2013/10/31 by Marilena Loverde, Marilena LoVerde · 12 citations
Mathematics · Physics and Astronomy · #Attractor #Black Holes and Theoretical Physics #Cosmic microwave background #Cosmic variance #Cosmology #Cosmology and Gravitation Theories #Coupling (piping) #Curvature #Dark energy #Galaxies: Formation, Evolution, Phenomena #Geometry #Hubble volume #Hubble's law #Inflation (cosmology) #Mathematical analysis #Mathematics #Mode coupling #Non-Gaussianity #Physics #Quantum mechanics #Statistical physics #Statistics #astro-ph.CO #hep-th
paper · pdf · doi:10.1103/physrevd.89.023505
published in Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields 89(2) (American Physical Society) · 9 pages, no figures; v2 typos corrected, references added, matches PRD accepted version
arxiv created 2013/12/19 · openalex publication_date 2014/01/09 · arxiv updated 2014/01/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
If the entire post-inflationary patch is large compared to our Hubble volume even a small level of non-Gaussianity can cause statistics of the primordial curvature field in our Hubble volume to be biased by mode coupling. We explicitly compute the variation of locally measured statistics of the primordial curvature \ensuremathζ from non-Gaussian mode coupling within a specific inflationary scenario: the curvaton model with a quadratic curvaton potential. This ``super cosmic variance" is calculated in two ways: (i) as a super observer who has access to the curvature perturbation field across the entire post-inflationary patch and therefore sees local statistics as biased by mode coupling and (ii) as a local observer who sees the statistics of \ensuremathζ determined by the local values of quantities in their Hubble patch. The two calculations agree and show that in the quadratic curvaton model patch-to-patch differences in statistics of \ensuremathζ can be interpreted entirely as a shift in the value of the curvaton field at freeze out. Applying the same arguments to single-field slow-roll inflation gives a simple picture of how non-Gaussian mode coupling between the curvature perturbations on very different physical scales must vanish in the attractor limit.