Singularities and Entropy in Bulk Viscosity Dark Energy Model |
| |
Authors: | MENG Xin-He and DOU Xu |
| |
Affiliation: | 1.Department of Physics, Nankai University, Tianjin 300071, China;2.Kavli Institute of Theoretical Physics China, Chinese Academy of Sciences, Beijing 100190, China |
| |
Abstract: | In this paper bulk viscosity is introduced to describe the effects of cosmic non-perfect fluid on the cosmos evolution and to build the unified dark energy (DE) with (dark) matter models. Also we derive a general relation between the bulk viscosity form and Hubble parameter that can provide a procedure for the viscosity DE model building. Especially, a redshift dependent viscosity parameterζ∝λ0 +λ1(1+z)n proposed in the previous work [X.H. Meng and X. Dou, Commun. Theor. Phys. 52 (2009) 377] is investigated extensively in this present work. Further more we use the recently released supernova dataset (the Constitution dataset) to constrain the model parameters. In order to differentiate the proposed concrete dark energy models from the well known $Lambda$CDM model, statefinder diagnostic method is applied to this bulk viscosity model, as a complementary to the Om parameter diagnostic and the deceleration parameter analysis performed by us before. The DE model evolution behavior and tendency are shown in the plane of the statefinder diagnostic parameter pair {r,s} as axes where the fixed point represents theΛCDM model. The possible singularity property in this bulk viscosity cosmology is also discussed to which we can conclude that in the different parameter regions chosen properly, this concrete viscosity DE model can have various late evolution behaviors and the late time singularity could be avoided. We also calculate the cosmic entropy in the bulk viscosity dark energy frame, and find that the total entropy in the viscosity DE model increases monotonously with respect to the scale factor evolution, thus this monotonous increasing property can indicate an arrow of time in the universe evolution, though the quantum version of the arrow of time is still very puzzling. |
| |
Keywords: | dark energy cosmology bulk viscosity unification of dark matter and dark energy |
|
| 点击此处可从《理论物理通讯》浏览原始摘要信息 |
|
点击此处可从《理论物理通讯》下载全文 |
|