Hilltop Quintessence

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.

7 pages, 9 figures, label on Fig. 4 corrected

References in corpus (6)

• Observational Constraints on the Nature of the Dark Energy: First Cosmological Results from the ESSENCE Supernova Survey
• Thawing quintessence with a nearly flat potential
• More hilltop inflation models
• Measuring deviations from a cosmological constant: a field-space parameterization
• Warm hilltop inflation
• Confronting pNGB quintessence with data

Cited by in corpus (3)

• Slow-roll k-essence
• Observational constraints on thawing quintessence models
• Perturbed dark energy: classical scalar field versus tachyon