Hemispherical Asymmetry and Local non-Gaussianity: a Consistency Condition

Abstract

In this paper we provide a consistency relation between the amplitude of the hemispherical bipolar asymmetry, $A$, and the amplitude of the primordial non-Gaussianity in the squeezed limit, $f_{NL}$, as $|A|\lesssim 10^{-1}{f}_{NL}$. We demonstrate that this consistency condition is at work for any model of inflation in which the curvature perturbations is sourced by a single light field with the Bunch-Davies initial condition, irrespective of the number of inflation fields which contribute to the background inflationary expansion. As a non-trivial example, we show that observable hemispherical asymmetry can be generated in single field non-attractor inflationary models. We also study hemispherical asymmetry generated in the models of multiple fields inflation. We show that $A$ is controlled by the weighted sum of non-Gaussianity contribution from each field. In particular, we show that observable hemispherical asymmetry can be generated in models where inhomogeneities are generated from a light scalar field modulating the surface of end of inflation.

V2: discussions improved, Eqs. (48) and (49) added, new references added

References in corpus (19)

• Planck 2018 results. VII. Isotropy and Statistics of the CMB
• Hemispherical power asymmetry in the three-year Wilkinson Microwave Anisotropy Probe sky maps
• A Hemispherical Power Asymmetry from Inflation
• Cosmic Microwave Background Statistics for a Direction-Dependent Primordial Power Spectrum
• Superhorizon Perturbations and the Cosmic Microwave Background
• Asymmetric Beams and CMB Statistical Anisotropy
• Constraints on cosmic hemispherical power anomalies from quasars
• A Scale-Dependent Power Asymmetry from Isocurvature Perturbations
• Hybrid inflation along waterfall trajectories
• Search for narrow resonances and quantum black holes in inclusive and b-tagged dijet mass spectra from pp collisions at sqrt(s) = 7 TeV
• Broken Isotropy from a Linear Modulation of the Primordial Perturbations
• Cosmic microwave background anomalies in an open universe
• Non-isotropy in the CMB power spectrum in single field inflation
• A new method for calculating the primordial bispectrum in the squeezed limit
• Gauging the cosmic microwave background
• On the squeezed limit of the bispectrum in general single field inflation
• Waterfall field in hybrid inflation and curvature perturbation
• No Large Scale Curvature Perturbations during Waterfall of Hybrid Inflation
• Isocurvature and Curvaton Perturbations with Red Power Spectrum and Large Hemispherical Asymmetry

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