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Paper   IPM / Astronomy / 12944
School of Astronomy
Title:   Hemispherical Asymmetry and Local non-Gaussianity: a Consistency Condition
Author(s):
 1 Mohammad Hossein Namjoo 2 Shant Baghram 3 Hassan Firouzjahi
Status:   Published
Journal: Phys. Rev. D
Year:  2013
Pages:   13
Supported by:  IPM
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 ,...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.