String Gas Cosmology and Non-Gaussianities

Abstract

Recently it has been shown that string gas cosmology, an alternative model of the very early universe which does not involve a period of cosmological inflation, can give rise to an almost scale invariant spectrum of metric perturbations. Here we calculate the non-Gaussianities of the spectrum of cosmological fluctuations in string gas cosmology, and find that these non-Gaussianities depend linearly on the wave number and that their amplitude depends sensitively on the string scale. If the string scale is at the TeV scale, string gas cosmology could lead to observable non-Gaussianities, if it is close to the Planck scale, then the non-Gaussianities on current cosmological scales are negligible.

17 pages, 1 figure 4 clarifying sentences added

References in corpus (17)

• Non-Gaussian features of primordial fluctuations in single field inflationary models
• The Trans-Planckian Problem of Inflationary Cosmology
• Eternal inflation and the initial singularity
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• Brane Gases in the Early Universe
• String Gas Cosmology
• Tensor Modes from a Primordial Hagedorn Phase of String Cosmology
• String Gas Cosmology and Structure Formation
• Non-perturbative Gravity, Hagedorn Bounce & CMB
• Moduli Stabilization with the String Higgs Effect
• Stabilization of Extra Dimensions at Tree Level
• Radion Stabilization by Stringy Effects in General Relativity
• On T-Duality in Brane Gas Cosmology
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• Challenges for String Gas Cosmology
• Inflation Free, Stringy Generation of Scale-Invariant Cosmological Fluctuations in D = 3 + 1 Dimensions

Cited by in corpus (15)

• Cosmology of the Very Early Universe
• String Gas Cosmology: Progress and Problems
• Evolution of cosmological perturbations and the production of non-Gaussianities through a nonsingular bounce: Indications for a no-go theorem in single field matter bounce cosmologies
• Thermal Fluctuations and Bouncing Cosmologies
• Primordial Trispectrum from Entropy Perturbations in Multifield DBI Model
• $\alpha$-vacuum and inflationary bispectrum
• String Gas Cosmology after Planck
• String Cosmology backgrounds from Classical String Geometry
• Unconventional Cosmology
• Solution of the Size and Horizon Problems from Classical String Geometry
• Quadra-Spectrum and Quint-Spectrum from Inflation and Curvaton Models
• Revisiting non-Gaussianity of multiple-field inflation from the field equation
• Differentiating G-inflation from String Gas Cosmology using the Effective Field Theory Approach
• Holographic Curvature Perturbations in a Cosmology with a Space-Like Singularity
• Tachyon-Dilaton-induced Inflation as an alpha'-resummed String Background