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arXiv 2209.00795gr-qcastro-ph.CO
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Horndeski理论中标量和张量引力波的传播

Propagation of scalar and tensor gravitational waves in Horndeski theory

Kei-ichiro Kubota, Shun Arai, Shinji Mukohyama

AI总结:

针对几何光学近似在波长接近背景曲率半径时精度降低的问题,本文提出Horndeski理论中引力波几何光学展开的高阶修正公式,推导振幅演化方程,还为广义布兰斯-迪克理论给出有效度规描述。

摘要:

引力波在传播过程中会穿过物质和暗能量的分布。因此,由致密双星系统发射的引力波是探测暗能量性质的有用工具。几何光学近似是研究波传播的常规方法,但当波长接近背景曲率半径时,该近似的精度会降低,这种情况在一般情形下可能发生。本文提出了几何光学展开的高阶修正公式,并将其应用于容纳多种暗能量模型的Horndeski理论。在背景层面,假设标量场的导数非零且类时,我们选择时间切片与标量场的等值面重合。当标量场表现为理想流体时,这种背景时间切片的选择具有优势:标量和张量引力波的声锥相对于背景时间切片都是直立的。随后,我们分析了几何光学展开中领先级和次领先级下引力波标量分量和张量分量的运动方程,在特定条件下推导了它们振幅的演化方程。特别地,对于广义布兰斯-迪克理论(Generalized Brans-Dicke theories),我们发现可以用有效度规简单描述引力波的方程。

英文摘要:

Gravitational waves travel through the distributions of matter and dark energy during propagation. For this reason, gravitational waves emitted from binary compact objects serve as a useful tool especially to probe the nature of dark energy. The geometrical optics approximation is a conventional way of investigating wave propagation. However, the approximation becomes less accurate as the wavelength approaches the curvature radius of the background, which can occur in generic situations. In this paper, we suggest a formulation for higher-order corrections of the geometrical optics expansion, applied to Horndeski theory which accommodates many dark energy models. At the level of the background, assuming that the derivative of the scalar field is non-vanishing and timelike, we choose the time slices to coincide with the contours of the scalar field. This choice of the background time slices is advantageous as the sound cones of both scalar and tensor gravitational waves are upright with respect to the background time slices whenever the scalar field behaves as a perfect fluid. We then analyze the equations of motion for scalar and tensor components of gravitational waves at the leading and next-to-leading order in the geometrical optics expansion, deriving the evolution equations for their amplitudes under certain conditions. In particular, for Generalized Brans-Dicke theories, we find a simple description of equations for gravitational waves in terms of an effective metric.

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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