Nonreciprocal black holes with primary hair in beyond Horndeski gravity: Exact solutions and stability
This research develops a systematic method to find exact, nonreciprocal black hole solutions in beyond Horndeski gravity by avoiding restrictive reciprocal conditions. The study yields two main types of solutions: those with khronometric hair and those with genuine scalar hair. It proves these complex geometries can be regularized and provides linear stability results for both axial and monopole perturbations.