2026/04/30 by Maciej Dunajski, Sebastian J. Szybka
Mathematics · Physics and Astronomy · #gr-qc #hep-th #math-ph #math.MP
The C^2 gluing procedure clarified. Includes a new appendix discussing convergence of the numerical code . Final version, to appear in CQG
arxiv created 2026/07/30 · arxiv updated 2026/08/03
We numerically study a formation of near extremal horizons from a gravitational collapse of radially symmetric gravitational waves in 4+1 dimensions within the framework of pure Einstein gravity with positive cosmological constant. Evolution of a regular initial data with cosmological horizon leads to a formation of a black hole with mass exceeding 99% of the extremal value corresponding to the black hole and cosmological horizons coinciding. We demonstrate how our results fit within the framework of characteristic gluing, and present some evidence that the third law of black hole thermodynamics may not hold in the cosmological context, where the extremality corresponds to the maximal mass of the Schwarzschild black hole in de--Sitter space.