Imprints of a hemispherical power asymmetry in the seven-year WMAP data due to non-commutativity of space-time

Abstract

Non-commutative geometry at inflation can give arise to parity violating modulations of the primordial power spectrum. We develop the statistical tools needed for investigating whether these modulations are evident in the Cosmic Microwave Background (CMB). The free parameters of the models are two directional parameters (theta,phi), the signal amplitude A*, and a tilt parameter n* that modulates correlation power on different scales. The signature of the model corresponds to a kind of hemispherical power asymmetry. When analyzing the 7-year WMAP data we find a weak signature for a preferred direction in the Q-, V-, and W bands with direction (l,b) = (-225 deg,-25 deg) +- (20 deg, 20 deg), which is close to another previously discovered hemispherical power asymmetry. Although these results are intriguing, the significance of the detection in the W-, V- and Q-bands are nonzero at about 2 sigma, suggesting that the simplest parameterization of the leading correction represents only partially the effects of the space-time non-commutativity possibly responsible for the hemispherical asymmetry. Our constraints on the presence of a dipole are independent of its physical origin and prefer a blue-tilted spectral index n* ~ 0 with the amplitude A* ~ 0.18.

arXiv comment8 pages, 6 figures

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Cited by in corpus (6)

• Inflation with stable anisotropic hair: is it cosmologically viable?
• Imprint of Inhomogeneous and Anisotropic Primordial Power Spectrum on CMB Polarization
• CMB statistical anisotropy from noncommutative gravitational waves
• A Pixel Space Method for Testing Dipole Modulation in the CMB Polarization
• Cosmological Power Spectrum in Non-commutative Space-time
• Aspects of Quantum Gravity in Cosmology