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arXiv 1503.07412gr-qcastro-ph.CO
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f(R)引力中的暗能量状态方程

Equation of state of dark energy in f(R) gravity

Kazufumi Takahashi, Jun'ichi Yokoyama

摘要:

f(R)引力是广义相对论最简单的推广之一,它可以在不引入宇宙学常数的情况下解释加速的宇宙膨胀。转换到爱因斯坦坐标系中,出现了一个新的标量自由度,它与物质场耦合。为了使f(R)理论能够通过广义相对论的定域检验,我们已经知道,具有所谓薄壳解的变色龙机制必须起作用。如果将薄壳层约束应用于宇宙学情形,人们声称暗能量的状态方程参数w必须非常接近-1。我们认为,这是由于不正确的使用泊松方程是有效的,只有在静态的情况下。通过微扰求解正确的Klein-Gordon方程,我们证明了即使w明显偏离-1,也存在薄壳解。

英文摘要:

f(R) gravity is one of the simplest generalizations of general relativity, which may explain the accelerated cosmic expansion without introducing a cosmological constant. Transformed into the Einstein frame, a new scalar degree of freedom appears and it couples with matter fields. In order for f(R) theories to pass the local tests of general relativity, it has been known that the chameleon mechanism with a so-called thin-shell solution must operate. If the thin-shell constraint is applied to a cosmological situation, it has been claimed that the equation-of-state parameter of dark energy w must be extremely close to -1. We argue this is due to the incorrect use of the Poisson equation which is valid only in the static case. By solving the correct Klein-Gordon equation perturbatively, we show that a thin-shell solution exists even if w deviates appreciably from -1.

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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