Small non-Gaussianity and dipole asymmetry in the CMB

Abstract

In this paper we provide a prescription for obtaining a small non-Gaussianity and the observed dipole asymmetry in the cosmic microwave background radiation. The observations inevitably lead to multi-field inflationary dynamics, where each field can create positive or negative large non-Gaussianity, resulting a fine cancellation but with an observable imprint on the hemispherical asymmetry. We discuss this possibility within a simple slow-roll scenario and find that it is hard to explain the observed dipole asymmetry. We briefly discuss some speculative scenarios where one can explain dipole asymmetry.

4 pages, 1 figure, revision accepted by PRD

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Cited by in corpus (31)

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• The CMB asymmetry from inflation
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• Hemispherical Asymmetry and Local non-Gaussianity: a Consistency Condition
• Asymmetric Sky from the Long Mode Modulations
• Microwave Background Correlations from Dipole Anisotropy Modulation
• CMB Power Asymmetry from Primordial Sound Speed Parameter
• CMB dipole asymmetry from a fast roll phase
• Large-scale anomalies in the cosmic microwave background as signatures of non-Gaussianity
• A viable explanation of the CMB dipolar statistical anisotropy
• Inflationary power asymmetry from primordial domain walls
• CMB Hemispherical Asymmetry: Long Mode Modulation and non-Gaussianity
• Hemispherical Power Asymmetry from a Space-Dependent Component of the Adiabatic Power Spectrum
• Quadrupole--octopole alignment of CMB related to primordial power spectrum with dipolar modulation in anisotropic spacetime
• Scale-dependent non-Gaussianity and the CMB Power Asymmetry
• Expected dipole asymmetry in CMB polarization
• Relating the inhomogeneous power spectrum to the CMB hemispherical anisotropy
• Hemispherical Power Asymmetry from Scale-Dependent Modulated Reheating
• Imprint of Inhomogeneous and Anisotropic Primordial Power Spectrum on CMB Polarization
• CMB hemispherical asymmetry from non-linear isocurvature perturbations
• Scale-dependent CMB asymmetry from primordial configuration
• Lensing as a Probe of Early Universe: from CMB to Galaxies
• Strongly scale-dependent CMB dipolar asymmetry from super-curvature fluctuations
• Scale-dependent hemispherical asymmetry from general initial state during inflation
• Primordial inhomogeneities from massive defects during inflation
• Primordial anisotropies from cosmic strings during inflation
• Scale-dependent CMB power asymmetry from primordial speed of sound and a generalized $\delta$N formalism
• Noncommutative Geometry and the Primordial Dipolar Imaginary Power Spectrum
• Isotropic non-Gaussian $g_{\mathrm{NL}}$-like toy models that reproduce the cosmic microwave background anomalies
• Detecting CMB modulations and non-Gaussianities from power multipoles
• Spectator fields and their imprints on the Cosmic Microwave Background