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arXiv · 1206.4309

Scale-Invariant Fluctuations from Galilean Genesis

Yi Wang·Robert Brandenberger
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Abstract

We study the spectrum of cosmological fluctuations in scenarios such as Galilean Genesis in which a spectator scalar field acquires a scale-invariant spectrum of perturbations during an early phase which asymptotes in the far past to Minkowski space-time. In the case of minimal coupling to gravity and standard scalar field Lagrangian, the induced curvature fluctuations depend quadratically on the spectator field and are hence non-scale-invariant and highly non-Gaussian. We show that if higher dimensional operators (the same operators that lead to the η-problem for inflation) are considered, a linear coupling between background and spectator field fluctuations is induced which leads to scale-invariant and Gaussian curvature fluctuations.

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Yi Wang, Robert Brandenberger. 2012-06-19. Scale-Invariant Fluctuations from Galilean Genesis. https://doi.org/10.1088/1475-7516%2F2012%2F10%2F021

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