January 28th 2026, @IFT-UAM/CSIC

IFT, Red Room

C/Blas Cabrera 13, Canto Blanco (Madrid)

11:00h     Welcome Coffee

11:30h     First Talk

Speaker: Robie A. Hennigar   (Durham University, UK)

Title: Building Regular Black Holes

Abstract: The study of regular (singularity-free) black holes has a long history, but progress has been limited by the absence of a dynamical framework in which they form and by conceptual issues at the kinematical level. In this talk I will discuss recent work in

which spherically symmetric regular black holes emerge as unique solutions of gravity theories with infinite towers of higher-curvature corrections, enabling explicit analyses of their formation and dynamics. I will review the construction, summarize key results, and highlight open problems.

15:00h     Second Talk

Speaker: Pablo A. Cano  (Universidad de Murcia)

Title: Amplification of new physics in the quasinormal mode spectrum of highly-rotating black holes

Abstract: The computation of quasinormal modes of rotating black holes in modified theories of gravity has been recently made possible thanks to the development of new techniques, like a modified Teukolsky equation and spectral methods. However, no method so far has been able to peek into the highly rotating regime — close to extremality. In this talk, I will consider a newly identified higher-curvature modification of GR that preserves the isospectrality of quasinormal modes in the eikonal limit. In this theory, eikonal perturbations can be described in terms of an effective scalar equation, and solving it we will obtain the corrections to the eikonal Kerr quasinormal modes for arbitrary rotation. For moderate rotation, we check that the eikonal computation gives a good approximation to the exact QNMs obtained from the modified Teukolsky equation, even for low harmonics. For high rotation, we discover that the corrections to GR become much larger and can lead to dramatic effects. Our results suggest that the observation of the ringdown of a highly rotating black hole would be a “golden event” to search for new physics.

16:15h   Farewell Coffee