Quintom Models with an Equation of State Crossing -1

By Wen Zhao, Yang-Hong Zhang. 2006

210 citations recorded by the source corpus.

In this paper, we investigate a kind of special quintom model, which is made of a quintessence field ϕ1 and a phantom field ϕ2, and the potential function has the form of V(ϕ12-ϕ22). This kind of quintom field can be separated into two kinds: the hessence model, which has the state of ϕ12>ϕ22, and the hantom model with the state ϕ12 -1 or <-1, and the potential of the quintom being climbed up or rolled down, the ω-ω′ plane can be divided into four parts. The late time attractor solution, if existing, is always quintessencelike or Λ-like for hessence field, so the big rip does not exist. But for hantom field, its late time attractor solution can be phantomlike or Λ-like, and sometimes, the big rip is unavoidable. Then we consider two special cases: one is the hessence field with an exponential potential, and the other is with a power law potential. We investigate their evolution in the ω-ω′ plane. We also develop a theoretical method of constructing the hessence potential function directly from the effective equation-of-state function ω(z). We apply our method to five kinds of parametrizations of equation-of-state parameter, where ω crossing -1 can exist, and find they all can be realized. At last, we discuss the evolution of the perturbations of the quintom field, and find the perturbations of the quintom δQ and the metric Φ are all finite even at the state of ω=-1 and ω′≠0.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/f9a2207725319c4cbda67fcdce6ac4d6e4f1aedf

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Citations in the corpus

Observational constraints on teleparallel dark energy (2011, background): “The first is to modify the content of the universe by introducing the dark energy sector, which can be based on a canonical scalar field (quintessence) [6–22], a phantom field [23–28], or on the combination of both these fields in a unified scenario called quintom [29–35] (see [36] for a review).”