arXiv 0807.24492008-07-15astro-ph

f（R）宇宙学的非线性演化I：方法论

Non-linear evolution of f(R) cosmologies I: methodology

Hiroaki Oyaizu

备注：: 15 pages, 11 figures
发表信息：: Phys.Rev.D78:123523,2008
DOI：: 10.1103/PhysRevD.78.123523

摘要：

介绍了一类度量变分f（R）模型的宇宙学模拟方法和实现，该模型在没有宇宙学常数的情况下加速宇宙膨胀，并避开了太阳系小场偏差的广义相对论界限.这样的模拟减少到解决一个非线性泊松方程的标量自由度引入的f（R）修改。我们详细的方法，有效地解决了非线性泊松方程，使用牛顿高斯赛德尔松弛格式耦合多重网格方法，以加速收敛。模拟结果表明，以满足测试比较模拟结果的分析解决方案，简单的情况下，和动态的模拟轨道和Zeldovich崩溃测试。最后，我们提出了几个静态和动态模拟使用现实的宇宙学参数，突出标准物理和f（R）物理之间的差异。总的来说，我们发现f（R）的修改会导致更强的引力吸引力，这会使暗物质的功率谱增强约20%，因为f（R）的修改量很大，但在观测上是允许的。更详细的研究非线性f（R）对功率谱的影响，在配套文件。

英文摘要：

We introduce the method and the implementation of a cosmological simulation of a class of metric-variation f(R) models that accelerate the cosmological expansion without a cosmological constant and evade solar-system bounds of small-field deviations to general relativity. Such simulations are shown to reduce to solving a non-linear Poisson equation for the scalar degree of freedom introduced by the f(R) modifications. We detail the method to efficiently solve the non-linear Poisson equation by using a Newton-Gauss-Seidel relaxation scheme coupled with multigrid method to accelerate the convergence. The simulations are shown to satisfy tests comparing the simulated outcome to analytical solutions for simple situations, and the dynamics of the simulations are tested with orbital and Zeldovich collapse tests. Finally, we present several static and dynamical simulations using realistic cosmological parameters to highlight the differences between standard physics and f(R) physics. In general, we find that the f(R) modifications result in stronger gravitational attraction that enhances the dark matter power spectrum by ~20% for large but observationally allowed f(R) modifications. More detailed study of the non-linear f(R) effects on the power spectrum are presented in a companion paper.

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英文摘要：

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