Nonlocal bispectra from super cosmic variance

Bekir Baytaş, Aruna Kesavan, Elliot Nelson, Sohyun Park, and Sarah Shandera
Phys. Rev. D 91, 083518 – Published 9 April 2015

Abstract

We present examples of non-Gaussian statistics that can induce bispectra matching local and nonlocal (including equilateral) templates in biased subvolumes. We find cases where the biasing from coupling to long wavelength modes affects only the power spectrum, only the bispectrum or both. Our results suggest that ruling out multifield scenarios is quite difficult: some measurements of the scalar correlations, including the shape of the bispectrum, can be consistent with single-clock predictions even when cosmic variance from super-horizon modes is at work. Furthermore, if observations of the density perturbations rule out single-clock inflation, we will face a serious cosmic variance obstacle in drawing any further conclusions about the particle physics origin of the scalar fluctuations.

  • Figure
  • Figure
  • Received 18 February 2015

DOI:https://doi.org/10.1103/PhysRevD.91.083518

© 2015 American Physical Society

Authors & Affiliations

Bekir Baytaş*, Aruna Kesavan, Elliot Nelson, Sohyun Park§, and Sarah Shandera

  • Institute for Gravitation and the Cosmos, The Pennsylvania State University, University Park, Pennsylvania 16802, USA

  • *bub188@psu.edu
  • aok5232@psu.edu
  • eln121@psu.edu
  • §spark@gravity.psu.edu
  • shandera@gravity.psu.edu

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Issue

Vol. 91, Iss. 8 — 15 April 2015

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