CMB anisotropy power spectrum using linear combinations of WMAP maps
Rajib Saha, Simon Prunet, Pankaj Jain, and Tarun Souradeep
In recent years the goal of estimating different cosmological parameters precisely has set new challenges in the effort to accurately measure the angular power spectrum of the CMB. This has required removal of foreground contamination as well as detector noise bias with reliability and precision. Re ... [Phys. Rev. D 78, 023003 (2008)] published Thu Jul 3, 2008.
Intuitive understanding of non-Gaussianity in ekpyrotic and cyclic models
Jean-Luc Lehners and Paul J. Steinhardt
It has been pointed out by several groups that ekpyrotic and cyclic models generate significant non-Gaussianity. In this paper, we present a physically intuitive, semianalytic estimate of the bispectrum. We show that, in all such models, there is an intrinsic contribution to the non-Gaussianity para ... [Phys. Rev. D 78, 023506 (2008)] published Thu Jul 3, 2008.
Can quantum gravitational effects influence the entire history of the Universe?
Edesio M. Barboza, Jr. and Nivaldo A. Lemos
In this work, a flat Friedmann-Robertson-Walker universe with dust and a cosmological constant is quantized. By means of a canonical transformation, the classical Hamiltonian is reduced to that of either a harmonic oscillator or anti-oscillator, depending on whether Lambda<0 or Lambda>0, respectivel ... [Phys. Rev. D 78, 023504 (2008)] published Thu Jul 3, 2008.
Is a dissipative regime during inflation in agreement with observations?
Alessandro Cerioni, Fabio Finelli, and Alessandro Gruppuso
We study the spectral index of curvature perturbations for inflationary models where the driving scalar field is coupled to a relativistic fluid through a friction term Gamma. In the regime in which Gamma can be at most as large as H, the Hubble parameter during inflation, we find that only Gamma<
UV survey finds 40% of the baryons missing from the nearby universe
Charles Day
By the time the universe was three minutes old, all the baryonic building blocks of normal matter had formed. As the young universe aged, a minority of those primordial baryonsa few percentjoined clumps of the far more abundant dark matter to condense and form the first galaxies. ... [Phys. Today 61, 12 (2008)] published Wed Jul 2, 2008.
A General Test of the Copernican Principle
Chris Clarkson, Bruce Bassett, and Teresa Hui-Ching Lu
To date, there has been no general way of determining if the Copernican principlethat we live at a typical position in the Universeis in fact a valid assumption, significantly weakening the foundations of cosmology as a scientific endeavor. Here we present an observational test for the Copernican as ... [Phys. Rev. Lett. 101, 011301 (2008)] published Wed Jul 2, 2008.
Cosmic string Y-junctions: A comparison between field theoretic and Nambu-Goto dynamics
Neil Bevis and Paul M. Saffin
We explore the formation of cosmic string Y-junctions when strings of two different types collide, which has recently become important since string theory can yield cosmic strings of distinct types. Using a model containing two types of local U(1) string and stable composites, we simulate the collis ... [Phys. Rev. D 78, 023503 (2008)] published Wed Jul 2, 2008.
Cosmological parameters from WMAP 5-year temperature maps
Antony Lewis
I calculate a hybrid cross-power spectrum estimator from the WMAP 5-year CMB temperature maps, discuss the goodness of fit, and then constrain cosmological parameters. The spectrum and results are generally consistent with previous results, though the power spectrum error bars are slightly smaller a ... [Phys. Rev. D 78, 023002 (2008)] published Wed Jul 2, 2008.
Cosmic string dynamics and evolution in warped spacetime
A. Avgoustidis
We study the dynamics and evolution of Nambu-Goto strings in a warped spacetime, where the warp factor is a function of the internal coordinates giving rise to a throat region. The microscopic equations of motion for strings in this background include potential and friction terms, which attract the ... [Phys. Rev. D 78, 023501 (2008)] published Tue Jul 1, 2008.
Two-photon transitions in primordial hydrogen recombination
Christopher M. Hirata
The subject of cosmological hydrogen recombination has received much attention recently because of its importance to predictions for and cosmological constraints from cosmic microwave background observations. While the central role of the two-photon decay 2s-->1s has been recognized for many decades ... [Phys. Rev. D 78, 023001 (2008)] published Tue Jul 1, 2008.
The Anomalous Acceleration of the Pioneer Spacecrafts. (arXiv:0807.0617v1 [physics.space-ph])
ePrint arXiv http://arXiv.org/
Distinct Scaling Regimes of Energy Release Dynamics in the Nighttime Magnetosphere. (arXiv:0807.0631v1 [physics.space-ph])
ePrint arXiv http://arXiv.org/
Advances in the measurement of the Lense-Thirring effect with planetary motions in the field of the Sun. (arXiv:0807.0435v3 [gr-qc] CROSS LISTED)
ePrint arXiv http://arXiv.org/