Pearson's random walk in the space of the CMB phases: evidence for parity asymmetry

Abstract

The temperature fluctuations of the Cosmic Microwave Background (CMB) are supposed to be distributed randomly in both magnitude and phase, following to the simplest model of inflation. In this paper, we look at the odd and even multipoles of the spherical harmonic decomposition of the CMB, and the different characteristics of these, giving rise to a parity asymmetry. We compare the even and odd multipoles in the CMB power spectrum, and also the even and odd mean angles. We find for the multipoles of the power spectrum, that there is power excess in odd multipoles, compared to even ones, meaning that we have a parity asymmetry. Further, for the phases, we present a random walk for the mean angles, and find a significant separation for even/odd mean angles, especially so for galactic coordinates. This is further tested and confirmed with a directional parity test, comparing the parity asymmetry in galactic and ecliptic coordinates.

Accepted for publication in Phys. Rev. D, 10 pages, 10 figures, 1 table. Some typographical errors corrected, and further references added

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• Alignments of parity even/odd-only multipoles in CMB
• Harmonic in-painting of CMB sky by constrained Gaussian realization
• Searching for hidden mirror symmetries in CMB fluctuations from WMAP 7 year maps
• Preferred axis of CMB parity asymmetry in the masked maps
• Symmetry and anti-symmetry of the CMB anisotropy pattern
• The Parity Odd Universe, Dark Energy and QCD
• Symmetry of the CMB sky as a new test of its statistical isotropy. Non Cosmological Octupole?
• On the Coherence of WMAP and Planck Temperature Maps
• Asymmetry of the CMB map: local and global anomalies
• Phase statistics of the WMAP 7 year data
• Testing cosmic homogeneity and isotropy using galaxy correlations