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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.

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