标题： 黑洞灰体因子和回声的（不）稳定性对抗小 bump 修正 显示英文标题

标题： (In)stability of the black hole greybody factors and ringdowns against a small-bump correction

摘要： 近期有观点提出，黑洞的greybody因子对于建模回响谱振幅非常重要。 我们研究了扰动方程中小凸起修正对greybody因子稳定性的影响。 我们发现：(I) 在与回响相关的频率区域内，greybody因子是稳定的；(II) 在较高频率下，特别是对于较尖锐的凸起修正，它会被不稳定化。 这种行为与高阶过调情况类似，后者也非常敏感于小的修正。 我们通过WKB分析澄清了这一（不）稳定性。 由于greybody因子在与回响主部分相关的频率区域是稳定的，我们得出结论，greybody因子适合用于建模回响振幅。 为了以自洽的方式研究凸起修正，我们考虑了可以在黑洞扰动的有效场论一般框架中实现的小凸起修正。 显示英文摘要

摘要： Recently, it has been proposed that the black hole greybody factors can be important to model ringdown spectral amplitudes. We study the stability of greybody factors against a small-bump correction in the perturbation equation. We find (I) that the greybody factor is stable in the frequency region relevant to ringdown and (II) that it is destabilized at higher frequencies, especially for a sharper bump correction. This behavior is similar to the case of higher overtones, which is also very sensitive to a small correction. We clarify this (in)stability with the WKB analysis. As the greybody factor is stable at the frequency region relevant to the main part of ringdown, we conclude that the greybody factor is suitable to model ringdown amplitude. In order to investigate a bump correction in a self-consistent manner, we consider the small-bump correction that can be realized in the general framework of effective field theory of black hole perturbations.