arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0705.1158astro-phgr-qchep-th
收藏

逃避太阳系检验的f（R）宇宙加速模型

Models of f(R) Cosmic Acceleration that Evade Solar-System Tests

Wayne Hu, Ignacy Sawicki

备注：
13 pages, 10 figures. Submitted to Phys. Rev. D
发表信息：
Phys.Rev.D76:064004,2007
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

本文研究了一类度量变分f（R）模型，它在没有宇宙学常数的情况下加速膨胀，并且在参数空间的小场极限下满足宇宙学和太阳系检验.仅太阳系的测试对这些模型的约束力就很弱，因为额外的标量自由度被锁定在高曲率广义相对论的预测上，在超过25个数量级的密度范围内，通过日冕。这种一致性要求星系晕在低曲率宇宙学背景下有足够的范围来维持星系的高曲率。如果f（R）模型中的星系晕和局部环境没有比LCDM中预期的更深的势，那么宇宙场振幅|f_R| > 10^{-6}将导致星系内部在加速时期演化为低曲率。因此，大偏差模型的可行性依赖于星系晕的结构和演化，需要对f（R）模型进行宇宙学模拟，而不是直接依赖于太阳系的测试。即使是保守地满足银河系和太阳系约束的微小偏差，也仍然可以通过未来的线性功率谱的100级测量来检验，而它们仍然无法通过宇宙距离测量来检测。虽然我们在一个特定类别的模型中说明了这些效应，但对f（R）的要求是以一种几乎与模型无关的方式来表述的。

英文摘要：

We study a class of metric-variation f(R) models that accelerates the expansion without a cosmological constant and satisfies both cosmological and solar-system tests in the small-field limit of the parameter space. Solar-system tests alone place only weak bounds on these models, since the additional scalar degree of freedom is locked to the high-curvature general-relativistic prediction across more than 25 orders of magnitude in density, out through the solar corona. This agreement requires that the galactic halo be of sufficient extent to maintain the galaxy at high curvature in the presence of the low-curvature cosmological background. If the galactic halo and local environment in f(R) models do not have substantially deeper potentials than expected in LCDM, then cosmological field amplitudes |f_R| > 10^{-6} will cause the galactic interior to evolve to low curvature during the acceleration epoch. Viability of large-deviation models therefore rests on the structure and evolution of the galactic halo, requiring cosmological simulations of f(R) models, and not directly on solar-system tests. Even small deviations that conservatively satisfy both galactic and solar-system constraints can still be tested by future, percent-level measurements of the linear power spectrum, while they remain undetectable to cosmological-distance measures. Although we illustrate these effects in a specific class of models, the requirements on f(R) are phrased in a nearly model-independent manner.

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。

↑