Effective field theory approach to modified gravity including Horndeski theory and Hořava–Lifshitz gravity
Effective field theory approach to modified gravity including Horndeski theory and Hořava–Lifshitz gravity
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DOI：
10.1142/s0218271814430081
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发表时间：
2014-09
影响因子：
2.2
通讯作者：
R. Kase;S. Tsujikawa
中科院分区：
文献类型：
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作者：
R. Kase;S. Tsujikawa
本文回顾了修正引力的有效场论，其中拉格朗日涉及时空3+1分解中出现的三维几何量。在平坦的各向同性宇宙学背景下，通过考虑高于2的空间导数，我们将几何标量扰动中的一般作用量扩展到二阶。我们的分析涵盖了广泛的引力理论，包括霍恩德斯基理论及其最近的推广，以及HořAVA-Lifshitz引力的可投影/不可投影版本。我们推导了线性宇宙学微扰的运动方程，并将它们应用于膨胀功率谱的计算以及伽利略理论中的暗能量动力学。我们还表明，我们的一般结果可以方便地恢复已在文献中导出的HořAVA-Lifshitz引力的稳定性条件。
In this paper, we review the effective field theory of modified gravity in which the Lagrangian involves three-dimensional geometric quantities appearing in the 3+1 decomposition of spacetime. On the flat isotropic cosmological background, we expand a general action up to second-order in the perturbations of geometric scalars, by taking into account spatial derivatives higher than two. Our analysis covers a wide range of gravitational theories — including Horndeski theory/its recent generalizations and the projectable/nonprojectable versions of Hořava–Lifshitz gravity. We derive the equations of motion for linear cosmological perturbations and apply them to the calculations of inflationary power spectra as well as the dark energy dynamics in Galileon theories. We also show that our general results conveniently recover stability conditions of Hořava–Lifshitz gravity already derived in the literature.