Future oscillations around phantom divide in f(R) gravity
Future oscillations around phantom divide in f(R) gravity
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DOI：
10.1088/1475-7516/2011/06/006
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发表时间：
2011-06-01
影响因子：
6.4
通讯作者：
Yokoyama, Jun'ichi
中科院分区：
文献类型：
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作者：
Motohashi, Hayato;Starobinsky, Alexei A.;Yokoyama, Jun'ichi
众所周知，引力的标量张量理论承认暗能量的幻相分割线w(DE) = -1有规律地交叉，而目前存在的暗能量的特殊情况——f(R)引力的可行模型——在最近的过去，在物质主导阶段结束后，就有了这样的交叉。最近有人指出，在这些模型的未来演化过程中，暗能量状态方程w（DE）可能会随着任意数量的幻分交叉而振荡。本文证明了交叉数可以是无限的，给出了该效应存在的解析条件，并用数值方法对其进行了研究。随着标量粒子（一种标量粒子，出现在f(R)重力中）的现有质量的增加，超出了这种振荡出现的边界，它们的振幅下降得非常快。结果，影响很快变小，它的开始被转移到遥远的未来。
It is known that scalar-tensor theory of gravity admits regular crossing of the phantom divide line w(DE) = -1 for dark energy, and existing viable models of present dark energy for its particular case - f(R) gravity - possess one such crossing in the recent past, after the end of the matter dominated stage. It was recently noted that during the future evolution of these models the dark energy equation of state w(DE) may oscillate with an arbitrary number of phantom divide crossings. In this paper we prove that the number of crossings can be infinite, present an analytical condition for the existence of this effect and investigate it numerically. With the increase of the present mass of the scalaron (a scalar particle, appearing in f(R) gravity) beyond the boundary of the appearance of such oscillations, their amplitude is shown to decrease very fast. As a result, the effect quickly becomes small and its beginning is shifted to the remote future.