English

Diagnosing holographic type dark energy models with the Statefinder hierarchy, composite null diagnostic and $w-w'$ pair

Cosmology and Nongalactic Astrophysics 2018-01-03 v1

Abstract

The main purpose of this work is to distinguish various holographic type dark energy (DE) models, including the Λ\LambdaHDE, HDE, NADE and RDE model, by using various diagnostic tools. The first diagnostic tool is the Statefinder hierarchy, in which the evolution of Statefinder hierarchy parmeter S3(1)(z)S^{(1)}_3(z) and S4(1)(z)S^{(1)}_4(z) are studied. The second is composite null diagnostic (CND), in which the trajectories of {S3(1),ϵ}\{S^{(1)}_3, \epsilon\} and {S4(1),ϵ}\{S^{(1)}_4, \epsilon\} are investigated, where ϵ\epsilon is the fractional growth parameter. The last is www-w' analysis, where ww is the equation of state for DE and the prime denotes derivative with respect to lnaln a. In the analysis we consider two cases: varying current fractional DE density Ωde0\Omega_{de0} and varying DE model parameter CC. We find that: (1) Both the Statefinder hierarchy and the CND have qualitative impact on Λ\LambdaHDE, but only have quantitative impact on HDE. (2) S4(1)S_4^{(1)} can lead to larger differences than S3(1)S_3^{(1)}, while the CND pair has a stronger ability to distinguish different models than the Statefinder hierarchy. (3) For the case of varying CC, the {w,w}\{w, w'\} pair has qualitative impact on Λ\LambdaHDE; for the case of varying Ωde0\Omega_{de0}, the {w,w}\{w, w'\} pair only has quantitative impact; these results are different from the cases of HDE, RDE and NADE, in which the {w,w}\{w, w'\} pair only has quantitative impact on these models. In conclusion, compared with HDE, RDE and NADE, the Λ\LambdaHDE model can be easily distinguished by using these diagnostic tools.

Keywords

Cite

@article{arxiv.1710.04848,
  title  = {Diagnosing holographic type dark energy models with the Statefinder hierarchy, composite null diagnostic and $w-w'$ pair},
  author = {Ze Zhao and Shuang Wang},
  journal= {arXiv preprint arXiv:1710.04848},
  year   = {2018}
}

Comments

12 pages, 8 figures, accepted by Sci. China Phys. Mech. Astron