Holographic dark energy in the DGP braneworld with Granda-Oliveros cutoff
Holographic dark energy in the DGP braneworld with Granda-Oliveros cutoff
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DOI：
10.1103/physrevd.89.123009
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发表时间：
2014-06-25
影响因子：
5
通讯作者：
Sheykhi, A.
中科院分区：
文献类型：
--
作者：
Ghaffari, S.;Dehghani, M. H.;Sheykhi, A.
本文在Granda-Oliveros红外截止的DGP膜世界框架下考虑全息暗能量（HDE）模型，L =（α H + β H-2）（-1/2）.有了这个IR截止的选择，我们能够推导出宇宙学参数的演化，如状态方程和减速参数w和q，作为红移参数z的函数。据我们所知，文献中提出的大多数HDE模型都没有解析地给出omega = omega（Z）和q = q（Z）。我们绘制这些参数与z的演变，并讨论的结果是兼容的最近的观察。通过适当地选择参数，该模型可以在z近似为0.6附近表现出从减速到加速的过渡。然后，我们建议在DGP膜世界的框架下的精粹和快子标量场和HDE之间的对应关系。这种对应关系使我们能够重建标量场和标量势的演化。我们还通过计算声速的平方v（s）（2）来研究所提出的模型的稳定性，其符号决定了模型的稳定性。我们的研究表明，v（s）（2）可以是积极的，只要适当地选择模型的参数。特别是，对于α> 1，β> 0，以及α < 1，β < 0，我们在宇宙历史中有v（s）（2）> 0，因此可以实现稳定的暗能量主导宇宙。这与标准宇宙学中的HDE相反，HDE在背景扰动下不稳定，因此不能导致稳定的暗能量主导的宇宙。
We consider the holographic dark energy (HDE) model in the framework of the DGP braneworld with Granda-Oliveros infrared (IR) cutoff, L = (alpha H + beta H-2)(-1/2). With this choice for IR cutoff, we are able to derive evolution of the cosmological parameters such as the equation of state and the deceleration parameters, w and q, as the functions of the redshift parameter z. As far as we know, most previous models of HDE presented in the literature, do not give analytically omega = omega(Z) and q = q(Z). We plot the evolution of these parameters versus z and discuss that the results are compatible with the recent observations. With suitably choosing the parameters, this model can exhibit a transition from deceleration to the acceleration around z approximate to 0.6. Then we suggest a correspondence between the quintessence and tachyon scalar fields and HDE in the framework of the DGP braneworld. This correspondence allows us to reconstruct the evolution of the scalar fields and the scalar potentials. We also investigate the stability of the presented model by calculating the squared sound speed, v(s)(2), whose sign determines the stability of the model. Our study shows that v(s)(2) could be positive provided the parameters of the model are chosen suitably. In particular, for alpha > 1, beta > 0, and alpha < 1, beta < 0, we have v(s)(2) > 0 during the history of the Universe, and so the stable dark-energy-dominated universe can be achieved. This is in contrast to the HDE in standard cosmology, which is unstable against background perturbations and so cannot lead to a stable dark-energy-dominated universe.