Thawing quintessence with a nearly flat potential
- Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235 (United States)
The thawing quintessence model with a nearly flat potential provides a natural mechanism to produce an equation of state parameter, w, close to -1 today. We examine the behavior of such models for the case in which the potential satisfies the slow-roll conditions: [(1/V)(dV/d{phi})]{sup 2}<<1 and (1/V)(d{sup 2}V/d{phi}{sup 2})<<1, and we derive the analog of the slow-roll approximation for the case in which both matter and a scalar field contribute to the density. We show that in this limit, all such models converge to a unique relation between 1+w, {omega}{sub {phi}}, and the initial value of (1/V)(dV/d{phi}). We derive this relation and use it to determine the corresponding expression for w(a), which depends only on the presentday values for w and {omega}{sub {phi}}. For a variety of potentials, our limiting expression for w(a) is typically accurate to within {delta}w < or approx. 0.005 for w<-0.9. For redshift z < or approx. 1, w(a) is well fit by the Chevallier-Polarski-Linder parametrization, in which w(a) is a linear function of a.
- OSTI ID:
- 21250010
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 77, Issue 8; Other Information: DOI: 10.1103/PhysRevD.77.083515; (c) 2008 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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