Enhanced CMBR non-Gaussianities from Lorentz violation

Abstract

We study the effects of Lorentz symmetry violation on the scalar CMBR bispectrum. Our quantitative results show that there can be enhancements in the bispectrum for specific configurations in momentum space, when the modified dispersion relations resulting from the symmetry breaking violate the adiabatic condition for a short period of time in the early Universe. The kind of configurations that are enhanced and the pattern of oscillations in wavenumbers that generically appear in the bispectrum strictly depend on the form of the modified dispersion relation, and therefore on the pattern of Lorentz violation. These effects are found to be distinct from those that appear when modelling very high-energy (transplanckian) physics via modified boundary conditions (modified vacuum). In fact, under certain conditions, the enhancements are even stronger, and possibly open a door to the experimental study of Lorentz violation through these phenomena.

26 pages plus bibliography, 3 figures, added bibliography, corrected typos, minor changes in the text

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• Non-Gaussianities in the Cosmological Perturbation Spectrum due to Primordial Anisotropy
• Constraining the initial conditions of the Universe using large scale structure
• Non-Gaussianities in the Cosmological Perturbation Spectrum due to Primordial Anisotropy II
• Multiple Soft Limits of Cosmological Correlation Functions
• Large Scale Anisotropic Bias from Primordial non-Gaussianity
• On the Initial State and Consistency Relations
• Power Spectrum and Non-Gaussianities in Anisotropic Inflation
• Effect of intermediate Minkowskian evolution on CMB bispectrum
• Aspects of Quantum Gravity in Cosmology