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Physical Sciences and Mathematics Commons

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Astrophysics and Astronomy

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Dartmouth Scholarship

2013

General relativity

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Full-Text Articles in Physical Sciences and Mathematics

Freezing Out Early Dark Energy, Jannis Bielefeld, W. L. Kimmy Wu, Robert R. Caldwell, Olivier Doré Nov 2013

Freezing Out Early Dark Energy, Jannis Bielefeld, W. L. Kimmy Wu, Robert R. Caldwell, Olivier Doré

Dartmouth Scholarship

A phenomenological model of dark energy that tracks the baryonic and cold dark matter at early times but resembles a cosmological constant at late times is explored. In the transition between these two regimes, the dark energy density drops rapidly as if it were a relic species that freezes out, during which time the equation of state peaks at +1. Such an adjustment in the dark energy density, as it shifts from scaling to potential domination, could be the signature of a trigger mechanism that helps explain the late-time cosmic acceleration. We show that the non-negligible dark energy density at …


Spectral Distortion In A Radially Inhomogeneous Cosmology, R. R. Caldwell, N. A. Maksimova Nov 2013

Spectral Distortion In A Radially Inhomogeneous Cosmology, R. R. Caldwell, N. A. Maksimova

Dartmouth Scholarship

The spectral distortion of the cosmic microwave background blackbody spectrum in a radially inhomogeneous space-time, designed to exactly reproduce a ΛCDM expansion history along the past light cone, is shown to exceed the upper bound established by COBE-FIRAS by a factor of approximately 3700. This simple observational test helps uncover a slew of pathological features that lie hidden inside the past light cone, including a radially contracting phase at decoupling and, if followed to its logical extreme, a naked singularity at the radially inhomogeneous big bang.