1994/12/07 by Harald F. Muller, Christoph Schmid, Muller, Harald F. +1
Physics and Astronomy · #Astrophysics (astro-ph) #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #astro-ph #gr-qc
paper · pdf · doi:10.48550/arxiv.gr-qc/9412022
9 pages, uses AMSTex, 1 figure (not included)
arxiv created 1994/12/07 · arxiv updated 2009/11/30
We analyze the non--Gaussian primordial fluctuations which are inescapably contributed by scalar fields Φ with vanishing expectation values, ⟨Φ⟩=0, present during inflation in addition to the inflaton field. For simplicity we take Φ to be non--interacting and minimally coupled to gravity. Φ is a Gaussian variable, but the energy density fluctuations contributed by such a field are χ2--distributed. We compute the three--point function \xxxT for the configuration of an equilateral triangle (with side length ℓ) and the skewness \dddRR, \it i.e. the third moment of the one--point probability distribution of the spatially smeared energy density contrast \deR, where R is the smearing scale. The relative magnitudes of the non--Gaussian effects, [ξ(N)]1/N/[ξ(2)]1/2, do not grow in time. They are given by numerical constants of order unity, independent of the scale ℓ. The "bi--skewness" \dddRS is positive. For smearing lengths R≪ S this shows that in our model (in contrast to Gaussian models) voids are more quiet than high--density regions.