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Ewan Stewart

Publications and source records attributed to Ewan Stewart.

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Scale Dependent Spectral Index in Slow Roll Inflation

Recent observations suggest that the spectral index of the primordial perturbations is very close to unity, as expected in models of slow roll inflation. It is still possible for such models to produce spectra which are scale dependent. We present a formula for the spectrum produced by an arbitrary inflaton potential (within the context of slow roll models); this formula explicitly illustrates and accounts for the possiblity of scale dependence. A class of examples are studied and comparisons made with the standard slow roll formula.

astro-ph

Solving the Coincidence Problem: Tracking Oscillating Energy

Recent cosmological observations strongly suggest that the universe is dominated by an unknown form of energy with negative pressure. Why is this dark energy density of order the critical density today? We propose that the dark energy has periodically dominated in the past so that its preponderance today is natural. We illustrate this paradigm with a model potential and show that its predictions are consistent with all observations.

astro-ph