Non-local bispectra from super cosmic variance

Abstract

We present examples of non-Gaussian statistics that can induce bispectra matching local and non-local (including equilateral) templates in biased sub-volumes. 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 multi-field 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.

17 pages, 2 figures

References in corpus (26)

• Planck 2013 results. XVI. Cosmological parameters
• Non-Gaussian features of primordial fluctuations in single field inflationary models
• The imprints of primordial non-gaussianities on large-scale structure: scale dependent bias and abundance of virialized objects
• Single field consistency relation for the 3-point function
• Planck 2013 Results. XXIV. Constraints on primordial non-Gaussianity
• Non-Gaussianities in Single Field Inflation and their Optimal Limits from the WMAP 5-year Data
• On Soft Limits of Inflationary Correlation Functions
• On the consistency relation of the 3-point function in single field inflation
• Primordial trispectrum from inflation
• The anisotropic power spectrum and bispectrum in the f(phi) F^2 mechanism
• Large-scale Bias and Efficient Generation of Initial Conditions for Non-Local Primordial Non-Gaussianity
• An Infinite Set of Ward Identities for Adiabatic Modes in Cosmology
• Constraints on primordial non-Gaussianity from 800,000 photometric quasars
• Position-dependent power spectrum of the large-scale structure: a novel method to measure the squeezed-limit bispectrum
• A Note on the Consistency Condition of Primordial Fluctuations
• One-particle-irreducible consistency relations for cosmological perturbations
• A universal bound on N-point correlations from inflation
• A non-Gaussian landscape
• Statistical Naturalness and non-Gaussianity in a Finite Universe
• Multiple Soft Limits of Cosmological Correlation Functions
• Double Soft Limits of Cosmological Correlations
• Non-Gaussian Mode Coupling and the Statistical Cosmological Principle
• Statistics of Anisotropies in Inflation with Spectator Vector Fields
• Cosmic Variance of the Spectral Index from Mode Coupling
• Super cosmic variance from mode-coupling: A worked example
• Local Observables in a Landscape of Infrared Gauge Modes

Cited by in corpus (9)

• Biasing and the search for primordial non-Gaussianity beyond the local type
• Large-scale anomalies in the cosmic microwave background as signatures of non-Gaussianity
• Cosmic variance in inflation with two light scalars
• Scale-dependent non-Gaussianity and the CMB Power Asymmetry
• Generating the cosmic microwave background power asymmetry with $g_{NL}$
• Constraining primordial and gravitational mode coupling with the position-dependent bispectrum of the large-scale structure
• Statistical anisotropies in temperature and polarization fluctuations from a scale-dependent trispectrum
• Influence of Unobservable Modes on Correlation Functions during Inflation
• On the space of non-Gaussian fields with single-clock bispectra