Exceptional Points and Resonance in Black Hole Ringdown

Explore exceptional points and resonance phenomena in black hole ringdown through a hyperboloidal framework that extends beyond standard quasinormal-mode descriptions. Examine how near-coalescence of both QNM eigenvalues and eigenfunctions creates genuine resonant behavior not captured by conventional analyses. Investigate spectral features using a phenomenological environmental black-hole model evolved on hyperboloidal slices, demonstrating enhanced mode contributions and characteristic departures from simple exponentially damped oscillations in the time domain. Learn to identify the EP frequency as the physically relevant observable in the near-EP regime, calculated as the averaged value of interacting modes. Gain insights into advanced mathematical physics concepts applied to gravitational wave astronomy and black hole physics through this specialized workshop lecture from the Erwin Schrödinger International Institute.