Title：Gravitational wave signatures from dark sector interactions
Time：2021/12/27 (Mon.) 12:30
Place：R517, New Physics Building, NTU

Abstract:
In this talk, we study the perturbations of general relativistic black holes, i.e., without any hair, and show that this setting can be used to probe the existence of dark sector interactions through gravitational waves emitted by orbiting dark matter particles. Using Horndeski theory and a fairly general interaction Lagrangian, representing potential cosmological interplay between dark energy and dark matter, we show that the perturbations can be effectively described by three coupling constants: a mass, a conformal factor, and an interaction charge. We briefly describe the influence of each of these constants to the perturbative dynamics. Afterwards, we focus on the interaction charge, which is the residue of dark sector interactions on the black hole background, and look at the waveforms generated by a dark matter particle falling straight into a Schwarzschild black hole, provided nontrivial interactions between the dark fields. If there is remaining time, we discuss details of the derivation of the Regge-Wheeler equation and the coupled Zerilli and scalar wave equations for a Schwarzschild-(anti) de Sitter black hole.