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arXiv 0710.0115gr-qcastro-phhep-phhep-th
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暗能量条件与暗能量模型

Null Energy Condition and Dark Energy Models

Taotao Qiu, Yi-Fu Cai, Xin-Min Zhang

摘要:

暗能量条件(NEC)要求宇宙的状态方程(EoS)$w_u$满足$w_u\geq-1$,这意味着,例如在一个物质和暗能量主导$w_u=w_mΩ_m+w_{de}Ω_{de}=w_{de}Ω_{de}\geq-1$的宇宙中。本文从NEC的要求出发,研究了暗能量模型的约束条件。我们将表明,与$Ω_{de}\sim0.7$,$w_{de}<-1$在目前的时代是可能的。然而,NEC排除了$w_{de}<-1$像Phantom模型中发生的那样永远存在的可能性,但如果$w_{de}<-1$像Quintom理论中预测的那样停留很短一段时间,则NEC可以满足要求。我们采取三个例子的暗能量的Quintom模型,即唯象EoS,两个标量场模型和单标量模型与修改后的Dirac-Born-Infeld(DBI)拉格朗日来说明这是如何发生的。

英文摘要:

Null Energy Condition (NEC) requires the equation of state (EoS) of the universe $w_u$ satisfy $w_u\geq-1$, which implies, for instance in a universe with matter and dark energy dominating $w_u=w_mΩ_m+w_{de}Ω_{de}=w_{de}Ω_{de}\geq-1$. In this paper we study constraints on the dark energy models from the requirement of the NEC. We will show that with $Ω_{de}\sim0.7$, $w_{de}<-1$ at present epoch is possible. However, NEC excludes the possibility of $w_{de}<-1$ forever as happened in the Phantom model, but if $w_{de}<-1$ stays for a short period of time as predicted in the Quintom theory NEC can be satisfied. We take three examples of Quintom models of dark energy, namely the phenomenological EoS, the two-scalar-field model and the single scalar model with a modified Dirac-Born-Infeld (DBI) lagrangian to show how this happens.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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