Can higher curvature corrections cure the singularity problem in f(R) gravity
Can higher curvature corrections cure the singularity problem in f(R) gravity
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DOI：
10.1103/physrevd.79.024009
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发表时间：
2008-10
影响因子：
5
通讯作者：
Tsutomu Kobayashi;K. Maeda
中科院分区：
文献类型：
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作者：
Tsutomu Kobayashi;K. Maeda
虽然f（R）修正的引力模型可以满足太阳系和宇宙学的约束，但它们有一个严重的缺点，即不存在强引力场的恒星。本文讨论了高曲率修正是否能一致地纠正这种不存在性。作为考虑中子星的f（R）模型必须付出的代价，出现了以下问题：（i）必须微调前导校正，使典型的能量标度{mu} <或近似。10{sup -19} GeV，这基本上来自自由落体时间的相对论性星星;（ii）领先的修正必须进一步微调，使它不是由二次曲率项。第二个问题是由于出现了一个中间曲率尺度，实验室重力实验将受到更高曲率改正的影响。因此，我们的分析意味着，在没有非常仔细和不自然的微调的情况下构建可行的f（R）模型是一个挑战。
Although f(R) modified gravity models can be made to satisfy solar system and cosmological constraints, it has been shown that they have the serious drawback of the nonexistence of stars with strong gravitational fields. In this paper, we discuss whether or not higher curvature corrections can remedy the nonexistence consistently. The following problems are shown to arise as the costs one must pay for the f(R) models that allow for neutrons stars: (i) the leading correction must be fine-tuned to have the typical energy scale {mu} < or approx. 10{sup -19} GeV, which essentially comes from the free fall time of a relativistic star; (ii) the leading correction must be further fine-tuned so that it is not given by the quadratic curvature term. The second problem is caused because there appears an intermediate curvature scale, and laboratory experiments of gravity will be under the influence of higher curvature corrections. Our analysis thus implies that it is a challenge to construct viable f(R) models without very careful and unnatural fine-tuning.