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arXiv 1406.2402hep-thastro-ph.COgr-qchep-ph
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球对称背景下修正引力的有效场论:首阶动力学和奇型扰动

Effective field theory of modified gravity on the spherically symmetric background: leading order dynamics and the odd-type perturbations

Ryotaro Kase, László Árpád Gergely, Shinji Tsujikawa

摘要:

在修正引力的有效场论框架下,考虑了具有度规张量和标量场的静态球对称背景的扰动。我们采用以前开发的2+1+1正则形式主义的双Arnowitt-Deser-Misner(ADM)分解的时空,挑出时间和径向方向。我们的构建块是一个一般的引力作用量,它依赖于由2+1+1正则变量和lapse构造的标量。变化的行动,以一阶扰动产生三个独立的背景运动方程,预期从球对称。线性微扰的动力学方程由适当的规范固定后的二阶拉格朗日量导出。我们推导出避免鬼和拉普拉斯不稳定性的奇型扰动的条件。我们表明,我们的研究结果不仅包括那些来自最一般的标量张量理论与二阶运动方程(Horndeski理论),但它们可以应用到更通用的理论超越Horndeski。

英文摘要:

We consider perturbations of a static and spherically symmetric background endowed with a metric tensor and a scalar field in the framework of the effective field theory of modified gravity. We employ the previously developed 2+1+1 canonical formalism of a double Arnowitt-Deser-Misner (ADM) decomposition of space-time, which singles out both time and radial directions. Our building block is a general gravitational action that depends on scalar quantities constructed from the 2+1+1 canonical variables and the lapse. Variation of the action up to first-order in perturbations gives rise to three independent background equations of motion, as expected from spherical symmetry. The dynamical equations of linear perturbations follow from the second-order Lagrangian after a suitable gauge fixing. We derive conditions for the avoidance of ghosts and Laplacian instabilities for the odd-type perturbations. We show that our results not only incorporates those derived in the most general scalar-tensor theories with second-order equations of motion (the Horndeski theories) but they can be applied to more generic theories beyond Horndeski.

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