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Full-Text Articles in Astrophysics and Astronomy
Dark Energy Scaling From Dark Matter To Acceleration, Jannis Bielefeld, Robert R. Caldwell, Eric Linder
Dark Energy Scaling From Dark Matter To Acceleration, Jannis Bielefeld, Robert R. Caldwell, Eric Linder
Dartmouth Scholarship
The dark sector of the Universe need not be completely separable into distinct dark matter and dark energy components. We consider a model of early dark energy in which the dark energy mimics a dark matter component in both evolution and perturbations at early times. Barotropic aether dark energy scales as a fixed fraction, possibly greater than one, of the dark matter density and has vanishing sound speed at early times before undergoing a transition. This gives signatures not only in cosmic expansion but in sound speed and inhomogeneities, and in number of effective neutrino species. Model parameters describe the …
Transition To Order After Hilltop Inflation, Marcelo Gleiser, Noah Graham
Transition To Order After Hilltop Inflation, Marcelo Gleiser, Noah Graham
Dartmouth Scholarship
We investigate the rich nonlinear dynamics during the end of hilltop inflation by numerically solving the coupled Klein-Gordon-Friedmann equations in an expanding universe. In particular, we search for coherent, nonperturbative configurations that may emerge due to the combination of nontrivial couplings between the fields and resonant effects from the cosmological expansion. We couple a massless field to the inflaton to investigate its effect on the existence and stability of coherent configurations and the effective equation of state at reheating. For parameters consistent with data from the Planck and WMAP satellites, and for a wide range of couplings between the inflaton …