Equivalence Principle and the Baryon Acoustic Peak
Equivalence Principle and the Baryon Acoustic Peak
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等效原理和重子声学峰值
DOI：
10.1103/physrevd.92.043514
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发表时间：
2015
影响因子：
5
通讯作者：
M. Zaldarriaga
中科院分区：
文献类型：
--
作者：
T. Baldauf;Mehrdad Mirbabayi;M. Simonovi'c;M. Zaldarriaga
我们研究了长波密度微扰$\delta(\lambda_L)$对短距离物理的主导作用。在非相对论性极限下，结果是均匀的加速度，由等效原理固定，并且由于平移不变性通常对统计平均值没有影响。同样的推理已被形式化，以获得宇宙学相关函数的“一致性条件”。在存在一个特征的情况下，例如$l_{\rm BAO}$处的声学峰值，这种天真的期望在$\lambda_L<l_{\rm BAO}$处就失效了。在这种情况下，我们计算了三点相关函数的一个泛域。同样的效应被证明是声学峰值传播的基础，并且可以计算到长模式下的所有阶。这可以用来改善微扰计算的结果——一种被称为“红外恢复”的技术——并明确地应用于功率谱的单回路计算。最后，本文认为BAO重建方案的成功是研究结果有效性的另一个经验证据。
We study the dominant effect of a long wavelength density perturbation $\delta(\lambda_L)$ on short distance physics. In the non-relativistic limit, the result is a uniform acceleration, fixed by the equivalence principle, and typically has no effect on statistical averages due to translational invariance. This same reasoning has been formalized to obtain a "consistency condition" on the cosmological correlation functions. In the presence of a feature, such as the acoustic peak at $l_{\rm BAO}$, this naive expectation breaks down for $\lambda_L<l_{\rm BAO}$. We calculate a universal piece of the three-point correlation function in this regime. The same effect is shown to underlie the spread of the acoustic peak, and is calculable to all orders in the long modes. This can be used to improve the result of perturbative calculations - a technique known as "infra-red resummation" - and is explicitly applied to the one-loop calculation of power spectrum. Finally, the success of BAO reconstruction schemes is argued to be another empirical evidence for the validity of the results.