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arXiv · 0809.4441

Hilltop Quintessence

Sourish Dutta·Robert J. Scherrer
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Abstract

We examine hilltop quintessence models, in which the scalar field is rolling near a local maximum in the potential, and w is close to -1. We first derive a general equation for the evolution of the scalar field in the limit where w is close to -1. We solve this equation for the case of hilltop quintessence to derive w as a function of the scale factor; these solutions depend on the curvature of the potential near its maximum. Our general result is in excellent agreement (delta w < 0.5%) with all of the particular cases examined. It works particularly well (delta w < 0.1%) for the pseudo-Nambu-Goldstone Boson potential. Our expression for w(a) reduces to the previously-derived slow-roll result of Sen and Scherrer in the limit where the curvature goes to zero. Except for this limiting case, w(a) is poorly fit by linear evolution in a.

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Sourish Dutta, Robert J. Scherrer. 2008-12-17. Hilltop Quintessence. https://doi.org/10.1103/physrevd.78.123525

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