference ◽  
Baryon Number ◽  
Electroweak Phase Transition ◽  
Hydrogen Burning ◽  
Quark Masses ◽  
Grand Unified Theories ◽  
Down Quark ◽  
Unified Theories ◽  
The Stability

Chapter 4 deals with the stability of the proton, hence of hydrogen, and how to reconcile that stability with the baryon number nonconservation (or baryon conservation) needed to establish a matter–antimatter imbalance in the infant universe. Sakharov’s three conditions for establishing a matter–antimatter imbalance are presented. Grand unified theories and experimental searches for proton decay are described. The concept of spontaneous symmetry breaking is introduced in describing the electroweak phase transition in the infant universe. That transition is treated as the potential site for introducing the imbalance between quarks and antiquarks, via either baryogenesis or leptogenesis models. The up–down quark mass difference is presented as essential for providing the stability of hydrogen and of the deuteron, which serves as a crucial stepping stone in stellar hydrogen-burning reactions that generate the energy and elements needed for life. Constraints on quark masses from lattice QCD calculations and violations of chiral symmetry are discussed.

Sign in / Sign up

Export Citation Format

Share Document