Approximate w_φ～Ω_φ Relations in Quintessence Models  

作　　者：罗民兴 苏奇平 

机构地区：[1]Zhejiang Institute of Modern Physics,Department of Physics,Zhejiang University [2]Key Laboratory of Frontiers in Theoretical Physics,Institute of Theoretical Physics,Chinese Academy of Sciences

出　　处：《Communications in Theoretical Physics》2010年第7期186-190,共5页理论物理通讯（英文版）

基　　金：Supported in part by the National Science Foundation of China under Grant No.10425525

摘　　要：Quintessence field is a widely-studied candidate of dark energy. There is ＂tracker solution＂ in quintessence models, in which evolution of the field φ at present times is not sensitive to its initial conditions. When the energy density of dark energy is negleetable （Ωφ 〈〈 1）, evolution of the tracker solution can be well analysed from ＂tracker equation＂. In this paper, we try to study evolution of the quintessence field from ＂full tracker equation＂, which is valid for all spans of Ωφ. We get stable fixed points of we and wφ （noted as wφ and Ωφ） from the ＂full tracker equation＂, i.e., we and ωφ will always approach ωφ and Ωφ respectively. Since wφ and Ωφ are analytic functions of φ, analytic relation of φ can be obtained, which is a good approximation for the we φ relation and can be obtained for the most type of quintessence potentials. By using this approximation, we find that inequalities ωφ 〈 we and 〈ωφ are statisfied if the we （or ωφ） decreases with time. In this way, the potentiai U（φ） can be constrained directly from observations, by no need of solving the equations of motion numerically.

关 键 词：QUINTESSENCE tracker equation APPROXIMATION 

分 类 号：O482[理学—固体物理]