Universal Tidal Zones in an Exact Regular Black Hole

Speaker: Dr Nader Haddad , University of Cambridge
Series: Universal Tidal Zones in an Exact Regular Black Hole

Regular black holes replace the Schwarzschild singularity with a finite-density core, at the price of violating the strong energy condition and introducing a Cauchy horizon. I present an exact, closed-form regular black-hole geometry — the magnetic solution of rational nonlinear electrodynamics first obtained by Ma and Kruglov — re-derived here from an integrability selection principle, and prove a theorem on its tidal structure: for radially infalling observers the tidal eigenvalues are independent of the infall energy, and the spacetime is partitioned into four tidal zones whose boundaries are fixed by the core scale alone, independently of the mass, with an isotropic-compression point and a trace node lying exactly on the strong-energy-condition boundary. I then discuss what this exactness buys — a two-line equation of state, a two-parameter first law, a proof that no growing test-scalar modes exist outside the horizon, two-method quasinormal spectra — and what it does not: the inner-horizon mass-inflation question, treated conditionally. Based on work accepted in Universe (2026).