Unscreening Modified Gravity in the Matter Power Spectrum.
Unscreening Modified Gravity in the Matter Power Spectrum.
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DOI：
10.1103/physrevlett.114.251101
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发表时间：
2015-01
影响因子：
8.6
通讯作者：
L. Lombriser;F. Simpson;A. Mead
中科院分区：
文献类型：
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作者：
L. Lombriser;F. Simpson;A. Mead
可能产生宇宙加速的可行的引力修正需要在高密度的区域进行筛选，比如太阳系，在那里广义相对论得到了很好的检验。筛选机制还可以防止大尺度结构中的强烈异常，并限制可以从宇宙学中推断这些引力模型的约束。我们发现，通过抑制物质功率谱中被屏蔽的高密度区域的贡献，允许未被屏蔽的低密度区域的更大贡献，修正的引力模型可以更容易地与调和宇宙学区分开来。此外，通过密度阈值的变化，可以更充分地处理具有其他影响的简并。以变色龙重力为例，采用f(R)模型的n体模拟和变色龙理论的光环模型，验证了该方法的有效性。我们发现，在k<0.3h/Mpc的剪切功率的百分比水平测量可以对变色龙模型产生更严格的约束，而不是从太阳系测试或未筛选矮星系的距离指标推断出来的约束。最后，我们验证了我们的方法也适用于Vainshtein机构。
Viable modifications of gravity that may produce cosmic acceleration need to be screened in high-density regions such as the Solar System, where general relativity is well tested. Screening mechanisms also prevent strong anomalies in the large-scale structure and limit the constraints that can be inferred on these gravity models from cosmology. We find that by suppressing the contribution of the screened high-density regions in the matter power spectrum, allowing a greater contribution of unscreened low densities, modified gravity models can be more readily discriminated from the concordance cosmology. Moreover, by variation of density thresholds, degeneracies with other effects may be dealt with more adequately. Specializing to chameleon gravity as a worked example for screening in modified gravity, employing N-body simulations of f(R) models and the halo model of chameleon theories, we demonstrate the effectiveness of this method. We find that a percent-level measurement of the clipped power at k<0.3h/Mpc can yield constraints on chameleon models that are more stringent than what is inferred from Solar System tests or distance indicators in unscreened dwarf galaxies. Finally, we verify that our method is also applicable to the Vainshtein mechanism.