论文标题
来自Horndeski重力的紧凑型二进制系统的灵感引力波形
Inspiral gravitational waveforms from compact binary systems in Horndeski gravity
论文作者
论文摘要
在与光相当的重力速度相当的Horndeski理论的子类中，我们研究了紧凑型二元系统的灵感阶段发出的重力辐射。我们计算依赖于标量场的点状粒子的能量孔张量的牛顿后扩展下的标量扰动的波形。这种标量模式不仅引起引力波的呼吸和纵向极化，而且还导致标量重力辐射除了与横向和无纹状张量极化相关的能量损失之外。我们计算出固定相近似下两个张量极化的傅立叶转换的重力波形，并表明所得波形在参数化的后源后（PPE）形式上降低至一个。 PPE参数与爱因斯坦框架中的标量电荷直接相关，后者的存在对于允许偏离一般相对论（GR）至关重要。我们将一般框架应用于几种具体理论，并表明具有高阶标量动力学术语的自发标量的新理论留下了与GR的有趣偏差，这可以通过从中子星状孔孔中发出的重力波的观察结果来探测。如果标量质量超过典型的轨道频率的顺序$ω\ simeq 10^{ - 13} $ 〜EV，对于最近提出的具有自相互作用电势的标量中子星是这种情况，重力波形实际上会在GR中减少。
In a subclass of Horndeski theories with the speed of gravity equivalent to that of light, we study gravitational radiation emitted during the inspiral phase of compact binary systems. We compute the waveform of scalar perturbations under a post-Newtonian expansion of energy-momentum tensors of point-like particles that depend on a scalar field. This scalar mode not only gives rise to breathing and longitudinal polarizations of gravitational waves, but it is also responsible for scalar gravitational radiation in addition to energy loss associated with transverse and traceless tensor polarizations. We calculate the Fourier-transformed gravitational waveform of two tensor polarizations under a stationary phase approximation and show that the resulting waveform reduces to the one in a parametrized post-Einsteinian (ppE) formalism. The ppE parameters are directly related to a scalar charge in the Einstein frame, whose existence is crucial to allow the deviation from General Relativity (GR). We apply our general framework to several concrete theories and show that a new theory of spontaneous scalarization with a higher-order scalar kinetic term leaves interesting deviations from GR that can be probed by the observations of gravitational waves emitted from neutron star-black hole binaries. If the scalar mass exceeds the order of typical orbital frequencies $ω\simeq 10^{-13}$~eV, which is the case for a recently proposed scalarized neutron star with a self-interacting potential, the gravitational waveform practically reduces to that in GR.
