HOLOGRAPHIC DARK ENERGY MODEL CHARACTERIZED BY THE CONFORMAL-AGE-LIKE LENGTH
HOLOGRAPHIC DARK ENERGY MODEL CHARACTERIZED BY THE CONFORMAL-AGE-LIKE LENGTH
复制标题
DOI：
10.1142/s0217751x12500856
复制
发表时间：
2012-02
影响因子：
1.6
通讯作者：
Zhuo-Peng Huang;Yue-Liang Wu
中科院分区：
文献类型：
--
作者：
Zhuo-Peng Huang;Yue-Liang Wu
从平坦Friedmann-Robertson-Walker(FRW)宇宙中宇宙时间t的四维时空体积出发，建立了一个具有共形类年龄尺度L=1/a(4)(T)积分(T)(O)dt‘a(3)(t’)的全息暗能量模型.结果表明，当早期具有恒定状态方程的背景组分w(M)支配宇宙时，暗能量的分数能量密度欧米伽(De)近似或等于9/4(3+w(M))(2)d(2)a(2)，w(De)给出的状态方程类似或等于-2/3+w(M)。暴涨时w(M)等于或等于-1，辐射为主时w(M)=1/3，物质为主时w(M)=0。当模型参数d取一阶正常值时，暗能量的分数密度在早期宇宙中自然可以忽略不计，即Omega(De)<；1在a<；<；1。有了这样的解析特征，该模型可以看作一个单参数模型，就像ACDM模型一样，这样，一旦d已知，现在的分数能量密度Omega(De)(a=1)就可以仅通过解Omega(De)的微分方程来确定。我们进一步将该模型推广到物质和辐射都存在的一般情况。文中还讨论了暗能量和背景成分之间可能发生相互作用的情况。
A holographic dark energy model characterized by the conformal-age-like length scale L = 1/a(4)(t) integral(t)(O) dt' a(3)(t') is motivated from the four-dimensional space-time volume at cosmic time t in the flat Friedmann-Robertson-Walker (FRW) 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 Omega(de) similar or equal to 9/4 (3 + w(m))(2) d(2)a(2) with the equation of state given by w(de) similar or equal to -2/3 + w(m). The value of w(m) is taken to be w(m) similar or equal to -1 during inflation, w(m) = 1/3 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, Omega(de) << 1 at a << 1. With such an analytic feature, the model can be regarded as a single-parameter model like the ACDM model, so that the present fractional energy density Omega(de)(a = 1) can solely be determined by solving the differential equation of Omega(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.