论文标题
黑洞中的非线性
Nonlinearities in Black Hole Ringdowns
论文作者
论文摘要
通常使用一阶BH扰动理论对扰动的黑洞（BH）发出的重力波菌株通常通过分析进行建模。在这封信中，我们表明二阶效应对于对BH合并模拟的响声进行建模是必需的。专注于菌株的$（\ ell，m）=（4,4）$角度谐波，我们在一系列二进制BH质量比中表现出了二次效应，这与理论期望一致。我们发现，二次$（4,4）$模式的振幅表现出二次缩放，其基本$（2,2）$模式 - 其父模式。非线性模式的幅度与线性$（4,4）$模式相当甚至大。因此，正确地对较高谐波的回路进行建模 - 将模式不匹配提高2个数量级 - 需要包含非线性效应。
The gravitational wave strain emitted by a perturbed black hole (BH) ringing down is typically modeled analytically using first-order BH perturbation theory. In this Letter we show that second-order effects are necessary for modeling ringdowns from BH merger simulations. Focusing on the strain's $(\ell,m)=(4,4)$ angular harmonic, we show the presence of a quadratic effect across a range of binary BH mass ratios that agrees with theoretical expectations. We find that the quadratic $(4,4)$ mode's amplitude exhibits quadratic scaling with the fundamental $(2,2)$ mode -- its parent mode. The nonlinear mode's amplitude is comparable to or even larger than that of the linear $(4,4)$ mode. Therefore, correctly modeling the ringdown of higher harmonics -- improving mode mismatches by up to 2 orders of magnitude -- requires the inclusion of nonlinear effects.
