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arXiv 1502.02011gr-qcastro-ph.CO
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共形费米坐标

Conformal Fermi Coordinates

Liang Dai, Enrico Pajer, Fabian Schmidt

摘要:

费米正规坐标(FNC)是一个有用的框架,用于隔离长波长时空微扰的局部可观察的物理效应。然而,它们在宇宙学上的应用受到了阻碍,因为它们只在比视界小得多的尺度上有效。我们介绍了一个推广,我们称之为共形费米坐标(CFC)。CFC保留了FNC的所有优势,但除此之外在视野之外也有效。它们使我们能够计算所有尺度上的长和短波长模式的耦合大于声音视界的宇宙流体,从时代的通货膨胀直到今天,通过消除二阶爱因斯坦方程的复杂性在很大程度上,并消除所有规范的模糊性。作为应用,我们给出了长波张量模对小尺度密度涨落影响的计算。我们恢复以前的结果,但澄清的物理内容的个人贡献的本地可测量的影响和“投影”条款。

英文摘要:

Fermi Normal Coordinates (FNC) are a useful frame for isolating the locally observable, physical effects of a long-wavelength spacetime perturbation. Their cosmological application, however, is hampered by the fact that they are only valid on scales much smaller than the horizon. We introduce a generalization that we call Conformal Fermi Coordinates (CFC). CFC preserve all the advantages of FNC, but in addition are valid outside the horizon. They allow us to calculate the coupling of long- and short-wavelength modes on all scales larger than the sound horizon of the cosmological fluid, starting from the epoch of inflation until today, by removing the complications of the second order Einstein equations to a large extent, and eliminating all gauge ambiguities. As an application, we present a calculation of the effect of long-wavelength tensor modes on small scale density fluctuations. We recover previous results, but clarify the physical content of the individual contributions in terms of locally measurable effects and "projection" terms.

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。

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