arXiv 1202.25902012-02hep-thastro-ph.COhep-ph

类共形年龄长度表征的全息暗能量模型

Holographic Dark Energy Model Characterized by the Conformal-age-like Length

Zhuo-Peng Huang, Yue-Liang Wu

备注：: 9 pages, typos corrected, published version
DOI：: 10.1142/S0217751X12500856

摘要：

在平坦的Friedmann-Robertson-Walker宇宙中，从宇宙时间$t$的四维时空体积出发，建立了一个以类共形年龄尺度$L= \frac{1}{a^4(t)}\int_0^tdt' a^3(t') $为特征的全息暗能量模型.结果表明，当具有恒定状态方程$w_m$的背景组分在宇宙早期占主导地位时，暗能量的分数能量密度标度为$Ω_{de}\simeq \frac94(3+w_m)^2d^2a^2$，状态方程由$w_{de}\simeq-\frac23 +w_m$给出. $w_m$的值在暴胀时期取为$w_m\simeq-1$，在辐射主导时期取为$w_m=\frac13$，在物质主导时期取为$w_m=0$。当模型参数$d$取一阶的正常值时，早期宇宙中暗能量的分数密度自然可以忽略不计，$Ω_{de} \ll 1$在$a \ll 1$。由于这种解析特性，该模型可以被看作是一个单参数模型，如$Λ$ CDM模型，因此，当前的分数能量密度$Ω_{de}(a=1)$可以通过求解$Ω_{de}$的微分方程来确定，一旦$d$被给出。我们进一步扩展该模型的一般情况下，物质和辐射都存在。还讨论了暗能量与背景成分之间可能的相互作用。

英文摘要：

A holographic dark energy model characterized by the conformal-age-like length scale $L= \frac{1}{a^4(t)}\int_0^tdt' a^3(t') $ is motivated from the four dimensional spacetime volume at cosmic time $t$ in the flat Friedmann-Robertson-Walker universe. It is shown that when the background constituent with constant equation of state $w_m$ dominates the universe in the early time, the fractional energy density of the dark energy scales as $Ω_{de}\simeq \frac94(3+w_m)^2d^2a^2$ with the equation of state given by $w_{de}\simeq-\frac23 +w_m$. The value of $w_m$ is taken to be $w_m\simeq-1$ during inflation, $w_m=\frac13$ in radiation-dominated epoch and $w_m=0$ in matter-dominated epoch respectively. When the model parameter $d$ takes the normal value at order one, the fractional density of dark energy is naturally negligible in the early universe, $Ω_{de} \ll 1$ at $a \ll 1$. With such an analytic feature, the model can be regarded as a single-parameter model like the $Λ$CDM model, so that the present fractional energy density $Ω_{de}(a=1)$ can solely be determined by solving the differential equation of $Ω_{de}$ once $d$ is given. We further extend the model to the general case in which both matter and radiation are present. The scenario involving possible interaction between the dark energy and the background constituent is also discussed.

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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英文摘要：

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